CONTROLLED POLYMER RECYCLING AND DEGRADATION – A TUTORIAL

8/11/2019 CONTROLLED POLYMER RECYCLING AND DEGRADATION A TUTORIAL

1/16

Proceedingsof TMCE 2014, May 19-23, 2014, Budapest, Hungary, Edited by I. Horvth, Z. Rusk

Organizing Committee of TMCE 2014, ISBN 978-94-6186-177-1

23

CONTROLLED POLYMER RECYCLING AND DEGRADATION A TUTORIAL

Gyrgy BnhegyiDepartment of Advanced Materials and Processes

Bay Zoltn Nonprofit Ltd. for Applied ResearchHungary

[email protected]

ABSTRACT

Polymer materials became an indispensable part of

our life in the 20th century and they will surely be

with us in the 21st century as well. They are, and will

be, indispensable because of their advantageous

properties, such as low density, relatively low

specific energy consumption during production, easyand large scale processability, but they also require

keen attention because of their environmental effects,

such as permanence, slow degradability, potentially

harmful additives etc. In this tutorial only a few

relevant aspects of this complicated problem can be

touched, and even those very briefly: the origin and

distribution of plastic waste; main directions of

utilizing/recycling/disposing this waste; recycling of

plastic packaging waste; electrical and electronic

waste; automotive waste; commingled plastic waste;

thermosets and elastomers; the inter-relation

between recycling and design; pros and cons of

controlled degradation; controlled photo-oxidative

degradation; bio-degradation and finally the

possibilities of a sustainable polymer technology.

KEYWORDS

Recycling, plastics, environment, thermoplastic,thermoset, rubber

1. INTRODUCTION

Nowadays it is fashionable and not only in thegreen circles to blame plastics for almost all

environmental problems. Philippics against PVC canbe read and heard everywhere, although the simplequestion: what would the environmentalists do withthe huge amounts of chlorine obtained as a byproductof caustic soda production is rarely answered (in fact,

the problem is usually not even recognized). Some ofthe hardliners would answer: you should not producecaustic soda either. I wonder how they could tolerateeach others smell without using soap whichrequires caustic soda. But let us not be sarcastic:

plastic waste is a huge problem that should be

handled carefully [1]. Waste should be considered as

a potentially valuable resource instead of simplybeing a burden [2]. Before seriously considering theelimination of plastics, the economic, social andother costs of replacement should also be considered.Simple negation of a technology may sound

attractive but a real answer should always discuss theconsequences. If we remain at the level of politicalpropaganda, the solutions will not survive the nextpolitical cycle.

Due to the complexity of the problem, which is notonly technical, but also economic and societal innature, and to demonstrate the actuality of thediscussions related to this topic, only a minor part ofthe references used in compiling this tutorial were

taken directly from the technical literature, most ofthem come from various surveys made by authorities,websites etc. No comprehensive review can be

attempted at this length, therefore only briefcomments on selected examples can be offered.

Nevertheless I hope that at least the versatility of thevarious approaches and the inter-relatedness of theemerging problems can be presented.

2. BASIC NOTIONS

Before starting the discussion of plastic waste, somevery basic notions should be clarified. Plastics gottheir name from the fact that they can be shapedrelatively easily in the molten state by highly

efficient methods (such as injection moulding orextrusion) and maintain their shape after cooling.

This basic property is closely related to their

molecular structure, i.e. to the fact that they arecomposed of long, relatively flexible, mostly linearmolecules - in contrast to low molecular materials.Upon melting low molecular materials (includingmetals and ionic solids) form low viscosity liquids,

mostly described by Newtonian viscosity, whilepolymers tend to exhibit visco-elastic properties bothin molten and in solid states.

Another important difference from low molecular


2/16

24 Gyrgy Bnhegyi

solids and liquids is that in plastics the molecules arerarely uniform. These polymer chains (repetitionunits are called monomers) are of different length,therefore the molar mass exhibits a distributioncharacteristic of the polymerization method. Thismolecular mass distribution has far-reachingconsequences on the viscosity of the polymer melt(essentially determined by the average molar mass),while the shape and breadth of the distribution curveinfluences such phenomena as the frequency or shearrate dependence of the viscosity or the melt strength.

Not only the molar mass values of the various

polymer molecules are not uniform, but also themolecules may exhibit various polymerizationdefects. One typical defect is branching, which maybe short chain branching (if the length of the branch

is negligible with respect to the longest linear chain)or long chain branching (if they are comparable).Branching means that at least some monomers aretrifunctional and not bifunctional. Trifunctional unitsmay be added to the monomers consciously or theymay be formed by chance as a polymerization defect.

If the branches are long and if the concentration ofthe branching units reaches a critical concentrationthe polymers becomes a gel, i.e. a non-flowingnetwork is formed.

On this basis so-called thermoplastic and thermoset

materials are distinguished: thermoplastics containlinear (or slightly branched) macromolecules wherethe branching density does not reach the criticalvalue necessary for gelling. Thermoplastics can bere-melted, which makes their recycling easier. Evenlinear macromolecules can be rendered thermoset bycrosslinking reactions (e.g. vulcanization, radiationcrosslinking), typically used in rubbers. Typicalthermoset resins are, however, relatively lowmolecular, easy flowing liquids which becomemultifunctional during the so-called curing reaction.Once the network is formed, it cannot melt (unless if

it is based on physical crosslinking or reversiblechemical bonding), only degrade at high temperature(hence the name: thermoset).

Plastics are typically amorphous (lacking long-rangeorder), exhibiting one typical transition temperature:the glass-rubber transition (Tg). Unlike melting, it isnot a thermodynamic transition (although somebelieve that a so-called second order transition existsclose to Tg), but a relaxation transition, where thequasi-solid amorphous material becomes a visco-elastic melt. (At even higher temperatures the melt

tends to become more purely viscous). Some other

plastics exhibit two, intimately mixed phases:crystalline and amorphous. The crystallites aretypically very small and the degree of crystallinitymay strongly depend on the thermal and shearhistory. Such, so-called semi-crystalline polymers

exhibit two transitions: the glass-rubber transition(Tg) and melting (Tm). Generally semi-crystallinepolymers exhibit higher thermal resistance, althoughtheir processing may become more complicatedbecause of secondary crystallization.

It should be noted that industrially available plasticsare much more than simple polymers, they are rather

compounds, usually intricately formulated multi-component materials. Even plastics containing onlyone kind of polymer need additives that render themwell processable and stable under e.g. outdoor

conditions. Other plastics are blends, i.e. mixtures ofmore types of polymers, still others contain organicor inorganic reinforcements or functional fillers. Thiscomplexity makes the recycling activity morecomplicated as an additive designed for a certainplastic compound may be detrimental for another

purpose. This emphasizes the necessity of selectivecollection and/or separation of various plastics from

the waste stream.

A last, practically important classification of plasticsis the distinction of so-called commodity plastics

(polyolefins, vinyls and styrenics nowadays alsoPET is added here), engineering plastics and highperformance polymers (the latter are sometimesdivided into high temperature and very hightemperature grades). Therefore the commerciallyavailable polymers are frequently represented by apyramid, consisting of two halves: amorphous andcrystalline polymers. The broad base of the pyramidis the family of commodity resins.

The next stage is the group of engineering plastics

(such as polyesters, polyamides, acrylics, polyacetal

etc.), while the top of the pyramid include highperformance engineering plastics. The higher weclimb on the pyramid, the higher are the temperatureresistance values and the price and the lower the

production volume. The decrease of productionvolume is faster than linear: almost 75% of the EUplastic consumption in 2011 belonged to thecommodity plastics. Almost 40% of the total demandwas used by the packaging industry, about 20% bybuilding and construction, 8% by the automotiveindustry and 5% by the electrical and electronicindustry [3] (see Figures 1 and 2).


3/16

CONTROLLED POLYMER RECYCLING AND DEGRADATION A TUTORIAL 25

Figure 1 Plastic consumption in the EU in 2011 by

plastic types (Source PlasticsEurope)

Figure 2 Plastics consumption in the EU in 2011 byapplications (Source PlasticsEurope)

3. PLASTIC WASTE ITS ORIGIN ANDDISTRIBUTION

No wonder then that the majority of plastic waste

also comes from the commodity plastics. Someimportant sources plastic wastes are listed below [4]:

Plastics conversion, processing waste, scrap, (in-house)

Packaging waste (selectively collected)

Post-consumer waste (selectively collected)

Municipal solid waste

Agricultural waste

Construction and demolition waste

Automotive waste (end-of-life vehicle, tires)

Electrical and electronic waste

While about 45% of the industrial waste is recycled,and only 10% ends up in the landfill, about 70-80%

of the domestic plastic waste is incinerated. Thecomposition of municipal solid waste (MSW) mayvary from country to country, even from town to

town, the definition of plastic waste is alsosomewhat ambiguous in various statistics (whether

rubber, man-made fiber or paint is included or not),but on the average 10-15 wt% of the MSW is plastic[5] (see e.g. Figure 3). The distribution of plastics inthe waste closely resembles the production rates [6]:about 81% of them belong to the commodity plastics(see Figure 4).

Figure 3 Distribution of the municipal solid waste in the

USA in 2010. Source:www.eschooltoday.com/waste-recycling/sources-of-waste.html

Figure 4 Distribution of plastics in the municipal solid

waste. Source:www.naturalstateresearch.com/

ProductsPage.html

4. WHAT CAN BE DONE WITH PLASTIC

WASTE?

There are more levels and possibilities of recycling[7]. The ideal is mechanical or material recyclingwhere the waste is mechanically ground (reclaim,regranulation, scrap reuse). It is feasible with

production waste or with selectively collected plasticwaste (e.g. packaging waste). It is less efficient withcommingled plastic waste (fractionation isnecessary), even less with municipal solid waste. Themain limitation of this technology is the

immiscibility of most thermoplastics with each other

and the contamination (partial degradation, soil,
http://www.eschooltoday.com/%0bwaste-recycling/sources-of-waste.htmlhttp://www.eschooltoday.com/%0bwaste-recycling/sources-of-waste.htmlhttp://www.naturalstateresearch.com/%0bProductsPage.htmlhttp://www.naturalstateresearch.com/%0bProductsPage.htmlhttp://www.naturalstateresearch.com/%0bProductsPage.htmlhttp://www.naturalstateresearch.com/%0bProductsPage.htmlhttp://www.eschooltoday.com/%0bwaste-recycling/sources-of-waste.htmlhttp://www.eschooltoday.com/%0bwaste-recycling/sources-of-waste.html


4/16

26 Gyrgy Bnhegyi

foreign particles etc.). Upgrading of plastic waste,where the original properties are reached or evenexceeded is very rare downgrading is much morefrequent. It means that in the majority of mechanicalrecycling technologies the original application is notfeasible, some less demanding products should be

sought. Chemical recycling means that waste isconverted into other, valuable raw materials bydepolymerisation [8], cracking, hydrogenation,hydrolysis (in the case of polycondensation

polymers), solvolysis (PUR), peptization (rubbers).Biological recycling by bacteria and enzymes meansconversion of plastics to lower molecular productssuch as biogas, biomass, and so on. This possibility isvery much limited with fossil based plastics. It can beused, however with so-called degradable plastics.

Energy recovery, i.e. direct burning or co-firing incement kilns, blast furnace, in combination withother fuels is an obvious option but one should takecare of the potentially dangerous byproducts. (This istrue for municipal waste incineration as well). One

cannot emphasize enough the responsibility of the

industrialized states vs. the developing countries:illegal waste trade, pollution, exporting the problemsshould be prevented by all means!

Figure 5 shows the flow chart of new and wasteplastic streams in the EU from a survey made in 2010[9]. The European Union issued several directivesrelated to the waste problem, e.g. the EU Directive94/62/EC of 20 December 1994 on packaging andpackaging waste, which prescribed 22.5 wt%recycling by 2008, or Directive 2008/98/EC whichdemand 50% recycling by 2020. Other relevant

directives are 2012/19/EU on the electronic and

electrical waste or the end of life vehicle directive2000/53/EC, which will be discussed later.

The question, whether material recycling or energyrecovery is more economic or useful, has been

investigated for a long time [10]. From the viewpointof energy utilization alone, incineration should be

preferred. Such questions are, however, morecomplicated than that and the whole complexity ofproblems, including environmental pollution and

social costs should also be included in the balance.

The answer always depends on the technology usedtherefore decision should be supported by constantlyupdated calculations. This will be discussed in somelength in relation to LCA (Lifecycle Analysis)

methods.

4.1. Plastic packaging waste

In view of the large amount of plastics used forpackaging, the importance of this kind of waste inenvironmental pollution and the relatively goodchance for collecting at least a substantial part of this

kind of waste before getting into the MSW streamplastic packaging waste is a good target of recycling[11], [12]. Recycling of agricultural plastic waste (atleast that of agricultural films) overlaps partly withthe technologies used for recycling plastic packaging

waste (films), although it has specific features due tothe different nature of contamination and to thedifferences in the additive package. (We will returnto this latter problem when treating the controlleddegradation problem).

The majority of packaging scrap is in the form of

films: bags, sacks, various kinds of food packaging(food contact and non-contact grades as well), shrink

Figure 5 Import, consumption, recycling and export of new and waste plastic in the EU based on a 2010 study [9]


5/16


films, stretch films, cling films and so on. There areproblems even with selectively collected films: onemajor problem is that most up-to-date films aremultilayer structures, where, in addition topolyolefins (LDPE, LLDPE, HDPPE, olefinplastomers, PP) typically there are other layers aswell (such as polyamides, tie-layer resins, which aretypically olefin copolymers with polar co-monomersor grafts). Another possible problem is contamination[13], [14] by greases, other organic components, soiletc. A third problem is that even various types ofpolyolefins are not necessarily compatible [15] (theyare, in fact, normally incompatible) which meanssevere downgrading in properties (especially inelongation at break) if simple melt mixing is applied.The use of compatibilizers (mostly block

copolymers) may be of some help. A furthercomplication may come from composite laminates,such as plastic/paper, plastic/aluminum orpaper/plastic/aluminum multilayer packaging. Theseare very modern and highly functional, but thecomponents cannot be easily separated from eachother, thus hampering recycling.

In addition to films other plastic packaging materialsare available in the form of injection molded orvacuum or thermoformed boxes, cups, blow moldedcontainers or bottles. Boxes and cups are usually

made of PE, PP or PS, while bottles and containersfrom HDPE [16] or PET (PVC is much less usednowadays for this purpose).

Collection of selective packaging waste should beginat the retail stores where e.g. a large portion of shrinkand stretch films can be recollected after productdelivery. Other parts of packaging waste can becollected selectively by the households. Nowadaysthis selective collection is mostly limited to PETbottles. In less developed countries the majority ofplastic waste can be found in MSW. If it goes to

landfill, it causes problems; if it is incinerated, atleast the energy content is recovered.

A typical recycling line [17] which can be used notonly for plastic packaging waste, but also for other

plastic scraps is shown in Figure 6. The milled wasteis first washed (cleaned, decontaminated), the variousadditives are added and finally the mixture iscompounded and granulated. Regranulation linesusually contain easily changeable melt-filtering units,as fine solid particles clog the filters relativelyfrequently in spite of the initial washing step. Inpost-consumer waste the polymer molecules aresomewhat degraded (oxidized and/or the averagemolecular weight is reduced). Oxidation may beaccompanied by discoloration and the antioxidantsand heat stabilizers are typically depleted. Therefore

additional stabilization is necessary. Contaminationlevel should be kept low if the recycled polymer is tobe used again for food packaging. Leachate levelshould be very low. The hazards can be significantlyreduced if the recycled plastic is used in multilayerfilms again where the recyclate is in the central layerand the outer layers are made of virgin resin. Co-injection and multilayer blow molding are similar

strategies in other applications.

Molecular weight reduction in post-consumer PETbottle recyclate may be quite serious. This may be

one reason why the majority of PET recyclate is usedfor fiber purposes and not for bottle production (seeFigure 7). Fiber spinning requires much more fluidplastic grades than bottle production.

If PET recyclate is to be used for the originalpurpose, chain-extension and recrystallizationprocesses are made [18]. In recycled PET bottle

manufacturing the multi-layer approach with centralrecyclate layers is also widely adopted.

Figure 6 Flow chart of a typical plastic waste regranulation line after [8].


6/16

28 Gyrgy Bnhegyi

Figure 7 Consumption of PET recyclate for variouspurposes. Source: University of Cambridge,

ImpEE project, Topics/Recycling Statistics

4.2. Electrical and electronic waste

In our consumer society the lifecycle of up-to-dateelectronic equipment became very short, newcommunication and data storage technologiesbecome completely obsolete within 5 years togetherwith the hardware. This is accompanied by an evergrowing amount of electrical and electronic waste,where not only the amount is alarming but thehazardousness of some components. Presently atleast two directives deal with this problem is the EU:the WEEE Directive 2002/96/EC and the RoHSDirective 2002/95/EC. Most industrial countries tryto regulate the selective collection of electronic wasteby the manufacturers and the vendors. This isimportant because of both the valuable andhazardous materials contents. The electronic wastecontains 49% metals, 33% plastic, 12% comes fromcathode ray tubes (which may diminish with LCDand other displays), the rest contains differentmaterials [19].

According to the same source in 2005 in the USabout 56% of the WEEE plastics fraction was HIPS,20% was ABS, 11% was PPE (poly-phenylene-ether,

which, together with HIPS constituted a popular

blend, called Noryl), while the residue (13%)contained other polymers. Nowadays probably thePC content is higher due to the widespread use ofPC-ABS alloys, but essentially E-waste plastic

fraction is a strongly mixed powder of engineeringplastics. The most important fraction of electronicwaste is that of metals: some precious metal (Au, Pd,Cu, Ni, Sn, Pb) components are present there insignificantly higher concentration than in natural ores[20], and can be recovered after mechanicalseparation followed by classical or hydro-metallurgical and electrochemical processes. It isquite possible that it will be less expensive to recover

some metals from the E-waste than from naturalresources.

The plastic fraction is less valuable (mainly becauseof the necessity of component separation and

contamination), nevertheless the constituents arelatively expensive engineering plastics. The E-waste recycling rate increased from 10% in 2000 to24.9% in 2011 [21]. The E-waste problem is notlimited to the USA or the EU countries, Asiancountries face the same problem [22]. Separation andreprocessing of the E-waste plastic fraction aresomewhat similar to those technologies used in theprocessing of the automotive shredder plasticsresidue. Material recycling is very much limited bythe technical difficulties of component separation,controlled decomposition into low molecular organic

compounds, incineration or co-firing are better suitedto this kind of waste. Plastics of different chemicalcomposition may be separated from each other byvarious techniques, based on density, wetting ortriboelectric behavior (see the next section). E-wastesare problematic because of the presence ofpotentially hazardous components: most importantlyhalogenated flame retardants, halogenated

hydrocarbons (coolants in refrigerators and airconditioners), and various kinds of batteries (e.g.lithium ion batteries).

This latter problem is dealt with by the RoHSdirective, which limits the use of halogenated flameretardants, Cr(VI) based compounds, lead basedsolder materials etc. The presence of printed circuitboards based on thermosets (mostly epoxies)complicates recycling further which will bediscussed in a later section. Prescribing the duty ofproduct collection by the manufacturers and vendorscan be easily circumvented by non-EU residentcompanies. This is a general problem of theconsumer society: legislation always lags behind theproblems. Alleviation of the E-waste problem is also

possible by careful design, which will also betouched briefly in a later section.

4.3. Automoti ve waste

In spite of the slowdown caused by the 2008

economic crisis, production and replacement of olderautomobiles by the companies and by the population

results in a heavy environmental burden. In order toreduce fuel consumption and CO2 emission theportion of plastics used in new car models increased

continuously (see Figure 8).

Similarly to the E-waste, again plastics are the least


7/16


valuable components of the waste. Therefore greatefforts are made to recover steel and other non-ferrous metals and the big problem is the economic

and useful reprocessing of automotive shredderresidue (ASR). As the so-called End-of life vehicle

(ELV) 2000/53/EC prescribes 85% reuse andrecovery of ELV by 2006 and 95% by 2015 plasticfractions must be dealt with. The average

composition of the ASR is shown in Figure 9, takenfrom a case study in Denmark [24]. Although the

margins vary widely, the organic fraction issubstantial.

The ferrous part is separated by magnetic field, whilethe rest is mostly sorted based on their densitydifferences [25], [26]. Non-magnetic separationtechnologies include trommel (size) separation,vibration sieving, air classification (cyclons), sinkand float, manual sorting, on-line spectroscopyassisted separation, eddy current separation and

triboelectric separation. The term sink and floatcovers methods based on both wetting (frothflotation) and density differences. If using organic

liquids (which are less tolerated nowadays forenvironmental reasons) selective partial swelling ofvarious plastic grades can be utilized to increasedensity differences. Due to the difficulties involvedin plastic separation one may think of burning theorganic residue, which has its own problems: highhumidity content (2-25%), relatively high inertcontent (5-40% - resulting in slag formation), widelyvarying and relatively low heating value (13-25MJ/kg comparable with that of wood but much lessthan that of pure polymers, coal or oil). Co-incineration with municipal solid waste or sewagesludge is also possible, but the presence of acidicgaseous products and heavy metal contamination inthe dust requires attention. Pyrolysis in reductiveatmosphere (CO, CO2, H2 mixture formation) is also

possible.

Figure 8 Average material consumption for a domestic light vehicle, model years 1995, 2000, and 2009 (Source:Wards Communications, Wards Motor Vehicle Facts and Figures, 2010Detroit, MI, 2010, pp. 65). The

picture is taken from a study made for the National Highway Traffic Safety Administration, USA [23]

Figure 9 Average composition of automotive car shredder residue, taken form [24]


8/16

30 Gyrgy Bnhegyi

Instead of describing a wide variety of technologies,here we briefly refer to a PhD Thesis written byBodzay, parts of which are published internationally[27-29] in which a density based fractionationmethod is described for ELV-ASR fraction assistedby on-line spectroscopic methods and variouspossibilities for upgrading (e.g. flame retardantaddition, mechanical upgrading by layered compositeformation or transformation to carbon nanotubes bylaser pyrolysis in the presence of silicate additives)are suggested. Essentially the following groups offractions can be treated as independent raw materialsources:


9/16


by pyrolytic technologies. This broad term involvesvarious technologies, as [33]

hydrous pyrolysis (steam cracking) at 300-350 Cand at relatively low pressure (


10/16

32 Gyrgy Bnhegyi

been widely described in simple terms [42]. Thesoftness of elastomers limits the size and efficiencyof grinding.

Using room temperature grinding relatively coarse

crumbs are obtained, while cryogenic grindingallows the production of sub-millimeter particles.Even the latter are, however, macroscopic in

comparison to normal fillers with a typical diameterof 1-10 microns. Crumb rubber can be compoundedinto fresh elastomer, followed by vulcanization, itcan also be used in the formulation of thermoplasticelastomers [43], or mixed with various

thermoplastics, as e.g. HDPE and nylon 6/10 [44].Crumb rubber is a useful (but not cheap) additive forasphalt in elastic pavements or in the top layer ofhighways. Deposition taxes, however, may influence

economic considerations. The problem with crumbrubber fillers in thermoplastic or in elastomericcompounds is the same which we had to face in thecase of milled thermoset composites: the surface isinactive the matrix-filler adhesion is low. It meansthat either we limit ourselves to low-end applications

(e.g. rubber mats, vibration or sound absorbers etc.),or we have to apply expensive post-treatment to thecrumb rubber surface. Another possible route is thebreakdown of the network into flowable sub-unitsusing so-called peptizing agents [45], which act

physically (as e.g. metal soaps) or chemically (thio-compounds). High temperature steam or supercriticalwater can also be used for the partial (or complete)breakdown of rubber networks. These peptizedrubbers can be processed more easily into

elastomeric or thermoplastic compounds than crumbrubber, but their production is more expensive.

Problems associated with rubber recycling could beavoided if thermoplastic elastomers would be usedinstead of traditional rubbers, as they are completelyrecyclable, but the compression set properties ofthermoplastic elastomers (especially at elevated

temperatures) are inferior to those of chemicallyvulcanized ones.

6. RECYCLING AND DESIGN

One possible solution (at least in long term) is to

force the manufacturers to collect their products andto recycle them. This would finally change their

minds not only retrospectively but they would haveto consider recycling from the beginning, whichmeans that they would have to design their products

taking into account the later recycling technology.

This is a real reverse engineering: disassembly

followed by sorting is much more effective thanshredding followed by sorting [46]. A very goodarticle is available which summarizes such greendesign principles [47], which are listed in Table 2.Observation of such principles would not solve allour present problems caused by the traditional designprinciples but would diminish the future problems.Forced application of such, or similar principlesusually meets resistance on the side of themanufacturers.

They argue that these obstacles reducecompetitiveness and drive away industry. If,

however, such laws are introduced for the whole EU

Table 1 Twelve principles of green engineering from [47]

No. Principle

1:Designers need to strive to ensure that allmaterial and energy inputs and outputs are asinherently nonhazardous as possible.

2:It is better to prevent waste than to treat or

clean up waste after it is formed.

3:Separation and purification operations shouldbe designed to minimize energy consumptionand materials use.

4:Products, processes, and systems should bedesigned to maximize mass, energy, space,

and time efficiency5:

Products, processes, and systems should beoutput pulled rather than input pushedthrough the use of energy and materials.

6:Embedded entropy and complexity must be

viewed as an investment when makingdesign choices on recycle, reuse, orbeneficial disposition.

7:Targeted durability, not immortality, shouldbe a design goal.

8:Design for unnecessary capacity or capability(e.g., one size fits all) solutions should be

considered a design flaw.

9:Material diversity in multicomponentproducts should be minimized to promotedisassembly and value retention.

10:Design of products, processes, and systemsmust include integration and

interconnectivity with available energy andmaterials flows.

11:Products, processes, and systems should bedesigned for performance in a commercialafterlife.

12: Material and energy inputs should berenewable rather than depleting.


11/16


(as happened with the REACh legislation in thechemical industry) we may control the importedgoods as well. At first it does cause additional costs,but later protects our markets from unfaircompetition. It is always a question, who pays theadditional costs? Environmental consciousness is aluxury for those living at substandard levels.Purely business-oriented green engineering andrecycling will not work but it has to be consideredthat environmental technologies are an asset in thelong run they are necessary. Laws, enforcement andstrict control are necessary but the transition may bealleviated by temporary state subsidy or selective taxreduction. Best practices should be promoted if anideal solution is not possible.

There are some good examples for the application of

these and similar principles e.g. in a brochurecontaining proposals for the packaging industry,especially for bottle manufacturers [48].

6.1. Pros and cons of control leddegradation

Another possible (long term) solution for the

recycling problem is if the polymer products aredesigned so that they return to the natural carboncycle after finishing their useful life. The advantagesof such a concept are obvious:

if the degradation rate is known and controllable,the lifetime can be designed

the environmental fate of the product is known

the manufacturer will have a competitive edge, amarketing advantage related to the greenproduct

new markets or at least niche markets maybecome available.

There are, however, not less obvious disadvantagesand risks:

such solutions usually involve expensive additivesor new raw materials

development costs can be enormous, their returnis questionable

the new markets may be risky, slowly developingand narrow

production should be tightly controlled

decomposition in the planned way requiresprecisely observed conditions the consumersshould be educated is disappointment is to beavoided

the most serious problem is cross-contaminationwith traditional plastics, which would render therecycling of traditional plastics problematic

therefore degradable plastics should be collected

separately (visible identification, labeling) the planned application should be carefully

designed and engineered to avoid mismatch ofplanned an real lifetime

6.2. Control led photo-oxidativedegradation

There are basically two philosophies used forcontrolled degradation: one is based on the controlledacceleration of thermo-photo-oxidative degradation,the other is based on bio-degradation. Thermal andphoto-oxidation of most polymers (at least that oftheir aliphatic part) is mainly based on a combinedcycle of two cyclic reactions (shown in Figure 10)which can be controlled by the use of antioxidants[49].

Figure 10 Basic reactions involved in the thermo-photo-oxidation of aliphatic polymer chains [46].

Under thermal or light impacts alkyl radicals areformed which react with the ambient oxygen,forming peroxy radicals. Peroxy radicals react withother alkyl chains and hydroperoxides and new alkylradicals are formed. Hydroperoxides may undergohomolysis giving rise to alkoxy and hydroxyl

radicals. Alkoxy radicals may also react with alkanesand new alkyl radicals are formed. So-called primaryantioxidants (usually sterically hindered phenols oramines) scavenge the reactive radical species byforming stable radicals instead, while secondaryantioxidants (usually organic phosphites or sulfides)deactivate hydroxyl radicals. Certain transition metalions may accelerate the left cycle thus leading toearlier degradation. Such ions are masked bycomplexing agents in high voltage polyethyleneinsulations where degradation is to be avoided, ormay be added intentionally to agricultural films or

other products, where shortened lifetime is required.


12/16

34 Gyrgy Bnhegyi

Pro-oxidants are activated by light or heat underoutdoor conditions. Such (environmentally benign)transition metal salts are called pro-oxidants and areavailable in masterbatch form. Lower molecularspecies produced by accelerated oxidation are finallyavailable for attack by microbes. In some other casesthe degradation does not reach the molecular level,but very fine polymer powder is formed, which isneutral and does not endanger the environment. Thisprocess is called oxo-biodegradation [50], its primaryuse is in agriculture (mulch films, greenhouse films,bags for compost collection). In other applicationsbiological pro-oxidants, as starch, are used whichare more prone to the environmental effects [51].Companies developing more expensive polymers thatare biologically degradable to the molecular level,

fiercely debate the claim that identification of oxo-biodegradable films with their products is reallyjustified [52].

6.3. Biodegradation

In popular green parlance plastics from renewable

resources are frequently mixed up withbiodegradable polymers, but this is a mistake. Thereare plastics made of non-renewable resources, whichare not biodegradable these are most syntheticpolymers. There are polymers made of renewableresources, but non-degradable: an example ispolyethylene made in Brazil from ethanol obtainedfrom sugar cane. There are polymers, which aremade of synthetic (non-renewable) raw materials, butare degradable e.g. polylactide can be made fromsynthetic lactic acid. And finally there are polymersmade of renewable resources which are degradable e.g. bacterial polyesters.

When we talk of degradability, it should be clearly

stated under which conditions is the materialdegradable (light? heat? humidity? soil? composting?aerobic? anaerobic?) otherwise the term is

meaningless or misleading. Most frequently usedbiodegradable plastics belong to polyesters: e.g. PBS

= polybutylene succinate, PBSA = polybutylenesuccinate adipate, PCL = polycaprolactone, PLA =polylactide or polyesteramides [53]-[55] PLA is inthe most advanced stage as far as applications areconcerned, here the major problems are related to the

price and to the relative rigidity of films, injectionmolded or blow molded articles made of thismaterial. These problems can be alleviated bycopolymerization, plasticization or blending. Themain area of application is food packaging. Proper

composting conditions should always be provided for

the collected biodegradable waste if completedecomposition is required. At present polymers of

biological origin cannot replace traditional ones inmost applications but a gradual market gain isexpected in the near future.

7. TOWARDS A SUSTAINABLEPLASTICS TECHNOLOGY

When assessing products and technologies nowadaysLife cycle analysis [56] is performed, which takes a

cradle to grave approach and calculates no onlyenergy consumption but also CO2 emission, ozonelayer depletion effects, resource consumption,ecotoxicity and much more. It requires a fairly broaddatabase regarding raw materials and technologies

and, although the method can be debated especiallythe relative weight factors ascribed to the variouseffects, this method is presently the most effectiveone for assessing the consequences of replacing onematerial or technology by another one. Eco-

efficiency assessment of plastics recycling methodshas been performed [57], LCA of a concreteintractable plastic waste to artificial crude oiltechnology [58] is available, a comparative study ofpractices in various European countries [59] based on

the LCA philosophy has been issued, and we alsocite a Scandinavian analysis on the economic

background and feasibility of plastics recycling [60].All these careful studies are necessary to makeconcrete decisions, but the simple old saying on theR-s remains true: reduce, reuse, recycle, recover,replace!

REFERENCES

[1] End-of-Waste Criteria for Waste Plastic forConversion, Technical Proposals, 2013, IPTS,

Seville, http://susproc.jrc.ec.europa.eu/activities/

waste/documents/Plastics2ndworkingdoc23may2012.

pdf

[2] Converting Waste Plastics into a Resource,Assessment Guidelines, United Nations Environment

Programme, 2009, http://www.unep.or.jp/Ietc/Publi

cations/spc/WastePlasticsEST_Compendium.pdf

[3] Plastics the Facts 2012, An analysis of Europeanplastics production, demand and waste data for

2011, 2012, Plastics Europe Market ResearchGroup, http://www.plasticseurope.org/documents/

document/20121120170458-final_plasticsthefacts_

nov2012_en_web_resolution.pdf

[4] How to develop a waste management and disposal

strategy, The Chartered Institute of Purchasing and
http://susproc.jrc.ec.europa.eu/activities/%0bwaste/documents/Plastics2ndworkingdoc23may2012.pdfhttp://susproc.jrc.ec.europa.eu/activities/%0bwaste/documents/Plastics2ndworkingdoc23may2012.pdfhttp://susproc.jrc.ec.europa.eu/activities/%0bwaste/documents/Plastics2ndworkingdoc23may2012.pdfhttp://www.unep.or.jp/Ietc/Publi%0bcations/spc/WastePlasticsEST_Compendium.pdfhttp://www.unep.or.jp/Ietc/Publi%0bcations/spc/WastePlasticsEST_Compendium.pdfhttp://www.plasticseurope.org/documents/%0bdocument/20121120170458-final_plasticsthefacts_%0bnov2012_en_web_resolution.pdfhttp://www.plasticseurope.org/documents/%0bdocument/20121120170458-final_plasticsthefacts_%0bnov2012_en_web_resolution.pdfhttp://www.plasticseurope.org/documents/%0bdocument/20121120170458-final_plasticsthefacts_%0bnov2012_en_web_resolution.pdfhttp://www.plasticseurope.org/documents/%0bdocument/20121120170458-final_plasticsthefacts_%0bnov2012_en_web_resolution.pdfhttp://www.plasticseurope.org/documents/%0bdocument/20121120170458-final_plasticsthefacts_%0bnov2012_en_web_resolution.pdfhttp://www.plasticseurope.org/documents/%0bdocument/20121120170458-final_plasticsthefacts_%0bnov2012_en_web_resolution.pdfhttp://www.unep.or.jp/Ietc/Publi%0bcations/spc/WastePlasticsEST_Compendium.pdfhttp://www.unep.or.jp/Ietc/Publi%0bcations/spc/WastePlasticsEST_Compendium.pdfhttp://susproc.jrc.ec.europa.eu/activities/%0bwaste/documents/Plastics2ndworkingdoc23may2012.pdfhttp://susproc.jrc.ec.europa.eu/activities/%0bwaste/documents/Plastics2ndworkingdoc23may2012.pdfhttp://susproc.jrc.ec.europa.eu/activities/%0bwaste/documents/Plastics2ndworkingdoc23may2012.pdf


13/16


Supply, http://www.cips.org/Documents/

About%20CIPS/Develop%20Waste%20v3%20-

%2020.11.07.pdf

[5] http://www.eschooltoday.com/waste-recycling/sources-of-waste.html

[6] http://www.naturalstateresearch.com/ProductsPage.html

[7] Hopewell, J., Dvorak R., Kosior E., (2009), Plasticsrecycling: challenges and opportunities;

Philosophical Transactions of the Royal Society B,

Vol. 364, No. 1526, pp. 21152126.

[8] Conversion technology: A complement to plasticrecycling, 2011, 4R Sustainability Inc.,

http://plastics.americanchemistry.com/plastics-to-oil

[9] Wong, Ch., (2010), A Study of Plastic Recycling

Supply Chain, Seed Corn Research Fundhttp://www.ciltuk.org.uk/Portals/0/Documents/PD/Se

edCornWong.pdf

[10] Lea W. R., (1996), Plastic incineration versusrecycling: a comparison of energy and landfill cost

savings, Jornal of Hazardous Materials, Vol. 47,

No.1-3, pp. 295-302.

[11] Achillas, D.S., Anotnakou, E., Roupakias, C.,Megalokonomos, P., Lappas A., (2008), Recycling

techniques of polyolefins from plastic wastes,

Global NEST Journal, Vol. 10, No.1, pp. 114-122.

[12] 2011 National Postconsumer Plastic Bag & Film

Recycling Report, Prepared by Moore RecyclingAssociates Inc. for the American Chemistry Council,

(2013), Sonoma, CA, http://plastics.american

chemistry.com/Education-Resources/Publications/2011-National-Post-Consumer-Recycled-Plastic-

Bag-and-Film-Report.pdf

[13] Walsh, Ch., (2013), Feasibility Study to reduce theamount of Primal Packaging of Meat going to

Landfill, http://www.eurocarne.com/informes/pdf/rd_w_g_f_fr_-_alternatives_to_landfill_for_plastic

_waste_-_final_report_29.04.13.pdf

[14] Sutta, S., Recycling Contaminated Plastics, GreenPlanet21, http://www.meatami.com/ht/a/Get

DocumentAction/i/76984

[15] Tall S., (2000), Recycling of Mixed Plastic Waste -Is Separation Worthwhile?, PhD Thesis, Department

of Polymer Technology, Royal Institute of

Technology, Stockholm, http://citeseerx.ist.psu.edu/

viewdoc/download?doi=10.1.1.198.7128&rep=rep1

&type=pdf

[16] Large Scale HDPE Recycling Trial, 2007, Wasteand Resources Action Programme, ISBN: 1-84405-

308-3, http://www.wrap.org.uk/sites/files/wrap/

WRAP_Large_Scale_HDPE_Recycling_Trial_Repor

t.4328448f.3769.pdf

[17] Al-Salem, S.M., Lettieri, P., Baeyens J., (2009),Recycling and recovery routes of plastic solid waste

(PSW): A review, Waste Management, Vol. 29.,

October, pp. 26252643.

[18] Dimonie, D., Socoteanu, R., Pop, S., Fierascu, I.,Fierascu, R., Petrea, C., Zaharia, C. Petrache, M.,

2012, Overview on Mechanical Recycling by Chain

Extension of POSTC-PET Bottles, in Material

Recycling Trends and Perspectives, ed. by Achilias

D.S., InTech, http://cdn.intechopen.com/pdfs/

32562/InTech-Overview_on_mechanical_recycling_

by_chain_extension_of_postc_pet_bottles.pdf

[19] Kang, H.-Y., Schoenung J. M., (2005), Electronicwaste recycling: A review of U.S. infrastructure and

technology options, Resources, Conservation and

Recycling, Vol. 45,pp. 368400.

[20] Gramatyka, P., Nowosielski, R., Sakiewicz P.,(2007), Recycling of waste electrical and electronicequipment, Journal of Achievements in Materialsand Manufacturing Engineering, Vol. 20, No. 1-2,

pp. 535-538.

[21] http://www.electronicstakeback.com/wp-content/uploads/Facts_and_Figures_on_EWaste_and_Recycl

ing.pdf (2013)

[22] Bo, B., Yamamoto, K., (2010), Characteristics of E-waste Recycling Systems in Japan and China,

World Academy of Science, Engineering and

Technology, Vol. 4., pp. 442-448.

[23] Park, C-K., Kan, C-D., Hollowell, W. Hill, S.I.(2012, December). Investigation of opportunities for

lightweight vehicles using advanced plastics andcomposites (Report No. DOT HS 811 692).

Washington, DC: National Highway Traffic Safety

Administration, www.nhtsa.gov/DOT/NHTSA/NVS/

Crashworthiness/Plastics/811692.pdf

[24] Moakley, J., Weller, M., Zelic M., (2010), AnEvaluation of Shredder Waste Treatments in

Denmark, Worcester Polytechnic Institute,

Worcester, MA, http://www.wpi.edu/Pubs/E-project/

Available/E-project-051110-050238/unrestricted/

Final_Report.pdf

[25] Duranceau, C., Spangenberger, J., (2011), All AutoShredding: Evaluation of Automotive Shredder

Residue Generated by Shredding Only Vehicles,

Argonne National Laboratory,

http://www.es.anl.gov/energy_systems/crada_team/p

ublications/all_auto_report.pdf

[26] Lee, J. J. S., Mo, J. P. T., Wu, D. Y., (2012),Polymer Recovery from Auto Shredder Residue by

Projectile Separation Method, Sustainability, Vol. 4,

pp. 643-655.

[27] Toldy, A., Bodzay, B., Tierean M., (2009),Recycling of mixed polyolefin wastes,
http://www.cips.org/Documents/%0bAbout%20CIPS/Develop%20Waste%20v3%20-%2020.11.07.pdfhttp://www.cips.org/Documents/%0bAbout%20CIPS/Develop%20Waste%20v3%20-%2020.11.07.pdfhttp://www.cips.org/Documents/%0bAbout%20CIPS/Develop%20Waste%20v3%20-%2020.11.07.pdfhttp://www.eschooltoday.com/waste-recycling/%0bsources-of-waste.htmlhttp://www.eschooltoday.com/waste-recycling/%0bsources-of-waste.htmlhttp://www.eschooltoday.com/waste-recycling/%0bsources-of-waste.htmlhttp://www.eschooltoday.com/waste-recycling/%0bsources-of-waste.htmlhttp://www.naturalstateresearch.com/ProductsPage.htmlhttp://www.naturalstateresearch.com/ProductsPage.htmlhttp://www.naturalstateresearch.com/ProductsPage.htmlhttp://www.naturalstateresearch.com/ProductsPage.htmlhttp://plastics.americanchemistry.com/plastics-to-oilhttp://www.ciltuk.org.uk/Portals/0/Documents/PD/SeedCornWong.pdfhttp://www.ciltuk.org.uk/Portals/0/Documents/PD/SeedCornWong.pdfhttp://www.eurocarne.com/informes/pdf/%0brd_w_g_f_fr_-_alternatives_to_landfill_for_plastic%0b_waste_-_final_report_29.04.13.pdfhttp://www.eurocarne.com/informes/pdf/%0brd_w_g_f_fr_-_alternatives_to_landfill_for_plastic%0b_waste_-_final_report_29.04.13.pdfhttp://www.eurocarne.com/informes/pdf/%0brd_w_g_f_fr_-_alternatives_to_landfill_for_plastic%0b_waste_-_final_report_29.04.13.pdfhttp://www.meatami.com/ht/a/Get%0bDocumentAction/i/76984http://www.meatami.com/ht/a/Get%0bDocumentAction/i/76984http://citeseerx.ist.psu.edu/%0bviewdoc/download?doi=10.1.1.198.7128&rep=rep1&type=pdfhttp://citeseerx.ist.psu.edu/%0bviewdoc/download?doi=10.1.1.198.7128&rep=rep1&type=pdfhttp://citeseerx.ist.psu.edu/%0bviewdoc/download?doi=10.1.1.198.7128&rep=rep1&type=pdfhttp://www.wrap.org.uk/sites/files/wrap/%0bWRAP_Large_Scale_HDPE_Recycling_Trial_Report.4328448f.3769.pdfhttp://www.wrap.org.uk/sites/files/wrap/%0bWRAP_Large_Scale_HDPE_Recycling_Trial_Report.4328448f.3769.pdfhttp://www.wrap.org.uk/sites/files/wrap/%0bWRAP_Large_Scale_HDPE_Recycling_Trial_Report.4328448f.3769.pdfhttp://cdn.intechopen.com/pdfs/%0b32562/InTech-Overview_on_mechanical_recycling_%0bby_chain_extension_of_postc_pet_bottles.pdfhttp://cdn.intechopen.com/pdfs/%0b32562/InTech-Overview_on_mechanical_recycling_%0bby_chain_extension_of_postc_pet_bottles.pdfhttp://cdn.intechopen.com/pdfs/%0b32562/InTech-Overview_on_mechanical_recycling_%0bby_chain_extension_of_postc_pet_bottles.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://www.nhtsa.gov/DOT/NHTSA/NVS/%0bCrashworthiness/Plastics/811692.pdfhttp://www.nhtsa.gov/DOT/NHTSA/NVS/%0bCrashworthiness/Plastics/811692.pdfhttp://www.nhtsa.gov/DOT/NHTSA/NVS/%0bCrashworthiness/Plastics/811692.pdfhttp://www.wpi.edu/Pubs/E-project/%0bAvailable/E-project-051110-050238/unrestricted/%0bFinal_Report.pdfhttp://www.wpi.edu/Pubs/E-project/%0bAvailable/E-project-051110-050238/unrestricted/%0bFinal_Report.pdfhttp://www.wpi.edu/Pubs/E-project/%0bAvailable/E-project-051110-050238/unrestricted/%0bFinal_Report.pdfhttp://www.es.anl.gov/energy_systems/crada_team/publications/all_auto_report.pdfhttp://www.es.anl.gov/energy_systems/crada_team/publications/all_auto_report.pdfhttp://www.es.anl.gov/energy_systems/crada_team/publications/all_auto_report.pdfhttp://www.es.anl.gov/energy_systems/crada_team/publications/all_auto_report.pdfhttp://www.wpi.edu/Pubs/E-project/%0bAvailable/E-project-051110-050238/unrestricted/%0bFinal_Report.pdfhttp://www.wpi.edu/Pubs/E-project/%0bAvailable/E-project-051110-050238/unrestricted/%0bFinal_Report.pdfhttp://www.wpi.edu/Pubs/E-project/%0bAvailable/E-project-051110-050238/unrestricted/%0bFinal_Report.pdfhttp://www.nhtsa.gov/DOT/NHTSA/NVS/%0bCrashworthiness/Plastics/811692.pdfhttp://www.nhtsa.gov/DOT/NHTSA/NVS/%0bCrashworthiness/Plastics/811692.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://www.electronicstakeback.com/wp-content/%0buploads/Facts_and_Figures_on_EWaste_and_Recycling.pdfhttp://cdn.intechopen.com/pdfs/%0b32562/InTech-Overview_on_mechanical_recycling_%0bby_chain_extension_of_postc_pet_bottles.pdfhttp://cdn.intechopen.com/pdfs/%0b32562/InTech-Overview_on_mechanical_recycling_%0bby_chain_extension_of_postc_pet_bottles.pdfhttp://cdn.intechopen.com/pdfs/%0b32562/InTech-Overview_on_mechanical_recycling_%0bby_chain_extension_of_postc_pet_bottles.pdfhttp://www.wrap.org.uk/sites/files/wrap/%0bWRAP_Large_Scale_HDPE_Recycling_Trial_Report.4328448f.3769.pdfhttp://www.wrap.org.uk/sites/files/wrap/%0bWRAP_Large_Scale_HDPE_Recycling_Trial_Report.4328448f.3769.pdfhttp://www.wrap.org.uk/sites/files/wrap/%0bWRAP_Large_Scale_HDPE_Recycling_Trial_Report.4328448f.3769.pdfhttp://citeseerx.ist.psu.edu/%0bviewdoc/download?doi=10.1.1.198.7128&rep=rep1&type=pdfhttp://citeseerx.ist.psu.edu/%0bviewdoc/download?doi=10.1.1.198.7128&rep=rep1&type=pdfhttp://citeseerx.ist.psu.edu/%0bviewdoc/download?doi=10.1.1.198.7128&rep=rep1&type=pdfhttp://www.meatami.com/ht/a/Get%0bDocumentAction/i/76984http://www.meatami.com/ht/a/Get%0bDocumentAction/i/76984http://www.eurocarne.com/informes/pdf/%0brd_w_g_f_fr_-_alternatives_to_landfill_for_plastic%0b_waste_-_final_report_29.04.13.pdfhttp://www.eurocarne.com/informes/pdf/%0brd_w_g_f_fr_-_alternatives_to_landfill_for_plastic%0b_waste_-_final_report_29.04.13.pdfhttp://www.eurocarne.com/informes/pdf/%0brd_w_g_f_fr_-_alternatives_to_landfill_for_plastic%0b_waste_-_final_report_29.04.13.pdfhttp://www.ciltuk.org.uk/Portals/0/Documents/PD/SeedCornWong.pdfhttp://www.ciltuk.org.uk/Portals/0/Documents/PD/SeedCornWong.pdfhttp://plastics.americanchemistry.com/plastics-to-oilhttp://www.naturalstateresearch.com/ProductsPage.htmlhttp://www.naturalstateresearch.com/ProductsPage.htmlhttp://www.eschooltoday.com/waste-recycling/%0bsources-of-waste.htmlhttp://www.eschooltoday.com/waste-recycling/%0bsources-of-waste.htmlhttp://www.cips.org/Documents/%0bAbout%20CIPS/Develop%20Waste%20v3%20-%2020.11.07.pdfhttp://www.cips.org/Documents/%0bAbout%20CIPS/Develop%20Waste%20v3%20-%2020.11.07.pdfhttp://www.cips.org/Documents/%0bAbout%20CIPS/Develop%20Waste%20v3%20-%2020.11.07.pdf


14/16

36 Gyrgy Bnhegyi

Environmental Engineering and Management

Journal, Vol. 8, No. 4., pp. 967-971.

[28] Vajna, B., Palsti, K., Bodzay, B. Toldy, A. Patachia,S. Buican, R. Catalin, C. Tierean M., (2010),

Complex Analysis of Car Shredder Light Fraction,

The Open Waste Management Journal, Vol. 3, pp.

47-56.

[29] Bodzay, B. Fejs, M. Bocz, K. Toldy, A. Ronkay, F.Marosi Gy., (2012), Upgrading Of Recycled

Polypropylene By Preparing Flame Retarded Layered

Composite, eXPRESS Polymer Letters, vol. 6, No.

11, pp. 895-902.

[30] A study to examine the benefits of the End of LifeVehicles Directive and the costs and benefits of a

revision of the 2015 targets for recycling, re-use and

recovery under the ELV Directive, (2006), GHK,

http://ec.europa.eu/environment/waste/pdf/study/final_report.pdf

[31] Recycling of PVC and Mixed Plastic Waste, 1996,ed. by La Mantia F.P., Chem Tech Publishing,

Toronto

[32] Plinke, E. Wenk, N. Wolff, G., Castiglione, D.Palmark M., (2000), Mechanical Recycling of PVC

Wastes, Study for DG XI of the European

Commission (B4-3040/98/000821/MAR/E3), ,http://ec.europa.eu/environment/waste/studies/pvc/m

ech_recylce.pdf

[33] Johnson, M. Derrick S., (2010), Pyrolysis: A

method for Mixed Polymer Recycling, GreenManufacturing Initiative, http://www.wmich.edu/

mfe/mrc/greenmanufacturing/pdf/GMI%20Pyrolysis%20of%20Mixed%20Polymers%20Review.pdf

[34] Thermoset Formulators Association

[35] Job S., (2010), Composite Recycling, Summary ofrecent research and development, Knowledge

Transfer Network, http://www.compositesuk.co.uk/

LinkClick.aspx?fileticket=LXN-MfM0360=&

[36] Thomas, R. Vijayan, P. Thomas, S., 2011,Recycling of thermosetting polymers: Their blends

and composites, in: Recent Developments inPolymer Recycling, ed. by Fainleib A. and

Grigoryeva O., Institute of MacromolecularChemistry of the National Academy of Sciences of

Ukraine, Kyiv, pp. 121-153,

[37] Yang, Y.X. Boom, R. Irion, B. van Heerden, D.-J.Kuiper, P. de Wit H., (2012), Recycling of

composite materials, Chemical Engineering and

Processing: Process Intensification, vol. 51, January,pp. 53-68.

[38] Asmatulu, E., Twomey, J., Overcash, M. (2014),Recycling of fiber-reinforced composites and direct

structural composite recycling concept, Journal of

Composite Materials, Vol. 48., No.5., 593-608.

[39] Allred R. E., Busselle L. D.: (1997) TertiaryRecycling Of Automotive Plastics and Composites,

in: Proc. of 12th Annual Technical Conf. of the

American Society for Composites, ed. by Ronald F.

Gibson R.F., Newaz, G.M., Dearborn, MI, pp. 1-12,

http://www.adherent-tech.com/publications/download_document/26

[40] Derosa, R., Telfeyan, E., Mayes J. S., (2005),Current State of Recycling Sheet Molding

Compounds and Related Materials, Journal of

Thermoplastic Composite Materials, Vol. 18, No.3.,219-240.

[41] Pattavarakorn D., Plastics Recycling,http://epg.science.cmu.ac.th/induschem/article-

download.php?id=398.[42] Recycling rubber, Practical action,

http://practicalaction.org/media/preview/10541

[43] Lievana E.J., (2005), Recycling of Ground TyreRubber and Polyolefin Wastes by Producing

Thermoplastic Elastomers, PhD Thesis, University

of Kaiserslautern, https://kluedo.ub.uni-

kl.de/files/1672/Dissertation-Emiliano_J._Lievana

.pdf

[44] Lula, J.W., Bohnert G.W., (1998), ProductFormulations Using Recycled Tire Crumb Rubbe,

Report, Allied Signal, http://www.osti.gov/bridge/

servlets/purl/645485-FECNtB/webviewable

[45] Rubber Handbook, Struktol, http://www.struktol.com/pdfs/rubberhb.pdf

[46] Rios, P., Stuart, J.A. Grant, E., (2003) PlasticsDisassembly vs Bulk Recycling: Engineering Design

for End-of-Life Electronics Resource Recovery,

Environmental Science and Technology, vol. 37, no.

23, pp. 5463-5470.

[47] Anastas, P.T., Zimmerman J.B., (2003), Throughthe 12 principles of green engineering,

Environmental Science and Technology, Vol. 37, No.

5, 94A-101A.

[48] Plastics Packaging Recyclability by Design, ISBN978-0-9558399-1-7 (2013), http://www.recoup.org/

business/default.asp?goto=eco_recbydesign

[49] Antioxidants, Technical Service Report, Ampacet,http://www.ampacet.com/usersimage/File/tutorials/A

ntioxidants.pdf

[50] Billingham, N.C., Bonora, M., De Corte, D., 2003,Environmentally Degradable Plastics Based onOxo-Biodegradation of Conventional Polyolefins,

in: Biodegradable Polymers and Plastics, ed. by

Chiellini, E., Solaro, R., Springer, Berlin, pp. 313-325.
http://ec.europa.eu/environment/waste/pdf/study/final_report.pdfhttp://ec.europa.eu/environment/waste/pdf/study/final_report.pdfhttp://ec.europa.eu/environment/waste/studies/pvc/mech_recylce.pdfhttp://ec.europa.eu/environment/waste/studies/pvc/mech_recylce.pdfhttp://www.wmich.edu/%0bmfe/mrc/greenmanufacturing/pdf/GMI%20Pyrolysis%20of%20Mixed%20Polymers%20Review.pdfhttp://www.wmich.edu/%0bmfe/mrc/greenmanufacturing/pdf/GMI%20Pyrolysis%20of%20Mixed%20Polymers%20Review.pdfhttp://www.wmich.edu/%0bmfe/mrc/greenmanufacturing/pdf/GMI%20Pyrolysis%20of%20Mixed%20Polymers%20Review.pdfhttp://www.compositesuk.co.uk/%0bLinkClick.aspx?fileticket=LXN-MfM0360=&http://www.compositesuk.co.uk/%0bLinkClick.aspx?fileticket=LXN-MfM0360=&http://www.adherent-tech.com/publications/down%0bload_document/26http://www.adherent-tech.com/publications/down%0bload_document/26http://epg.science.cmu.ac.th/induschem/article-download.php?id=398http://epg.science.cmu.ac.th/induschem/article-download.php?id=398http://practicalaction.org/media/preview/10541https://kluedo.ub.uni-kl.de/files/1672/Dissertation-Emiliano_J._Lievana%0b.pdfhttps://kluedo.ub.uni-kl.de/files/1672/Dissertation-Emiliano_J._Lievana%0b.pdfhttps://kluedo.ub.uni-kl.de/files/1672/Dissertation-Emiliano_J._Lievana%0b.pdfhttp://www.osti.gov/bridge/%0bservlets/purl/645485-FECNtB/webviewablehttp://www.osti.gov/bridge/%0bservlets/purl/645485-FECNtB/webviewablehttp://www.recoup.org/%0bbusiness/default.asp?goto=eco_recbydesignhttp://www.recoup.org/%0bbusiness/default.asp?goto=eco_recbydesignhttp://www.ampacet.com/usersimage/File/tutorials/Antioxidants.pdfhttp://www.ampacet.com/usersimage/File/tutorials/Antioxidants.pdfhttp://www.ampacet.com/usersimage/File/tutorials/Antioxidants.pdfhttp://www.ampacet.com/usersimage/File/tutorials/Antioxidants.pdfhttp://www.recoup.org/%0bbusiness/default.asp?goto=eco_recbydesignhttp://www.recoup.org/%0bbusiness/default.asp?goto=eco_recbydesignhttp://www.osti.gov/bridge/%0bservlets/purl/645485-FECNtB/webviewablehttp://www.osti.gov/bridge/%0bservlets/purl/645485-FECNtB/webviewablehttps://kluedo.ub.uni-kl.de/files/1672/Dissertation-Emiliano_J._Lievana%0b.pdfhttps://kluedo.ub.uni-kl.de/files/1672/Dissertation-Emiliano_J._Lievana%0b.pdfhttps://kluedo.ub.uni-kl.de/files/1672/Dissertation-Emiliano_J._Lievana%0b.pdfhttp://practicalaction.org/media/preview/10541http://epg.science.cmu.ac.th/induschem/article-download.php?id=398http://epg.science.cmu.ac.th/induschem/article-download.php?id=398http://www.adherent-tech.com/publications/down%0bload_document/26http://www.adherent-tech.com/publications/down%0bload_document/26http://www.compositesuk.co.uk/%0bLinkClick.aspx?fileticket=LXN-MfM0360=&http://www.compositesuk.co.uk/%0bLinkClick.aspx?fileticket=LXN-MfM0360=&http://www.wmich.edu/%0bmfe/mrc/greenmanufacturing/pdf/GMI%20Pyrolysis%20of%20Mixed%20Polymers%20Review.pdfhttp://www.wmich.edu/%0bmfe/mrc/greenmanufacturing/pdf/GMI%20Pyrolysis%20of%20Mixed%20Polymers%20Review.pdfhttp://www.wmich.edu/%0bmfe/mrc/greenmanufacturing/pdf/GMI%20Pyrolysis%20of%20Mixed%20Polymers%20Review.pdfhttp://ec.europa.eu/environment/waste/studies/pvc/mech_recylce.pdfhttp://ec.europa.eu/environment/waste/studies/pvc/mech_recylce.pdfhttp://ec.europa.eu/environment/waste/pdf/study/final_report.pdfhttp://ec.europa.eu/environment/waste/pdf/study/final_report.pdf


15/16


[51] Kalambur, S., Rizvi, S. S. H., (2006), An OverviewOf Starch-Based Plastic Blends From Reactive

Extrusion, Journal Of Plastic Film & Sheeting, Vol.

22,No. 1, pp.39-58,

[52] Oxo-Biodegradable Plastics, Position Paper,European Bioplastics, (2009), http://en.european-

bioplastics.org/wp-content/uploads/2011/04/pp/

Oxo_PositionsPaper.pdf

[53] Selke, S., 2006, Plastics Recycling andBiodegradable Plastics,, in: Handbook of Plastics

Technologies, ed. by Harper, C., McGraw-Hill, New

York, pp. 8.1-8.109.

[54] http://www.biodeg.net/bioplastic.html

[55] Leja, K., Lewandowicz G., (2010), PolymerBiodegradation and Biodegradable Polymers a

Review, Polish Journal of Environmental Studies,

Vol. 19, No.2., pp. 255-266.

[56] ILCD Handbook: Analysing of existingEnvironmental Impact Assessment methodologies foruse in Life Cycle Assessment, European Union,

(2010), http://eplca.jrc.ec.europa.eu/uploads/2014/

01/ILCD-Handbook-LCIA-Background-analysis-

online-12March2010.pdf

[57] Hur, T., Lim, S.-T., Lee H.-J., A Study on The Eco-efficiencies for Recycling Methods of PlasticsWastes, http://www.lcacenter.org/InLCA-LCM03/

Hur-presentation.pdf

[58] Agilyx: For Plastic You Cant Recycle, (2012)http://www.agilyx.com/media-room/wp-content/

uploads/2012/06/Agilyx-Life-Cycle-Analysis.pdf

[59] Saiter, J.-M., Sreekumar, P. A., Youssef B., 2011,Different ways for re-using polymer based wastes.

The examples of works done in European countries,

in: Recent Developments in Polymer Recycling, ed

by Fainleib A. , Grigoryeva, O., Institute of

Macromolecular Chemistry of the National Academy

of Sciences of Ukraine, Kyiv,, pp. 261-291.

[60] Action 4.1.: Market Condition for Plastic Recycling,Plastic zero, (2013), http://www.plastic-zero.com/

media/30825/action_4_1_market_for_recycled_polymers_final_report.pdf
http://en.european-bioplastics.org/wp-content/uploads/2011/04/pp/%0bOxo_PositionsPaper.pdfhttp://en.european-bioplastics.org/wp-content/uploads/2011/04/pp/%0bOxo_PositionsPaper.pdfhttp://en.european-bioplastics.org/wp-content/uploads/2011/04/pp/%0bOxo_PositionsPaper.pdfhttp://www.biodeg.net/bioplastic.htmlhttp://eplca.jrc.ec.europa.eu/uploads/2014/%0b01/ILCD-Handbook-LCIA-Background-analysis-online-12March2010.pdfhttp://eplca.jrc.ec.europa.eu/uploads/2014/%0b01/ILCD-Handbook-LCIA-Background-analysis-online-12March2010.pdfhttp://eplca.jrc.ec.europa.eu/uploads/2014/%0b01/ILCD-Handbook-LCIA-Background-analysis-online-12March2010.pdfhttp://www.lcacenter.org/InLCA-LCM03/%0bHur-presentation.pdfhttp://www.lcacenter.org/InLCA-LCM03/%0bHur-presentation.pdfhttp://www.agilyx.com/media-room/wp-content/%0buploads/2012/06/Agilyx-Life-Cycle-Analysis.pdfhttp://www.agilyx.com/media-room/wp-content/%0buploads/2012/06/Agilyx-Life-Cycle-Analysis.pdfhttp://www.plastic-zero.com/%0bmedia/30825/action_4_1_market_for_recycled_polymers_final_report.pdfhttp://www.plastic-zero.com/%0bmedia/30825/action_4_1_market_for_recycled_polymers_final_report.pdfhttp://www.plastic-zero.com/%0bmedia/30825/action_4_1_market_for_recycled_polymers_final_report.pdfhttp://www.plastic-zero.com/%0bmedia/30825/action_4_1_market_for_recycled_polymers_final_report.pdfhttp://www.plastic-zero.com/%0bmedia/30825/action_4_1_market_for_recycled_polymers_final_report.pdfhttp://www.plastic-zero.com/%0bmedia/30825/action_4_1_market_for_recycled_polymers_final_report.pdfhttp://www.agilyx.com/media-room/wp-content/%0buploads/2012/06/Agilyx-Life-Cycle-Analysis.pdfhttp://www.agilyx.com/media-room/wp-content/%0buploads/2012/06/Agilyx-Life-Cycle-Analysis.pdfhttp://www.lcacenter.org/InLCA-LCM03/%0bHur-presentation.pdfhttp://www.lcacenter.org/InLCA-LCM03/%0bHur-presentation.pdfhttp://eplca.jrc.ec.europa.eu/uploads/2014/%0b01/ILCD-Handbook-LCIA-Background-analysis-online-12March2010.pdfhttp://eplca.jrc.ec.europa.eu/uploads/2014/%0b01/ILCD-Handbook-LCIA-Background-analysis-online-12March2010.pdfhttp://eplca.jrc.ec.europa.eu/uploads/2014/%0b01/ILCD-Handbook-LCIA-Background-analysis-online-12March2010.pdfhttp://www.biodeg.net/bioplastic.htmlhttp://en.european-bioplastics.org/wp-content/uploads/2011/04/pp/%0bOxo_PositionsPaper.pdfhttp://en.european-bioplastics.org/wp-content/uploads/2011/04/pp/%0bOxo_PositionsPaper.pdfhttp://en.european-bioplastics.org/wp-content/uploads/2011/04/pp/%0bOxo_PositionsPaper.pdf


16/16

38 Gyrgy Bnhegyi