Chemistry Project Polymers Synthesis and Property Analysis

8/12/2019 Chemistry Project Polymers Synthesis and Property Analysis

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Chemistry Project


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CONTENTS

Acknowledgements -------------------------------------------------------------

Aim of the Project -------------------------------------------------------------

General Overview -------------------------------------------------------------

Brief Theory, Synthesis and Analysis of3 ------------------------------

1. Bakelite2. Polystyrene3.Epoxy Resin

Result ------------------------------------------------------------------------------

References


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AcknowledgmentsI am very grateful to my chemistry teacher, Ms. Sadhana Bhargava, who has

been a constant source of inspiration and guidance. She supported me with all

my ideas and helped me to the maximum extend possible. She also gave me

enough extra time to find all the required information to turn my ideas into single

project. Even though what I initially wanted to make (conductive Polymers)

wasnt possible to do with our existing lab apparatus, yet she encouraged me

to search for something similar, yet interesting enough for me. This project would

never have existed, if it wasnt for her passion to teach. I would also like to thank

our lab assistant, Mr. Babe Lal for all the timely help he provided. Apart from this,

I would like to thank all those people whove published their useful work on

the internet, without which, I perhaps wouldnt even have enough information

to make even a single polymer.

PolymersSynthesis and Property AnalysisAim of the Project

The aim of this project is to find out the optimum conditions for synthesis of the

following polymers,

1. Bakelite*

2. Polystyrene**

3. Epoxy Resin**

and to study their physical properties like flexibility, strength, bounciness, color

etc.

[* Synthesized using chemicals available in the school laboratory]

[** Synthesized using Industrial Reagents]


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General OverviewA polymer is a large molecule (macromolecule) composed of repeating

structural units typically connected by covalent chemical bonds. While polymer

in popular usage suggests plastic, the term actually refers to a large class of

natural and synthetic materials with a variety of properties.

Due to the extraordinary range of properties accessible in polymeric materials,

they have come to play an essential and

ubiquitous role in everyday life - from plastics and

elastomers on the one hand to natural

biopolymers such as DNA and proteins that are

essential for life on the other. A simple example is

polyethylene, whose repeating unit is based onethylene (IUPAC name ethane) monomer (Image

2.1). Most commonly, as in this example, the

continuously linked backbone of a polymer

consists mainly of carbon atoms. However, other

structures do exist; for example, elements such as

silicon form familiar materials such as silicones,

examples being silly putty and waterproof

plumbing sealant. The backbone of DNA is in fact based on repeating units of

polysaccharides (e.g. cellulose) which are joined together by glycoside bonds

via oxygen atoms.

Natural polymers (from the Greek poly meaning many and merosmeaning

parts) are found in many forms such as horns of animals, tortoise shell, rosin

(from pine trees), and from distillation of organic materials. One of the most

useful of the natural polymers was rubber, obtained

from the sap of the heave tree. (Rubber was named by

a chemist found that a piece of solidified latex gum

was good for rubbing out pencil marks on paper. In

Great Britain, erasers are still called rubbers.)Natural

rubber had only limited use as it became brittle in the

cold and melted when warmed. In 1839, Charles

Goodyear discovered, through a lucky accident, that


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by heating the latex with sulfur, the properties were changed making the rubber

more flexible and temperature stable. That process became known

as vulcanization.

The first synthetic polymer, a phenol-formaldehyde polymer, was introduced

under the name Bakelite (Image 2.2 & 2.3), by Leo Baekeland in 1909. Its

original use was to make billiard balls. Rayon, the first synthetic fiber was

developed as a replacement for silk in 1911.Although many polymers were

made in the following years, the technology to mass produce them was not

developed until World War II, when there was a need to develop synthetic

rubber for tires and other wartime applications and nylon for parachutes. Since

that time, the polymer industry has grown and diversified into one of the fastest

growing industries in the world. Today, polymers are commonly used in

thousands of products as plastics, elastomers, coatings, and adhesives. They

make up about 80% of the organic chemical industry with products produced

at approximately 150 kg of polymers per person annually in the United States.

Furthermore, conductive polymers are organic polymers that conduct electricity.

Such compounds may be true metallic conductors or semiconductors. It is

generally accepted that metals conduct electricity well and that organic

compounds are insulating, but this class of materials combines the properties of

both. The biggest advantage of conductive polymers is their processibility.

Conductive polymers are also plastics (which are organic polymers) and

therefore can combine the mechanical properties (flexibility, toughness,

malleability, elasticity, etc.) of plastics with high electrical conductivities. Their

properties can be fine-tuned using the

exquisite methods of organic synthesis.

1. BakeliteBrief Description

Bakelite is a material based on the

thermosetting phenol formaldehyde resin,

developed in 19071909by Belgian Dr. Leo

Baekeland. Formed by the reaction under


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heat and pressure of phenol (a toxic, colorless crystalline solid) and

formaldehyde (a simple organic compound), generally with a wood flour filler, it

was the first plastic made from synthetic components. It was used for its

electrically nonconductive and heat-resistant properties in radio and telephone

casings and electrical insulators, and was also used in such diverse productsas kitchenware, jewelry, pipe stems, and children's toys. In 1993 Bakelite was

designated an ACS National Historical Chemical Landmark in recognition of its

significance as the worlds first synthetic plastic. The retro appeal of old Bakelite

products and labor intensive manufacturing has made them quite collectible in

recent years. Image 6.1 shows the structure of Bakelite.


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Precautions1. Wear safety goggles at all times in the laboratory.2. Formalin is an irritant to the skin, eyes, and mucous membranes.3. Phenol is toxic via skin contact. It is listed as a carcinogen.4. Glacial acetic acid is an irritant and can cause burns on contact.5. Work under a hood and wear gloves and protective clothing

when working with these materials.

Materials Needed

Chemicals: Apparatus:

1. 25g 40% formaldehyde 1. 150-mL beaker

2. 20 g phenol 2. Stirring rod

3. 55 mL glacial acetic acid

4. conc Hydrochloric acid

Procedure First make the Phenol-formaldehyde reaction mixture by mixing 25 g 36-

40% formaldehyde + 20 g phenol+ 55 mL glacial acetic acid.

Under a hood, measure 25 mL of the phenol-formaldehyde reactionmixture into a 150-mL beaker.

Place the beaker on a white paper towel. Add 10 mL of concentrated hydrochloric acid, slowly, with stirring. Add additional hydrochloric acid, drop wise, with stirring. (You will need

approximately 2 mL of HCl.) As the polymerization point is reached, a

white precipitate will form and dissolve.

At the point where polymerization begins, the white precipitate willnot dissolve.

Continue to stir as the plastic forms and becomes pink in color. Wash the plastic well before handling.


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What actually happened?I was slightly nervous to try out something absolutely new and was uncertain of

its results. I took the chemicals given to me by Bagola sir and followed the

instructions. I took the phenol-formaldehyde reaction mixture in a beaker,

placed it over a sheet of paper. Took a test tube full of HCl, and added it to the

beaker slowly with constant stirring. And by slowly I mean I almost emptied the

test tube in about two minutes. I couldnt figure the polymerization point as no

precipitate appeared. Thinking theres something wrong with the procedure, I

went to ask for maamsadvice. She asked me to indirectly heat it. Due to

certain reasons, I didnt hear indirectly and heated the beaker over the flame

for about 30seconds. Nothing happened. Depressed, I walked away from it

wondering what to do next. And then suddenly there was this loud noise of

some kind of explosion. It was the beaker. All the contents had poured out like

foam, except solid. It was light pink in color. It had lots of pours in it and kind of

looked like pumice stone. Maam said it happened because Id supplied alot of

heat by direct heating, and it seemed the most plausible explanation to it and

so to obtain a proper polymer, I modified the experimental setup after discussing

it with maam. I setup a large water filled beaker on a tripod stand with wire

gauze and in a boiling tube took the reaction mixture. I fixed this boiling tube

using a clamp stand, half dipped in the beaker so that the contents were evenly

heated. I added the same amount HCl as before, except this time, I added afew drops after every30 seconds. This time, after 3 minutes, I could see

something suddenly happen in the boiling tube. I alerted maam but again

it exploded. The sudden reaction broke the boiling tube, and caused a crack in

the beaker. I collected the polymer and washed it. Its physical appearance was

the same as before. Both these experiments suggested that the reaction was

extremely fast, but its activation energy was fairly high. So no matter if its directly

heated, or indirectly,

the moment it gainssufficient energy, the

polymerization

starts rapidly.


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For determining the optimum conditions for the synthesis of Bakelite, I decided

to take a reaction mixture in a beaker, heat it to a certain temperature

(indirectly), and then add HCl to find out the optimum temperature. I chose

beaker over boiling tube, because as was apparent by the pores, greater

the surface area, safer it would be to carry out the reaction.

Property Analysis

Chemistry Behind it

Phenol and Formaldehyde react in the following manner to make the polymer.


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2. POLYSTYRENEBrief Description

Polystyrene (pronounced / plistarin/) (IUPAC Poly(1-phenylethane-1,2-diyl)),

sometimes abbreviated PS, is an aromatic polymer made from the

aromatic monomer styrene, a liquid hydrocarbon that is commercially

manufactured from petroleum by the chemical industry. Polystyrene is one of

the most widely used kinds of plastic. Polystyrene is a thermoplastic substance,

which is in solid (glassy) state at room temperature, but flows if heated above its

glass transition temperature (for melding or extrusion), and becoming solid

again when cooling off. Pure solid polystyrene is a colourless, hard plastic with

limited flexibility. It can be cast into olds with fine detail. Polystyrene can be

transparent or can be made to take on various colours. Solid polystyrene is used,

for example, in disposable cutlery, plastic models, CD and DVD cases, and

smoke detector housings. Products made from foamed polystyrene are nearlyubiquitous, for example packing materials, insulation, and foam drink cups.

Polystyrene can be recycled, and has the number "6" as its recycling symbol.

Polystyrene does not biodegrade, and is often abundant as a form of pollution

in the outdoor environment, particularly alongshore and waterways.


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Precautions

1. Wear safety goggles at all times in the laboratory.2. Styrene may pose health risks if it comes in contact with the body.3. Styrene resin is sticky, so use gloves.4. Work under a hood and wear gloves and protective clothing


Materials Needed

Chemicals: Apparatus:

1. Vinyl Benzene (Styrene Casting Resin) 1. Test tubes

2. Methyl ethyl ketone (Casting resin catalyst) 2. Stirring rod

3. Thermostat

4. Measuring Cylinder

5. A 5 mL Syringe6. Stop

Watch

Procedure

Take 4 clean, numbered test tubes and to each add 3mL of Vinyl Benzene.

Fill the syringe with methyl ethyl ketone. Start the stop watch.

Make the volume of Vinyl Benzene in test tube one equal to 5 mL.

Now note the time as you add 5 divisions of the syringe, i.e. 0.5 mL to test tube

one and stir it well.

Repeat the above 2 steps with 4.5 mL of Vinyl Benzene and 1.0 mL of methyl

ethyl ketone, in the second test tube and so one.

Place these in the thermostat with temperature set to 40 *C


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What actually happened

Property Analysis


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Chemistry Behind it

The chemical makeup of polystyrene is a long chain hydrocarbon with

every other carbon connected to a phenyl group (the name given to the

aromatic ring benzene, when bonded to complex carbon

substituents).Polystyrene's chemical formula is (C8H8) n; it contains the chemical

elements carbon and hydrogen. Because it is an aromatic hydrocarbon, it burns

with an orange-yellow flame, giving off soot, as opposed to non-aromatic

hydrocarbon polymers such as polyethylene, which burn with a light yellow

flame (often with a blue tinge) and no soot. Complete oxidation of polystyrene

produces only carbon dioxide and water vapor. This addition polymer of styrene

results when vinyl benzene styrene monomers (which contain double bonds

between carbon atoms) attach to form a polystyrene chain (with each carbonattached with a single bond to two other carbons and a phenyl group).

3. EPOXY RESINBrief Description

Epoxy or polyepoxide is a thermosetting polymer formed from reaction of an

epoxide "resin" with polyamine "hardener". Epoxy has a wide range of

applications, including fiber-reinforced plastic materials and general purpose

adhesives. Credit for the first synthesis of biphenyl-A-based epoxy resins is shared

by Dr. Pierre Capstan of Switzerland and Dr. S.O. Greenlee of the United States in1936.The applications for epoxy-based materials are extensive and include

coatings, adhesives and composite materials such as those using carbon fiber

and fiberglass reinforcements (although polyester, vinyl ester, and other

thermosetting resins are also used for glass-reinforced plastic). The chemistry

of epoxies and the range of commercially available variations allows cure


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polymers to be produced with a very broad range of properties. In general,

epoxies are known for their excellent adhesion, chemical and heat resistance,

good-to-excellent mechanical properties and very good electrical

insulating properties. Many properties of epoxies can be modified (for example

silver-filled epoxies with good electrical conductivity are available, althoughepoxies are typically electrically insulating). Variations offering high thermal

insulation, or thermal conductivity combined with high electrical resistance for

electronics applications, are available.

Precautions

1. Wear safety goggles at all times in the laboratory.2. The hardner, Triethylenetetramine may cause allergic reactions. Wear

gloves at all times.

3. Both the chemicals are sticky so avoid contact with bare hands.4. Work under a hood and wear gloves and protective clothing


Materials NeededChemicals: Apparatus:

1. Epoxy Resin (formed by reaction between + 1. Test tubesepichlorohydrin and bisphenol-A) 2. Stirring rod

2. Hardener (Triethylenetetramine) 3.Thermostat

4. Measuring

Cylinder

5. a 5 mL Syringe

6. Stop Watch


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What actually happened?

at 40 *C

at 40 *C


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at 7 *C


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Property Analysis

Chemistry Behind it

Epoxy is a copolymer; that is, it is formed from two different chemicals. These are

referred to as the "resin" and the "hardener". The resin consists of monomers or

short chain polymers with an epoxide group at either end. Most common epoxy

resins are produced from a reaction between epichlorohydrin and biphenyl-A,

thought he latter may be replaced by similar chemicals. The hardener consists

of polyamine monomers, for example Triethylenetetramine (TETA). When these

compounds are mixed together, the amine groups react with the epoxide

groups to form a covalent bond. Each NH group can react with an epoxide

group, so that the resulting polymer is heavily cross-linked, and is thus rigid

and strong. The process of polymerization is called "curing", and can

be controlled through temperature and choice of resin and hardener

compounds; the process can take minutes to hours. Some formulations benefit

from heating during the cure period, whereas others simply require time, and

ambient temperatures.


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RESULT

Bakelite

Its optimum synthesis temperature range was found to be 70-80 *C. Its

synthesis requires high activation energy but the reaction is kinetically very fast.

Polystyrene

It cures faster at higher concentrations of the catalyst. The strength of the

polymer was independent of the concentration ratio of the resin

and catalyst. Its kinetics are complex as its concentration v/s curing time

graph was found to be irregular. The optimum temperature range forsynthesis of this polymer was found to be over 40 *C at the tested

concentrations of the catalyst.

Epoxy

Resin It cures faster at high concentrations of its catalyst. It also cures

faster at higher temperature. The strength of the polymer was independent of

the concentration ratio of the resin and catalyst. The reaction maybe following

first order kinetics as the concentration v/s curing time graph was found to be

close to linear. The optimum temperature range for synthesis of this polymer was

found to be 5-10 *C at the tested concentrations of the catalyst.


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++

REFERENCES

http://www.google.co.in/webhp?hl=en

http://en.wikipedia.org/wiki/Polystyrene

http://en.wikipedia.org/wiki/Styrene

http://en.wikipedia.org/wiki/Epoxy

http://en.wikipedia.org/wiki/Bakelite

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1420502

http://answers.yahoo.com/question/index?qid=20090717144012AAKmCyb

http://inventors.about.com/od/pstartinventions/a/plastics.htm

http://www.barrule.com/workshop/images/info/foams/index.htm

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430229/

http://www.pslc.ws/mactest/styrene.htm

http://www.americanchemistry.com/s_plastics/sec_pfpg.asp?CID=1421&DID=52

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http://www.google.co.in/webhp?hl=enhttp://en.wikipedia.org/wiki/Polystyrenehttp://en.wikipedia.org/wiki/Styrenehttp://en.wikipedia.org/wiki/Epoxyhttp://en.wikipedia.org/wiki/Bakelitehttp://papers.ssrn.com/sol3/papers.cfm?abstract_id=1420502http://answers.yahoo.com/question/index?qid=20090717144012AAKmCybhttp://inventors.about.com/od/pstartinventions/a/plastics.htmhttp://www.barrule.com/workshop/images/info/foams/index.htmhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430229/http://www.pslc.ws/mactest/styrene.htmhttp://www.americanchemistry.com/s_plastics/sec_pfpg.asp?CID=1421&DID=5213http://www.americanchemistry.com/s_plastics/sec_pfpg.asp?CID=1421&DID=5213http://www.americanchemistry.com/s_plastics/sec_pfpg.asp?CID=1421&DID=5213http://www.americanchemistry.com/s_plastics/sec_pfpg.asp?CID=1421&DID=5213http://www.pslc.ws/mactest/styrene.htmhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430229/http://www.barrule.com/workshop/images/info/foams/index.htmhttp://inventors.about.com/od/pstartinventions/a/plastics.htmhttp://answers.yahoo.com/question/index?qid=20090717144012AAKmCybhttp://papers.ssrn.com/sol3/papers.cfm?abstract_id=1420502http://en.wikipedia.org/wiki/Bakelitehttp://en.wikipedia.org/wiki/Epoxyhttp://en.wikipedia.org/wiki/Styrenehttp://en.wikipedia.org/wiki/Polystyrenehttp://www.google.co.in/webhp?hl=en

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Chemistry Project Polymers Synthesis and Property Analysis