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THE ENVIRONMENTAL ADVANTAGE OF NATURAL RUBBER LATEX
PRODUCTS
Amir-Hashim, M.Y.* and Ikram, A.,
Rubber Research Institute of Malaysia,
Malaysian Rubber Board
e-mail: [email protected]
rapidly-growing urban population
increasing industrial activity
increasing per capita income
changing lifestyles
growing consumerism
generates
large
quantities
of
solid
wastes;
pollution
Incineration (thermal destruction – byproducts)
Recycle (selective materials)
Composting – maximize rate of natural
decomposition
Landfill (space)
Waste Management - Environmental responsibility
and sustainability
Waste disposal problem
Commodity plastics that end up in landfills
do not degrade in a microbial environment
Products from fossil fuels unsustainable
..global oil reserves drying up
..increasing crude oil prices
..increasing petrochemical industry’s cost
Latex products
Gloves
Latex thread
Condoms
Catheters
Foam products
Apparel articles
Balloons
Finger cots
Teats/soothers
Pharmaceutical rubber articles
Aerobic biodegradation of hydrocarbon waste
• Microbial population density
• Substrate availability
• Physical contact waste and microflora
• Mineral nutrients
• Temperature
• Soil acidity
• Moisture contents
• Toxic/Inhibitory materials
Soil
High molecular weight
NR polymer
biotic
abiotic
Mineral nutrients
Oxygen supply
Moisture content
Temperature
Soil acidity
Presence of toxic
materials
Low molecular weight oxidation
products (carboxylic acids, aldehydes,
alcohols)
Material disintegration
microorganisms
peroxidation
Biomass + CO2 + H2O
Scheme of NR polymer breakdown
Biodegradation of rubber gloves in soils
Materials - Gloves (NR, nitrile,
polychloroprene, plasticized PVC)
Buried in moistened soil
Treatment – Low and High nutrients
Sampling -12, 24 and 40 weeks
AFTER 40 WEEKS BURIAL
MEAN PERCENT INITIAL WEIGHT REMAINING OF DECOMPOSING
GLOVE MATERIALS BURIED IN SOIL AS AFFECTED BY NUTRIENT
TREATMENTS
Glove material Nutrient treatment
High Low Control
NR 18 62 70
Polychloroprene 100 87 99
Nitrile 96 97 97
Plasticized PVC 74 87 89
Manila-paper 5 17 31
Changes in degraded NR latex films
colonisation by bacteria and fungi
X 25,000
Bar = 1 m
X 300
Bar = 50 m
Changes in degraded NR latex films
colonisation by actinomycetes
X 1,600
Bar = 10 m
X 3,000
Bar = 5 m
Changes in degraded NR latex films
Control, 0-time
X19,500
Bar = 1 m
48 weeks
X 15,000
Bar = 1 m
Scanning electron micrographs showing the effect
of soil burial (40 weeks) on the surface
appearance of NR latex glove specimens
Unburied Buried
Network structure visualisation of degraded NR gloves
Undegraded glove (bar = 0.5 m
Degraded glove, 24 weeks (bar = 0.5 m
Micrographs of degraded NR latex glove pieces showing
hyphae on surfaces and within the rubber matrix
h, hyphae; rm, rubber matrix
12 weeks
24 weeks
dense colonisation at 40
weeks
Bacterial colonies from
degrading glovesFungal colonies from
degrading gloves
2000 1800 1600 1400 1200 1000 800 700.0
0.012
0.014
0.016
0.018
0.020
0.022
0.024
0.026
0.027
Wavenumber, cm-1
Ab
sorb
an
ce U
nit
s
Soil buried
Unburied control
1745 cm-1
1030 cm-1
Fig.3. Changes in a typical FTIR-ATR spectra of soil buried NR latex films. A
thin film (0.09 mm, low modulus) was compared to an unburied sample.
Non-S cured prevulcanised latex films degraded faster than S-vulcanised films
EFFECT OF ADDITIVES ON THE ENVIRONMENTAL DEGRADATION
OF LATEX FILMS
__________________________________________________________________________
Mean % of initial weight remaining,
Treatment __________________________________________________________
12 wks 24 wks 36 wks 48 wks
__________________________________________________________________________
HA-S-Acc 76.9 a-d 37.0 c 11.9 cd 9.9 cd
HA-S 50.2 e 16.0 de 0.1 e 0 f
SPVL 98.5 a 85.2 a 56.6 a 60.1 a
SPOVL 86.8 ab 64.3 ab 30.2 b 23.0 b
PPVNRL2 62.5 c-e 26.9 cd 5.3 c-e 1.7 ef
PPVNRL2B 67.9 b-e 10.4 e 1.2 de 3.0 ef
PPVNRL2C 55.3 e 16.0 de 10.7 cd 0.3 ef
PPVNRL2D 75.1 b-d 34.5 c 2.3 de 4.0 d-f
PPVNRL2E 55.7 de 25.8 cd 4.9 cd 5.5 de
PPVNRL2F 81.9 a-c 40.7 bc 16.3 bc 15.8 bc
__________________________________________________________ _______________
Decomposing NR (top) and polyurethane (bottom) condoms
buried over 12 months in soil
Environmental regulations and societal concerns making new demands on production of consumer goods in 21st centuryNew processes/products compatible with the environment and Nature’s recycling systemNatural materials as materials of choice for next generation of products increase demand from agricultural sector address problems of sustainability & pollution reduce environmental load resulting from disposal in landfills
SUMMARY
Design of environmentally-compatible NR latex products
disadvantages of chemical-inserted polymers
advantage of direct linked polymers
Physical properties
Natural materials natural solution to growing environmental threat and uncertainty of petroleum supply
Natural Rubber (NR) offers a choice for a cleaner environment
made in Nature
a green product by design, a renewable resource
contributes towards sustainability and global C recycling
REFERENCES• Ikram and Amir-Hashim , M.Y. NR Biodegradability in Soil in relation to waste
disposal of used Latex Products,. 5th International Latex Conference, Akron,
Ohio, July 30-31 2002.
• Ikram A and Amir-Hashim M.Y., Environmental Degradation of Powdered NR
Latex Gloves in Soil, Malaysian Rubber Technology Developments, Volume 3, No
1, 2003, pp 11-15
• A.Ikram, M.Y. Amir Hashim, M.Asrul and T.S. Tan, (2004), Influence of Thickness
and Modulus on the Environmental Degradation of Vulcanized NR Latex Films, J.
Rubb. Res. Volume 7(1). 2004 p 14
• Ikram A., Amir Hashim M.Y., Fauzi M.S. and Shamsul Bahri A.R., (2005),
Comparing the Environmental Degradation of a Synthetic Polybutadiene
Copolymer and NR Latex Examination Gloves, J. Rubb. Res. Volume 8(1). 2005
p 50
• Ikram, A., and Amir-Hashim, M.Y. (2005), Building on the Environmental
Advantage of Natural Polymers for a 21st century green materials world.
International Rubber Conference 2005, Yokohama, Japan
• A.Ikram, M.S Ma’zam, M.Y. Amir-Hashim, M.S. Fauzi, A.R. Shamsul Bahri and S.
Kamaruzaman, (2005), Effect of Antioxidants and Latex Vulcanising Agents on
the Environmental Degradation of Latex Films, J.Rubb.Res. (8(4) p 220
• Ikram, A., Ng, K.P., Amir-Hashim, M.Y. and Fauzi, M.S. (2007), The Role of Zinc
through Its Influence on Chemical Residues in Affecting the Environmental
Degradation of Prevulcanised Latex Films, J. Rubb. Res., 10(4), 193-206
Science & Technology Unit
Rubber Research Institute of MalaysiaMalaysian Rubber Board
Malaysian Rubber Export Promotional Council
Ministry of Plantation & Commodity