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: amir@lgm.gov.my

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