Journal of Natural Sciences Research www.iiste.org ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online) Vol.4, No.3, 2014 1 A Solvent-swelling method to visualize rubber particles network in biodegraded household Natural Rubber (NR) latex gloves Shamsul Bahri A.R. Microscopy Research group, Faculty of Agro-technology and Food Science, Universiti Malaysia Terengganu, 21030, K. Terengganu, Terengganu, Malaysia E-mail: shamsul@umt.edu.my Abstract The environmental degradation of household NR latex gloves buried in soil was examined using Transmission and Scanning electron microscope. Gloves pieces were treated with acetone to remove the autooxidation formulation prior to soil burial and compared with the untreated gloves. All gloves had been allowed to degrade for various time periods (3, 12, and 18 months). Degradation degree of the samples was evaluated on the integrity of rubber network of the latex particles within the samples using electron microscope. Prior to observation under microscope, samples were prepared using a solvent-swelling method. There were marked differences between network densities of latex particles for treated and untreated samples as early as 3 month treatment. Latex particles in treated samples showed a very coarse and loose rubber network that occasionally surrounded by a network of higher density latex particles, though a few remnants of latex particles can still be seen. Whereas the untreated samples showed some distinguished latex particles membrane and the integrity of rubber network was still intact. The disintegration of rubber network became more apparent in 12 and 18 months of burial. Rubber particles network in 18 months samples disintegrated totally, and the network coalesced into free polymeric strands. Solvent-swelling method gives a clearer picture on rubber particle network. Key words: solvent-swelling method, latex biodegradation, rubber particle network, household NR latex. Introduction Generally the environmental degradation of carbon-chain polymers uses both abiotic and biotic chemistry to return the products of oxo-degradation to the biological carbon cycle (Scott, 1997, 2000, 2002; Billingham et al., 2002). Although natural rubber (NR) is a polymer “made in nature” with environmental advantages, thick latex film products appear to be bio-resistant because they take longer time to break down naturally after being discarded in waste management infrastructures. Conversely, thin latex products such as examination and surgical gloves are capable to degrade within a realistic time scale. Bacteria, fungi and the mycelium-forming actinomycetes degrade vulcanised NR products but microbial rubber degradation alone can be a very slow process (Rose and Steinbuchel, 2005; Shah et. al., 2013; Imai et. al. 2011). The application of electron microscopy to study degradation process of NR latex is preferred for its high resolution and resolving power. Conventional transmission electron microscopy (TEM) is an imaging technique whereby a beam of electrons is transmitted through a thin specimen, then an image is formed, magnified and directed to appear either on a fluorescent screen or on layer of photographic film for viewing or to be detected by a sensor such as CCD camera for image capturing and digital archiving. Ultrathin section of polymer samples (up to 130μm in thickness) is normally required in order for the beam to penetrate and formed the image. Routine in-house method to visualize polymer ultrastructure using a TEM requires samples to be cryosectioned with a cryo-ultramictrotome, contrasted with heavy metals and visualized the sections using a TEM. However, this technique provide limited information on the interaction between the matrixes (i.e. rubber) with other components (i.e. fillers) A solvent-swelling method by mixing and polymerized styrene with NR latex films offers an alternative toward visualizing the rubber particle network and its inter-relation with other components. This paper describes initial work using the solvent-swelling procedure on degraded NR latex gloves and visualized using a TEM in an attempt to have a better understanding on the microstructure of degrading rubber particles in NR latex films.