Natural Rubber Latex Research Paper

Natural rubber latex is a natural and sustainable industrial material harvested from rubber trees known as Hevea brasiliensis. Natural ruber latex consist of cis-1,4- polyisoprene polymer and present in a spherical shape between 0.1 to 2.0 µm in diameter, covered by a layer of proteins and lipids which separate the hydrophobic rubber hydrocarbon from the aqueous phase (Blackley, 1997; Nawamawat et al., 2011). Natural rubber latex is the material of choice for the fabrication of thin elastic films in many products such as gloves, condoms, catheters, toys, balloons and etc., owing to its high strength, elasticity, comfort in use, good barrier properties and ‘green image’ (Adun & Jitladda, 2013; Amir Hashim & Rosni, 2009; Kevin, 1994). This unique

This process involves two stages which are compounding process and shaping and drying process (Abi Santhosh, Kuruvila, & Sabu, 2005; Guillaume, Bernard, & Bruno, 2011). The manufacture of natural rubber latex products require the sulphur vulcanization process, where many chemicals are involved. In this process, sulphur is added into the natural rubber latex compound as the main crosslinker to form the carbon-to-sulphur crosslinking network between the rubber chains, whilst other chemicals such as zinc diethyl-dithiocarbamate and zinc oxide are functioning as accelerator and activator for crosslinking reactions (Siti Nor Qamarina & Amir Hashim, 2009). The use of accelerators and activator is important since both could hasten and enhance the crosslink formation, to obtain the desirable physical properties in thin-film natural rubber latex products (Abi Santhosh, et al., 2005; Chong, 1977; Sureerut, Shigeyuki, Benjamin, & Jitladda, 2012). Although the sulphur vulcanization process of natural rubber latex has been acceptance by the industry for the production natural rubber latex products for decades, the actual crosslinking mechanism is still unclear until today, and thought to be similar to that occurring in the dry natural rubber products. A detailed description of such a process has been described elsewhere (Abi Santhosh, et al., 2005; Blackley,

In peroxide crosslinking reactions, organic peroxide decomposes to produce reactive free radicals that will react to release hydrogen ions from the carbon hydrogen in the rubber chain, encouraging formation of free radicals on the rubber chains. This leads to the formation of carbon-to-carbon bonds which serve as crosslinks (Blackley, 1997; Ma'zam, Dazylah, & Mok, 2006; Roberts, 1988). However, natural rubber latex films produce from this process are often exhibited poor physical strength and ageing properties (Davies & Gazeley, 1993; Ma'zam, et al., 2006; Ma'zam, Pendle, & Blackley, 1991; Mei et al., 2005). For this reason, the peroxide vulcanization process has thus far received little interest from the natural rubber latex industry. Ma’zam (1989) and Blackley (1997) suggested, the poor strength of peroxide-vulcanized natural rubber latex film compared to sulphur-vulcanized natural rubber latex film is due to the nature of crosslinking in the film. Thus, it is necessitates to study the relationship between physical properties and morphological structure of both peroxide-vulcanized and sulphur-vulcanized natural rubber latex films, and hence generate fundamental knowledge in