Non-isoprene Components of Natural Rubber

Non-isoprene components of Hevea brasiliensis latex account for around 10% of its dry matter while they account for about 5% of the raw dry rubber derived from latex (Table 9.5.2). They comprise proteins, carbohydrates, hpids and inorganic constituents and represent the main composition dilference between natural rubber (NR) and its synthetic counterpart, namely poly(cis-1,4-isoprene) synthetic rubber (IR). They could therefore be involved in the irreplaceable specific qualities of NR. The nature and quantity of these non-isoprene components can vary greatly depending on the clones, the exploitation system and environmental conditions. Some of these components are either dissolved or suspended in the aqueous medium of the latex while the others are adsorbed on the surface of rubber particles. 

Many hydrophilic non-isoprene components of latex are leached by the numerous washing operations with water during the process leading to dry rubber. Nevertheless, it is interesting to observe the initial allocation of non-isoprene in latex compartments. 

Approximate values only (highly dependent on clone, season and physiological status of the tree), averaged from data published by Wititsuwannakul, 2001. 

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