Characterization of the Large and Small Rubber Particles in Fresh Hevea Latex

Abstract

Abstract The rubbers from small and large rubber particles were separated from the serum and cream phases of centrifuged fresh Hevea latex, respectively. The small rubber particles (SRP) consist of rubber molecules showing a unimodal molecular weight distribution (MWD), with a peak-top value falling between the two peak values of the bimodal MWD observed in rubbers from the large rubber particles (LRP). The rubbers in LRP from mature trees and SRP from seedlings are polyisoprene molecules terminated by phospholipids comprising branching points, while those in SRP from mature trees are presumed to be linear molecules containing no phospholipid terminal. The serum rubber was found to be soft and viscous rubber differing from the cream rubber containing in LRP. Thus, it can be presumed that the particle size of rubber latex is an important parameter influencing the MW, MWD and physical properties of Hevea rubber.