Confirmation molecular structure of the Hevea rubber molecule and its effects in storage hardening

Abstract

© Published under licence by IOP Publishing Ltd. Lipids are the one of major non-rubber components discovered in natural rubber (NR) latex, which reported to be the significant parameter affecting the properties of NR [1, 2]. Our previous work suggested that lipids are the major factor dominate branching formation in NR [3], which could bring about the change in physical properties of NR during long term storage as called storage hardening (SH) phenomenon. However, lipids found in NR consist of neutral and polar lipids, i.e., phospholipids and glycolipids [3]. The information on types of lipids affecting the storage hardening behaviour in NR have not yet been investigated. Therefore, the aim of this work was to study the relationship between types of lipids on the gel formation in NR under accelerated storage. In the present work, natural rubber was treated by deproteinization, acetone extraction, chloroform:methanol extraction and transesterification for eliminating proteins, neutral lipids, polar lipids and linked lipids, respectively. The molecular structure of the rubber samples and the remaining non-rubber components were analyzed using nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR). Moreover, the rubber samples were subjected to study the storage hardening behaviour under accelerated condition using phosphorus pentoxide (P2O5).