Quantitative analysis of the higher fatty acids in acetone solutes (AS) from raw natural rubber and their impacts on the structure and properties of NR/silica composites

Abstract

Traditionally, non-isoprene components as higher fatty acids in raw NR (natural rubber) were neglected in composites. Here, linoleic acid (LA), stearic acid (SA) in acetone solutes (AS) from different raw NR were analyzed quantificationally by high resolution pyrolysis gas chromatography mass spectrometry (HRPyGC–MS) firstly, where the relative amounts of LA and SA in AS were arranged as AS-STR (Standard Thailand Rubber) > AS-WF > AS-SMR (Standard Malaysia Rubber) > AS-MRSS (Myanmar Smoked Sheet Rubber). The impacts of LA and SA on the structure and properties of NR/silica composites were also investigated. Consequently, the mechanical and dynamical properties of composites were improved significantly by increasing the amount of LA or SA. Further, LA performed better than SA on decreasing the low rolling resistance of composites. Finally, esterification reaction, hydrogen bond between −COOH and Si-OH in NR/silica/LA and NR/silica/SA systems both were verified via Fourier transformation infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The present findings provide a new introspection about regulating the quality of raw NR from the hevea brasiliensis planting.