The Occurrence of Phase Separation in Microcrystalline Cellulose Filled Natural Rubber Films

Abstract

This paper describes the use of microcrystalline cellulose (MCC) as hydrophilic filler in two types of natural rubber latexes which are high ammonia natural rubber (HA) and epoxidised natural rubber latex (ENR). Light microscopy (LM), Scanning electron microscopy (SEM) and tensile strength measurements were then conducted on the resulting films. The light microscopy analysis revealed that more MCC particles appeared at the air–facing (AF) surfaces relative to the substrate-facing (SF) surfaces of the HA films with increasing MCC content. In contrary, the ENR25 films showed more or less similar MCC particles appearing at both air-facing surfaces and substrate-facing surfaces. Further SEM cryo-fracture analysis at the cross sections of the MCC filled ENR25 films indicated that the MCC particles were randomly dispersed in the rubber matrix. It can be suggested that the phase separation of MCC particles to the films surfaces occurred due to the incompatibility of MCC with the rubber matrix. Thus, it can be inferred that the occurrence of phase separation is minimised in the MCC filled ENR films in comparison to the MCC filled HA films.