Compatibilitation of cyclic natural rubber (resiprene-35) with polypropylene in the presence of oleic acid and benzoyl peroxide

Abstract

Cyclic natural nubber (CNR: Resiprene-35) has been compatibilised with polypropylene in the presence of various contents of oleic acid and benzoyl peroxide in xylene reflux to improve its adhesion as printing binder on the thermoplastic substrate. The dried blends were then compression molded at 175 C for 25 minutes to form specimens according to ASTM D 412. Mechanical testing of the specimens showed optimum tensile strength: 18.13 MPa, elongation: 7.36%, and modulus of elasticity: 246.33 MPa when composition of the blend: polypropylene : CNR : oleic acid : benzoyl peroxide: 80 php : 20 php : 0.05 php : 0.025 php. Analysis of functional group using FTIR spectroscopy of the optimum specimen after exhaustive Sokhlet extraction in n-hexane showed small amount of carbonyl absorption at 1712 cm -1 , indicating possible chemical interaction of bound oleic acid with CNR and polypropylene matrices. SEM micrographs of the optimum blend's specimen surface showed better compatibility when compared to that of blend compatibilised without oleic acid and benzoyl peroxide.