Grafting of vinyl monomers onto natural rubber. I. Graft copolymerization of methyl methacrylate onto natural rubber using quinquevalent vanadium ion as the initiator

Grafting of Vinyl Monomers onto Natural Rubber. I. Graft Copolymerization of Methyl Methacrylate onto Natural Rubber Using Quinquevalent Vanadium Ion as the InitiatorRubber occupies a dominant position among natural macromolecules being modified for commercial use by copolymerization with synthetic polymers.Copolymers of natural rubber are prepared and characterized by techniques applicable to wholly synthetic copolymers, and their properties could be duplicated by the characteristics of a n appropriate synthetic rubber.The successful grafting of vinyl monomers onto natural rubber involves the creation of free radical on the backbone of rubber.This can be achieved by several methods, such as chem-ical14 and irradiation.-Out of all these methods, the chemical method has attracted attention in recent years.Graft copolymerization of vinyl monomers onto natural rubber has been studied by using benzoyl peroxide as the initiator?In the recent past, we have used a multitude of chemical initiators for grafting vinyl monomers onto a number of natural and synthetic fibers.This paper presents the results of studies of graft copolymerization of MMA onto natural rubber using V5+ ion as the initiator. EXPERIMENTALCrepe natural rubber with ash content = 0.6% and acetone extract = 2.2% was obtained as a gift sample from Dr. S. K. De, IIT, Kharagpur.The purification of monomers, preparation of solution of V6+, and the method of rate measurements were discussed in our previous papers.10JlExtraction of the grafted product was carried out in benzene to remove the h e mopolymer completely.The percentage of grafting and percent efficiency were calculated according to our previous procedure.