Liquid Natural Rubber: Preparation and Application

Abstract

Liquid natural rubber (LNR) is a modified form of natural rubber (NR) with a shorter polymeric chain. The preparation of LNR can either be done via mechano-oxidation or redox reaction or photosensitized oxidation. Mechanooxidation, being the earliest method to be developed, is still widely used with some modifications. Pilot plant scale has already been tested on two redox reaction methods using phenylhydrazine-air and sodium nitrite/chlorite - hydrogen peroxide as oxydo-reducing couples. Photosensitized oxidation of NR is made possible by using a photosensitizer which is active in visible light and able to induce degradative oxidation. Research in the field is quite active but so far no method has developed into a commercial scale. The short nature of the LNR polymeric chain allows many chemical modifications possible and thereby enlarging the field of applications of NR. The potential applications of LNR are in the preparation of thermoplastic NR, adhesives, binders, bitumen, low hardness vulcanizates, paints and varnishes.