The Determination of “Head-Head” and “Tail-Tail” Structures in Poly(Isoprene)S

Abstract

Abstract Pyrolysis-gas chromatography has indicated the presence of head-head structures in free radical initiated poly(isoprene)s. Microozonolysis has confirmed the presence of both head-head (15-20 per cent) and tail-tail (4-7 per cent) structures in these polymers. These structures (which are absent in natural rubber) are present in lesser amounts in Lithium and Ziegler poly(isoprene)s (1-3 per cent). Non-equivalent amounts of head-head and tail-tail structures in particular samples indicate a chain reversal in which neither head nor tail units are involved. It has been postulated that chain reversal may occur at points of 3,4 addition.