EFFECTS OF POLYMER STRUCTURE ON GAS BARRIER OF ETHYLENE VINYL ALCOHOL (EVOH) AND CONSIDERATIONS FOR PACKAGE DEVELOPMENT

摘要

This paper is a focused review of the effects that polymer structure, including crystalline structure and degree of crystallinity have on the gas barrier properties of EVOH (ethylene vinyl alcohol resins). The practical effect that different processing techniques such as cast film and blown film have on the degree of crystallinity is examined. The influence that the resulting degree of crystallinity has on EVOH's sensitivity to moisture and oxygen barrier properties is described. A practical method of making initial determination of the barrier thickness required for a given packaging application and shelf life is explained.