INFLUENCE OF ZnSt2 ON STRUCTURE OF ACRYLATE-BASED IONOMERS WITH DIFFERENT LANTHANIDE (La(Ⅲ)) ION AND ACID CONTENTS

A series of acrylate processing aid (ACR)-based ionomers with different lanthanide (La(Ⅲ)) ion and acid contents were synthesized, and the interaction between ionomer and zinc stearate (ZnSt2) was investigated immediately after thermally annealing the ionomer/ZnSt2 (3/1 in weight) mixtures at 180℃. The results revealed that the ion groups in ionomer have a strong interaction with ZnSt2. The annealed mixtures contained hot alcohol extractable and unextractable ZnSt2. The melting of ZnSt2 and the thermal behavior of the ionomer in the annealed mixtures were seriously influenced by the contents of La(Ⅲ) and acid in the ionomers. The ionomer containing 0.25 mmol/g acid and 0.37 mmol/g La(Ⅲ) has a detectable cluster phase. Annealing its ZnSt2 mixture could break down the cluster phase and lower glass transition temperature of the ionomer matrix. However, washing away the extractable ZnSt2 led to the reappearance of the cluster transition temperature and return of the glass transition temperature of matrix to the original position.