Novel Route to Blends of Polystyrene and Poly(2,6-Dimethyl-1,4-Phenylene Ether):Synthesis, Properties, and Applications

摘要

A method for preparing the chemical blend Polystyrene (PS)/Poly(2,6-dimethyl-1,4-Phenylene Ether) (PPE) is described. For the preparation of polymer beads via a free radical initiated suspension polymerization, PPE has to be endcapped in order to avoid the inhibiting effect on the styrene polymerization. A 'cold' endcapping method, to modify PPE under mild conditions in styrene without further purification and isolation of PPE, is presented. Related modification reactions of PPE using various end groups, which can be used for purposes such as (block) copolymerization, are described. Several low polar mass model compounds were synthesized to gain a better understanding of the inhibiting effect from the terminal 2,6-xylenol group of PPE. The phase behavior of the miscible PS/PPE blend was studied as a function of pressure. Compression or injection molding of the blend results in a two phase and multiple phase separated blend respectively. As a consequence of the phase separation phenomenon under pressure, conventional processing of PS/PPE-Ac blends is not feasible. The application of the system for preparing high Tg PS foams is described.