In situ copolymerization and compatibilization of polyester and polystyrene blends. I. Synthesis of functionalized polystyrenes and the reactions with polyester

The in situ compatibilization process between polystyrene (PS) and polybuty lene terephthalate (pBT) is carried out by adding three types of hydroxy fu nctionalized polystyrenes (PS-Fs). The PS-F was used to promote the in situ copolymerization reaction and compatibilization during melt blending in th e mixer. The results of different characterization techniques including Fou rier transform infrared (FTIR), GPC and the differential scanning calorimet ry (DSC) demonstrate that the slow alcoholysis reaction between the PS-F an d PET took place after the 60 min thermal treatment. In order to achieve go od mechanical properties of the reactive blends of PS-F and PET, it is impo rtant to control the level of degradation of PET. On the other hand, the op timum degradation is necessary to promote the in situ reaction to the PS-F. In this paper titanium butoxide (TNBT) and triphenyl phosphite (TPP) were used in order to control the reaction and degradation. The addition of 1% T NBT into the blends of PS-F/PBT enhances the miscibility of the PS-F and PE T as a catalyst for the alcoholysis reaction. It is found that the stabiliz er TPP not only prevents the excess thermal degradation of PET but also pro motes the reaction between the PS-Fs and PET by coupling reaction. The anio nic polymerization procedure of three different PS-Fs and the characterizat ion results of the reaction between PS-Fs and PET are described. (C) 2001 E lsevier Science Ltd. All rights reserved.