To explore the relationship between the properties of the PTFE micropowders and the irradiation conditions, several PTFE micropowders were prepared by electron beam irradiation from 5 to 4000 kGy in air at room temperature. The properties of the irradiated PTFEs were characterized by particle size and its distribution (PSD) determination, differential scanning calorimetric (DSC) and thermogravimetric (TG) analysis, melt flow rate (MFR) and contact angle (CA) measurements. The results indicate that the particle size, the melting and crystallization temperature (Tm and Tc) and the melt viscosity of the irradiated PTFE are lower (smaller) than those of the pristine PTFE. By linear regression, the correlation between Tm (or Tc) of the PTFE micropowder and irradiation dose is established. The variation of surface properties of the irradiated PTFE micropowder is also reported.

To increase the molecular weight of poly (phenylene sulfide ether) (PPSE), a novel route has been developed via the reduction of poly (phenylene sulfoxide ether sulfide ether) (PPSOESE) precursor. The synthesis of high molecular weight PPSOESE is essential for the ultimate purpose. Effects of process parameters on preparation of PPSOESE were firstly investigated and the optimization was performed by response surface methodology (RSM). Average number molecular weight (Mn) and Yield of PPSOESE were defined as the experimental responses. The statistical analyses indicate that the most significant factor is monomer concentration, followed by reaction temperature and the interaction of reaction temperature • monomer concentration. Under optimal conditions, the and Yield responses were obtained as 1.78 ×104±1.02 % and 93.6±1.3 %, which are in agreement with the predicted values of 1.80 ×104and 95.4 %, respectively. Structure of PPSOESE was also characterized. The highest intrinsic viscosity and yield of PPSE by the reduction of PPSOESE reached to 0.78 dL/g and 93.2%, respectively, much greater than the reported results. The work is helpful for forthcoming preparation and study of high molecular weight PPSE.