Rheological and morphological properties of thermal‐aged poly(phenylene sulfide) resin

This paper discusses the morphological properties of thermal‐aged poly(phenylene sulfide) (PPS) resin by Fourier‐transform infrared spectroscopy (FT‐IR) and solid‐state 13 C‐NMR. Also included is a method of applying the dynamic melt viscoelastic properties to determine the molecular weight distribution of the PPS resin. For virgin PPS resin, two resonance peaks were detected by NMR magic angle spinning (MAS) and cross polarization (CP) studies. However, four additional peaks can be seen for heat‐treated PPS resin, indicating that the aromatic ring in PPS resin was attacked by sulfur‐containing species or by the aryl ether group. The two most important reactions are crosslinking and chain extension. However, the chain extension is predominant when PPS is heated in nitrogen. The results coincide with the phenomenon observed in FT‐IR studies. The molecular weight distribution of thermal‐aged PPS resin was determined from dynamic melt viscoelasticity data. Results show that the longer the preheated time the broader the molecular weight distribution. It indicates that crosslinking and chain‐extension reaction may have occurred when PPS resin was heated in air.