A poly(styrene-ran-cinnamic acid) (SCA) containing 6.8 mol% of CA, with a M w ($217 000) comparable to commercial polystyrene (PS), was successfully synthesised via emulsion free-radical copolymerisation as evidenced by 1744 and 1703 cm À1 infrared peak occurrences, respectively characteristic of free and dimeric carboxyl C]O stretches. Upon the interchain hydrogen bond cross-linking by CA, the impact toughness of the SCA was considerably improved by 47.2% against PS, the glass transition, heat deflection and Vicat softening temperatures were significantly enhanced until 117.0, 108.0 and 118.3 C, respectively, compared with PS (95.2, 87.6 and 96.0 C), while the extensional viscosities were near one order-of-magnitude higher than PS by which the temperature window required for appropriate meltstrengths would be greatly broadened. Meanwhile, the SCA displayed other properties basically analogous to PS. This work presents a modified PS, SCA, with enhanced toughness, heat resistance and melt strength that potentially extend its styrofoam and commodity applications.

To enhance the compatibility of poly(ethylene terephthalate) (PET)/liquid crystalline polymer (LCP) composite, thereby mechanically strengthening the PET matrix, an optimally compatibilized composite of chain-extended and-carboxylated PET ionomer and poly(4-hydroxybenzoic acid-ran-6-hydroxy-2-naphthoic acid) (HBA-HNA) was successfully prepared. Upon PET carboxylated chain extension with pyromellitic dianhydride and subsequent ionization with Zn(OH) 2 , the compatibility of the composite was distinctly improved, as verified by the refined dispersed-phase morphology, increased number of refined HBA-HNA fibrils, reduced crystallinity, and improved complex viscosity. Compared with PET, the optimally compatibilized composite displayed a 70.1 and 148.7% increase in Young's modulus and tensile strength, respectively. Tentatively mechanistically, the interfacial interaction may change from weak hydrogen bonding to strong ion-dipole interactions due to the introduction of ionic groups, which remarkably boosts the interfacial compatibility, thereby achieving synergistic effects of the ionization and HBA-HNA inclusion to maximally strengthen PET. It seems that the synergistic ionization/LCP inclusion by a one-pot method establishes a promising preparation approach to commercial PET engineering resins.

No abstract

A polymer-supported Pd0 nanocatalyst is prepared by using mechanochemical reduction as the driving force for the reaction.

A half-critical weight-average molecular weight ( M ¯ w ) (approximately 21,000 g mol−1), high-ion-content Zn-salt poly(styrene–ran–cinnamic-acid) (SCA–Zn) ionomer was successfully synthesized by styrene–cinnamic-acid (10.8 mol %) copolymerization followed by excess-ZnO melt neutralization. At 220 °C, the SCA–Zn’s viscosity was only approximately 1.5 magnitude orders higher than that of commercial polystyrene (PS) at 102 s−1, and the PS/SCA–Zn (5–40 wt %) melt blends showed apparently fine, two-phased morphologies with blurred interfaces, of which the 95/5 and 90/10 demonstrated Han plots suggesting their near miscibility. These indicate that any PS–(SCA–Zn) processability mismatch was minimized by the SCA–Zn’s half-critical M ¯ w despite its dense ionic cross-links. Meanwhile, the SCA–Zn’s Vicat softening temperature (VST) was maximized by its cross-linking toward 153.1 °C, from that (97.7 °C) of PS, based on its half-critical M ¯ w at which the ultimate glass-transition temperature was approximated. Below approximately 110 °C, the PS/SCA–Zn (0–20 wt %) were seemingly miscible when their VST increased linearly yet slightly with the SCA–Zn fraction due to the dissolution of the SCA–Zn’s cross-links. Nevertheless, the 60/40 blend’s VST significantly diverged positively from the linearity until 111.1 °C, revealing its phase-separated morphology that effectively enhanced the heat resistance by the highly cross-linked SCA–Zn. This work proposes a methodology of improving PS heat resistance by melt blending with its half-critical M ¯ w , high-ion-content ionomer.