Poly(styrene-ran-cinnamic acid) (SCA), an approach to modified polystyrene with enhanced impact toughness, heat resistance and melt strength

Abstract

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.

Zn‐salt poly(styrene–ran–cinnamic acid) ionomer as a polystyrene with improved impact toughness, heat resistance, and minimally compromised processability

“…Materials: ZnO (AR, ≥99.0%) was provided by Shanghai Aladdin Biochemical Technology Co., Ltd. Potassium bromide (working chemical, ≥99.9%) was obtained from Aladdin Industrial Corp. A commercial PS resin (injection grade, GPPS 666D) was purchased from Sinopec Yanshan Petrochemical Co. SCA was synthesized by our laboratory via the emulsion radical copolymerization of styrene and cinnamic acid. 34 Table 3 shows the molecular weights and their distributions for different batches of synthesized SCA. Compared to commercial PS, the molecular weight and molecular weight distribution of the product resin did not deviate significantly between synthetic batches, indicating that the polymerization process was highly reproducible.…”

“…To minimize any uncertainty in the results, the arithmetic T A B L E 3 Molecular weights and their distributions derived from six parallel polymerization batches of poly(styrene-rancinnamic acid) (SCA), that is, polystyrene (PS) copolymerized with a small amount (10 wt.%) of cinnamic acid, compared with those of a commercial PS Source: Reproduced with permission. 34 Copyright 2019, the Royal Society of Chemistry.…”

“…Finally, the absorption spectra were acquired at a resolution of 4 cm À1 based on 24 scans using an FTIR spectrometer (Bruker, Source: Reproduced with permission. 34 Copyright 2019, the Royal Society of Chemistry.…”

“…Reproduced with permission. 34 Copyright 2019, The Royal Society of Chemistry [Color figure can be viewed at wileyonlinelibrary.com] TensorII, Billerica, MA, USA) in transmission mode under N 2 atmosphere. Mechanical testing: The fully dried PS and SCA samples were plasticized in a plasticorder (Harbin Harp Electrical Technology Co., Ltd., RM-200C, China) at 200 C and 80 rpm for 6 min.…”

“…In previous work by our team, a poly(styrene-ran-cinnamic acid) (SCA) with a comparable molecular weight to commercial PS was synthesized via the random copolymerization of styrene monomer with a small amount of cinnamic acid monomer in an emulsion free-radical polymerization process. 34 We conducted the first systematic characterization of SCA and found that introducing reversible hydrogen bond cross-links between molecular chains improved all the properties of commercial PS. In particular, the impact strength was improved by 47.2%.…”