Stabilization of polystyrene by Friedel-Crafts chemistry: effect of position of alcohol and the catalyst

Abstract

Polystyrene has been copolymerized with 4-vinylbenzyl alcohol, 4-(2-hydroxyethyl)styrene, and 4-(3-hydroxypropyl)styrene and it has been shown that thermal cross-linking of these copolymers is dependent upon the alcohol content. When the alcohol content is low, no thermal cross-linking is observed. When various phosphate esters are present as catalysts with these low alcohol content copolymers, cross-linking is observed at temperatures of about 250°C but not at lower temperatures. Cross-linking enhances the thermal stability of the copolymers. Studies of the thermal stability of the copolymers and their blends with the catalysts have been performed using thermogravimetric analysis and thermogravimetric analysis coupled to Fourier transform infrared spectroscopy. There is little difference in the thermal stability of all three copolymers and their blends with the catalysts.

Enhancement of char formation of polymer nanocomposites using a catalyst

“…Thermal insulation provided by the char further decreases heat release rate (though not necessarily total heat release). Lewis acids [13,14] or FriedelCrafts alkylation and reagents [15][16][17] were previously used as catalysts to enhance char formation, primarily in polystyrene (PS). Enhanced char formation of acrylonitrile-butadiene-styrene (ABS) [18] and acrylonitrile-styrene (SAN) [19] using such transition metal chlorides was also reported using thermal gravimetric analysis (TGA).…”

Cross-linking of polystyrene by Friedel–Crafts chemistry: reaction of p-hydroxymethylbenzyl chloride with polystyrene

“…by copolymerization, which subsequently form a cross-linked product through the Friedel-Crafts alkylation reaction and ultimately lead to the formation of char, is an effective way to stabilize polystyrene. [6][7][8][9] We have previously reported on the study of multi-functional additives which could cross-link polystyrene at controllable temperature. 10 p-Hydroxymethylbenzyl chloride was found to be an effective cross-linking agent of polystyrene, and combined with appropriate amount of catalyst precursor and inhibitor, the crosslinking temperature was in the desired range of above the processing temperature and below the degradation temperature.…”

XPS characterization of Friedel-Crafts cross-linked polystyrene

“…A rather facile reaction occurs but only in a sealed tube, when the reaction is conducted under flowing conditions, the alkylating agent volatilized before it could react. This problem was solved through the use of a copolymer of styrene with vinylbenzyl alcohol [6], [7] . In this system, the alcohol functionality acts as the alkylating agent and releases water, a benign product of the reaction.…”