Friedel–crafts crosslinking methods for polystyrene modification. IV. Macromolecular structure of crosslinked particles

Abstract

Crosslinked polystyrene particles were prepared by Friedel–Crafts suspension crosslinking of polystyrene using 2,4‐dichloromethyl‐2,5‐dimethyl benzene as crosslinking agent. The polymer was dissolved in nitrobenzene and reaction occurred in a 70 wt % aqueous solution of ZnCl2 with poly(vinyl alcohol) as a suspending agent. The spherical particles produced were swollen in toluene, chloroform, and tetrahydrofuran to determine their equilbrium polystyrene volume fraction. Analysis of the crosslinked macromolecular structure gave values of number‐average molecular weight between crosslinks of M̄c = 900–5900 increasing as the nominal crosslinking ratio X decreased from 0.75 to 0.0625 mol of crosslinking agent per mole of polystyrene repeating unit. Porosimetric analysis contributed to the understanding of the importance of the pore structure for swelling behavior.

Microgels based on isotactic poly(styrene): Synthesis and characterization

“…An emulsion with water could not form due to sensitivity of the catalyst to water. Friedel–Crafts alkylation is optimal for functionalizing phenyl groups and was thus selected for cross‐linking the i PS chains . Prior to utilization in emulsion the process was tested for applicability with isotactic oligostyrene, poly(styrene), and poly(diphenyl‐ethylstyrene) (poly(DPES)) (see Chapter S‐III ).…”

“…Friedel-Crafts alkylation is optimal for functionalizing phenyl groups and was thus selected for cross-linking the iPS chains. [16][17][18][19] Prior to utilization in emulsion the process was tested for applicability with isotactic oligostyrene, poly(styrene), and poly(diphenylethylstyrene) (poly(DPES)) (see Chapter S-III). These investigations showed that both poly(styrene) and poly(DPES) can be chemically cross-linked by Friedel-Crafts alkylation.…”

“…In this work highly isotactic poly(styrene) is accessible by coordinate polymerization, and subsequently cross‐linked by Friedel–Crafts alkylation. This method circumvents the contradicting requirements for reaction conditions described above, and has already been successfully applied to atactic poly(styrene) . If the precursor polymer is synthesized with an enantiomerically pure complex, the resulting polymer chain is cryptochiral .…”

“…This method circumvents the contradicting requirements for reaction conditions described above, and has already been successfully applied to atactic poly(styrene). [16][17][18][19] If the precursor polymer is synthesized with an enantiomerically pure complex, the resulting polymer chain is cryptochiral. 20 If the chirality can be retained after crosslinking, the microgel could serve as chirality inducing agent for asymmetric reactions.…”

Anionic living polymerization of useful monomers that can provide intermolecular chemical links

“…A crosslinked polymer is insoluble in methanol but swells with methanol by the suppression of elasticity due to network structures. In the swelling equilibrium state, the following modified Flory-Rehner's equation is valid [38,39],…”