Über polystyrole mit p‐ständigen vinyl‐ und isopropenylgruppen

Abstract

ZUSAMMENFASSUNG:Es wird iiber die Herstellung von Polystyrolen mit freien, p-standigen Vinylgruppen durch Abspaltung von HBr aus Styrollp-(P-Bromathy1)-styrol-Copolymeren berichtet. Durch Copolymerisation solcher Polymerisate mit Styrol lassen sich losliche Pfropfcopolymere oder auch vernetzte Formkorper erhalten; von letzteren werden einige mechanische Eigenschaften mitgeteilt.In Styrol /p-(a-Hydroxy-isoprop y1)-styrol-Copolymere (Copolymerisationsparameter bei 50°C: rl (Styrol) = 0,50 f 0,05; r2 = 0,56 j , 0,05) lassen sich durch WasserabspaltungIsopropenylgruppen einfiihren. SUMMARY:The pwparatimof polystyrene with free vinyl groups in p-position is described by splitting off of HBr from styrenelp-(P-bromoethy1)-styrene-copolymers. By copolymerisation of such polymers with styrene soluble graft copolymers or crosslinked products can be obtained. Some mechanical properties of the latter are reported.I n styrene/p-(a-hydroxy-isopropyl)styrene-copolymers (reetivity ratios at 50 "C. : rl (styrene) = 0.50 j , 0.05; r2 = 0.56rt 0.05) isopropenyl groups can be introduced by dehydratisation.

Cross-linking of polystyrene by Friedel–Crafts chemistry to improve thermal stability

“…The reactivity ratios for the alcohol are not available but those for styrene and the alcohol with an extra methyl group at the benzylic carbon, 1-(p-vinylphenyl)ethanol (r1=0.480 and r2=0.410) [6] are known and they predict a composition quite close to that found for the two copolymers which contain the smallest amount of the alcohol.…”

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

“…In all cases the copolymers were found to contain more of the alcohol than expected from the feed ratio. Reactivity ratios are available for the combination of 2-(4-vinylphenyl)-1-propanol with styrene and they are: r1=0.480 and r2=0.410 [10] . These reactivity ratios predict a composition similar to that obtained.…”