Polymerization by crystallization of molten trioxane suspended in inert media, in presence of ethylenoxide

Abstract

The method of polymerization of trioxane solutions during crystallization by cooling is extended to molten trioxane in presence of ethylenoxide, suspended in mineral oil (thickened with polyisobutylene) and activated with small quantities of BF,.Et,O, Operating with quantities of catalyst in the order of 4.0-10-5 moles/mole of trioxane, copolymers with prevailing polyoxymethylene structure are obtained, characterized by high mrjlecular weight (qlnb = 1.5 in 0.5 yo solution in p-chlorophenol at 60 "C;) and good thermal SI aldity (kzzo = 0.03y0/min.), with yields of 45 to 60%. ZUSAMMENFASSUNG: Die Methode, Trioxan, wihrend es aus einer abkiihlenden Losung auskristallisiwt, zu polymerisieren, wird auf die Copolymerisation von geschmolzenem Trioxan mit At hvlenoxid mit tels BF,-hherat in Suspension in mit Polyisobutylen verdicktem Mineraloi ubertragen. Mit ca. 4 Mol Initiator /Mol Trioxan entstehen Copolymere mit iiberwie; :r nder Polyoxymethylen-Struktur in 45 bis 60 Yo Ausbeute, welche sich durch hohe Molrhulargewichte (qinh = 1,s bei 60°C in OJ-proz. Losung inp-Chlorphenol) und durch hoha: thermische Stabilitat (Gewichtsverlust bei 220 "C unter Stickstoff = 0,03 yo /Min.) auszeii4inen. GerieralIn preceding papers 1* 2, a new method of polymerization was described, by which polyoxymethylene of high molecular weight with high yields could be obtained. It consisted essentially in preparing an almost saturated solution of trioxane in a suitable solvent at temperatures above room temperature, adding to it a small quantity of a cationic catalyst and after a certain period of time cooling the reaction mixture gradually.

Polymerization by crystallization of trioxane from cyclohexane solutions in presence of 1,3‐dioxolane

“…Crude copolymers I and I1 show different melting behaviors; while the melting point of copolymer I regularly decreases as D / T increases, that of copolymer I1 has a practically constant value, coincident with the fusion temperature of the homopolymer. A similar behavior was also previously noted in trioxaneethylene oxide copolymer prepared by the crystallization-polymerization method (15).…”