The synthesis and characterization of poly(methylene terephthalate)

Abstract

AbstractPoly(methylene terephthalate) (1GT) has been synthesized via the reaction of cesium or potassium terephthalates with dibromomethane or bromochloromethane in N‐methylpyrrolidone at temperatures of 80–125°C. The polymerization was relatively slower with the latter substrate, though the potassium salt was found to be equally as efficient as its cesium counterpart with dibromomethane. The polymer is insoluble in all common polyester solvents, and its high molecular weight nature (DPn ≥ 25) was inferred from elemental analyses and its fiber forming capacity. Thermal analyses indicated that 1GT possesses poor thermal stability and decomposes rapidly during melting, the initial process being thought to be the splitting out of formaldehyde. 1GT polymers were shown to contain a homologous series of cyclic oligomers (from dimer to decamer); the two most predominant were tentatively identified as the cyclic trimer and tetramer. No change in the cyclization efficiency was observed when the potassium counterion was substituted for cesium with Br CH2 Br whereas a drastic reduction in the cyclic content was obtained using Br CH2 Cl (with Cs+). The two most important features of the polymerization are the insensitivity of the reaction to the stoichiometric equivalence of the reactants and the production of reasonably high molecular weights at low conversions. It is suspected that the polymerization might be occurring through an interfacial mechanism.