Low-Molecular Fluoropolymers: Structure and Thermal Properties

Abstract

The main representatives of low-molecular-weight fluoropolymers obtained by the thermogasdynamicmethod of polytetrafluoroethylene (PTFE) pyrolysis, radiation polymerization of tetrafluoroethylene(TFE) in various solvents, and direct fluorination of low-molecular-weight paraffins are characterized. Thefeatures of the morphology, structure, molecular chain length, and thermal properties of the polymersobtained by various methods are shown. During repeated heat treatment of low-molecular weight fluoropolymers(heating to a temperature when the process of weight loss ends), regardless of the method of obtainingthe polymer, new more dispersed low-molecular-weight fluoropolymers are formed, which may not differfrom the original ones (fluoroparaffins) or differ in a number of characteristics (telomers, UPTFE (PTFEconverted into low-molecular ultrafine powder) fractions). A new low-molecular-weight product is formedduring the pyrolytic processing of high-molecular-weight copolymers of ethylene with TFE. The product isa low-molecular-weight form of ETFE, differing from the original objects in morphology, molecular chainlength, and thermal properties.