Thermal degradation fluoropolymers

A major environmental and health issue is currently the toxicity of PFOA and its salts used in the polymerization process and in processing of the majority of fluoropolymers [27,28] and issues involving the use of PTFE coating on cookware and its thermal degradation [29-32]. More on this subject is in Appendix 1. 

Baker, B.B. Kasprzak, D.J. Thermal degradation of commercial fluoropolymer in air. Polym. Degrad. Stabil. 1994, 42, 181-188. 

Emulsifier Removal by Other Methods One approach to reduce the emulsifier content of fluoropolymer dispersions is based on the thermal degradation of the emulsifiers at sufficiently high temperatures [43]. To avoid adverse effects for the dispersion, a nonionic stabilizer is added. The stabilized dispersion is heated... 

Fluoropolymers of the kind used as polymer processing additives (PPAs) are quite impervious to chemical attack and thermal degradation. They are of low surface energy, and are generally incompatible with other pol)nners. 

Another consideration in raising the mold temperature is the longevity of the mold itself It has been dem-onstratedl" that operating the mold at extreme temperatures, even in the absence of thermal degradation of the plastic, affect the mold life and maintenance costs detrimentally. The balance of cycle time reduction and cost increase is unfavorable, especially for resins such as fluoropolymers that require high temperatures. 

Fluoropolymers are among the most inert materials, yet they are capable of producing corrosive byproducts because of thermal degradation. These plastics have very high melting temperatures. Decomposition temperatures of fluoropolymers are not signifi-... 

This section presents information and data related to thermal stability of resins and basic properties as a function of temperature. Thermal stability of fluoropolymers has special importance because of the high processing temperatures required by these thermoplastics and the toxic and corrosive nature of their degradation products. Fluoroplastics have useful properties at temperature extremes above and below ambient conditions. 

Fluoropolymers are, generally, very stable at or below their specified maximum use temperatures. The rate of degradation of these plastics at higher temperatures is a function of their chemical stmc-tures in addition to temperature, time at temperature, and, to some extent, on the pressure and the atmosphere of decomposition. In actual processing, degradation is tracked by indirect measurement of molecular weight. Thermal exposure leads to a reduction in the molecular weight, which can be quantified by an increase in the MFR, heat of fusion of polymer, and in specific controlled measurements. 

Fluoropolymers are among the most versatile plastics thanks to their properties. Thermal stability is a major feature of these polymers spurring their application where high temperature exposures are encountered. Fluoropolymers can produce toxic products if they are overheated. Precautions should be taken to remove any degradation fragments produced during the processing and fabrication of parts from fluoropolymers. 

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