Originally Posted by
choddo
not sure I’d call ptfe a plastic. Those are mostly carbon and hydrogen based polymers and ptfe is carbon and flourine. Whether that makes it more or less of an environmental hazard I wouldn’t like to bet, but I’m reluctant to put it or the earlier mentioned MoS2 on my chain. Don’t really want to put graphite or graphene on there (partly as the latter is damn expensive) but might have to as phase 2 of this wax experiment.
Yup. Polytetrafluoroethylene is a polymer which is what “plastics” are. Right there in the name. It can be molded and reshaped. PTFE isn’t an environmental hazard but the precursors and some forms of flurocarbons are environmental hazards. Once made into the plastic PTFE, there’s not much that will break the polymer down as it is a very inert material. You can heat it over 250°C and it will fall apart but that’s cooking it pretty hard.
A “plastic”, by the way, is any of a very wide range of materials made from organic chemicals that can be molded and shaped. They fall into two fairly broad classifications of thermoplastics and thermoset plastics. Thermoplastics can be melted and reformed endlessly…plastic drink bottles, plastic film, the coating on cable housings, handlebar tape (perhaps), etc.
Thermoset plastics can be molded but once they are molded, they can’t be reformed. Tires are thermosets. The material used to make disc pads is thermoset plastic…specifically a phenol/formaldehyde resin which many people know as “bakelite”. Epoxies used as the matrix for carbon fiber is thermoset plastic. None of the thermosets are amenable to recycling because they can’t be melted and reformed. They also tend to cross link and keep on cross linking for as long as the material lasts. “Dry rot” on tires is due to the rubber cross linking with age and become less elastic and more brittle. It’s even worse because as you apply heat to process the material, it cross links more.