Polyethylene glycol, one of the chemical components in Polyether block amide serves what purpose?
Polyether block amide Polyether block amide or PEBA is a thermoplastic elastomer (TPE). It is known under the tradename of VESTAMID® E (Evonik Industries), and PEBAX (Arkema). It is a block copolymer obtained by polycondensation of a carboxylic acid polyamide (PA6, PA11, PA12) with an alcohol termination polyether (Polytetramethylene glycol PTMG), PEG). The general chemical structure is:
Perfluoroalkoxy alkane Perfluoroalkoxy alkanes or PFA are fluoropolymers. They are copolymers of tetrafluoroethylene (CF) and perfluoroethers (CFOR, where R is a perfluorinated group such as trifluoromethyl (CF)). In terms of their properties, these polymers are similar to polytetrafluoroethylene (PTFE). The big difference is that the alkoxy substituents allow the polymer to be melt-processed. On a molecular level, PFA has a smaller chain length, and higher chain entanglement than other fluoropolymers. It also contains an oxygen atom at the branches. This results in a material that is more translucent and has improved flow, creep resistance, and thermal stability close to or exceeding PTFE. Similarly advantaged processing properties are found in fluorinated ethylene propylene (FEP), the copolymer of tetrafluoroethylene and hexafluoropropylene.