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:
Polychlorinated biphenyl A polychlorinated biphenyl (PCB) is an organic chlorine compound with the formula CHCl. Polychlorinated biphenyls were once widely deployed as dielectric and coolant fluids in electrical apparatus, carbonless copy paper and in heat transfer fluids. Because of their longevity, PCBs are still widely in use, even though their manufacture has declined drastically since the 1960s, when a host of problems were identified. Because of PCBs' environmental toxicity and classification as a persistent organic pollutant, PCB production was banned by the United States Congress in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001. The International Agency for Research on Cancer (IARC), rendered PCBs as definite carcinogens in humans. According to the U.S. Environmental Protection Agency (EPA), PCBs cause cancer in animals and are probable human carcinogens. Many rivers and buildings including schools, parks, and other sites are contaminated with PCBs, and there have been contaminations of food supplies with the substances.