PP Fabric
2017-06-28 17:03:46
Polypropylene, a synthetic resin built up by the polymerization of propylene. One of the important family of polyolefin resins, polypropylene is molded or extruded into many plastic products in which toughness, flexibility, light weight, and heat resistance are required. It is also spun into fibres for employment in industrial and household textiles. Propylene can also be polymerized with ethylene to produce an elastic ethylene-propylene copolymer.
Propylene is a gaseous compound obtained by the thermal cracking of ethane, propane, butane, and the naphtha fraction of petroleum. Like ethylene, it belongs to the “lower olefins,” a class of hydrocarbons whose molecules contain a single pair of carbon atoms linked by a double bond. The chemical structure of the propylene molecule is CH2=CHCH3. Under the action of polymerization catalysts, however, the double bond can be broken and thousands of propylene molecules linked together to form a chainlike polymer (a large, multiple-unit molecule).
Essentially, the molecule consists of a backbone of carbon atoms with attached hydrogen atoms; attached to every other carbon atom is a pendant methyl group (CH3). The methyl groups can adopt a number of tacticities, or spatial arrangements in relation to the carbon chain, but in practice only the isotactic form (i.e., with the methyl groups arranged along the same side of the chain) is marketed in significant quantities.