polibutiléntereftalát

Polibutiléntereftalát, known in English as polybutylene terephthalate (PBT), is a semi-crystalline thermoplastic polyester produced by polycondensation of terephthalic acid (or dimethyl terephthalate) with 1,4-butanediol. It combines mechanical strength and stiffness with good toughness, and it offers high dimensional stability and excellent electrical insulating properties.

PBT has a melting temperature around 223–235°C and a glass transition temperature near 40°C. It can be processed by injection molding, extrusion, blow molding, and other standard thermoplastic methods. In reinforced form, such as glass-fiber reinforced grades, its stiffness and heat resistance are further improved. PBT can also be blended with other polymers or elastomers to tailor properties like impact resistance.

The polymer exhibits good chemical resistance to many hydrocarbons and oils, and it generally shows good resistance to wear and low friction in moving parts. Its moisture uptake is relatively low for an engineering polymer, though humidity can influence dimensional stability at elevated temperatures. PBT is less resistant to strong bases and to prolonged exposure to high temperatures in moist environments.

Applications of polibutiléntereftalát include automotive components (interior and exterior parts), electrical and electronic housings and connectors, gears, fasteners, and various consumer electronics housings. It is widely used in engineering plastics formulations and as a base resin for blends and composites.

Recycling options include mechanical recycling and chemical recycling approaches such as glycolysis to reclaim monomers. Overall, PBT offers a favorable balance of processability, mechanical performance, and electrical properties for a broad range of engineering applications.