Polyester Elastomers:
1. Multi-block copolymers with formula (-A-B-)n
2. Related structurally to polyurethane and polyamide elastomers.
3. Hard segments composed of tetramethylene terephthalate units.
4. Soft segments composed of aliphatic polyether or polyester glycols.
General properties:
1. The copolyesters are prepared by transesterification of dimethyl terephthalate polytetramethylene ether glycol (PTMEG) and 1,4-butanediol
( -O - (CH2)4 -OOC- C6H5 - CO-)
2. Resilience, high resistance to deformation, outstanding flex resistance, good abrasion resistance,
3. Good retention of properties at low and elevated temperatures
4. High modulus, good elongation and tear strength resistant to non-oxidizing acids, some aliphatic hydrocarbons, aromatic fuels, grease, alkaline solutions, hydraulic fluids and hot oils.
5. Weathering resistance is low, but can be improved by additives.
1. Polyester elastomers are generally tougher over a broader temperature range than the urethanes
2. Can be processed by injection , extrusion, rotational and blow molding and casting process
Applications:
Applications of copolyester elastomers include hydraulic hose, fire hose, power transmission belts, flexible couplings, diaphram, gears, protective boots, seals, oil field parts, sports shoe soles, wire and cable insulation, fiber optic jacketing, electrical connectors, fastner knobs and bushings.
No comments:
Post a Comment