Liquid crystalline polymer
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Liquid crystalline polymerGenerally polymers of high m.p. temperature suffer during molding process, due to heat disorder effect and are very difficult to process. On the contrary some polymers have tendency to alien their chains parallel over long distance in the direction of the flow of the melt during melting, there chain arrange without entanglement prior to the flow of their melt or solution are known as liquid crystal polymer.
E.g. Kevlar.
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Properties:
- They are very tough.
- Their fibers have very high tensile strength, Tm & Tg.
- They have high crystallinity in solid state.
- Behave as “self-reinforced plastics”.
Applications:
- T.V. screen, Optical fibers making, electronics & telecomm.
Transportation, automotive, military, aerospace
conducting polymer ----- 4
- The polymer those have conjugation through out the chain, arc found to have measurable conductivities:- polypyrrole, polyaniline, polythiopene.
- Conductivity can be increased by P-doping or N-doping. P-doping is carried out by oxidizing agents such as-I2, Br2 etc. & n-doping is carried out by reducing agent such as-Na, K etc.
Application: - 3
- Electrode Rechargeable batteries.
- It is used for coating films, corrosion resistance, and printed circuit board.
- In oxidation -reduction reaction.
- Sensors: In the gas separation. For pH, O2, NO2, SO2.
- Optical fiber: radiation from computer screen & also used in smart windows.
- In electronics: photodiodes, light emitting wall papers, data storage.
applications of rubber
- Tyres: Rubber possesses viscoelastic property, therefore used in manufacturing of tyres.
- Electrical industry: due to the remarkable resistance to electricity, hard rubber is largely used in electrical industry as insulating coating for wires, in making switch board, plug, socket, electrical gloves...etc.
- Articles: Due to elasticity, toughness, strength it is used for making tubes for bicycle, automobile. & airplanes, golf balls, mechanical rubber goods.
- Mounting: Rubber possesses high load bearing capacity & resilience. Thus it is used for mounting. Mounting is the section of the rubber sandwiched between two metal plates. That reduces the machine vibration & improves quietness of the machine equipments.
- Rubber lined tanks: due to the good chemical resistivity, it is used for making rubber lined tanks.
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