Material properties
This type of material has excellent heat resistance and molding processability. The polymerization method is mainly melt polycondensation, and fully aromatic LCP is often supplemented by solid-phase polycondensation to produce high molecular weight products. Non-fully aromatic LCP plastic raw materials are often produced by one- or two-step melt polymerization. In recent years, the technology of continuous melt polycondensation to produce high molecular weight LCP has been developed. Liquid crystalline aromatic polyester has an unusually regular fibrous structure due to its oriented macromolecular chains in the liquid crystal state. It has special properties and the strength of its products is very high, no less than that of metals and ceramics. The tensile strength and flexural modulus can exceed various thermoplastic engineering plastics developed over the past 10 years. It has good mechanical properties, dimensional stability, optical properties, electrical properties, chemical resistance, flame retardancy, processability, good heat resistance and low thermal expansion coefficient. Depending on the monomers used, the performance, processability and price of the liquid crystal polyester produced are also different. Different fillers selected and different amounts of fillers added also affect its performance.
A: Liquid crystals can be divided into lyotropic liquid crystal polymers and thermotropic liquid crystal polymers. The former is in a liquid crystal state in a solvent, and the latter is in a liquid crystal state due to temperature changes. B: The molecular main chain of liquid crystal polymer molecules is rigid, the molecules are closely packed together, and are highly oriented during the molding process. Therefore, they have a small linear expansion coefficient, low molding shrinkage, very outstanding strength and elastic modulus, and excellent heat resistance. They have a high load deformation temperature, some of which can be as high as 340°C or more. C: LCP has good weather resistance and radiation resistance, and has excellent flame retardancy, which can extinguish the flame without continuing to burn. Its combustion level reaches UL94V-0 level. LCP plastic raw material is one of the special plastics with the best fire safety. D: Generally, thermotropic liquid crystal polymers have good fluidity and are easy to process and shape. The molded product has a unique skin-core structure of liquid crystal polymer. The resin itself has fiber properties and is highly oriented in the molten state, so it can achieve fiber reinforcement. This is also the most eye-catching feature of liquid crystal polymers. E: Thermotropic liquid crystal polymer can also be made into polymer blend materials with a variety of plastics. In these blend materials, the liquid crystal polymer acts as a glass fiber reinforcement, which can greatly improve the strength, rigidity and heat resistance of the material. F: The density of LCP plastic raw materials is 1.4~1.7g/cm3. Liquid crystal polymers have high strength and high modulus mechanical properties, and are self-reinforcing due to their structural characteristics. Therefore, unreinforced liquid crystal plastics can reach or even exceed the level of mechanical strength and modulus of ordinary engineering plastics reinforced with dozens of percent glass fibers; if reinforced with glass fibers, carbon fibers, etc., it far exceeds other engineering plastics. G: LCP liquid crystal polymer also has excellent thermal stability, heat resistance and chemical resistance. The creep shortcomings of most plastics are negligible for liquid crystal materials, and it has excellent wear resistance and wear reduction properties. H: LCP plastic raw materials have excellent electrical insulation properties. Its dielectric strength is higher than that of general engineering plastics, and its arc resistance is good. As an electrical application product, its electrical properties are not affected when the continuous use temperature is 200~300°C. The intermittent use temperature can reach about 316°C. I: LCP plastic raw materials have outstanding corrosion resistance. LCP products will not be corroded in the presence of acid with a concentration of 90% and alkali with a concentration of 50%. Industrial solvents, fuel oil, detergents and hot water will not be dissolved after contact, and will not cause stress cracking.
