Introduction to PC Polycarbonate
Introduction
Polycarbonate (PC for short) is a polymer containing carbonate groups in the molecular chain, which can be divided into aliphatic, aromatic, aliphatic-aromatic and other types according to the structure of the ester group. Among them, the mechanical properties of aliphatic and aliphatic-aromatic polycarbonates are low, thus limiting their application in engineering plastics.
Only aromatic polycarbonates have been industrially produced. Due to its structural peculiarities, polycarbonate has become the fastest growing general engineering plastic among the five major engineering plastics.
Chemical Properties
Polycarbonate (PC) is a polyester class of carbonic acid, carbonic acid itself is not stable, but its derivatives (such as phosgene, urea, carbonate, carbonate) have a certain stability.
According to the different structure of the alcohol, polycarbonate can be divided into two categories of aliphatic and aromatic.
Aliphatic polycarbonate. Such as polyethylene carbonate, polytrimethylene carbonate and its copolymers, low melting point and glass transition temperature, poor strength, can not be used as a structural material; but the use of its biocompatibility and biodegradable properties, can be in the slow-release carriers for drugs, surgical sutures, bone support materials and so on to obtain applications.
Polycarbonate is resistant to weak acids, weak bases and neutral oils.
Polycarbonate is not resistant to UV light and strong alkali.
PC is a linear carbonate polyester with carbonate groups in the molecule alternating with other groups that can be aromatic, aliphatic, or both. Bisphenol A-based PC is the most important industrial product.
PC is an almost colorless glassy amorphous polymer with good optical properties. pc high molecular weight resin has high toughness, cantilever beam notched impact strength of 600~900J/m, unfilled grades of heat distortion temperature of about 130 ℃, glass fiber reinforced can make this value increased by 10 ℃. pc's flexural modulus of up to 2400MPa or more, the resin can be processed into large Rigidity products. Below 100 ℃, the creep rate under load is very low. pc hydrolysis resistance is poor, can not be used to repeat the products subjected to high pressure steam.
The main performance defects of PC are insufficient hydrolytic stability, sensitive to chipping, resistance to organic chemicals, poor scratch resistance, long-term exposure to ultraviolet light will be yellowing. Like other resins, PC is susceptible to the erosion of certain organic solvents.
PC materials are flame retardant and oxidation resistant.
Physical Properties
Density: 1.18-1.22 g/cm³ Linear Expansion: 3.8×10-5 cm/°C Heat Deflection Temperature: 135°C Low Temperature -45°C
Polycarbonate colorless transparent, heat-resistant, impact resistance, flame retardant BI level, in the ordinary use of temperature have good mechanical properties. Compared with the performance close to polymethyl methacrylate, polycarbonate has good impact resistance, high refractive index, good processing performance, and UL94 V-2 grade flame retardant performance without additives. However, polymethylmethacrylate is less expensive than polycarbonate, and large devices can be produced by propriety polymerization.
The wear resistance of the material is relative, to compare ABS material with PC material, it is PC material wear resistance is better. However, compared to most plastic materials, the wear resistance of polycarbonate is relatively poor, in the lower level, so some polycarbonate devices for easy to wear the use of the surface needs to be specially treated.
Classification
Anti-static PC, conductive PC, fiber reinforced fireproof PC, UV weather resistant PC, food grade PC, chemical resistant PC.
Main advantages
1. Mechanical properties: high strength, fatigue resistance, dimensional stability, creep is also small (high-temperature conditions also rarely change);
2. Heat aging resistance: enhanced UL temperature index of 120 ~ 140 ℃ (outdoor long-term aging is also very good);
3. Solvent resistance: no stress cracking;
4. Stability to water: easy to decompose in the presence of water at high temperatures (use caution in high temperature and high humidity environments);
5. Insulation properties: excellent (humidity, high temperature can also maintain the stability of electrical properties, is the manufacture of electronic and electrical parts of the ideal material);
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