Acrylic is also called acrylic or acrylic, English abbreviation PMMA, with high transparency, low price, easy machining and other advantages, is the usual glass replacement material often used, its chemical name is poly methyl methacrylate.
Polymethyl methacrylate has good comprehensive mechanical properties, ranking first in general-purpose plastics. Its tensile strength, bending strength, and compression strength are all higher than those of polyolefins, and it is also higher than that of polystyrene, polyvinyl chloride, etc., and its impact toughness is poor. However, it is slightly better than polystyrene. The cast bulk polymerized polymethyl methacrylate sheet has higher mechanical properties such as drawing, bending, and compression, and can reach the level of engineering plastics such as polyamide and polycarbonate.
The strength of poly(methyl methacrylate) is related to the stress acting time, and the strength decreases as the action time increases. The mechanical properties of polymethyl methacrylate (orientated plexiglass) after stretching orientation are significantly improved, and the notch sensitivity is also improved.
The heat resistance of polymethyl methacrylate is not high. Although its glass transition temperature is 104°C, the maximum continuous use temperature varies from 65°C to 95°C depending on the operating conditions. The heat distortion temperature is about 96°C. °C (1.18 MPa), Vicat softening point about 113 °C. The heat resistance can be improved by copolymerizing the monomer with propylene methacrylate or ethylene glycol diacylate. The polymethyl methacrylate also has poor cold resistance, and the embrittlement temperature is about 9.2°C. The thermal stability of polymethyl methacrylate is medium, superior to polyvinyl chloride and polyoxymethylene, but less than polyolefins and polystyrene, the thermal decomposition temperature is slightly higher than 270°C, and the flow temperature is about 160°C. There is a wide range of melt processing temperatures.
The thermal conductivity and specific heat capacity of polymethyl methacrylate are all intermediate levels in plastics, 0.19 W/CM.K and 1464 J/Kg.K, respectively.
Chemical resistance and solvent resistance
Polymethyl methacrylate is resistant to dilute inorganic acids, but strong inorganic acids can attack it, but it is resistant to alkalis, but it can be etched by warm sodium hydroxide and potassium hydroxide, and it can be salt-tolerant. And oils and fats, aliphatic hydrocarbons, insoluble in water, methanol, glycerol, etc., but can absorb alcohol swelling, and stress cracking, intolerance ketones, chlorinated hydrocarbons and aromatics. Its solubility parameter is approximately 18.8 (J/CM3)1/2. It can be dissolved in many chlorinated hydrocarbons and aromatics such as dichloroethane, trichloroethylene, chloroform, toluene, etc. Vinyl acetate and acetone can also make it Dissolved.