Performance of the mechanical properties of plexiglass products
Plexiglass chemical called "poly (methyl methacrylate)" it has good mechanical properties to the forefront in the general-purpose plastics, stretching, bending, compression strength were higher than polyolefin, and also higher than the polystyrene, polyvinyl chloride etc., impact toughness is poor, but also slightly better than polystyrene. The poured bulk polymerization higher polymethyl methacrylate sheet (e.g. aeronautical plexiglass plate) tensile, bending, compression, and other mechanical properties, can reach the level of engineering plastics such as polyamides, polycarbonates.
Generally, the tensile strength of the poly (methyl methacrylate) can reach the level of 50-77MPa, flexural strength of 90-130MPa, and the upper limit of the performance data has been reached or even exceeded certain engineering plastics. Elongation at break was only 2% -3%, so the mechanical performance characteristics substantially belong to the hard and brittle plastic, and having a notch sensitivity, easy to crack under stress, but the fracture fracture unlike polystyrene and ordinary inorganic glass as sharp and uneven. 40 ℃ is a second order transition temperature, equivalent to the temperature of the methyl side starts moving, more than 40 ° C, the toughness of the material, the ductility improvement. Poly (methyl methacrylate) is a low surface hardness and easily scratched.
Plexiglass (polymethyl methacrylate), the strength and stress time, with increasing duration of action, the intensity decreased. By the stretch orientation after the poly (methyl methacrylate) (orientation PMMA) has significantly improved mechanical properties, notch sensitivity is also improved.
Plexiglass (polymethyl methacrylate), the heat resistance is not high, although its glass transition temperature of up to 104 ℃, maximum continuous use temperature is between 65 ° C to -95 ° C, but with the different working conditions change, thermal deformation a temperature of about 96 ° C (1.18MPa), the Vicat softening point of about 113 ° C. Yl acrylate monomer and methyl acrylate, propylene or diesters of ethylene glycol acetate copolymer The method of improving the heat resistance. Poly (methyl methacrylate) in cold resistance is also poor, the embrittlement temperature of about 9.2 ° C. The thermal stability of poly (methyl methacrylate) is moderate, better than PVC and polyoxymethylene, but less than a polyolefin and polystyrene, the thermal decomposition temperature slightly higher than 270 ° C, the flow temperature of about 160 ° C, therefore still there are a wide melt-processing temperature range.
Plexiglass products of thermal conductivity and specific heat capacity of the plastic belonged to the middle level, respectively 0.19W/CM.K and 1464J/Kg.K