I. Mechanical properties
Polymethyl methacrylate (PMMA) has good comprehensive mechanical properties. It is in the forefront of general plastics. Its tensile, bending and compressive strength are higher than that of polyolefin, polystyrene and polyvinyl chloride. Its impact toughness is poor, but it is also slightly better than that of polystyrene. The mechanical properties of poured bulk polymethyl methacrylate (PMMA) sheets, such as aeronautical PMMA sheets, are higher in tension, bending and compression, which can reach the level of engineering plastics such as polyamide and polycarbonate.
II. Electrical Performance
Polymethyl methacrylate (PMMA) has less electrical properties than non-polar plastics such as polyolefin and polystyrene due to its polar methyl ester group at the side of the main chain. The polarity of methyl ester group is not too large, and polymethyl methacrylate still has good dielectric and electrical insulation properties. It is worth pointing out that polymethyl methacrylate (PMMA) and acrylic plastics as a whole have excellent arc resistance. Under the action of arc, there will be no carbonized conductive path and arc track on the surface. The temperature of 20 is a second-order transition temperature, which corresponds to the temperature at which the side methyl ester group begins to move. The side methyl ester group is frozen below 20 and the electrical properties of the material are improved when the side methyl ester group is above 20 C.
3. Solvent Resistance
1. Polymethyl methacrylate can withstand dilute inorganic acid, but strong inorganic acid can make it erode and alkali-resistant, but warm sodium hydroxide and potassium hydroxide can make it erode, salt-resistant and oil-resistant, fat-resistant hydrocarbons, insoluble in water, methanol, glycerol and so on, but can absorb alcohol swelling, and produce stress cracking, not resistant to ketones, chlorinated hydrocarbons and aromatic hydrocarbons. Its solubility parameter is about 18.8 (J/CM3) 1/2. It can be dissolved in many chlorinated hydrocarbons and aromatics, such as dichloroethane, trichloroethylene, chloroform, toluene and so on. It can also be dissolved by ethylene acetate and acetone.
2. Polymethyl methacrylate has good resistance to ozone and sulfur dioxide.
Polymethyl methacrylate (PMMA) has excellent atmospheric aging resistance. After four years of natural aging test, the tensile strength and transmittance of the samples decrease slightly, the color yellows slightly, the anti-craze property decreases obviously, the impact strength increases slightly, and other physical properties almost remain unchanged.