1. Polymethyl methacrylate contains a polar side methyl group, has a relatively obvious hygroscopicity, water absorption rate is generally 0.3% -0.4%, before molding must be acrylic sheet
Must be dried, drying conditions are 80 °C -85 °C drying 4-5h. The
2. Polymethyl methacrylate has significant non-Newtonian fluid properties in the molding processing temperature range, the melt viscosity decreases significantly with increasing shear rate, and the melt viscosity is also sensitive to temperature changes. Therefore, for the polymethyl methacrylate molding process, increasing the molding pressure and temperature can significantly reduce the melt viscosity and achieve better fluidity. The
3. The temperature at which polymethyl methacrylate starts to flow is about 160°C, the temperature at which decomposition starts is higher than 270°C, and there is a wider processing temperature range. The
4. The polymethyl methacrylate melt has a high viscosity, and the cooling rate is faster. The products are prone to internal stress. Therefore, strict control over the process conditions is required during molding, and post-processing is also required after the molding of the product. The
5. Polymethyl methacrylate is an amorphous polymer, shrinkage and its range of changes are small, generally about 0.5% -0.8%, is conducive to molding a high dimensional accuracy of plastic parts. The
6. The polymethyl methacrylate has a very good cutting performance, and its profiles can be easily machined to various required sizes.