Acrylic process characteristics

1. Polymethyl methacrylate contains polar side methyl groups and has obvious hygroscopicity. The water absorption rate is generally 0.3%-0.4%. It must be dried before molding. The drying conditions are 80℃-85℃ for 4-5h .

2. Polymethyl methacrylate has effective and obvious non-Newtonian fluid characteristics in the temperature range of molding processing. The melt viscosity will decrease significantly with the increase of shear rate, and the melt viscosity is also very sensitive to the change of temperature. Therefore, for the molding of polymethyl methacrylate, increasing the molding pressure and temperature can significantly reduce the melt viscosity and achieve better fluidity.

3. The temperature at which polymethyl methacrylate begins to flow is about 160°C, and the temperature at which it begins to decompose is higher than 270°C, with a wide processing temperature range.

4. Polymethyl methacrylate has a high melt viscosity and a fast cooling rate, and the product is prone to internal stress. Therefore, the process conditions are strictly controlled during molding, and post-processing is also required after the product is formed.

5. Polymethyl methacrylate is an amorphous polymer, the shrinkage rate and its variation range are small, generally about 0.5%-0.8%, which is conducive to molding plastic parts with high dimensional accuracy.

6. The cutting performance of polymethyl methacrylate is very good, and its profiles can be easily machined into various required sizes.

Processing technology

Polymethyl methacrylate can be cast, injection molded, extruded, thermoforming and other processes.