Process characteristics of acrylic

Acrylic, also known as PMMA or plexiglass, comes from English acrylic (acrylic plastic), and its chemical name is polymethylmethacrylate.

Process characteristics of acrylic (polymethylmethacrylate)

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

2. Polymethylmethacrylate 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 polymethylmethacrylate, increasing the molding pressure and temperature can significantly reduce the melt viscosity and obtain better fluidity.

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

4. Polymethylmethacrylate melt has high viscosity and fast cooling rate, and the product is easy to produce internal stress. Therefore, the process conditions are strictly controlled during molding, and the product also needs post-treatment after molding.

5. Polymethylmethacrylate is an amorphous polymer with small shrinkage and its variation range, generally about 0.5% - 0.8%, which is conducive to forming plastic parts with high dimensional accuracy.

6. Polymethylmethacrylate has good cutting performance, and its profile can be easily machined into various required sizes.