Polymethyl methacrylate (polymethyl methacrylate, commonly known as PMMA), known as acrylic, plexiglass, English Acrylic, Taiwan, China is called pressure, and Hong Kong is mostly called agaric glue, with high clarity, money , It is convenient for machining and manufacturing, etc. It is a glass that is often used instead of raw materials.
advantage:
The relative density is lower than that of laminated glass:
The density of PMMA is about 1.15-1.19 g/cm3, which is half of glass (2.40-2.80 g/cm3) and 43% of metal aluminum (belonging to light metal).
High impact toughness:
The molecular mass of PMMA is about 2 million. It is a long-chain polymer, and the chain forming the molecular structure is very soft. Therefore, PMMA has a relatively high strength, and its tensile and impact resistance are relatively high. General glass is 7 to 18 times higher. There is a kind of plexiglass that has been heated and stretched, in which the molecular chain segments are very orderly, which greatly improves the elasticity of the material. Use steel nails to nail this kind of plexiglass, even if the steel nails penetrate, it will not cause cracks. This kind of plexiglass is also not easy to break into pieces after being thermally penetrated by a rifle bullet. Therefore, the PMMA processed by Lashen can be used for explosion-proof glass and canopy on aircraft.
PMMA has a lower melting point:
The melting point of PMMA is about 130–140°C (265–285°F), which is much lower than the high temperature of laminated glass, which is about 1000°C.
Taiwan Chimei has higher light transmittance
Invisible light: PMMA is the most transparent polymer material at present, with a light transmittance of 92%, which is higher than that of glass.
Ultraviolet rays: Calcite can penetrate ultraviolet light, but it is expensive, and ordinary glass can only penetrate 0.6% of ultraviolet light. PMMA can effectively filter out ultraviolet light with a wavelength below 300nm, but the filtering effect between 300nm and 400nm is weak. Some manufacturers coat a thin film on the surface of PMMA to improve its effect and performance of filtering out 300nm to 400nm ultraviolet rays. On the other hand, in the case of direct ultraviolet rays, compared with polycarbonate, PMMA has better reliability
Infrared Sensing: PMMA allows infrared sensing (IR) based on light wavelengths below 2800nm. Most of IR wavelengths of light can be blocked below 25,000nm. The existing colored plate PMMA can allow special light wavelength IR to pass through, while blocking invisible light (used in remote operation or thermal induction, etc.).
The laminated glass transition temperature of PMMA is about 105°C.
Material physical properties:
Due to its large branched chain, the viscosity of polymethyl methacrylate is relatively high, so the processing speed is relatively slow when heat treatment is used. The plexiglass plate can not only be drilled with a CNC lathe, but also can be drilled with a planer, and can be used toluene , chloroform, etc., can be bonded into various shapes, and can also be processed into various handicrafts such as large canopy canopies, small dentures and dental trays by injection molding, injection, extrusion and other plastic forming methods. Cyanoacrylates, dichloromethane, or chloroform, etc. can slightly melt the plexiglass plates, and then firmly bond the two plexiglass plates together. To produce 1KG of PMMA, about 2KG of crude oil is required. Under the condition of aerobic exercise, PMMA begins to ignite at 458 ℃, and after igniting, it turns into carbon dioxide, water, carbon monoxide and some low-molecular substances including formaldehyde.