What is Pmma material?
What is PMMA material? What is PMMA material performance? What is PMMA?
PMMA commonly known as 'plexiglass', with excellent optical properties and weather resistance characteristics. White light penetration of up to 92%. PMMA products have very low birefringence, especially suitable for making DVDs and so on.
PMMA has room temperature creep characteristics. As the load increases, the time increases, can lead to stress cracking phenomenon. PMMA has good impact resistance.
Injection molding process conditions
Drying: PMMA has hygroscopicity and therefore the drying process before processing is necessary. Recommended drying conditions for 90C, 2 to 4 hours.
Melting temperature: 240 ~ 270C.
Mold temperature: 35 ~ 70C.
Injection speed: medium
Typical use
Automobile industry (signal light equipment, instrument panel, etc.), pharmaceutical industry (storage containers, etc.), industrial applications (DVD, light diffuser), consumer goods (beverage cups, stationery, etc.).
The above information for the investigation. For the brown, do not know if it is the result of adding toner and the like, and think that it is the most direct supplier of the company's suppliers, and it is the most realistic way for future production.
Poly (methyl methacrylate) (PMMA) colorless transparent glass, specific gravity 1.19, the surface hardness is low, easy to scratch hard objects. Hard to fire, but can slowly burn, after the fire can continue to burn, burning fragile, melt dripping, bright flame, the bottom of the blue, the top white, issued a strong flower fruit and rotten vegetable odor.
1. Transparency: PMMA is an amorphous polymer, the arrangement of its internal molecules will not interfere with the light into its various parts of the passage of time, which can make the light at the same speed forward (ie, uniform refractive index) Will not make the light scattered around the interference. So PMMA has excellent optical properties, a high degree of light transmittance (90 ~ 92%, and wavelength).
The surface of a very smooth sheet or bar, in the bend to a certain extent can also be injected from the end of all the light reflected in its internal forward, and finally from the other end of the injection, as if the water in the pipe through the same (certain Curvature refers to the position after bending and the original position of the angle, can not exceed 42 °; curved curved, the arc radius must be greater than the rod diameter or sheet thickness of 3 times). But when the surface of a part of the sanding, the light can escape from here and show the light. This feature can be used to fabricate edge light emitting devices, surgical medical devices, and the like.
2. Mechanical properties: PMMA mechanical strength than ordinary glass more than 10 times higher, but compared with other plastic strength can only be considered moderate. Its shortcomings are light and brittle, easy to crack (or appear brown), the surface hardness is low, easy to scratch and lose luster; wear resistance is poor, the static friction coefficient between each other is 0.8, the dynamic friction coefficient of steel is 0.45 ~ 0.50, so easy to scratch the sanding.
3. Electrical properties: PMMA's electrical properties are good, especially at low frequency operating conditions. However, some of its electrical properties are unique: the dielectric loss tangent decreases with increasing frequency. Temperature and frequency have an effect on the dielectric constant, while the climate and humidity have little effect on electrical properties. But the electrical performance than PE, PS and so poor.
4. Thermal performance: PMMA heat resistance is not good enough, the use of temperature is only 80 ℃. Can be crosslinked by its monomer with ethylene glycol diacrylate or methacrylic acid propylene ester to improve the heat resistance. The specific heat of PMMA is lower than most thermoplastics, which is conducive to rapid thermal plasticization. In addition it also has a certain cold resistance, in the low temperature -50 ~ -60 ℃, the impact strength change is very small.
5. Chemical properties; PMMA has a certain resistance to chemical corrosion, but with the temperature weakened. Strong resistance to chemical corrosion of gas, long-term and ozone, sulfur dioxide contact, no corrosion; chlorine can corrosion its surface. Can be dissolved in ethyl acetate or butyl ester, glacial acetic acid, chloroform and benzene; can absorb a variety of alcohol organic compounds, so that the volume of expansion, rough surface rough hair, but insoluble in aliphatic compounds.
6. Weatherability: with excellent weather resistance, exposure to tropical climate in many years of transparency and color changes rarely.
