Acrylic Plastic Parts from Transparent Clear

acrylic acid and its esters polymerization of polymers obtained collectively referred to as acrylic esters, the corresponding plastics collectively referred to as polyacrylic acid plastics, of which methyl methacrylate is the most widely used. Polymethyl methacrylate abbreviation code for PMMA, commonly known as Plexiglas, is by far the most excellent texture in the synthetic transparent materials, the price is more suitable for the varieties.

Performance of PMMA

Poly(methyl methacrylate) is a rigid, hard, colorless and transparent material, with a density of 1.18-1.19g/CM3, a small refractive index of about 1.49, and a light transmission rate of 92%, with a haze of no more than 2%, which is a high-quality organic transparent material.

1. Mechanical properties of PMMA

Poly(methyl methacrylate) has good overall mechanical properties, in the forefront of general-purpose plastics, tensile, bending, compression and other strengths are higher than polyolefins, but also higher than Polystyrene, polyvinyl chloride, etc., the impact toughness is poorer, but also slightly better than polystyrene. Cast the body of the polymerization of polymerized polymethyl methacrylate sheet (such as aviation with plexiglass sheet) tensile, bending, compression and other mechanical properties of some higher, can reach the level of polyamide, polycarbonate and other engineering plastics.

Generally speaking, the tensile strength of polymethyl methacrylate can reach the level of 50-77MPa, bending strength can reach 90-130MPa, the upper limit of these performance data has reached or even exceeded some engineering plastics. Its elongation at break is only 2%-3%, so the mechanical properties of the characteristics of the plastic is basically hard and brittle, and notch sensitivity, easy to crack under stress, but the fracture fracture is not like polystyrene and ordinary inorganic glass as sharp jagged. 40 ℃ is a secondary transition temperature, equivalent to the side of the methyl group began to move the temperature, more than 40 ℃, the material's toughness, ductility has been improved. The surface hardness of polymethylmethacrylate is low, making it susceptible to abrasion.

The strength of poly(methyl methacrylate) is related to the time of stress application, and the strength decreases as the time of application increases. The mechanical properties of polymethylmethacrylate (oriented plexiglass) after tensile orientation are significantly improved, and notch sensitivity is also improved. The heat resistance of polymethyl methacrylate is not high, although its glass transition temperature reaches 104 ℃, but the maximum continuous use temperature is changed with different working conditions between 65 ℃ -95 ℃, the heat distortion temperature of about 96 ℃ (1.18MPa), Vicat softening point of about 113 ℃. Heat resistance can be improved by copolymerizing the monomer with propylene methacrylate or bis(ester)glycol acrylate. The cold resistance of polymethyl methacrylate is also poor, with a brittleness temperature of about 9.2°C. The temperature of polymethyl methacrylate is also poor. Thermal stability of poly(methyl methacrylate) belongs to the medium, better than polyvinyl chloride and polyformaldehyde, but not as good as polyolefins and polystyrene, thermal decomposition temperature is slightly higher than 270 ° C, the flow temperature of about 160 ° C, so there is still a wide range of melt processing temperature. Thermal conductivity and specific heat capacity of poly(methyl methacrylate) belong to the middle level in plastics, respectively 0.19W/CM.K and 1464J/Kg.K. 2.

2. Electrical properties of PMMA

The electrical properties of poly(methyl methacrylate) are not as good as those of non-polar plastics such as polyolefins and polystyrene due to the presence of a polar methyl ester group in the side position of the main chain. The polarity of the methyl ester group is not too large, and poly(methyl methacrylate) still has good dielectric and electrical insulation properties. It is worth pointing out that polymethyl methacrylate and even the entire acrylic plastics, have excellent arc resistance, under the action of the arc, the surface will not produce carbonized conductive pathway and arc trail phenomenon. 20 ℃ is a secondary transition temperature, corresponding to the side of the methyl ester group began to move the temperature, below 20 ℃, the side of the methyl ester group in the freezing state, the material's electrical properties than in the 20 ℃ or more will be improved. The electrical properties of PMMA will be improved when the material is above 20℃.

3. PMMA's chemical and solvent resistance

Poly(methyl methacrylate) is resistant to dilute inorganic acids, but concentrated inorganic acids can make it erode, alkali resistance, but warm sodium hydroxide, potassium hydroxide can make it corrode, resistant to salts and fats, resistant to aliphatic hydrocarbons, insoluble in water, methanol, glycerol, etc., but can absorb alcohols dissolved, and stress cracking, intolerance of ketones, chlorinated hydrocarbons and aromatic hydrocarbons. Its solubility parameter is about 18.8(J/CM3)1/2 , and it can be dissolved in many chlorinated hydrocarbons and aromatic hydrocarbons, such as ethylene dichloride, trichloroethylene, chloroform, toluene and so on, and ethylene vinyl acetate and acetone can also make it dissolved. Poly(methyl methacrylate) has good resistance to gases such as ozone and sulfur dioxide.

4. Weather resistance of PMMA

Poly(methyl methacrylate) has excellent resistance to atmospheric aging, its specimens after 4 years of natural aging test, weight change, tensile strength, light transmission rate slightly decreased, color slightly yellowish, silver grain resistance decreased more obviously, impact strength also slightly improved, other physical properties are almost unchanged.

5. PMMA flammability

Poly(methyl methacrylate) is easy to burn, limited oxygen index of only 17.3.

The application of polymethyl methacrylate PMMA

As a transparent material with excellent performance, polymethyl methacrylate is widely used in the following aspects:

1. Lamps, lighting equipment, such as a variety of household lamps, fluorescent lampshades, automobile taillights, signal lamps, road signs.

2. Optical glass, such as the manufacture of a variety of lenses, mirrors, prisms, television screens, Fresnel lenses, camera lens zero.

3. Preparation of a variety of instruments and meters dial, cover, dial.

4. Preparation of optical fiber.

5. Commodity advertising windows, billboards.

6. Aircraft cockpit glass, aircraft and automobile bulletproof glass (with intermediate laminated materials).

7. All kinds of medical, military, architectural glass.

8. In the field of microfluidic chip, it is used to process microfluidic chip made of PMMA.