I. Basic Information

1. Chemical formula: (C?H?O?)n.

2. English name: Polymethyl Methacrylate, abbreviated as PMMA. It is also known as Poly (methyl 2 - methylpropenoate), Poly (methyl methacrylate), etc.

3. Density: Usually between 1.19 - 1.22g/cm3.

4. Molecular weight: Between 500,000 - 1,000,000.

5. Glass transition temperature: Up to 104℃.

II. Performance Characteristics

1. Physical properties: It is transparent in appearance and has a smooth surface, similar to some characteristics of inorganic glass. It is soluble in organic solvents such as dichloroethane, chloroform, and acetone, but insoluble in ethanol, diethyl ether, or petroleum ether, etc.

2. Chemical properties: It can resist relatively dilute inorganic acids, but concentrated inorganic acids can corrode it; it has good alkali resistance, but hot and humid sodium hydroxide and potassium hydroxide can corrode it; it can resist salts, oils, and aliphatic hydrocarbons. It can absorb alcohols, swell, and cause stress cracking. It is not resistant to ketones, chlorinated hydrocarbons, and aromatic hydrocarbons; it has good resistance to ozone and sulfur dioxide; its oxygen index is 17.3. It is a flammable plastic that cannot self-extinguish after the ignition source is removed. The flame is light blue, and it emits an odor similar to rotten fruits and vegetables when burning.

3. Optical properties: It is a highly transparent amorphous thermoplastic. Its light transmittance can reach 90%-92%, which is higher than that of glass. Its refractive index is 1.49, and its haze is no more than 2%. It can transmit most ultraviolet and infrared rays.

4. Mechanical properties: Its tensile strength is 55 - 77MPa, its flexural strength is 110MPa, and its elongation at break is 2.5%-6%. It is a hard and brittle plastic and is notch-sensitive, and it is prone to cracking under stress; 40℃ is a secondary transition temperature. When the temperature exceeds 40℃, the toughness and ductility of the material are improved; it has room-temperature creep characteristics. With the increase of load and time, stress cracking may occur; its surface hardness is low, it is easy to be scratched, and its wear resistance is poor, and its ability to resist silver streaks is also poor.

5. Electrical properties: Its main chain side position contains polar methyl ester groups. Its electrical properties are inferior to those of non-polar plastics such as polyolefins and polystyrene. However, it still has good dielectric and electrical insulation properties and good arc resistance. Under the action of an arc, there will be no carbonized arc trace phenomenon on the surface.

III. Synthesis and Processing

1. Synthesis method: Using methyl methacrylate as the raw material, the polymerization reaction is carried out through the free radical polymerization mechanism. The initiation methods include light, heat, or initiators, and industrial production can be carried out by methods such as bulk polymerization, emulsion polymerization, and suspension polymerization.

2. Processing technology: It must be dried before molding. The drying conditions are drying at 80 - 100℃ for 4 - 6 hours. It can be processed by processes such as casting, injection molding, and thermoforming.

IV. Material Classification

1. Colored transparent organic glass: The light transmission is soft. According to different transparencies, it can be divided into three types: fully transparent, semi-transparent, and opaque.

2. Pearlescent organic glass: It is made by adding pearlescent powder or fluorescent powder to ordinary organic glass. It has bright colors and a smooth surface, and is suitable for making human and animal shapes, trademarks, decorations, etc.

3. Embossed organic glass: It has transparent and semi-transparent colorless types. It is brittle and easy to break, and is suitable for making specific decorative items.

4. Magnetic organic glass: Its gloss is not as bright as that of pearlescent organic glass. It is also brittle and easy to break, and is suitable for making watch dials, boxes, medical devices, and materials for making human and animal shapes.

V. Application Fields

1. Substitute for glass: It is used as bulletproof glass and window glass in aerospace equipment, airplanes, automobiles, ships, etc., and is also applied to instrument parts, signal display lamp covers, etc.

2. Construction field: It is used for indoor and outdoor lighting and non-illuminated signal display, ceiling lighting equipment, high-grade decorations, furniture, partition materials, etc., and can also be applied to building lighting bodies, transparent roofs, canopies, etc.

3. Optical instruments: It is an ideal material for manufacturing various optical lenses, including glasses, magnifying glasses, lenses, etc., and can also be used to make information transmission materials such as optical discs and optical fibers.

4. Medical devices: It is widely used in plastic surgery for manufacturing artificial limbs, false noses, artificial eyes, teeth and dentures, medical light guide tubes, artificial corneas, etc., and is also used as a transparent protective cover for infant incubators.

5. Artwork field: It can replace traditional glass for picture frames to avoid glare problems. It is also suitable for making imitation amber handicrafts, glass ornaments, etc., and can also be used as a protective cover for precious collections.

6. Other fields: It is widely used in sanitary ware, such as bathtubs, wash basins, vanities, etc.; PMMA copolymers can also be used in fiber, leather treatment agents, plastic and rubber adhesives, etc.