Polymethyl methacrylate is a popular name, abbreviated as PMMA. The chemical name of this polymer transparent material is polymethyl methacrylate, which is a polymer compound polymerized from methyl methacrylate. It is an important thermoplastic that was developed earlier. There are four types of organic glass: colorless transparent, colored transparent, pearlescent, and embossed organic glass. Plexiglas is commonly known as acrylic, Zhongxuan acrylic, and acrylic. Plexiglas has the advantages of good transparency, chemical stability, mechanical properties and weather resistance, easy dyeing, easy processing, and beautiful appearance. Plexiglass is also called gelatin glass, acrylic, etc. Basic introduction Chinese name: Organic glass Foreign name: methyl methacrylate Abbreviation: PMMA Chemical name: Polymethyl methacrylate Composition: Polymerization of methyl methacrylate Performance: Equal transparency, chemical stability History, principles, types, characteristics , electrical properties, physical properties, chemical properties, application, structure, use, machinery, medical, construction, difference, production method, construction method, main influence, history In 1927, a chemist from a German company between two glass plates When acrylate is heated, the acrylate polymerizes, creating a sticky, rubbery interlayer that can be used as shatterproof safety glass. When they used the same method to polymerize methyl methacrylate, they obtained a plexiglass plate with extremely good transparency and other good properties. It is polymethyl methacrylate. Application of plexiglass In 1931, the German company built a factory to produce polymethyl methacrylate, which was first used in the aircraft industry, replacing celluloid plastic and used as aircraft cockpit covers and windshields. If various dyes are added when producing organic glass, it can be polymerized into colored organic glass; if fluorescent agents (such as zinc sulfide) are added, fluorescent organic glass can be polymerized; if artificial pearl powder (such as basic carbonic acid) is added Lead), pearlescent organic glass can be produced. Principle: Organic glass, in English: (Polymethyl methacrylate), abbreviated as: PMMA; the chemical name of organic glass is polymethyl methacrylate, which is a polymer compound polymerized from methacrylate. It has a smooth surface, bright colors, small specific gravity, high strength, corrosion resistance, moisture resistance, sun resistance, good insulation performance and good sound insulation. It can be divided into three types: tube-shaped materials, rod-shaped materials and plate-shaped materials. The polymers obtained by polymerizing acrylic acid and its esters as raw materials are collectively called acrylic resins, and the corresponding plastics are collectively called polyacrylic plastics, among which polymethyl methacrylate is the most widely used. The abbreviation code of polymethyl methacrylate is PMMA, commonly known as plexiglass. It has good light transmittance and can transmit more than 92% of sunlight and 73.5% of ultraviolet rays. It has high mechanical strength, certain heat and cold resistance, and corrosion resistance. , good insulation properties, stable dimensions, easy to form, brittle texture, easily soluble in organic solvents, insufficient surface hardness, easy to rub, can be used for transparent structural parts that require a certain strength, such as oil cups, car lights, and instrument parts. Optical lenses, decorative gifts, etc. Adding some additives to it can improve its performance, such as heat resistance, friction resistance, etc. This material is widely used in the production of advertising light boxes, nameplates, etc. Types of plexiglass can be divided into four types according to their shapes: 1. Colorless and transparent plexiglass, the most common and widely used plexiglass material. 2. Colored transparent organic glass, commonly known as color plate. The light transmission is soft, and light boxes and handicrafts made of it make people feel comfortable and generous. There are three types of colored organic glass: transparent and colored, translucent and colored, and opaque and colored. The luster of magnetic plexiglass is not as bright as pearlescent plexiglass, and it is brittle and easy to break. It is suitable for making dials, boxes, medical equipment and modeling materials for people and animals. Transparent organic glass: high transparency, suitable for making lamps. The chandelier made of it is exquisite, crystal clear. Translucent plexiglass is similar to frosted glass, with soft reflection. Crafts made of it make people feel comfortable and generous. Chandelier 3. Pearlescent plexiglass is made by adding pearlescent powder or fluorescent powder to ordinary plexiglass. This type of plexiglass has bright color and high surface finish. After the outer form is hot-pressed by the mold, even if it is ground and polished, it still maintains the molded pattern, forming a unique artistic effect. It can be used to make figures, animal shapes, trademarks, decorations and promotional exhibition materials.

4. Embossed plexiglass is divided into transparent, translucent and colorless. It is brittle and easy to break. It is used in indoor doors and windows and other decorations. It has the characteristics of being light-transmitting but shape-proof. It is usually used for indoor partitions or separations between rooms. Doors and windows are used. Characteristics: Polymethylmethacrylate is often called organic glass, abbreviated as PMMA. It has the advantages of high transparency, low price, and easy machining. It is a commonly used glass substitute material. Plexiglas is an important thermoplastic that was developed earlier. It has transparency, stability and weather resistance, is easy to dye and process, and has a beautiful appearance. It is widely used in the construction industry. ①High transparency. Plexiglas is an excellent polymer transparent material with a light transmittance of 92%, which is higher than that of glass. The lamp tube of the sun lamp, which is called an artificial small sun, is made of quartz. This is because quartz can completely transmit ultraviolet rays. Ordinary glass can only transmit 0.6% of ultraviolet rays, but plexiglass can transmit 73%. Organic glass ②High mechanical strength. The relative molecular mass of plexiglass is about 2 million. It is a long-chain polymer compound, and the chains forming the molecules are very soft. Therefore, plexiglass has relatively high strength, and its tensile and impact resistance is 7-7 higher than that of ordinary glass. 18 times. There is a kind of organic glass that has been heated and stretched, in which the molecular segments are arranged in a very orderly manner, which significantly improves the toughness of the material. If a nail is driven into this kind of plexiglass, even if the nail penetrates, there will be no cracks in the plexiglass. This kind of plexiglass will not break into pieces after being penetrated by bullets. Therefore, stretched plexiglass can be used as bulletproof glass and can also be used as canopy on military aircraft. ③Light weight. The density of plexiglass is 1.18g/cm3; for a material of the same size, its weight is only half that of ordinary glass and 43% that of metallic aluminum (a light metal). ④Easy to process. Plexiglas can not only be cut with lathes and drilled with drills, but can also be bonded into various shapes with acetone, chloroform, etc., and can also be processed into shapes as large as airplanes using plastic molding methods such as blow molding, injection, and extrusion. Cockpit covers, products as small as dentures and dental trays. Advantages 1. The aesthetics of plexiglass: mirror effect, exquisite craftsmanship, no wrinkles, and no seams; 2. The visual effects of plexiglass: various colors and strong visual impact; 3. The light transmittance of plexiglass : The light transmittance can reach 96%, the light transmittance is excellent, and the light is relatively soft; 4. Impact resistance of organic glass: more than 200 times that of ordinary glass products, with almost no risk of breakage; 5. Durability of organic glass Resistance: The product has good protection for the built-in light source, extending the service life of the light source product; 6. Weather resistance of plexiglass: it can be maintained for a long time without fading, and the service life of good quality boards can be as long as 6-13 years; 7. The flame resistance of plexiglass: it will not spontaneously ignite and is self-extinguishing; 8. The energy saving of plexiglass: the light transmittance is very good, which relatively reduces the light source, saves electricity and reduces the cost of use; 9. The rationality of plexiglass: Reasonable design, rainproof and moisture-proof, open structure, convenient for cleaning and maintenance. Electrical properties: Because polymethyl methacrylate contains polar methyl ester groups on the side of the main chain, its electrical properties are inferior to non-polar plastics such as polyolefin and polystyrene. The polarity of the methyl ester group is not too great, and polymethylmethacrylate still has good dielectric and electrical insulation properties. It is worth pointing out that polymethyl methacrylate and even the entire acrylic plastic have excellent arc resistance. Under the action of arc, the surface will not produce carbonized conductive paths and arc tracks. 20°C is a secondary transition temperature, corresponding to the temperature at which the side methyl ester groups begin to move. Below 20°C, the side methyl ester groups are in a frozen state, and the electrical properties of the material will be improved compared to those above 20°C. Physical properties Polymethyl methacrylate has good comprehensive mechanical properties, ranking among the best among general plastics. Its tensile, bending, and compression strengths are higher than those of polyolefins, polystyrene, polyvinyl chloride, etc., and its impact toughness is relatively high. Worse, but slightly better than polystyrene. The mechanical properties of cast bulk polymerized polymethylmethacrylate sheets (such as organic glass sheets for aviation) are higher in terms of tensile, bending, and compression, and can reach the level of engineering plastics such as polyamide and polycarbonate. Generally speaking, the tensile strength of polymethyl methacrylate can reach 50-77MPa, and the flexural 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 its mechanical performance characteristics are basically hard and brittle plastic, and it has notch sensitivity and is easy to crack under stress. However, when it breaks, the fracture surface is not like polystyrene and ordinary inorganic glass. So sharp and jagged. 40°C is a secondary transition temperature, which is equivalent to the temperature at which the side methyl groups begin to move. Above 40°C, the toughness and ductility of the material are improved. Polymethyl methacrylate has a low surface hardness and is easily scratched. The strength of polymethylmethacrylate is related to the stress action time. As the action time increases, the strength decreases. The mechanical properties of polymethyl methacrylate (oriented organic glass) after stretch orientation are significantly improved, and the notch sensitivity is also improved. The heat resistance of polymethyl methacrylate is not high. Although its glass transition temperature reaches 104°C, its maximum continuous use temperature changes between 65°C and 95°C depending on the working conditions. The heat distortion temperature is about 96 ℃ (1.18MPa), Vicat softening point is about 113℃. The heat resistance can be improved by polymerizing the monomer with propylene methacrylate or diester glycol acrylate. Polymethyl methacrylate also has poor cold resistance, with a brittleness temperature of about 9.2°C. The thermal stability of polymethyl methacrylate is medium, better than polyvinyl chloride and polyformaldehyde, but not as good as polyolefin and polystyrene. The thermal decomposition temperature is slightly higher than 270°C, and its flow temperature is about 160°C, so it is still There is a wide melt processing temperature range. The thermal conductivity and specific heat capacity of polymethyl methacrylate are both at medium levels among plastics, which are 0.19W/M.K and 1464J/Kg.K respectively. Chemical properties: Polymethyl methacrylate can withstand relatively high resistance to chemical reagents and solvents. Dilute inorganic acid, but concentrated inorganic acid can cause it to corrode, it can resist alkali, but warm sodium hydroxide and potassium hydroxide can corrode it, it can resist salt and grease, and it can resist aliphatic hydrocarbons. It is insoluble in water, methanol, glycerol, etc., but can absorb alcohols to swell and cause stress cracking. It is not resistant to 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 dichloroethane, trichloroethylene, chloroform, toluene, etc. Vinyl acetate and acetone can also make it Dissolve. Polymethylmethacrylate has good resistance to gases such as ozone and sulfur dioxide. Weather-resistant polymethyl methacrylate has excellent atmospheric aging resistance. After 4 years of natural aging test, its weight changes, tensile strength, light transmittance slightly decreased, color slightly yellowed, silver streak resistance The decrease is obvious, the impact strength is slightly improved, and other physical properties are almost unchanged. Flammability Polymethyl methacrylate is easily flammable, with a limiting oxygen index of only 17.3. Application: Plexiglass is widely used, not only in commerce, light industry, construction, chemical industry, etc. Moreover, plexiglass production is widely used in advertising decoration and sand table models, such as: signs, billboards, light box panels and Chinese and English alphabet panels. The selection of organic glass materials depends on the shape design. What kind of shape, what kind of organic glass, color and variety should be tested repeatedly to achieve the best effect. Only with good shape design and careful processing can it become a beautiful handicraft. 1. Architectural applications: shop windows, soundproof doors and windows, lighting covers, phone booths, etc. 2. Advertising applications: light boxes, signboards, signs, display racks, etc. 3. Transportation applications: trains, cars and other vehicle doors and windows, etc. 4. Medical applications: baby incubators, Various surgical and medical equipment, civilian products: bathroom facilities, handicrafts, cosmetics, brackets, aquariums, etc. 5. Industrial application: instrument surface panels and protective covers, etc. 6. Lighting application: fluorescent lamps, chandeliers, street lampshades, etc. 7. Home application: fruit plate , tissue boxes, acrylic art paintings and other household daily products structure 1. Plexiglas is made of polymethyl methacrylate. Polymethyl methacrylate contains polar side methyl groups and has strong hygroscopic properties and average water absorption rate. The acrylic sheet must be kept dry. The required drying conditions are 5-6 hours at 78°C-80°C. 2. Plexiglas is an invisible polymer, and its shrinkage range is decreasing, generally between 0.45% and 0.9. Therefore, it provides good conditions for the molding accuracy during acrylic production. In general, molding It's all very precise. 3. The adaptability range of polymethyl methacrylate to the surrounding temperature does not have ordinary fluidity, but non-Newtonian fluidity. Therefore, when the temperature is high, the viscosity of organic glass will decrease. This is the reason why organic glass Very sensitive to temperature.

4. The temperature of plexiglass during the flow process is generally around 150°C, but when the plexiglass begins to decompose, the temperature is higher than 270°C, so it is still very flexible in terms of temperature changes and will not be affected by Produced under the influence of temperature, high temperature resistance is a characteristic of organic glass. 5. Plexiglas also has good cutting performance. It can be processed by laser cutting after measuring the size. It is simple and high-quality. This feature is not possessed by glass. Therefore, acrylic can withstand various high and low temperatures. Environment, consumers don’t have to worry about temperature issues during the production process. Purpose Mechanical Plexiglas has the above excellent properties, making it extremely versatile. In addition to being used as canopies and windshield *** windows on airplanes, they are also used as windshields and windows of jeeps, skylights of large buildings (which can prevent breakage), TV and radar screens, protective covers for instruments and equipment, and telecommunications instruments. casings, optical lenses on telescopes and cameras. There are many kinds of daily necessities made of plexiglass, such as buttons made of pearlescent plexiglass. Various toys and lamps are also particularly beautiful because of the decorative effect of colored plexiglass. Medical There is another wonderful use of plexiglass in medicine, which is to make artificial corneas. If the transparent cornea of ??the human eye is covered with opaque material, light cannot enter the eye. This is blindness caused by leukoplakia panformis, and it cannot be treated with medication. Therefore, medical scientists conceived the idea of ??using artificial cornea to replace the cornea covered with white spots. The so-called artificial cornea is to use a transparent material to make a mirror column with a diameter of only a few millimeters, then drill a small hole in the cornea of ??the human eye, fix the mirror column on the cornea, and let light enter the eye through the mirror column. Human eyes can see again. As early as 1771, some ophthalmologists used optical glass to make lens pillars and implanted them into the cornea, but they were not successful. Later, crystal was used instead of optical glass, but it failed after only half a year. In World War II, when some planes crashed, the canopy made of plexiglass on the plane was blown up, and plexiglass fragments were embedded in the pilot's eyes. After many years, although these fragments were not removed, they did not cause further inflammation or other adverse reactions in the human eye. This accidental incident shows that plexiglass has good compatibility with human tissue. It also inspired ophthalmologists to use plexiglass to make artificial corneas. It has good light transmittance, stable chemical properties, is non-toxic to the human body, can be easily processed into the desired shape, and is compatible with the human eye for a long time. Artificial corneas made of plexiglass have been commonly used clinically. Architecture In terms of architecture, plexiglass is mainly used in lighting bodies, roofs, ceilings, stairs and indoor wall panels. The application of plexiglass in lighting lampshades and automobile lamps on highways and high-end roads is also quite fast. With the construction of hotels, guesthouses and high-end residences in big cities, lighting bodies have developed rapidly. Lighting bodies made of extruded plexiglass panels have the characteristics of high overall structural strength, light weight, high light transmittance and good safety performance. Compared with inorganic glass lighting devices, it has great advantages. In terms of sanitary ware, plexiglass can be used to make bathtubs, wash basins, dressing tables and other products. Plexiglas bathtubs are widely used due to their luxurious appearance, depth, easy cleaning, high strength, light weight and comfortable use. The United States and Japan have made mandatory provisions in law that Chinese primary and kindergarten buildings must use plexiglass. As our country's laws continue to improve, it is expected that corresponding regulations will be made in the near future. At the same time, various parts of our country have accelerated the pace of urban construction, and street signs, advertising light boxes, and phone booths made of plexiglass will also appear in large numbers. Therefore, plexiglass has a lot of room for development and a very broad market prospect! Differences between plexiglass and ordinary glass. Plexiglass seems to be one family, but in fact they are two completely different families. The structure of ordinary glass is silicate, but the "parents" of plexiglass are acetone, methanol, sulfuric acid and hydrogen cyanide. Plexiglass is generally much more stubborn than ordinary glass. Although its density is less than half that of ordinary glass, it does not break as easily as glass. It has very good transparency, crystal clear, and good thermoplasticity. By heating it, you can shape it into any glass rod, glass tube or glass plate. Because of its attractive appearance and personality, it is has a wide range of uses. When jet aircraft fly at high speed in the clouds, they often encounter special conditions such as severe vibrations, sudden changes in temperature, and pressure from the airflow. This is a severe test for the window glass of the aircraft cockpit.

What can withstand this test is plexiglass. If it is a fighter jet and the plexiglass is hit by a bullet while chasing the enemy, it will not break completely, but only perforate a small hole, so that accidents like glass fragments injuring people will not happen again. If the thickness of ordinary glass exceeds 15 centimeters, it will turn green and make it impossible to see clearly through the glass. The plexiglass is 1 meter thick, so you can clearly see what's on the other side. Because its light transmittance is quite good, and ultraviolet rays can also penetrate it, it is often used to make optical instruments. Plexiglas also has an amazing property. As long as the curvature of a curved plexiglass rod is less than 48 degrees, light can be projected along it like water through a water pipe. How interesting that light can take detours! Using this unique skill, it becomes a treasure for manufacturing surgical light-transmitting glass instruments. Therefore, doctors don’t have to worry about seeing clearly when operating in the operating room. Plexiglas is light, tough, chemically stable, and malleable when heated, so it has a wide range of uses. If you add some appropriate dyes to the raw materials of organic glass, you can make red, green and purple... colorful colored organic glass according to people's needs. Production method: Pasting method: Organic glass is cut into a certain shape and pasted on a flat surface. Hot pressing method: After heating the organic glass sheet, it is hot pressed in the mold. The handicrafts made by this modeling method have the characteristics of plump shape, smooth curves, strong three-dimensional sense, and a relief effect. The hot pressing mold can be shaped with wood and clay, and then cast lead and gypsum materials are used as male and female molds. The plexiglass can be pressed into shape after heating. Mosaic method: Cut organic glass blocks of different colors into required geometric figures and mosaic them on the base plate. This method requires tight splicing, sharp edges and corners, and can achieve a strong but integrated effect. Vertical grinding method: After bonding rod-shaped organic glass or thick plate-shaped organic glass, it is directly ground and polished on the grinding wheel. The handicrafts made by this method are similar to some kind of sculptures, with rich and colorful surface shapes forming a unique artistic image. Breaking and grinding method: overlap and paste the plate-shaped organic glass together, and then directly grind the cross-section to shape. The handicrafts made by this method can have varied colors and simple and natural effects. Thermal simmering method processes the organic glass into a certain shape, heats the organic glass, and quickly molds and kneads it into shape directly by hand. These methods require that you have a good idea of ??the composition in advance, move quickly, and complete it in one go. The handicrafts made by this method have the advantages of bold lines and simple image. The above methods can be used interchangeably, and the best method can be determined according to the artistic requirements of the styling design. Construction Methods There are many kinds of plexiglass materials. There is a big difference between imported and domestic plexiglass. Imported plexiglass is very smooth when cut, while some domestically produced plexiglass has too many impurities and will cause blistering. Acrylic cutting generally uses low-speed machines because the power of the laser tube is not very high and the accuracy of thin materials is relatively high. The general speed does not exceed 3 meters/minute. Cutting of thick materials (10-20mm) Generally, 75mm focusing lens is used for organic glass above 10mm, and 100mm focusing lens is used for organic glass above 25mm. The deepest cutting of organic glass is 32mm. 10mm organic glass cutting: the cutting speed is generally 0.08-0.12 meters/minute, and the light intensity is 60-70%. It is most stable when the light intensity is 60%. The leaking air jet cup adjusts the air flow to make the edge smoother. Because the larger the blowing air is, the molten object is blown back to the plexiglass by the auxiliary high-pressure gas during cutting to form a non-smooth surface. Try to turn down the wind as much as possible. Sometimes, customers need to add paper or film cutting. At this time, the wind should not be too low, otherwise it will catch fire. When cutting plexiglass, the speed and light intensity must be matched well. The slower the speed, the better the smoothness. For plexiglass above 15mm, it is best to use imported high-power lasers. When engraving organic glass, use a leaking air jet cup. Try not to engrave too deeply. It will be difficult to achieve the flatness of the bottom when engraving too deep. The greater the gas, the effect of the edge of the engraving will be affected. To engrave more finely and clearly, do not engrave too deeply or use small air. Acrylic What you need to pay attention to when engraving is the resolution setting. If you output BMP format, the resolution should generally be above 600dpi. At this time, the speed is 8-18 meters/min, the light intensity is 20%-30%, and the air blower is turned off when cleaning. The bottom is smoother.

Cutting of thin materials (2-10mm) Organic glass below 5 mm uses a 50mm focusing lens. The cutting speed is generally 0.35-0.8 m/min and the light intensity is 45-65%. Organic glass 5-10mm generally uses a 63.5 mm focusing lens. Mirror, cutting speed is 0.15-0.3 m/min, light intensity is 50-75%, large-area engraving machine, if serious vibration (vibration) occurs during engraving, it will also cause the accuracy of the engraving machine to be poor. Lower, so the width of the plexiglass cutting machine should not exceed 1 meter. Also, some white powder is produced during the process of carving character images on plexiglass, which makes it feel clearer. If you need to wipe it off with water after engraving, it will appear blurry. It depends on the specific effect and what kind of processing is done. Physical properties of organic glass:

Density: 1.19g/cm 3 Transmittance: 99% Impact strength ≥16kg/cm 3 Tensile strength ≥61Kg/cm 3 Thermal deformation temperature ≥78℃ Thermal softening temperature ≥105℃

The bonding method of plexiglass should be based on different needs. 502 can be used for those with low requirements, but chloroform, abbreviated as chloroform for high requirements, is not necessarily the best. Acetone is also required. But it is best to have several mixed formulas that mainly affect the plexiglass and are not harmful to the human body. However, the use of some plexiglass daily necessities will cause certain harm to the human body, but the harm is not great, because the organic compounds contained in the plexiglass cups will not dissolve in Watery. Plexiglas is a popular name. The chemical name of this polymer transparent material is polymethyl methacrylate, or PMMA for short in English. It is polymerized from methyl methacrylate. There is also another name on the market - acrylic. . Usually, plexiglass is also the name for a variety of plastic products. Plastic is a chemical polymer material, and most polymer chemical materials are normally harmless to human health.