聚甲基丙烯酸甲酯的聚合研究.doc
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1、, 聚甲基丙烯酸甲酯 的聚合研究 姓 名 唐小峰 班 级 高化0801 学 院 化学与材料科学学院 聚甲基丙烯酸甲酯的聚合研究目录摘要2Contents3History3Synthesis4Processing4Handling, cutting, and joining4Properties5Poly(methyl acrylate)71.1前言71.2 聚甲基丙烯酸甲酯的制备71.21原料使用条件81.2.2聚甲基丙烯酸甲酯的制备81.3 PMMA的物理性能91.4 PMMA化学性能91.5 压克力性能101.6 工艺特性101.7 聚甲基丙烯酸甲酯的用途10摘要聚甲基丙烯酸甲酯(PMMA
2、)是由甲基丙烯酸甲酯自由聚合而成,有浇铸成型、注塑成型、挤出成型、热成型等制备方法。研究了聚甲基丙烯酸甲酯的物理化学性能以及在不同条件下制的的聚甲基丙烯酸甲酯的工艺特性。最后,介绍了聚甲基丙烯酸甲酯生产和市场现状,包括(生产厂家、产品牌号、市场消费)等。简述了聚甲基丙烯酸甲酯生产技术及市场发展并提出建议。关键词 PMMA 浇铸 注塑 挤出 热工艺特点 市场 发展Poly(methyl methacrylate) (PMMA) is a transparent thermoplastic, often used as a light or shatter-resistant alternativ
3、e to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate. The material was developed in 1928 in various laboratories, and was first brought to market in 1933 by Rohm and Haas Company, under the trademark Plexiglas.4 It has since been sold under
4、 many different names including Lucite and Perspex.The often-seen spelling poly(methyl 2-methylpropanoate) with -an- is an error for poly(methyl 2-methylpropenoate), based on propenoic acid.PMMA is an economical alternative to polycarbonate (PC) when extreme strength is not necessary. Additionally,
5、PMMA does not contain the potentially harmful bisphenol-A subunits found in polycarbonate. It is often preferred because of its moderate properties, easy handling and processing, and low cost, but behaves in a brittle manner when loaded, especially under an impact force, and is more prone to scratch
6、ing compared to conventional inorganic glass.Contents 1 History o 1.1 Names 2 Synthesis 3 Processing 4 Handling, cutting, and joining 5 Acrylate resin casting 6 Properties o 6.1 Modification of properties 7 Poly(methyl acrylate) 8 Uses o 8.1 Transparent glass substitute o 8.2 Daylight redirection o
7、8.3 Medical technologies and implants o 8.4 Artistic and aesthetic uses o 8.5 Other uses 9 See also 10 References o 10.1 Bibliography o 10.2 External links HistoryThe first acrylic acid was created in 1843. Methacrylic acid, derived from acrylic acid, was formulated in 1865. The reaction between met
8、hacrylic acid and methanol results in the ester methyl methacrylate. The German chemists Fittig and Paul discovered in 1877 the polymerization process that turns methyl methacrylate into polymethyl methacrylate. In 1933 the German chemist Otto Rhm patented and registered the brand name PLEXIGLAS. In
9、 1936 the first commercially viable production of acrylic safety glass began. During World War II acrylic glass was used for submarine periscopes, windshields, canopies, and gun turrets for airplanes.5NamesPMMA has been sold under a variety of brand names and generic names. It is often generically c
10、alled acrylic glass,6 although it is chemically unrelated to glass. It is sometimes called simply acrylic, although acrylic can also refer to other polymers or copolymers containing polyacrylonitrile. Other notable trade names include: Lucite7 Plexiglas8 Optix (Plaskolite)9 Perspex10 Altuglas11unrel
11、iable source? (Arkema) SynthesisPMMA is routinely produced by emulsion polymerization, solution polymerization and bulk polymerization. Generally radical initiation is used (including living polymerization methods), but anionic polymerization of PMMA can also be performed. To produce 1kg (2.2lb) of
12、PMMA, about 2kg (4.4lb) of petroleum is needed. PMMA produced by radical polymerization (all commercial PMMA) is atactic and completely amorphous.ProcessingThe glass transition temperature (Tg) of atactic PMMA is 105 C. The Tg values of commercial grades of PMMA range from 85 to 165 C (185to 329F);
13、the range is so wide because of the vast number of commercial compositions which are copolymers with co-monomers other than methyl methacrylate. PMMA is thus an organic glass at room temperature i.e., it is below its Tg. The forming temperature starts at the glass transition temperature and goes up
14、from there.12 All common molding processes may be used, including injection molding, compression molding and extrusion. The highest quality PMMA sheets are produced by cell casting, but in this case, the polymerization and molding steps occur concurrently. The strength of the material is higher than
15、 molding grades owing to its extremely high molecular mass. Rubber toughening has been used to increase the strength of PMMA owing to its brittle behavior in response to applied loads.Handling, cutting, and joiningPMMA can be joined using cyanoacrylate cement, more commonly known as superglue, with
16、heat (welding), or by using solvents such as di- or trichloromethane to dissolve the plastic at the joint which then fuses and sets, forming an almost invisible weld. Scratches may easily be removed by polishing or by heating the surface of the material.Laser cutting may be used to form intricate de
17、signs from PMMA sheets. PMMA vaporizes to gaseous compounds (including its monomers) upon laser cutting, so a very clean cut is made, and cutting is performed very easily. However, the pulsed lasercutting introduces a high internal stresses along the cut edge, which when exposed to solvents produces
18、 undesirable stress-crazing at the cut edge and several millimetres deep. Even ammonium-based glass-cleaner and almost everything short of soap-and-water produces similar undesirable crazing, sometimes over the entire surface of the cut parts, at great distances from the stressed edge. Annealing the
19、 PMMA sheet/parts is therefore an obligatory post-processing step when intending to chemically bond lasercut parts together. This involves heating the parts in an air circulating oven from room temperature up to 90C (at a rate of no more than 18 degrees per hour) down to room temperature (at a rate
20、of no more than 12 degrees per hour). Temperature should be maintained as follows: one hour for 3mm thickness, two hours for up to 6mm thickness, four hours for up to 12mm thickness, and six hours for up to 20mm thickness. A rapid annealing cycle is reliable for thin sheets and involves placing them
21、 in a pre-heated oven to 80C for one hour, then removing parts from oven and allowing to cool to room temperature. This added time component should be factored into the whole fabrication process, and the alternative Zero-rake sawcutting technique may provide better cost-effectiveness, unless complex
22、 non-straight line edges are required. In this respect PMMA has an advantage over competing polymers such as polystyrene and polycarbonate, which require higher laser powers and give more messy and charred laser cuts.In the majority of applications, it will not shatter. Rather, it breaks into large
23、dull pieces. Since PMMA is softer and more easily scratched than glass, scratch-resistant coatings are often added to PMMA sheets to protect it (as well as possible other functions).Methyl methacrylate synthetic resin for casting (simply the bulk liquid chemical) may be used in conjunction with a po
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