[Weekly topic] Special lecture on polymer materials "Plastics", learn some knowledge every day (5) Polystyrene "enrich yourself"”

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This post was last edited by tclz007 on 2013-12-7 18:34 Starting from this month, the polymer materials sector will start to learn* Activities, I hope sea friends will come to learn * , put forward good suggestions and actively learn * , those who discuss in depth will receive a corresponding amount of wealth and charm rewards~~! In order to allow everyone to come to discuss more actively and learn more actively, * , where the top ten sofas each time will receive "learning * "Positive rewards" Some people may think that they have nothing to do during the day at work, working like a handyman, not knowing what to do, not knowing what to study, day after day, year after year, and unable to see their future. What a terrible thing it is! We must work hard from now on, even if we learn every day * A little bit of knowledge will add up to a lot, and enrich yourself. Now you have to clarify your goals. Only by enriching your brain first can you enrich others. . . . . . Just spend a few minutes a day and you will see the future! ! ! (Anyway, I have learned it. Whether you learn it or not is up to you, except for those who know how to do it, like Haichuan Dana. . . ) Without further ado, let’s start from the basics today~~! Polystyrene 1. PS properties PS is a non-toxic, colorless, odorless, tasteless solid particle with hard texture and excellent transparency. 2. The average molecular weight of PS is between 200,000 and 300,000, its transparency reaches 88%~92%, and its refractive index is 1.59~1.60. Under stress, birefringence occurs, that is, there is stress---an optical effect. 3. PS is easy to color, is not resistant to organic solvents, is soluble in aromatic hydrocarbons and chlorinated hydrocarbons, is easily corroded by similar, higher fatty esters, and hydrocarbons, and is resistant to the effects of certain mineral oils, organic acids, alkali, salts, and lower alcohols. 4. PS has poor heat resistance, is not resistant to boiling water, is brittle, and has low impact strength. Products are prone to cracking due to internal stress. 5. PS is easy to burn and emits a lot of black smoke when burning. The oxygen index of PS is 18.2. 6. 1. Bacteria cannot grow on PS. 2. PS has low hygroscopicity, only 0.02%, but its moisture permeability is greater than that of PE. 3. Its heat deformation temperature is 70~100 degrees, and its continuous use temperature is 60~80 degrees. 4. Annealing at 5 to 6 degrees below the heat distortion temperature can reduce the internal stress in PS products and increase the heat distortion temperature of the products. 7. 1. PS has excellent electrical insulation properties and excellent radiation resistance. It is often used as a transparent baffle for corona treatment, but it is not resistant to sunlight and easily changes color under sunlight. 2. It is easy to decompose at temperatures above 300 degrees, and general-purpose PS is easy to decompose under the action of ultrasonic waves. 3. PS can be used for extrusion, injection, blow molding, vacuum thermoforming, welding, painting, etc. Typical properties of PS are listed in Table 2--36. Table 2-36 Typical performance items of PS Standard grade impact resistance Heat resistance grade density/(g/cm3) 1.04 1.05 1.07 Tensile strength/Mpa 45 33 46 Elongation/% 2 30 30 Tensile modulus/Mpa 2900 2700 2800 Impact strength notch/(KJ/M2) 2 9 3 Rockwell hardness 70 50 90 Heat distortion temperature/'C 95 90 105 Water absorption/% 0.05 0.07 0.07 Vicat softening point/'C 79 79 118 Table 2-37 PS processing technology conditions project standard level impact resistance level heat resistance level 30% GF level molding method injection extrusion injection extrusion injection compression injection molding temperature/'C 230~245 205~245 230~260 220~260 237~260 215 237~270 Molding shrinkage rate/% 0.004~0.007 0.004~0.007 0.002~0.006 0.001~0.003 8. Modification of PS - high-impact PS and ABS resin. In order to improve the shortcomings of PS such as easy brittleness and poor heat resistance, a series of modified polystyrenes have been made by copolymerization, blending and other methods. High impact polystyrene and ABS resin are widely used in the packaging industry. Applications of high-impact PS Applications of ABS resin 9. Applications of PS General PS instrument casings, automobile lampshades, lighting products, high-frequency capacitors, high-frequency insulation, optical fiber, packaging materials PS foam insulation, insulation and shock-absorbing materials for construction, transportation, refrigeration, and chemical equipment. However, PS foam insulation materials can also bring fire hazards! During the Spring Festival of 2011, a large number of simple houses were built after the Shenyang Wanxin Fire and the Wenchuan Earthquake, and a large number of thin steel/PS insulation building materials were used. Special Lecture Series on Polymer Materials: "Plastics", learn some knowledge every day (5) Polystyrene "enrich yourself"” http://bbs.hcbbs.com/thread-1257435-1-1.html Special lecture on polymer materials "Plastics", learn some knowledge every day (4) ABS plastic "enrich yourself"” http://bbs.hcbbs.com/thread-1257228-1-1.html Special lecture on polymer materials "Plastics", learn some knowledge every day (3) PVC "enrich yourself"” http://bbs.hcbbs.com/thread-1256914-1-1.html Special lecture on polymer materials "Plastics", learn some knowledge every day (2) Polyethylene "enrich yourself"” http://bbs.hcbbs.com/thread-1256622-1-1.html Special lecture on polymer materials "Plastics", learn some knowledge every day (1) Engineering plastics "enrich yourself"” http://bbs.hcbbs.com/thread-1256345-1-1.html Welcome everyone to come and listen to my broadcast. I hope that like me, people who want to gain knowledge every day will listen, and we can learn together every day. * , discuss~~! [Special Lecture] Special Lecture on Polymer Materials "Plastics", which is being updated continuously. http://bbs.hcbbs.com/thread-1256917-1-1.html