Polycarbonate has a glass transition temperature of about 147.doc
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1、Polycarbonate has a glass transition temperature of about 147 C (297F),5 so it softens gradually above this point and flows above about 155 C (311F).6 Tools must be held at high temperatures, generally above 80 C (176F) to make strain- and stress-free products. Low molecular mass grades are easier t
2、o mold than higher grades, but their strength is lower as a result. The toughest grades have the highest molecular mass, but are much more difficult to process.聚碳酸酯的玻璃化转变温度约147下(297F),5,所以它软化逐渐上面这点和流动高于约155C(311F),6工具必须保持在高温下,一般在80C(176F),以应变和应力产品。低分子量等级是比高年级更容易模制,但它们的强度是作为结果低。最艰难的等级最高的相对分子质量,但更难以处理
3、。Unlike most thermoplastics, polycarbonate can undergo large plastic deformations without cracking or breaking. As a result, it can be processed and formed at room temperature using sheet metal techniques, such as bending on a brake. Even for sharp angle bends with a tight radius, heating may not be
4、 necessary. This makes it valuable in prototyping applications where transparent or electrically non-conductive parts are needed, which cannot be made from sheet metal. Note that PMMA/Plexiglas, which is similar in appearance to polycarbonate, is brittle and cannot be bent at room temperature.与大多数热塑
5、性塑料,聚碳酸酯,可以承受较大的塑性变形,不开裂或断裂。其结果是,它可以被处理,形成在室温下利用金属片的技术,如制动器上的弯曲。即使是尖锐角的弯曲半径紧,加热可能没有必要。原型透明或者非导电性部件的应用中是需要的,它不能被由金属板制成的,这使得它具有很高的价值。请注意,聚甲基丙烯酸甲酯/有机玻璃,这是在外观上类似于聚碳酸酯,是脆的,并且不能在室温下弯曲。Main transformation techniques for polycarbonate resins: extrusion into tubes, rods and other profiles including multiwall
6、 extrusion with cylinders (calenders) into sheets (0.520mm (0.0200.79in) and films (below 1mm (0.039in), which can be used directly or manufactured into other shapes using thermoforming or secondary fabrication techniques, such as bending, drilling, routing, laser cutting etc. injection molding into
7、 ready articles聚碳酸酯树脂的主要转换技术:包括多层管,棒等型材挤压成挤出与气缸(压延)成片(0.5-20毫米(0.020-0.79在)和薄膜(低于1毫米(0.039英寸),可以直接使用或制造成其它形状,使用热成型或二次加工技术,例如作为弯曲,钻孔,路由,激光切割等。准备物品的注塑成意外的由聚碳酸酯往往是由于应力腐蚀开裂。请记住,拉伸应力和攻击化学需要。的应力可以被施加的应力,残余应力或两者。施加的压力的一个例子:一个女的管螺纹挖掘的聚碳酸酯部件。外螺纹锥度螺丝,并把它扩大了女性的一部分,把它变成紧张。来自残余应力淬火内应力,辍学后的模具,不同的地区以不同的速度冷却的部分。应用的
8、压力,必须设计出的部分不同的横截面厚度的一部分。得到残余应力退火。的时间和温度是依赖于特定的塑料。快速检查,以判断残余应力是存在于一个透明的聚碳酸酯部件放置偏光太阳镜偏光过滤器,甚至一对在前面的一个电灯泡,让现在通过部分偏振光闪耀。CrackingUnexpected cracking by polycarbonate is often due to stress corrosion. Remember that both tensile stress and an attacking chemical are needed. The stress can either be applied
9、stress, residual stress or both. An example of applied stress: a female pipe thread tapped into the polycarbonate part. The male thread screws into it and the taper expands the female part, putting it into tension. Residual stress comes from quenched in stress, after dropping out of the mold, when t
10、he different areas of the part cool at different rates. Applied stress has to be designed out of the part by varying the cross sectional thickness of the part. Residual stress gets annealed out. The time and temperature is dependent on the particular plastic. A quick check to tell if residual stress
11、 is present in a transparent polycarbonate part is to place a polarized filter or even a pair of polarized sunglasses in front of a light bulb and let the now polarized light shine through the part.Examine the part while wearing a pair of polarized sunglasses. Because of polycarbonates special optic
12、al properties, often the polarizing lens in front of the light is not necessary. If a pattern of residual stress is present youll see it in the plastic. While the patterns you see are an indication of tensile stress the real total stress is somewhat more complicated. However, if there is a need to k
13、now this additional information, do not hesitate to give us a call.Chemical AttackThe attacking chemicals are most often an ester or a ketone. An ester is the dehydration product of a reaction between carboxylic acid and an alcohol. Ethyl Acetate is an example.检查的一部分,而戴着一副偏光太阳镜的。由于聚碳酸酯的特殊的光学性质,经常在前面
14、的光的偏振透镜是没有必要的。如果图案中的残余应力存在,你会看到它在塑料中。的模式,你看到的是一个指示的拉应力真正的总应力是较为复杂的。但是,如果有必要知道这些额外的信息,请不要犹豫,给我们一个电话。化学攻击攻击的化学品是最常见的酯或酮。的酯是羧酸和醇之间的反应的脱水产物。乙酸乙酯是一个例子。Figure 2. Diagram of ethyl acetate.)The esters we see most often causing trouble are the synthetic lubricating oils and some cutting oils. For example, sy
15、nthetic oil is put into the air compressor supply. In a few days or few weeks, all of the polycarbonate pressure regulators tapping into the supply line develop cracks. Always check the MSDS sheets on your lubricants and dont use anything that says esters if there is polycarbonate parts anywhere in
16、your system.我们看到的最常见的引起麻烦的酯的合成润滑油和一些切削油。例如,合成的油放入空气压缩机供给。在几天或几个星期,所有的聚碳酸酯的压力调节器的供给线打入产生裂纹。请务必检查物料安全数据表上的润滑油,并说:“酯”如果有聚碳酸酯部件在您的系统中的任何地方,不使用任何。HydrolysisRemember the water molecule that is given off when the PC molecule is being made? Give back the water and the PC molecule may come apart. This proces
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