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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
17、s is referred to as Hydrolysis and it is bad news. So we cant use PC in high humidity at elevated temperatures - no steam for polycarbonate!Studies have shown a rapid drop in average molecular weight for PCs under hot/humid conditions. This means that the PC polymer chains are being cut to pieces by
18、 the water molecules. One study found the average molecular weight of a commercial grade PC dropped to approximately 65% of its initial value after 40 weeks at 100% relative humidity at only 65 C. This reduction in molecular weight leads to a loss of mechanical properties, and causes brittle rather
19、than ductile fractures.水解请记住时，PC分子，水分子吗？给后面的水和PC分子可以拆开来。这个过程被称为“水解”是坏消息。因此，我们可以不使用PC在高湿度在高温下 - 无蒸汽聚碳酸酯！研究已经表明，用于PC的热/潮湿的条件下均分子量的快速下降。这意味着，PC的聚合物链被切断成碎片由水分子。一项研究发现的商业级PC的平均分子量在100的相对湿度下降到约65，40周后的初始值在65C.分子量的减少导致的损失的机械性能和原因，脆而不韧骨折。This susceptibility of PC to hydrolysis also has implications for proc
20、essing. PC must be dried before processing in a hopper dryer or on trays at 120 C for 3 to 4 hours. The drying operation should reduce the moisture content to approximately 0.02%.Chemicals that Attack PolycarbonateThe chemicals that attack PC are numerous:Strong Bases Ammonium Hydroxide Sodium Hydro
21、xide Potassium HydroxideHalogenated Solvents Methylene Chloride Chloroform Carbon Tetra Chloride这种敏感性的PC水解处理的影响。 PC，必须用前处理中的料斗干燥器或托盘上，在120干燥3至4小时。在干燥操作应减少至约0.02的水分含量。攻击聚碳酸酯的化学品攻击PC的化学物质，是众多：森基氢氧化铵氢氧化钠氢氧化钾卤化溶剂苯基二氯化磷氯仿氯化碳四The Ketones Acetone Acetonitrile Ethyl Acetate Methyl Ethyl Ketone-(MEK)Other St
22、uff Benzene (An aromatic) Benzyl Alcohol Lacquer Thinner Mineral Spirits Jet Fuel Dimethyl Sulfoxide Diethyl Ether Carbon Disulfide Xylene Urea The Ketones Acetone Acetonitrile Ethyl Acetate Methyl Ethyl Ketone-(MEK) Other Stuff Benzene (An aromatic) Benzyl Alcohol Lacquer Thinner Mineral Spirits Je
23、t Fuel Dimethyl Sulfoxide Diethyl Ether Carbon Disulfide XyleneUrea酮的丙酮乙腈乙酸乙酯甲基乙基酮（MEK）中其他的东西苯（一种芳族）苯甲醇漆稀释剂矿物油喷气燃料二甲基亚砜乙醚二硫化碳二甲苯尿素Failure AnalysisWhat do we do when you come to us asking, Why did this PC part crack?We break open a fracture and examine it with an optical microscope. The telltale sign
24、s of stress corrosion cracking are the same kind of waviness that you can see on a broken beer bottle fractured surface. The fracture will stop where it passes out of the stressed area.We will try to collect a droplet of liquid from the surface. Sometimes we can get just enough liquid out of the cra
25、cks for our microanalytical techniques. We use Infrared Spectroscopy and possibly Gas Chromatography to identify the droplet.We will ask you to bring a thimble full of each of the fluids that the PC may have come in contact with.Please use clean, glass containers. We dont want to end up analyzing ei
26、ther the plastic container, the cover or any other contaminant. We will check the liquids for esters and for a match with whatever we collected from the part.We will use DSC, Differential Scanning Calorimetry, if we need to know the PCs glass transition temperature. This often comes up if you ask th
27、e question, Is this defective part made from a new batch of resin equal to former parts made from a previous batch?SummaryWhile polycarbonate is a remarkably strong, versatile plastic with a wide number of applications, you must keep in mind its hydroscopic nature and its vulnerability to certain so
28、lvents and chemicals.失效分析我们该怎么办时，你到我们这里来问，“为什么这台电脑破解？”我们破开的骨折，并检查它用光学显微镜。应力腐蚀开裂的迹象，你可以看到一个破碎的啤酒瓶破裂面的波纹，是同一种。骨折将停止它传递出的受力面积。我们将努力收集一小滴液体从表面。有时候，我们可以得到足够的液体，我们的微分析技术的裂缝。我们用红外光谱，气相色谱可能确定液滴。我们会要求您带来充满的流体，PC可能已经接触到了顶针。请使用干净的玻璃容器。我们不希望最终分析的塑料容器，盖子或其他任何污染物。我们将检查的液体酯和与之匹配的无论我们收集到的部分。我们将用差示扫描量热仪，DSC，如果我们需要知道
29、PC的玻璃化转变温度。这常常会出现，如果你问的问题，“这是有缺陷的部件，由一批新的树脂等于由一个批次的前部分？总结聚碳酸酯塑料具有广泛的应用是一个非常强大的，多功能的，你必须记住它的吸湿性性质，它的某些溶剂和化学品的脆弱性。聚碳酸酯耐环境应力开裂性能的研究作者：江盛玲,华幼卿双击自动滚屏发布时间：2011-6-2 14:21:59 阅读：232次 【字体：大 中 小】（北京化工大学材料科学与工程学院 碳纤维及功能高分子教育部重点实验室，北京 100029）摘要：研究了聚碳酸酯（PC）的耐环境应力开裂（ESCR）行为；探讨了摩尔质量及分布、后处理工艺、温度、溶剂等因素对PC耐环境应力开裂性能的影
30、响。结果表明：摩尔质量越高，分布越窄，则PC临界应变值越高，耐环境应力开裂性能越好；退火热处理有利于提高PC环境应力开裂性能。此外，温度降低和试样与溶剂溶度参数差#8710;增大均有利于提高PC耐环境应力开裂性能。同时提出了聚合物耐环境应力开裂模型，对环境应力开裂机理进行了探讨。关键词：聚碳酸酯；耐环境应力开裂；临界应变；模型中图分类号：TQ323.4+1 文献标识码：B 文章编号：1005-5770（2011）05-0082-04Study on Environmental Stress Crack Resistance Property of PolycarbonateJIANG Shen
31、g-ling, HUA You-qing（College of Materials Science and Engineering, Beijing University of Chemical technology, Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029, China）Abstract: Environmental stress crack resistance (ESCR) properties of polycarbonate (PC) w
32、ere studied. Effects of molecular weight, distribution, post-processing, temperature and solvent on ESCR properties of PC were researched. The results showed that higher molecular weight and lower of dispersion gave higher critical strain and better environmental stress crack resistance. The anneali
33、ng heat treatment was beneficial to improve ESCR property of PC. In addition, decreasing temperature and increasing solubility parameter of solvent and solubility of sample were both beneficial to ESCR of PC. Put forward a model about ESCR of PC and mechanism of ESCR were discussed.Keywords：Polycarbonate; environmental stress crack resistance; critical strain; model
