广东工业大学 模具专业英语2 09E2-5.ppt

参考译文 塑料没有被普遍认可的定义，但认为它是一种以合成高聚物作为主要成分的材料。高聚物是一种高分子(量)材料，通过连接许多小分子而成。有些塑料，聚合物是唯一组成成分，但更多塑料中通常要加入多种其它物质，比如填充剂、着色剂（颜料）、抗氧剂、增塑剂等。这些添加剂将改善塑料的特殊性能或有助于成型。目前几乎所有塑料都是以有机高聚物为基体的。在很多人的脑海里，塑料一词是与那些廉价、色彩明亮、“寿命”有限的产品紧密联系在一起的。目前塑料定义已可能迎来新的术语，以阐述具有不同属性可用于工程领域的各种聚合物材料。 第五讲 专业名词及术语 curing 固化 ，硬化 epoxide n.?环氧化物 [e`p?ksaid] phenol n.?苯酚,石碳酸 ?? [`fi:n?l] silicone n.?(聚)硅酮, 硅有机树脂 ?? [``silik?un] asbestos n.?石棉[?z`best?s] 专业名词及术语 ? ?melamine [`mel?mi(:)n] n.?三聚氰胺  ??polyester[.p?li`est?] n.?聚酯纤维, 涤纶 polymerization ? [.p?lim?rai`zei??n] n.?聚合  epoxy resin?n.?环氧树脂  专业名词及术语 ??lend itself to v.?有助于 Know-how n.?〈口〉实际知识,技术秘诀,诀窍 idle reture stroke 空回程 the marked creep effects 明显的蠕变效应  阅读课文—— Production of Plastic  11.4 EXTRUSION PROCESS 11.4 EXTRUSION PROCESS This often serves the function of producing the plastic in an intermediate form for subsequent reprocessing, as well as being used to produce a polymer in its final form. Therefore it can be said to be the most important of the plastic processes and consequently has received a lot of attention. The actual extruding part of the process is similar to that used for metals in that the material flows through a die orifice of the required shape under pressure. After leaving the die the polymer swells appreciably, the amount of swelling depending upon the shear rate(due to the screw)and the molecular weight distribution of the polymer. If the die is of non-uniform cross section the pressure upon the die walls will not be uniform and it has been found that die swell then will not be uniform. Therefore it can be seen that designing and making dies for varying polymers is an uncertain business, and a lot of trade ‘know-how’ and trial and error is required. 11.4 EXTRUSION PROCESS The earlier stages of the extrusion process when the material is brought to a state suitable for extrusion is not similar to that us