高分子专业英语选讲课文翻译资料
流动状态以及根据流动面的自由与否，通常包括剪切、延伸和挤压流动。
The thermo-mechanical history experienced by the polymer during flow and solidification results in the development of microstructure (morphology, crystallinity, and orientation distributions) in the manufactured article. The ultimate properties of the article are closely related to the microstructure. Therefore, the control of the process and product quality must be based on an understanding of the interactions between resin properties, equipment design, operating conditions, thermo-mechanical history, microstructure, and ultimate product properties. Mathematical modeling and computer simulation have been employed to obtain an understanding of these interactions. Such an approach has gained more importance in view of the
expanding
utilization
of
computer
aided
design/computer
assisted
manufacturing/computer aided engineering (CAD/CAM/CAE) systems in conjunction with plastics processing.
经历了流动和固化（或冷却）的聚合物热机械过程导致了制造业微结构的变革（形态学、结晶学和取向分布）。最终产品的性能与微结构紧密相关。因此，加工和产品质量的控制必须基于树脂性能、设备设计、操作条件、热机械过程、微结构和最终产品性能之间相互作用的理解。数学模型和计算机被同时用于获得这些相互作用的理解。鉴于进一步利用计算机辅助设计/计算机辅助制造/计算机辅助工程（CD/CAM/CAE）系统协同塑料加工诸如这一趋近获得了更多的重要性。
The following discussion will highlight some of the basic concepts involved in plastics shaping operations. It will emphasize recent developments relating to the analysis and simulation of some important commercial processes, with due consideration to elucidation of both thermo-mechanical history and microstructure development. More extensive reviews of the subject can be found in standard references on the topic (1~6).
下面的讨论将重点放在包括塑料成型操作一些基本概念上。适当考虑说明热机械过程和微结构发展，将强调最近关于分析和一些重要商品加工模型的进展。在上端（1～6）的标准参考中能够找到本主题更广泛的综述。
As mentioned above, shaping operations involve combinations of fluid flow and heat transfer, with phase change, of a visco-elastic polymer melt. Both steady and unsteady state processes are encountered. A scientific analysis of operations of this type requires solving the relevant equations of continuity, motion, and energy (i.e. conservation equations).
如上面提到的，成型操作包括液体流动和热传递，对于相态变化，还包括粘弹性聚合物的熔融。稳定和非稳定状态加工是相冲突的。这种典型操作的科学分析需要解决相关连续、运转和能量平衡（如守恒方程）。
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Austarita G , Nicolas L. Polymer prscessing and properties
New York: Plenum press 1984, 1~3
UNIT 29 Synthetic Plastics
第二十九单元 合成塑料
It would be difficult to visualise our modern world without plastics. Today they are an
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高分子专业英语选讲课文翻译资料
integral part of everyones lifestyle with applications varying from commonplace articles to sophisticated scientific and medical instruments. Nowadays designers and engineers readily turn to plastics because they offer combinations of properties not available in any other materials. Plastics offer advantages such as lightness , resilience , resistance to corrosion , colour fastness , transparency , ease of processing , etc. , and although they also have their limitations , their exploitation is limited only by the ingenuity of the designer.
现代社会没有塑料真是难以想象。今天它们是组成每个人生活的必备部分，从不断变化的平凡物品到尖端科技的医学仪器。当今的设计师和工程师已开始着手塑料的研究，因为它们提供了不能应用于任何其它材料的综合性能。塑料所呈现的优点诸如质轻、弹性、防腐、不易褪色、透明性、易于加工等等，尽管也有它们的制约，它们的开发仅因设计师的创造力受到限制。
It is usual to think that plastics are a relatively recent development but in fact, as part of the larger family called “polymers”, they are a basic ingredient of plant and animal life. Polymers are materials which consist of very long chain-like molecules. Natural materials such as silk, shellac, bitumen, rubber and cellulose have this type of structure. However, it was not until the 19th century that attempts were made to develop a synthetic polymeric material and the first success was based on cellulose. This was a material called “Parkesine”, after its inventor Alexander Parkes, and although it was not a commercial success it was a start and eventually led to the development of “Celluoid”. This material was an important break-through because it became established as a good replacement of natural materials which were in short supply .
通常认为塑料是一种相对新的发展，但事实上作为 “聚合物”大家族的成员，它们是动植物生活的一个基本组成部分。聚合物是由象链一样非常长的分子组成的材料。象丝、虫胶、沥青、橡胶和纤维素之类的天然材料有这种类型的结构。然而，直到19世纪才尝试开发了一种合成聚合物材料，首次成功基于赛璐珞。这是一种叫做“硝化纤维素塑料”的材料，它的发明者是Alexander Parkes ,尽管不是一种开始的商业成功，最终导致了“赛璐珞”的发展。这种材料是一个重要的突破因为它成为了供应短缺的天然材料的良好替代品。
During the early twentieth century there was considerable interest in these new synthetic materials. Phenol-formaldehyde (“bakelite”) was introduced in 1905 and about the time of the second World War materials such as nylon, polyethylene and acrylic (“Perspex”) appeared on the scene. Unfortunately many of the early applications for plastics earned them a reputation as being cheap substitutes. It has taken them a long time to overcome this image but nowadays the special properties of plastics are being appreciated which is establishing them as important materials in their own right. The ever increasing use of plastics in all kinds of applications means that it is essential for designers and engineers to become familiar with the range of plastics available and the types of performance characteristics to be expected so that they can be used to the best advantage.
二十世纪初，人们十分关注这些新合成材料。酚醛树脂（“电木粉”）于1905年问世，大约在第二次世界大战期间象尼龙、聚乙烯和丙烯酸类（“有机玻璃”）的材料相继出现。可惜塑料的许多早期应用带来的是廉价代用品的名声。这种印象花费了长久的时间才被消除，但如今，塑料的特性正在被人们认识到，而塑料也正在确立它们作为重要材料的地位。塑料在各种应用中的用途不断增加，这意味着对于
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高分子专业英语选讲课文翻译资料
设计师和工程师来说，通晓塑料应用的范围和预期的性能特征是十分必要的，以致能以最好的方式利用它们。
The words “polymers” and “plastics” are often taken as synonymous but in fact there is a distinction. The polymer is the pure material which results form the process of polymerisation and is usually taken as the family name for materials which have long chain-like molecules and this includes rubber. Pure polymers are seldom used on their own and it is when additives are present that the term plastic is applied. Polymers contain additives for a number of reasons. In some cases impurities are present as a result of the polymerisation additives such as stabilisers, lubricants, fillers, pigments, etc., are added to enhance the properties of the material.
单词“聚合物”和“塑料”通常被看作是同义的，但事实上是有区别的。聚合物是缘于聚合反应过程的纯物质，常常被看作具有长链分子材料的系列名称，这也包括橡胶。纯的聚合物很少独自使用，当存在添加剂时它适用于专有名词塑料。由许多原因聚合物含有添加剂。在某些情况下作为聚合反应的结果存在杂质，去除这些杂质以获得纯的聚合物可能是不经济的。在其它情况下，添加象稳定剂、润滑剂、填充剂、颜料等之类的添加剂，以增强材料的性能。
There are two important classes of plastics: 有两种重要类别的塑料：
(1) Thermoplastic materials. In a thermoplastic material the long chain-like molecules are held together by relatively weak Van der Waals forces. A useful image of the structure is a mass of randomly distributed long strands of sticky wool. When the material is heated the intermolecular forces are weakened so that is becomes soft and flexible and eventually, at high temperatures, it is a viscous melt. When the material is allowed to cool it solidifies again. This cycle of softening by heat and solidifying when cooled can be repeated more or less indefinitely and is a definite advantage in that it is the basis of most processing methods for these materials. It does have its drawbacks, however, because it means that the properties of thermoplastics are heat sensitive. A useful analogy which is often used to describe these materials is that like candle wax they can be repeatedly softened by heat and will solidify when cooled.
（1） 热塑性材料。在热塑性材料中象长链一样的分子间力是相对较弱的范德华力。对于结构一个有效的比喻是一大团自由分布的粘性纤维长线。当材料被加热时，内部的分子作用力变弱，以致变得柔软和柔韧，最终在高温下，成为粘性熔融体。当材料被冷却时再次固化。加热软化、冷却固化大体上能反复多次地循环，对于材料这是一个明显的优点，也是许多加工方法的基础。然而，热塑性材料的确有其缺点，因为这意味着热塑性塑料的特性是热敏的。常常用于描述这些材料的有效比拟是象烛蜡加热能够反复软化而当冷却时又将固化。
Examples of thermoplastics are polyethylene, polyvinyl chloride, polystyrene, nylon, cellulose acetate, acetal, polycarbonate, polymethyl methacrylate and polypropylene. 热塑性塑料的例子是聚乙烯、聚氯乙烯、聚苯乙烯、尼龙、醋酸纤维素、聚甲醛、聚碳酸酯、聚甲基丙烯酸甲酯和聚丙烯。
(2) Thermosetting materials. A thermosetting material is produced by a chemical reaction which has two stages. The first stage results in the formation of long chain-like molecules similar to those present in thermoplastics, but still capable of further reaction. The second stage
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of the reaction takes place during moulding, usually under the application of heat and pressure. The resultant moulding will be rigid when cooled but a close network structure has been set up within the material. During the second stage the long molecular chains have been interlinked by strong bonds so that the material cannot be softened again by the application of heat. If excess heat is applied to these materials they will char and degrade. This type of behaviour is analogous to boiling an egg. Once the egg has cooled and is hard, it cannot be softened again by the application of heat.
（2） 热固性材料。热固性材料是通过两步化学反应生产而来的。第一步形成类似于存在于热塑性塑料中象长链一样的分子形式，但还能够进一步反应。第二步反应在模塑时发生，通常在加热加压条件下进行。当冷却时最终的模塑将是刚硬的，但在材料中建立了封闭的网状结构。在第二步反应中长分子链通过强键相互连接，所以材料加热不再软化。如果将这些材料超高温加热将炭化并分解。这种行为类似于煮熟的鸡蛋。一旦鸡蛋冷却则变硬，加热不能再次软化。
Since the cross-linking of the molecules is by strong chemical bonds thermosetting materials are characteristically quite rigid materials and their mechanical properties are not heat sensitive. Examples of thermosets are phenol formaldehyed, melamine formaldehyde, urea formaldehyde, epoxies and some polyesters.
因为由强化学键交链的热固性塑料十分刚硬，它们的机理性能不是热敏的。热固性塑料的例子是酚醛树脂、胺醛树脂、脲醛树脂、环氧树脂和一些聚酯。
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