工程材料品种繁多,成千上万,但基本上可分为三大类,即:金属材料、无机非金属材料(亦称陶瓷或硅酸盐材料)和有机非金属材料(高分子聚合材料或塑料)。此外也可将金属与非金属材料组合起来做成所谓复合材料。高分子聚合物和塑料是同一种工程材料的两个名称。顾名思义,塑料应该是有可塑性的材料,然而多数的高分子聚合物在常温下常常是不可塑的。美国材料检验学会(ASTM)给塑料下的定义(D883)为:“以高分子有机物质为主要成分的固体材料,它们在制造或加工为成品的过程中的某一阶段是可以流动成形的。”在上述定义中的高分子是指重复的长链分子,这些单体分子可以彼此由物理的连接而聚合(称为加聚作用,如 There are a wide variety of engineering materials in tens of thousands, but basically they can be divided into three categories: metal materials, inorganic non-metallic materials (also called ceramic or silicate materials) and organic non-metallic materials (polymeric materials or plastic). In addition, metal and non-metallic materials can also be combined into a so-called composite material. Polymers and plastics are two names of the same engineering material. As the name suggests, plastics should be malleable materials, however, most polymers are often not plastic at room temperature. The ASTM definition of plastics (D883) is: “Solid materials based on macromolecular organic substances that are flow-formable at some stage in the manufacture or processing of a finished product . ”Polymers in the above definition refer to repeating long chain molecules that can be physically linked to one another by polymerization (referred to as polyaddition, such as