液晶高分子是什么.doc

液晶高分子是什么？我公司生产的液晶聚合物称为Vectra，具有其他塑料所没有的特性。那么液晶聚合物 到底是一种什么物质呢？ 液晶是什么？手表，移动电话的表示部分或者手提电脑的屏幕等都有使用液晶。那么这个液晶到底是一种什么物质呢？液晶状态是指从表面上看象液体似地流动，但从微观角度上看分子排列非常整齐，即使在液体状态下也能显示出结晶的性能。因此，它与水这样的普通液体不同，具有特殊的性质。液晶 = 液体 + 结晶 塑料材料的液晶性质我公司生产的液晶聚合物称为Vectra，具有这种液晶的特性。 但是我公司生产的Vectra从颗粒上或成品上看都象固体，不象具有液体的性质。其实，Vectra只有在高温熔融状态下才能显示其液晶的特性。塑料即使在高温熔融状态下分子排列非常整齐，我们称具有这种状态的塑料为液晶高分子（Liquid Crystaline Polymer,LCP）。象Vectra这样的在高温熔融状态下显示出液晶的特性称为热熔融型。一般塑料: -一般塑料的熔融状态折叠式分子链结构液晶聚合物 : - LCP的熔融状态伸展式分子链结构成型用LCP的特征液晶聚合物的LCP在成型加工上有什么样的特征呢？ 低的熔融粘度成型加工上具有良好的流动性 固化速度快 不容易出现溢料 自我补强效果增加制品强度 减小模压收缩 良好的耐热性 但是容易造成各向异性 这些都是由于熔融时具有强的分子排列性和棒状的分子链结构，在熔融状态下能保持其分子排列性并迅速固化而引起的。想了解更多的Vectra的特征和物性，请参考制品介绍网页和塑料详细数据。What is liquid crystal polymer ?One of our products Vectra is a kind of liquid crystal polymer having various characteristics which other plastic materials do not have. But what kind of material is liquid crystal polymer first of all ? What is liquid crystal ?There are so many products on the market which utilize liquid crystal, for example displays for wristwatches, portable telephones, note type personal computers, and so on. Then what kind of substance is this liquid crystal polymer ?A state of liquid crystal is a state in which materials flow like liquid as a whole, but from a micro point of view the molecules of the materials line up almost regularly and orderly like a crystal. Therefore liquid crystal has peculiar properties which are quite different from ordinary liquid such as water. Liquid crystal = Liquid Crystal Nature of liquid crystal in plastic materialsOur product Vectra also has the nature of liquid crystal, therefore it is called a liquid crystal polymer. However, the pellets and the moldings of Vectra look like solids from any viewpoint. They may surely have the nature of crystal but do not look like to have the nature of liquid.Actually, it is only when Vectra is melted and flowing under high temperature that it shows the nature of liquid crystal.When the molecular chains of high polymers are kept almost lined up regularly even if they are turned into the state of fluid either by melting or by dissolution in solvents, such polymers are called liquid crystal polymers or LCPs. Among them, those which show liquid-crystal nature in a thermally molten state such as Vectra are called thermotropic type.Ordinary plastics : -Ordinary plastics in molten state (It looks as if woolen yarn were entangled)If solidified after molding, crystalline portions consisting of folded high molecules appear.Liquid crystal polymer : -LCP in molten state(Molecules are oriented) Orientation is fixed by solidificationCharacteristics of LCP for moldingWhat is the characteristics of Vectra which is a liquid crystal plastic for molded products ? Low melt viscosity - Easy to flow during molding Quick solidification - Less flash Self-reinforcing effect - Stronger product Smaller molding shrinkage, but be careful with anisotropic molding shrinkage Superior heat resistance Be careful with anisotropy in properties, in designing stage. These merits and demerits are due to the characteristic of a liquid crystal state where strong orientation of molecules occurs in the melt and entanglement among molecules are much less, and also due to the characteristic of quick solidification or crystallization from a molten state while orientation of molecules is maintai