How are rubber and plastic calender classified? What are the features and uses?
Two, according to the classification of characteristics, according to various plastic physical and chemical characteristics, plastic can be divided into thermosetting plastic and hot plastic plastic two types. (1) thermoplastic plastics thermoplastics (Thermo plastics): refers to the heat will melt, can flow into a mold cooling after molding, and then heated and melted plastic; can be used for heating and cooling, which produces a reversible change (liquid vs. solid), is called a physical change. General purpose thermoplastic plastic, its continuous use temperature below 100 degrees Celsius, polyethylene, polyvinyl chloride, polypropylene, polystyrene and called the four major plastic. Thermoplastic plastics are divided into hydrocarbons, polar genes of vinyl, engineering, cellulose and other types. Become soft when heated, harden when cooled, soften and harden repeatedly, and maintain a definite shape. Soluble in a certain solvent; having a soluble property. Thermoplastic plastics with excellent electrical insulation, especially polytetrafluoroethylene (PTFE), polystyrene (PS), polyethylene (PE), polypropylene (PP) has a dielectric constant and very low dielectric loss dielectric, is suitable for high frequency and high voltage insulation materials. Thermoplastics are easy to shape, but they have low heat resistance and are easy to creep. The creep degree varies with the load, the temperature, the solvent and the humidity. In order to overcome the weakness of thermoplastics, meet the need of the application of space technology, new energy development and other fields, all the countries in the development of heat-resistant resin melt molding, such as polyetheretherketone (PEEK), polyethersulfone (PES), polysulfone (PASU) and polyphenylene sulfide (PPS) etc..
Classification of plastic, according to the characteristics of classification, according to different kinds of plastic use characteristics, usually plastic is divided into general plastic, engineering plastics and special plastic three types. General plastics generally refer to plastics with large output, wide use, good formability and cheap price. There are five general types of plastics, namely polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and propylene butadiene styrene copolymer (ABS). They are all thermoplastics.
The composites with their matrix resin have higher mechanical properties and chemical resistance, heat forming and welding, and the interlaminar shear strength is better than that of epoxy resin. Such as PEEK as matrix resin and carbon fiber composite material, fatigue resistance exceeds epoxy / carbon fiber. The utility model has the advantages of good impact resistance, good creep resistance, good processability, continuous use at 240~270 DEG C at room temperature, and is a very ideal heat-resistant insulating material. Using polyethersulfone as composite material matrix resin and carbon fiber with high strength and hardness at 200 DEG C, in -100 C can still maintain a good impact resistance; non-toxic, non flammable, smoke at least, radiation resistance, expected key parts of it can be used to make the space shuttle, also can be molded into radome. Formaldehyde crosslinked plastics include phenolic plastics and amino plastics (such as urea formaldehyde melamine formaldehyde etc.). Other crosslinked plastics include unsaturated polyester, epoxy resin, phthalic two, diallyl resin, etc.. (2) thermosetting plastics are plastics that can be cured or insoluble under heat or other conditions, such as phenolic plastics, epoxy plastics, etc.. Thermosetting plastics can be divided into two types: formaldehyde, cross-linking and other cross-linking. After the hot processing, a non melting curing substance is formed, and the resin molecule is cross-linked into a network structure by a linear structure. Further heat will break down
