www.juzhi.com.cn, China presents the definition, characteristics and classification of plastics for your reference.

The definition of plastic

• Plastic refers to those materials which could flowage molding during machining process, plastic mainly consists of resin, rosin, colophony (or directly polymerized from monomers during machining process), plastic also consists of some additives as assistant components such as plasticizer, filling materials, lubricant, colorant, etc.

The characteristics of plastic:

• Most plastic have light weight, chemical stability, stainless
• Good impact resistance
• Good transparent and wearable performance
• Good electric isolation and low heat exchange rate
• Good molding and good colorization performance, low machining cost
• Most plastic are poor in heat resistant, with higher heat expansion rate and easily burnt
• Poor sizes stability, easily distortion
• Most plastic are poor in low temperature resistant, easily turned into brittle at low temperature
• Easily aging
• Some plastic are easily solved in solvent

The classification of plastic:

• Plastic could be classified by its usage characteristics, physical and chemical performances or machining methods.

Plastic classification by usage characteristics:

• According to different usage characteristics of all kinds of plastic, plastic could be classified into three types: Universal Plastic, Engineering Plastic and Special Plastic

Universal Plastic

• Universal Plastic refers to those plastic of large output capacity, wide application fields, good molding performance, cheap prices, such as Polyethylene (PE), Polypropylene (PP), Phenolics, Bakelite, etc.

Engineering Plastic

• Engineering Plastic refers to those plastic which could bear some extend of outer forces, have good mechanical performance, high temperature resistant, low temperature resistant, good sizes stability, could be used as engineering structural frameworks, such as polyamide, polysulfone (PSF), etc.
• Engineering Plastic could be classified further into two types: Universal Engineering Plastic, Special Engineering Plastic

• Universal Engineering Plastic includes polyamide, polyoxymethylene (POM), polycarbonate (PC), modified polyphenylenexxide (PPO), thermoplastic polyester, ultra high molecular weight polyethylene (UHMWPE), methylpentene polymer, vinyl alcohol copolymers, etc.
• Special Engineering Plastic could be classified further into cross linkage type and non cross linkage type.
  
  
  • Cross linkage type of special engineering plastic includes cross linkage polyimide (PI), heat resistant epoxy resin, etc.
  • Non cross linkage type of special engineering plastic includes polysulfone (PSF), polyethersulfone (PES), polyphenylenesulfide (PPS), polyimide (PI), polyetheretherketone (PEEK), etc.

Special Plastic

• Special Plastics refer to those plastics with special functions which could be adopted for aviation, spaceflight and others special application fields. You know, fluorine plastic and organic silicon have special functions such as excellent heat resistant, self lubricant. Reinforced plastics and foamed plastics (expanded plastics, cellular plastics) have special performances of high strength, high cushion performance, etc. So these plastics belong to special plastic.

• Reinforced Plastics: Reinforced plastics could be classified according to its shapes into granular type (such as Ca-plastic reinforced plastics), fiber type (such as fiberglass reinforced plastics or fiber cloth reinforced plastics) and sheet type (such as mica reinforced plastics). Reinforced plastics could be classified according to its materials into cloth basis reinforced plastics (such as rag reinforced plastics or asbestos reinforced plastics), inorganic minerals filled plastics (such as quartz or mica filled plastics) and fiber reinforced plastics (such as carbon fiber reinforced plastics).
• Foam Plastics: Foam Plastics could be further classified into hard foam plastics, half hard foam plastics and soft foam plastics. Hard foam plastics have not flexility, large compression hardness, which would be only distorted under some certain stress value and could not recover to its former figures. Soft foam plastics have good flexility and little compression hardness which could be easily distorted while could recover to its former figures with little distortion remained when the stress are released. The flexility and others performances of half hard foam plastics are between hard foam plastics and soft foam plastics.

Plastic classification by physical and chemical performances:

• According to different physical and chemical performances of all kinds of plastic, plastic could be classified into two types: Thermosetting Plastics and Thermoplastic Plastics.

Thermosetting Plastics:

• Thermosetting Plastics, or Thermoset Plastics refer to those plastics which would be solidified or could not be melted easily when they are heated, such as bakelite, phenolplast, epoxy plastic.
• Thermosetting Plastics, or Thermoset Plastics have two types, one is methanal cross linked type, such as bakelite, phenolplast, aminoplastic; another is others cross linked type, such as unsaturated polyester, ethoxyline resin, diallyl phthalate resin, etc.

Thermoplastic:

• Thermoplastic refer to those plastics which could be reused time after time within some temperature range, such as polyethylene (PE), polypropylene (PP), polycarbonate (PC), polytetrafluoroethylene (PTFE), etc. Thermoplastic could be further classified into hydrocarbon type, ethylene type with polarity structure, engineering type, cellulose type, etc.

• Hydrocarbon Type Plastics: Hydrocarbon type plastics belong to nonpolarity plastics which could be further classified into crystalline hydrocarbon type plastics and non crystalline hydrocarbon type plastics. Crystalline hydrocarbon type plastics includes polyethylene (PE) and polypropylene (PP), etc. Non crystalline hydrocarbon type plastics includes polystyrene (PS),etc.
• Ethylene Type Plastics with Polarity Structure: Except for fluorine plastic, most ethylene type plastics with polarity structure are non crystalline transparent body, including polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyvinyl acetate, etc. Most of ethylene type monomer could be polymerized by adopting free radical type catalyzers.
• Thermoplastic Engineering Plastics: Thermoplastic engineering plastics mainly includes polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polyphenyleneoxide (PPO), polyethylene glycol terephthalate, polysulfone (PSF), polyethersulfone (PES), polyimide (PI), polyphenylenesulfide (PPS), etc. Polytetrafluoroethylene (PTFE), modified polypropylene could also be classified as thermoplastic engineering plastics.
• Thermoplastic Cellulose Plastics: Thermoplastic cellulose plastics mainly includes cellulose acetate, acetyl cellulose, cellulose acetate butyrate, celluloid, cellophane, etc.

Plastic classification by machining methods:

• According to different machining methods of all kinds of plastic, plastic could be classified into several types: Film Pressure Plastic, Laminating Plastic, Injection Plastic, Extrusion Plastic, Blow Molding Plastic, Cast Plastic and Reaction Injection Molding Plastic, etc.

• Film Pressure Plastic refers to those plastics whose physical machining performances are similar with common solidity plastics;
• Laminating Plastic refers to those fabric materials dipped with resin and then folded, hot pressed into integral entity;
• Injection Plastic, Extrusion Plastic and Blow Molding Plastic refer to those plastics whose physical and machining performances are similar with common thermoplastic plastics;
• Cast Plastic refers to liquid mixture resin which could be harden and molded into finished products without pressure or little pressure when they are poured into moulds, such as nylon, etc.
• Reaction Injection Molding Plastic refers to those liquid plastic raw materials which could be injected into female mould cavities with some pressure and then reacted and solidified into finished products, such as polyurethane (PU), etc.

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