The five major general purpose plastics are polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and acrylonitrile-butadiene-styrene copolymer (ABS).
Polyethylene (PE) : is currently the largest production of plastic variety. It has good low temperature resistance, good chemical stability, and can withstand the erosion of most acids and bases. It can be divided into high density polyethylene (HDPE), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). It is often used to make films, pipes, containers, etc., such as common plastic bags and plastic bottles.
• Advantages:
o Good chemical stability, can resist most acid and alkali erosion.
o Good flexibility and ductility, easy to process.
o Excellent low temperature resistance, can still maintain good performance in low temperature environment.
• Disadvantages:
o Relatively low strength and hardness.
o Poor high temperature resistance, easy to deform in case of heat.
Polypropylene (PP) : Relatively low density, is the lightest general purpose plastic. Strength, rigidity and transparency are better than polyethylene. Widely used in automobiles, household appliances, daily necessities and other fields, such as car bumpers, plastic POTS, plastic tableware.
• Advantages:
o Low density, light weight.
o Good strength and rigidity.
o Relatively good heat resistance.
• Disadvantages:
o High brittleness at low temperature.
o General weather resistance.
Polystyrene (PS) : has good transparency and gloss, electrical insulation performance is excellent. Common products are transparent cups, lunch boxes and so on.
• Advantages:
o High transparency, good gloss.
o Good electrical insulation performance.
o Easy to form.
• Disadvantages:
o is brittle and easy to crack, low impact strength.
o Poor heat resistance.
Polyvinyl chloride (PVC) : has good chemical corrosion resistance and flame retardant. Commonly used in the production of pipes, plates, wire and cable insulation, such as water pipes, plastic doors and Windows.
• Advantages:
o Good chemical resistance.
o The price is relatively low.
o Good flame retardant.
• Disadvantages:
o Poor thermal stability, need to add stabilizer during processing.
o Has certain pollution to the environment.
Acrylonitrile-butadiene-styrene copolymer (ABS) : the comprehensive performance is good, with high strength, toughness and heat resistance. Often used in the production of electrical enclosures, auto parts, such as computer keyboards, car dashboards.
• Advantages:
o Good overall performance, with high strength, toughness and heat resistance.
o Good surface gloss, easy to paint and color.
• Disadvantages:
o The price is relatively high.
o General weather resistance.
There are many types of plastic materials, in addition to the five general purpose plastics mentioned above, there are the following common types:
Polycarbonate (PC) : has good transparency, strength and heat resistance. Often used in the production of optical discs, lampshades, protective glasses, etc. For example, some high-quality eyeglass lenses are made of polycarbonate.
• Advantages:
o High transparency, close to glass.
o High strength, good toughness.
o Good heat and cold resistance.
• Disadvantages:
o The price is higher.
o Relatively poor wear resistance.
Polyamide (PA, commonly known as nylon) : has good wear resistance, self-lubrication and strength. Often used in the production of mechanical parts, textile equipment, auto parts and so on. For example, some car engine parts will use nylon material.
• Advantages:
o Excellent wear resistance and self-lubrication.
o High strength, good toughness.
o Good oil resistance.
• Disadvantages:
o Large water absorption, poor dimensional stability.
o Poor resistance to acid and light.
Polyformaldehyde (POM) : has excellent mechanical properties and wear resistance. Commonly used in the manufacture of gears, bearings, zippers, etc.
• Advantages:
o High mechanical strength and rigidity.
o Excellent fatigue and wear resistance.
• Disadvantages:
o Sensitive to gaps.
o Poor thermal stability.
Polyphenyl ether (PPO) : has high heat resistance, electrical properties and mechanical properties. Often used in electronic appliances, automotive industry and other fields.
• Advantages:
o Has high heat resistance and mechanical properties.
o Good electrical performance.
• Disadvantages:
o Processing and molding difficulties.
o The price is higher.
Polyester (PET and PBT) : PET is often used to make beverage bottles, films, etc. PBT is used in electronic appliances, automobiles and other fields, such as electrical sockets.
• PET benefits:
o High transparency, good strength.
o Good resistance to chemicals.
• PET disadvantages:
o Slow crystallization speed, molding processing is difficult.
• PBT benefits:
o Good molding processing performance.
o Good heat and weather resistance.
• PBT disadvantages:
o The price is relatively high.
Polymethyl methacrylate (PMMA, commonly known as acrylic) : extremely transparent, similar to glass, but more impact-resistant than glass. Often used in the production of advertising light boxes, signboards and so on.
• Advantages:
o High transparency, excellent optical performance.
o High surface hardness, scratch resistance.
• Disadvantages:
o large brittleness, poor impact resistance.
o The price is higher.
Fluorine plastic: has excellent corrosion resistance and high temperature resistance, often used in chemical, electronic and other fields of special environment.
• Advantages:
o Chemical resistance
o High temperature resistance
o is a good insulating material
o Surface is not easy to adhere to other substances
• Disadvantages:
o Processing is difficult.
o The mechanical properties are relatively weak
o The price is relatively high
o Poor air permeability
Thermoplastic elastomer (TPE, TPR, etc.) : It has the elasticity of rubber and the machinability of plastic, and is often used to make soles, sealing rings, etc.
• Advantages:
o has elastomeric and soft properties similar to rubber.
o Easy to process, recyclable.
• Disadvantages:
o Relatively low strength and heat resistance.
Liquid crystal polymer (LCP) : with high strength, high heat resistance and good electrical properties, suitable for electronics, aerospace and other high-end fields.
• Advantages:
o color heat resistance.
o Very low water absorption.
o Excellent electrical properties
o High strength and high modulus
o Good chemical resistance
o Excellent molding processing performance
• Disadvantages:
o more brittle.
o General weather resistance
o Higher price
o Liquidity is too good
