Working with Thermoplastics - Setting and Softening
The word "plastic" means soft or flexible, but modern plastics include a large range of synthetic polymers that are hard and rigid. We use various plastic products in our daily lives such as shopping bags, casings for electrical plugs and sockets, electronic gadgets, and many more.
Plastic has various unique properties compared to other materials, and it is being used to increase the quality of our daily life. We use plastic bags, nylon shirts, chairs, etc.; all are different types of plastic products. You can recognize by a touch that these products are not same. Some of them are very soft and some of them are significantly harder. We also use them as electrical and thermal insulators; for example plastic handle used in a pan and insulation around electrical fittings.
These different types of plastics are divided into two types, thermosetting and thermosoftening plastics. They have different properties and application areas.
Thermosoftening Plastics or Thermoplastics
The intermolecular forces between the polymer chains of thermoplastics are very weak; due to this, they can be remolded into new
shapes easily. They can be softened between the temperature 65ºC and 200ºC (149°F to 392°F) and once set, can be returned to their plastic state by reheating. The methods that are used to mould them are injection molding, extrusion, vacuum forming, compression molding, and rotational molding.
Types of Thermoplastics
Acrylonitrile Butadiene Styrene (ABS)
This is a plastic that can be molded in every method provided above. It is strong, tough, hard, and durable. It is used for making dashboard, car trims, toys, and phone parts. Electrical products are also made by this type of plastic.
Nylon is molded by injection molding and extrusion method. The main property of this plastic is that it is self lubricating and chemical resistant. It is used to make engineering products like bearings, gears, and hinges.
Acetate or cellulose
Acetate is stiffer than other types of plastic. It is transparent, light and has high resistance to heat. The method used for molding this plastic is injection molding. It is used for making tool handles, frames, and pen parts.
Polystyrene is a very light, very tough, and transparent plastic. It is waterproof and brittle in nature. It can be molded using the vacuum forming method. It is used for packaging, electrical product casing, and for making toys.
Polyethylene is the most used thermoplastic in our daily life. The main property of this plastic is its insulation towards electricity. It is flexible, soft and stiff. It is used for packaging, bags, bottles, and for some home appliances.
In thermosetting plastic, the polymer chains form strong cross linked covalent bonds that make it very rigid and hard. After given a shape, they can’t be remolded or softened. It has more resistance to heat than thermoplastics. The products made up of this type of plastic can only be recycled when you have finished with it.
Examples of Thermoplastic Materials
Urea formaldehyde is very strong and good insulator of electricity and heat. It is brittle in nature and is very stiff. It is used for manufacturing electrical fittings, handles, and knobs.
Polyester resin is brittle in nature if fiber is not used as reinforcement. It presents in liquid raw state and has chemical resistance property. This plastic is used for bonding glass, Kevlar, and carbon fibers.
Epoxy resin is a good insulation material and brittle in nature. It is used as an adhesive for bonding fibers and in encapsulation.
The reflective index of Polycarbonate is very high. It is very strong and transparent material and used for making lenses for glasses.
Thermoplastic and Thermosetting Plastic Suppliers
De-Comp Composites supplies various products of thermoplastics and thermosetting plastics. All the products are classified in various sections such as vacuum bagging film, bleeders, release films, peel plies, tapes, autoclave hoses, sealant tapes, tool prep liquids, and more. Color, size and use temperature is also written on the right side of the product so as you can choose them according to your needs.
De-Comp Composites is basically for plastic materials but the EIS offers basically plastic products. However, they also provide some plastic materials like electrical insulation materials and adhesive sealants. The plastic products you can find in this company are wires and cables, test and management equipments, and tapes and fasteners.
BCC Products offers very useful plastic products and materials such as paste materials, modeling boards, laminating resins, surface coats, casting epoxy, casting urethanes, prototyping materials, silicones, urethane elastomers, and adhesives. Each section has a number of similar products that are used for different requirements.
Both types of plastics are very important materials and they have different properties, structure, and applications. Thermoplastics are easy to recycle and are very cheap whereas thermosetting plastics are rigid and their recycling is very difficult. Besides, they also display negative impact on environment. Therefore, we should avoid excess use of plastic materials.
Composites, D-Comp, "Product List", http://www.decomp.com/product_list.htm
BCC, "BCC Products", http://www.bccproducts.com/
Your One Source of Material, EIS, "Products", http://www.eis-inc.com/products/default.html
Absorb Chemistry for GCSE, "Properties of Plastics and Disposal Waste",http://intranet.stthomasmore.org.uk/resource/Absorb%20Chemistry/Absorb%20Chemistry%20for%20GCSE/HTML/units/LR1205.htm
Image- "Thermosetting", Flickr, By Joost J, http://www.flickr.com/photos/joost-ijmuiden/5805381497/
Image-"Thermoplastics", Flickr, By Joost J, http://www.flickr.com/photos/joost-ijmuiden/5453282232/
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