In today’s daily life There is a tendency to use plastic that is increasing. Because it can be used to replace natural resources such as wood and steel because it is cheap, lightweight, can be produced as needed. Some plastics, when cooled, can solidify according to our purpose. And when being wet, it can weaken Some types can be permanently hardened, such as nylon, artificial rubber that can be used to produce clothing, films, containers, vehicle components, etc. with modern technology. Therefore resulting in many forms of plastic products Plastics are therefore accepted and used more and more.
Plastic is divided into 2 types
1. Thermoplastic is a widely used plastic. Is a plastic that, when heated, will weaken And when faced with coldness, this plastic will harden Can be changed Can be re-melted by heat The molecular structure of the polymer chain is a straight line or a short branch. Soluble in some solubility Can be molded by injection while the plastic is weak and flows with heat and pressure Into the mold with gaps in the desired shape After the plastic flows into the mold Will be cooled down And remove from the mold And will get the desired product Can be used And can be recycled by grinding and melting by heating To be molded into a new product again
Types of thermoplastics include
– Polyethylene (PE) is a plastic with a small amount of water vapor. But the air can pass in and out Turbidity and heat resistance It is the most commonly used plastic in the industry such as water pipes, tanks, bags, bottles, pallet support
– Polypropylene (PP) is a plastic with a small amount of water vapor Having a harder appearance than polyethylene, high fat and heat Can be used to make plastic sheets Heat resistant food packaging bag And plastic straws etc.
– Polystyrene (PS) is transparent, fragile, resistant to acids and alkalis. Steam and air permeable enough Popularly made into electrical and electronic parts Office equipment, etc.
– SAN (Styrene-acrylonitrile) is transparent. Commonly used to produce electrical parts Car parts etc.
– ABS (Acrylonitrile-butadiene-styrene) has properties similar to polystyrene. But better chemical resistance, tougher, translucent, more popular to produce plastic cups, plastic trays etc.
– Polyvinylchloride (PVC) . Steam and air are permeable enough. And can protect fat well, has a clear appearance Commonly used as a bottle for oil and cooking bottles Alcohol bottles include wine, beer, used to make plastic sheets, wrap cheeses, laminate the inner layer of plastic bags, etc.
– Nylon is a very tough plastic Resistant to temperature increases Used for making vacuum plastic food bags.
– Polyethylene terephthalate: PET) is sticky, transparent, expensive and used to make thin films Packing beverages and food.
– Polycarbonate (PC) is transparent, strong, resistant to strong adhesion and impact. Able to endure high heat Acid resistant but not alkali resistant Does not stain and stain food Popular as cups, plates, bowls, baby bottles and bottles for children.
2. Thermosetting plastic) is plastic that has the structure of the body. It has special features that are resistant to temperature changes and resistant to chemical reactions that permanently molten various shapes. Cannot melt again when exposed to heat Or can be melted again This property therefore Thermosetting plastic Not so popular, this type of plastic has molecules that connect together into a mesh, held tightly together. The molecular adhesion force is very tough, such as phenolic resin, epoxy and polyurethane etc. These plastics are used through molding. In the form of a low viscosity liquid, it can flow along the mold or mold. Then the resin is cured by heat or chemical reaction. Causing erection The product can be removed from the design without having to wait for it to cool. Because the product will freeze inside the mold
Types of thermosetting plastics include
– Melamine Formaldehyde (Melamine Formaldehyde: MF) consists of molecules that form a bond together to become clear and hard plastic. Is a plastic that is extremely heat resistant Scratch resistant Therefore popular as a kitchenware Electronics components Coated plywood And attach the layer of wood to plywood. The disadvantage is that when vinegar is absorbed into the plastic easily And smudges, but not toxic because they do not react with plastic chemicals
– Phenol-Formaldehyde or Phenolics is the first polymer produced in 1910, in which Phenol Aleks nowadays are widely popular. Because it is strong The cost of production is not much. Good electrical resistance and resistance to salt and oil solvents Popularly used in producing caps, jars, pots, pans, electrical switches, heating plates, handles, irons, radio and television frames And toaster base
– Epoxy (EP) is in the epoxide group (Cyclic-CH2OCH. The word Cyclic means Molecules shaped in triangular rings) that are attached to the molecule Oxygen in the carbon chain and the epoxide group That is at the end of the carbon chain Making the epoxy very tough and resistant to corrosion And does not shrink during drying Used to coat the surface of household appliances and pipes.