1. The definition of plastic:
Plastic is a material with high polymer as the main component. It is composed of synthetic resin and fillers, plasticizers, stabilizers, lubricants, pigments and other additives. It is in a fluid state during manufacturing and processing to facilitate modeling , It presents a solid shape when the processing is completed. The main component of plastic is synthetic resin. "Resin" refers to a high-molecular polymer that has not been mixed with various additives. The resin accounts for about 40% to 100% of the total weight of the plastic. The basic properties of plastics are mainly determined by the properties of the resin, but additives also play an important role.
2. The reasons for plastic modification:
The so-called "plastic modification" refers to the method of adding one or more other substances to the plastic resin to change its original performance, improve one or more aspects, and thus achieve the purpose of expanding its scope of application. Modified plastic materials are collectively referred to as "modified plastics".
Plastic modification refers to changing the properties of plastic materials in the direction expected by people through physical, chemical or both methods, or to significantly reduce costs, or to improve certain properties, or to give plastics The new function of the material. The modification process can occur during the polymerization of the synthetic resin, that is, chemical modification, such as copolymerization, grafting, crosslinking, etc., can also be conducted during the processing of the synthetic resin, that is, physical modification, such as filling and co-polymerization. Mixing, enhancement, etc.
3. Types of plastic modification methods:
1) Reinforcement: The purpose of increasing the rigidity and strength of the material is achieved by adding fibrous or flake fillers such as glass fiber, carbon fiber, and mica powder, such as glass fiber reinforced nylon used in power tools.
2) Toughening: The purpose of improving the toughness and impact strength of the plastic is achieved by adding rubber, thermoplastic elastomer and other substances to the plastic, such as toughened polypropylene commonly used in automobiles, home appliances and industrial applications.
3) Blending: uniformly mix two or more incompletely compatible polymer materials into a macro-compatible and micro-phase-separated mixture to meet certain requirements in terms of physical and mechanical properties, optical properties, and processing properties. The required method.
4) Filling: The purpose of improving physical and mechanical properties or reducing costs is achieved by adding fillers to the plastic.
5) Other modifications: such as the use of conductive fillers to reduce the electrical resistivity of the plastic; the addition of antioxidants and light stabilizers to improve the weather resistance of the material; the addition of pigments and dyes to change the color of the material; the addition of internal and external lubricants to make the material The processing performance of the semi-crystalline plastic is improved; the nucleating agent is used to change the crystalline characteristics of the semi-crystalline plastic to improve its mechanical and optical properties.
