The so-called "plastic modification" refers to the method of adding one or more other substances into the plastic resin to change its original performance, improve one or more aspects of performance, so as to expand its scope of application. Modified plastics are generally referred to as "modified plastics".
The modification methods of plastics are roughly the following types:
1. Reinforcement: By adding fiberglass, carbon fibers, mica powder and other fiberglass or sheet fillers to achieve the purpose of increasing the rigidity and strength of materials, such as glass fiber reinforced nylon used in power tools.
2. Toughening: By adding rubber, thermoplastic elastomer and other substances into plastics, the purpose of improving its toughness/impact strength is achieved, such as toughened polypropylene commonly used in automobiles, household appliances and industrial applications.
3. Blending: The method of homogeneously mixing two or more incompatible polymer materials into macro-compatible and micro-phase-separated mixture to meet some requirements on physical and mechanical properties, optical properties and processing properties.
4. Alloys: Similar to blends, but with good compatibility between components, it is easy to form homogeneous systems, and some properties that a single component can not achieve, such as PC/ABS alloy, or PS modified PPO, can be obtained.
5. Filling: Improving physical and mechanical properties or reducing costs by adding fillers to plastics.
6. Other modifications: using conductive fillers to reduce the resistivity of plastics; adding antioxidants/light stabilizers to improve the weatherability of materials; adding pigments/dyes to change the color of materials; adding internal/external lubricants to improve the processing properties of materials; using nucleating agents to change the crystallization characteristics of semi-crystalline plastics to improve their mechanical and optical properties, etc.
In addition to the physical modification methods mentioned above, chemical reactions are also used to modify plastics to obtain specific properties, such as maleic anhydride grafted polyolefin, polyethylene crosslinking, peroxide degradation in textile industry to improve fluidity/fibrillation performance, etc.
Many modification methods are often used together in industry, such as adding rubber and other toughening agents in the process of plastics reinforcement and modification in order to reduce the impact strength, or physical mixing and chemical crosslinking in the production of thermoplastic vulcanizates (TPV).
In fact, any kind of plastics raw materials at least contain a certain proportion of stabilizers when they leave the factory to prevent their degradation in storage, transportation and processing. Therefore, in a strict sense, "non-modified plastics" do not exist. However, in industry, the basic resins produced by chemical plants are usually referred to as "non-modified plastics" or "pure resins".
