(1) Select additives according to intended purposes
Select appropriate additive varieties based on the target performance requirements. The added additives shall fully exert their expected functions and meet specified standards. The specified standards generally refer to national standards, international standards, or performance requirements proposed by customers.
The selection scope of additives is listed as follows:
- Toughening: Elastomers, thermoplastic elastomers, and rigid toughening materials.
- Reinforcement: Glass fiber, carbon fiber, whiskers, and organic fibers.
- Flame retardancy: Bromine-based (conventional bromine series and environmentally friendly bromine series), phosphorus-based, nitrogen-based, intumescent nitrogen/phosphorus composite flame retardants, antimony trioxide, and hydrated metal hydroxides.
- Antistatic: Various types of antistatic agents.
- Conductive: Carbon materials (carbon black, graphite, carbon fiber, carbon nanotubes), metal fibers and metal powders, metal oxides.
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Magnetic properties: Ferrite magnetic powder, rare earth magnetic powders, mainly including three categories:
Samarium–cobalt series (SmCo₅, Sm₂Co₁₇), neodymium–iron–boron series (NdFeB), samarium–iron–nitrogen series (SmFeN), and alnico magnetic powder.
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Thermal conductivity: Metal fibers and metal powders, metal oxides, nitrides and carbides;
carbon materials such as carbon black, carbon fiber, graphite and carbon nanotubes;semiconductor materials such as silicon and boron.
- Heat resistance: Glass fiber, inorganic fillers, heat-resistant agents such as substituted maleimides and β-nucleating agents.
- Transparency: Nucleating agents. For PP, sorbitol-based α-nucleating agent Millad 3988 delivers the best effect.
- Wear resistance: Graphite, molybdenum disulfide, copper powder, etc.
- Insulation: Calcined kaolin.
- Barrier property: Mica, montmorillonite, quartz, etc.
(2) Additives are resin-selective
Red phosphorus flame retardants are effective for PA, PBT and PET.
Nitrogen-based flame retardants work well for oxygen-containing resins such as PA, PBT and PET.
Nucleating agents show good performance for copolymerized polypropylene.
Thermal modification with glass fiber is effective for crystalline plastics but poor for amorphous plastics.
For carbon black filled conductive plastics, the conductive effect is better in crystalline resins.
