1. Recycling of plastic

Daily commodities made of plastic now make up a sizable portion of resource waste. For instance, beverage bottles are currently a significant category in material recycling. The body and top of beverage bottles, however, are often made of two separate materials. For instance, the PET material used to make the bottle body and the PE material used to make the bottle cap are incompatible with one another, making recycling problematic.

The majority of plastic goods are challenging to handle and degrade, however compatibilizer research and applications in recycling and modification can efficiently address these issues. Utilizing compatibilizers to combine and regenerate waste plastics into new plastic alloys or new modified plastics is a practical solution to the issue of "white pollution" that also lowers costs and improves social and economic advantages.

2. Choosing a compatibilizer

Regardless of the kind of plastic recovered, the base resin is typically made of the recycled plastic, and the compatibilizer is a copolymer made by grafting two strong polar groups together. MAH, acrylic acid, butyl acrylate, methyl methacrylate (MMA), glycidyl methacrylate (GMA), and other graftable groups are examples. MAH is the most popular grafting monomer.

3. Use in the recycling system

①System for PET/PE bottles

The beverage bottle's body and cap are often composed of separate materials; for instance, the body is made of PET material while the cap is made of PE. When recycling, several grafts including maleic anhydride (MAH) and glycidyl methacrylate (GMA) are often used compatibilizers in PET/PE systems.

②System made of discarded PC and ABS

A thermoplastic engineering material with widespread use, high demand, and exceptional all-around performance is polycarbonate (PC). To minimize melt viscosity, enhance processing efficiency, lessen product internal stress, and create high-strength and anti-corrosion materials, it is frequently combined with ABS. The automobile sector, electrical appliances, manufacturing, computers, health care, and other industries all require blended materials with impact, tensile, and heat resistant qualities. Research on waste PC and waste ABS recycling offers significant economic benefits and is important for sustainable development. Styrene/maleic anhydride random copolymer, styrene/acrylonitrile/maleic anhydride terpolymer, ABS grafted maleic anhydride, etc. are compatibilizer components that can be employed.Blending creates materials with more complete qualities, which may be promoted and utilized in industries like home appliances, cell phones, and vehicle parts.

③Flexible packaging made of a mixture of paper, plastic, and aluminum.

One typical type of flexible packaging material is paper/plastic/aluminum composite. Soft packaging boxes for a range of beverages are frequently made with it. It is made of paper, plastic, and aluminum foil and typically has a six-layer structure: polyethylene (PE), paper layer, plastic (PE), aluminum foil, adhesive (AD), and polyethylene. Of these, about 75%, 20%, and 5%, respectively, are made of paper, plastic (PE), and aluminum, which are all recyclable resources.

When compared to PE, which is non-polar and has few functional groups like polar hydroxyl and phenolic hydroxyl, the main component of wood fiber, cellulose, is polar. As a result, the compatibility between the two is poor, and the presence of aluminum foil also worsens the interface. Complexity. It is required to resolve the interfacial compatibility and interfacial bonding of wood fibers, aluminum foil, and polymers in order to produce composite materials with desirable qualities.

According to studies, maleic anhydride grafted polyethylene (PE-g-MAH) may significantly boost the interfacial compatibility of the composite system, and the final mixed system gets better the more PE-g-MAH, the composite material, is used. The impact strength steadily rose, the water absorption initially increased and then reduced, and the tensile and flexural strengths first increased and then declined. This is due to the fact that PE-g-MAH can improve interfacial bonding and promote compatibility between wood fiber and plastic matrix, but it is also connected to the strength of the PE-g-MAH coating that is applied to the surface of the wood fiber[3].

④System of wood-plastic composites

Using wood fiber as its primary raw material, wood-plastic composite material is a brand-new composite material with excellent performance and high added value that can be blended with different polymers using a variety of composite techniques. Wood-plastic is a brand-new form of composite material that combines the benefits of both wood and plastic while also being resource- and environmentally-friendly. It is a novel technique for handling used plastics. However, since waste plastics (such as PE, PP, etc.) have essentially little polarity and wood fibers have a significant polarity, the two phases cannot connect well, which lowers performance.The bonding state can be improved by surface treating waste plastics with a suitable quantity of compatibilizer.

The compatibilizer may combine two or more outdated polymers with various types and qualities to create new materials, eliminating resource waste and frequently improving the performance of the resulting new systems.

Compatibilizers are essential for both the modification of original resins and the recycling of used plastics. The needs of resource recovery will guide additional study on this subject.