Modifiers for Recycled Plastics

The demand for recycled plastic compounds is rising. However, weathering, aging, degradation from multiple processing histories and contamination can cause quality and performance issues with recycled materials. Adding impact modifiers will help to boost the impact and toughness properties of recycled compounds. Adding compatibilizers will help to ‘tie-together’ dissimilar or incompatible polymers / contamination and boost the mechanical properties of the final compound. In addition, compatibilizers can allow you to utilize lower cost feed-stocks that are based on mixed-polymers.

Impact modifiers are typically based on rubbers or elastomers that are added to a recycled material to improve impact, toughness, elongation and flexibility. There are a number of different types of impact modifiers and which one to use will be dependent on the polymer type that is being modified, the desired end performance, cost or other factors. Loading levels from a few percent to 30% are common depending on the desired end properties.

Compatibilizers are, by definition, a substance that is added to an immiscible blend that will increase its stability. In practical terms, a compatibilizer is a modifier that is added to a blend of materials, often a polar and non-polar thermoplastic, to ‘tie them together’ so that they will have improved properties. Compatibilizers are often block or grafted thermoplastics so that one part of the compatibilizer interacts with one component in the blend, while the other part of the compatibilizer interacts with the other part of the blend.

Compatibilizers are also used when creating thermoplastic blends such as polycarbonate / ABS blends or nylon / polypropylene blends or for improving the dispersion of fillers like calcium carbonate.

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