ADDITIVES | COMPATIBILISERS
Sweden’s Nexam Chemical has developed a concept it calls Reactive Recycling for improving the performance of mixed recycled polymer streams that are difficult to recycle. An example is recycled PP containing HDPE. ”Nexamite R201 provides compatibilisation of PP and PE by reacting the polymers together creating a PP/PE hybrid,” says the company’s Chief Marketing Officer Lars Öhrn. “Tensile testing is showing less varia- tions when R201 is added to an 85% rPP and 15% rHDPE mix.”
Another application example is PE containing
Above: Tensile testing of an ocean plastic blend (left) and the same material compatibilised with 2 wt% compatibilisers developed by Intermix Performance Materials (right). Note the break in the uncompatibilised sample and the high elongation in the compatibilsed material.
become promising materials which could be reprocessed into products, regardless of the composition and inseparability of the recycled HDPE/iPP blends. This can significantly decrease the cost for plastics recycling and enhance the recycle efficiency.” Intermix currently has five employees focusing
on research and business development for the products and is collaborating with a number of toll manufacturers to scale up production of the compatibilisers from gram to kilogram scale. “Products made of recycled HDPE/iPP blends may soon be realised,” says Lin.
PA. Tensile testing has shown improved mechanical performance and surface appearance when adding Nexamite R405 to a mix of 93% HDPE and 7% PA6. Yield stress is also improved and break strength is said to be on a par with pure HDPE. Öhrn does not disclose the specific reactive chemistry employed but says it is not based on maleic anhydride grafting. “It functions in polyole- fins but can also bridge and react with polyconden- sates. As with all reactive extrusion you need to have proper mixing and energy input for best results,” he says. Nexamite R201 and R405 are both offered in masterbatch form. The latest addition to the Nordic Grafting
Company’s portfolio is Acti-Tech compatibiliser 16MA11F. It is based on a Vistamaxx semi-crystal- line copolymer from ExxonMobil grafted with maleic anhydride (MA). NGC, which is a licensee of ExxonMobil technology, says the new additive is compliant with the EU 10/2011 food contact regulation and offers recyclers and processers an easy-to-add and universal compatibiliser to enhance the value of blends containing various
Table 1: Comparison of key mechanical properties of HDPE and HDPE/PA6 blends with and without Nexamite compatibilisers
100% HDPE 93% HDPE /7% PA6
88% HDPE/7% PA6/ 5% Nexamite R405 Source: Nexam Chemical
Yield Stress (MPa) 25.6 23.7 27.3
Yield Strain (%) 12.9 10
10.6
Break Strength (MPa) 42.7 34.2 42.6
Table 2: Comparison of key mechanical properties of rHDPE, rPP, and rHDPE/rPP blends with and without Nexamite compatibilisers
Yield stress (MPa)
100% rPP 100% rHDPE 85% rPP/15% rHDPE
80% rPP/15% rHDPE/5% Nexamite R201 Source: Nexam Chemical
42 COMPOUNDING WORLD | May 2022
27.6 34.7 27.1 27.2
Yield strain (%)
11.3 8.8
10.2 12.5
Break
Strength (MPa)
33.1 30.3 24.9 30.1
Break Strain (%)
632 747 505 648
Break Strain
123 150 18
MFI
Std dev (g/10min) 62
2.5 1.2 2.4 1
www.compoundingworld.com
IMAGE: INTERMIX PERFORMANCE MATERIALS
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