ADDITIVES | COMPATIBILISERS


Figure 1: Impact strength after ageing at 135°C for an automotive bumper TPO recyclate containing paint residues with and without BYK’s Recyclobyk 4373 compatibiliser


90% of the original impact strength is still present (Figure 1). BYK is also planning future developments for its Scona functionalised polymer product range. “These are mainly non-polar polymers modified by chemical grafting with additional functional monomers,” says Garlinsky. “Typically, unsaturated monomers such as maleic anhydride (MSA), 2,3-epoxypropyl meth- acrylate (GMA), methacrylic anhydride (AA), which contain additional functional groups, are grafted onto the polymer by a radical addition mechanism. In this way, a large number of functional polymers with completely different properties can be created.” One of the new products BYK plans to launch is


a grafted PET based on recycling feedstock. Garlinsky says it can be used as a novel high-per- formance polymeric modifier to improve the intrinsic viscosity of recycled PET. Formed at Cornell University in the US, Intermix


Performance Materials says it has successfully scaled up one of its materials that compatibilises virgin and post-consumer blends of polyethylene (PE) and polypropylene (PP). “We are currently working with four end-users of polyolefins to explore the use of their materials in a number of applications,” says Geoff Coates, Co-founder of Intermix and Professor in the Department of Chemistry and Chemical Biology. “These include recycling of post-consumer plastic packaging, development of polymer alloys for use in athletic gear, remediation of PE and PP rope recovered from the ocean, and reinforcement in composite pipe construction. Intermix is also investigating a new generation of compatibilisers with a major polyolefin producer and was recently granted STTR grants from the NSF (Phase 1) and DOE (Phase 2),” he says. Intermix adds that its polymer additive enables


44 COMPOUNDING WORLD | May 2023


Source: BYK


the valorisation of mixed plastics at low cost producing a higher quality resultant resin. PP and PE account for about two-thirds of all plastics in the post-consumer waste stream. However, due to their different structures they are not miscible, causing them to phase separate, somewhat like oil and water. This results in plastic mixtures with unaccept- ably poor strength.


Intermix has developed a multi-block copoly- mer (MBCP) that, when added to a stream of mixed PP and PE, enables these two polymers to be combined to yield a polymer alloy that is said to be mechanically comparable to pure PE and PP samples without laborious and expensive sorting. The MBCP additive can compatibilise mixtures of PE and PP with as little as 0.5% of the additive and at contamination levels of up to 70/30. Strong demand for compatibilisers and coupling agents for virgin and recycled polymers is reported by Nordic Grafting Company (NGC). “However, the lack of available post-industrial and post-con- sumer recycled (PIR and PCR) materials have pushed compounders, recyclers and converters further in their waste management and sourcing of plastic materials,” says Quentin Le Piouff, Market Development Manager.


“Many players involved with mechanical recycling have begun using previously rejected or challeng- ing waste streams such as mixed polyolefins, highly contaminated polyolefins or flexible multi-layer packaging, enabled by improvements in machinery and by new compatibiliser solutions,” he says. “For mixed or multi-layer polymer materials from PIR and PCR, compatibilisation is an ideal solution. It is also good for reducing PIR generation, by enabling the use of in-house recycled plastic into existing products of converters, without lowering end-properties. There is also a demand for a higher


www.compoundingworld.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64