Kathrin Lehmann, Evonik, summarised the advantages of organomodified siloxanes (OMS) as functional PIN synergists. Inclusion of specific functional groups onto the ends or sides or siloxane molecular chains enables either full polymer compatibility, or to ensure that part of the OMS molecule embeds in the polymer whilst part remains outside giving interface properties.
OMS can thus improve melt flow behaviour, surface appearance or electrical performance of PIN FR polymer compounds and reduce “die drool” in cable extrusion. For example, 1% of specific OMS with inorganic FRs can enable to combine UL94-V0 with melt flow and CTI specifications in polyamides / glass fibre polyamides, TPO/polyethylene or polypropylene. This addresses applications such as thin wall electronics parts or performance cables.