Bulk rheology and surface tribo-rheometry toward the investigation of polyisobutylene migration in model and recycled multilayer agricultural films

Abstract

This paper is dealing with the polyisobutylene (PIB) migration phenomenon through the post-consumer agricultural waste multilayer films based on four linear low-density polyethylene (LLDPE) matrices. Through this work, a bridge between shear, elongational rheology, and tack surface properties was revealed on both model and recycled blends. Hereto, effects of aging time and temperature were investigated and rationalized depending on the short- and long-chain branching in LLDPE matrices as well their polyethylene (PE) crystallization. The linear viscoelastic properties were influenced despite the small PIB amounts. This migration influenced also the slippage in steady flow regime. It was also demonstrated that transient uniaxial extensional properties are very sensitive in the presence of PIB, which seems to hold back the PE strain hardening properties. Therefore, the axial force and the surface friction coefficient were determined and discussed in correlation with bulk rheological findings. Hence, the obtained results contributed to unveiling new insights on the physical mechanisms governing the PIB migration with or without fillers to inhibit its migration in their recycled films.