Identification of polybutene-1 (PB-1) in easy peel polymer structures

Polybutene-1 (PB-1) is dispersed via extrusion in polyethylene (PE) based sealing layers to achieve 'easy peel' properties. PB-1 forms islands there. During opening of packagings with such sealing layers, cohesive fracture occurs within the sealed area along these PB-1 islands. The aim of this study was to find suitable methods for the identification of PB-1 in such PE based sealing layers. For this investigation PE-LD films with 3, 6, 9, 12 and 15 wt.-% PB-1 were extruded. FTIR spectroscopy and FTIR microscopy are suitable methods to identify low concentrations PB-1 in PE-LD layers in opposite to GC-FID and DSC. Raman spectroscopy is a suitable method to distinguish PB-1 from PE-LD.