Polymer Engineering and Science, Vol.42, No.1, 134-145, 2002
Investigation of structure development in polyamide 11 and polyamide 12 tubular film extrusion
The processability of single bubble polyamide 11 and polyamide 12 films was investigated. The development of crystalline structure and chain orientation of polyamide 11 and polyamide 12 films in single bubble film blowing was studied by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXS), infrared M spectroscopy, and birefringence. DSC measurements of both films revealed a spontaneous increase in glass transition temperature (T-g) and cold crystallization temperature (T-c) during aging at room conditions, with crystallinity and melting point remaining constant. Single bubble polyamide 11 and polyamide 12 films exhibited triclinic alpha and monoclinic gamma crystals, respectively. The level of biaxial orientation was evaluated by calculating White-Spruiell biaxial orientation factors with pole figure data. We were not able to produce biaxially oriented double bubble films with either polyamide 11 or polyamide 12.