Preparation And Performance Study Of Copolyamide 6/56 Film

Polyamide 6 films are widely used in the packaging industry for their excellent properties.The properties of bio-based polyamide 56(PA56)are close to PA66,and copolymer modifications have unique advantages for enhancing the performance of polymer materials.It is crucial to develop new eco-friendly and high-performing copolyamide film materials.In this paper,PA6/56 is prepared by copolymerizing bio-based PA56 salt with caprolactam,and the resin structure-properties and processing for film applications are investigated:The structure and properties of PA6/56 with varied copolymerization ratios were investigated.The results showed that the PA6/56 has good thermal stability,and the melting point decreases with the increase of copolymerization ratio.The melting point of PA6/56 with20% copolymerization ratio was 200.3 ℃,which is 19.2 ℃ lower than that of PA6,which can reduce the application processing temperature.According to the polarizing microscope observation,when the copolymerization ratio is 10%,large crystals began to appear in the crystallization process of PA6/56,and the average radial growth rate of crystals was slightly higher than that of other copolymerization ratio samples,the influence of the second component PA56 on the copolymer was significant.But overall,as the copolymerization ratio increased,the copolymer’s crystallisation ability weakened and of crystallinity decreased.The processing properties of PA6/56 were investigated.The results showed that PA6/56 was a typical pseudoplastic non-Newtonian fluid in the range of 250-270 ℃.The 10%copolymerization sample has slightly higher viscous flow activation energy than the other two polymers,indicating that it is more sensitive to temperature changes.PA6/56 films was prepared and characted.The results showed that the tensile strength of the polymer decreased and the elongation at break increased significantly after copolymerization.Compared to PA6,the 15% copolymerization ratio of PA6/56 improved elongation at break from 689% to 801%,which was better than the corresponding 695% for PA6/66.The results show that the preferred longitudinal and transverse stretching temperatures are around 45 ℃ and 60 ℃ respectively,and the stretching multiplier was 3 times.