Preparation And Properties Of Biaxially Oriented Nylon 612 Antibacterial Film

Biaxially oriented nylon film is widely used in the field of food packaging due to its excellent comprehensive properties.At present,BOPA film products are mainly concentrated on PA6 and PA66 films.With the improvement of people’s environmental protection awareness and the depletion of petroleum resources,it has become an inevitable trend to develop alternatives to traditional nylon film.The emergence of bio-based long carbon chain nylon not only makes up for the defect of traditional nylon film performance degradation after water absorption but also has great significance for relieving oil pressure and responding to environmental protection packaging.However,conventional nylon films do not have antibacterial properties.The derivation of bacteria during use will not only affect the shelf life of the packaged products but even directly threaten people’s health when it comes into contact with the human body.The antibacterial properties of stretched nylon films can broaden their application range in the packaging field.To this end,this study selected semi-bio-based nylon 612(PA612),which is a polycondensation of monomer hexamethylene diamine and bio-based dodecanedioic acid,as the matrix.In order to improve the antibacterial properties of PA612,Nano-zinc oxide(m-Zn O)was modified by the γ-aminopropyltriethoxysilane coupling agent(KH550)was used as an antibacterial agent,and PA612/m-Zn O composites with different contents of antibacterial agents were prepared.In order to improve the rigidity and barrier properties of long carbon chain PA612,under the optimal content of antibacterial agent,polymetaxylylene adipamide(MXD6)with a benzene ring structure was introduced to prepare PA612/m-Zn O/MXD6 composite material with different MXD6 contents.The effect of crystal structure and orientation on the macroscopic properties of PA612/mZn O/MXD6 biaxially oriented thin films was investigated.The main research contents are as follows:1.Research on PA612/m-Zn O composite material.The coupling agent KH550 successfully modified the nano-zinc oxide particles,and the m-Zn O nanoparticles were well dispersed in the PA612 matrix.The addition of m-Zn O made PA612 effective against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli Bacilli have antibacterial activity.When the addition amount of m-Zn O exceeds 4 wt%,the antibacterial rates against Staphylococcus aureus and Escherichia coli both reach more than 90%.The addition of m-Zn O can effectively improve the crystallinity of PA612,and has a certain enhancement effect.The research shows that the comprehensive properties of the PA612/m-Zn O composite film are the best when 4 wt%m-Zn O is added.2.Research on PA612/m-Zn O/MXD6 composites.The addition of MXD6 significantly improves the stiffness of the composites.And improve the crystallinity of PA612,and enhance the barrier properties of the composite material.The research shows that the PA612/mZn O/MXD6 composite with 30 % MXD6 has the best comprehensive properties.3.Research on PA612/m-Zn O/MXD6 biaxially oriented film.PA612/m-Zn O/MXD6 cast films with m-Zn O content of 4 % and MXD6 content of 30 % were prepared by extrusion casting,and uniaxially stretched with different stretching ratios were prepared by a biaxial stretching machine.film and biaxially oriented film.Stretching not only improved the dispersion of m-Zn O particles in the PA612 matrix,but also changed the crystal structure of PA612,and promoted the crystallization and crystal orientation of PA612/m-Zn O/MXD6 films.The improvement of nanoparticle dispersibility improves the antibacterial properties of the films,and the crystal orientation improves the mechanical properties,optical properties,barrier properties of the films.It can be seen that the experimentally prepared PA612/m-Zn O/MXD6 biaxially oriented composite film has excellent comprehensive properties and has broad application prospects in the field of packaging.