Structural Design And Synthetic Research Of Antibacterial Polyvinyl Chloride Copolymers

Polyvinyl chloride(PVC),one of the most widely used medical polymer materials,has problems with the migration of plasticizers and infections caused by the easy adhesion and proliferation of bacteria on its surface.Therefore,endowing PVC materials with excellent antibacterial properties and good processability is an objective requirement for medical PVC,as well as an urgent need to achieve high performance and high added value from traditional PVC materials.In this study,binary and ternary copolymers based on vinyl chloride were synthesized through structural design,and quaternary ammonium salt cationic antibacterial polymers were further synthesized to prepare migration-resistant antibacterial PVC materials and PVC matrix resin materials with dual functions of plasticizer and antibacterial.The main research contents are as follows:(1)Based on the excellent antibacterial and migration resistance of macromolecular quaternary ammonium salt antibacterial agents,vinyl chloroacetate(VCA)was selected as a quaternary functional monomer,and three binary copolymers of low molecular weight vinyl chloride and vinyl chloroacetate with different copolymerization compositions were synthesized through precipitation polymerization.Further,a series of macromolecular quaternary ammonium salt cationic antibacterial agents were successfully synthesized through the quaternization reaction between VCA in the copolymer and N,N-alkyldimethyl tertiary amines with different carbon numbers.The intrinsic antibacterial results showed that the macromolecular quaternary ammonium salt cationic antibacterial agents with different carbon numbers had excellent antibacterial properties against both E.coli and S.aureus.Antibacterial PVC composites were prepared by mixing macromolecular quaternary ammonium salt cationic antibacterial agents with different mass fractions and PVC matrix.The antibacterial PVC composite containing 5 wt%macromolecular quaternary ammonium salt cationic antibacterial agent has excellent antibacterial properties,with antibacterial ratio of up to 99.9%.At the same time,the migration-resistance test results showed that the macromolecular quaternary ammonium salt cationic antibacterial agent has very low mobility(<0.4%).(2)A series of P[(VC)-co-(VND)-co-(VCA)]terpolymers with molecular weights ranging from 62000 to 72000 g/mol were synthesized by suspension polymerization using vinyl neodecanoate(VND)as an internal plasticizer and vinyl chloroacetate(VCA)as a quaternary functional monomer.The test results showed that the glass transition temperature of terpolymers decreased significantly compared to pure PVC,with a minimum of 47.3℃.The plasticization process showed that the introduction of VND could significantly reduce the viscosity of the melt and improved processability.The results of mechanical properties showed that the tensile strength and impact strength of terpolymers were both improved compared to pure PVC,and the tensile strength of terpolymers being 80.0 MPa and the maximum impact strength of terpolymers being 3.0 k J/m~2,which was increased by 149%and 137%compared to pure PVC.(3)P[(VC)-co-(VND)-co-(VCA)]terpolymers were plasticized and pressed respectively into a sheet,and quaternized on their membrane surface using a weak polar solvent swelling method to obtain polymer films that integrate internal plasticizer and antibacterial functions.The mixed solvent of n-hexane to tetrahydrofuran with a mass ratio of 13:7 is suitable as a reaction medium for the surface quaternization of terpolymers.The antibacterial results showed that the antibacterial ratios of antibacterial PVC materials with a feed rate of 80 wt%PVC were 98.4%and above against E.coli and S.aureus when the actual content of VCA was 3%and above,while the antibacterial ratios of antibacterial PVC materials with a feed rate of 70 wt%PVC were 99.9%when the actual content of VCA was 4%and above.