| In recent years,due to serious environmental pollution,the call for protecting the environment has become higher and higher,and environmental friendly materials have been favored by many scholars.Polylactic acid(PLA)has been widely used in the medical field,agricultural fabrics,hygiene products and other fields due to its good biocompatibility and biodegradability,such as bone stents,disposable infusion equipment,non-woven fabrics and plastic products.However,its high hardness,high brittleness,and poor toughness limit the application of polylactic acid in food packaging,industrial production,and plastic products that require foaming and blowing molding.Thermoplastic polyurethane elastomer(TPU)is a polyester with high strength and high ductility.Its excellent wear resistance,high elasticity and low temperature resistance make it widely used in many fields such as clothing,construction,medical treatment,etc.By preparing PLA/TPU composite materials,the flexibility,elasticity and impact resistance of PLA can be improved.During this process,the activity of the molecular chain segment increases,the energy required for rearrangement movement,the intermolecular force and the strength decreases significantly,and the ductility enhanced greatly.Therefore,PLA/TPU composite materials have great room for development.In this paper,PLA/TPU composites were prepared by solution blending method.PLA and TPU were dissolved in N,N dimethylformamide(DMF)under water bath conditions,and mixed evenly by high-speed stirring,until PLA and TPU were completely.After dissolving in the solvent,pour it into the mold,dry and form in a vacuum drying oven.At the same time,a lysozyme(LYM)carbon nanotube(CNTs)hybrid material was prepared and added to the PLA/TPU composite material for modification.The PLA/TPU/LYM/CNTs composite material was studied.At the same time,as the thermal and mechanical properties,the effect of LYM/CNTs hybrid materials on the compatibility and interface properties of PLA/TPU composites was analyzed.Scanning electron microscope,differential scanning calorimeter,thermogravimetric analysis,dynamic mechanical analysis and tensile test were used to characterize the microstructure,thermal and mechanical properties of the composite.The experimental results show that TPU significantly changes the thermal performance of PLA,the glass transition temperature of PLA decreases significantly.As the TPU content increased,the glass transition temperature and thermal decomposition temperature gradually decreased;fluidity of PLA from 4.78g+(10 min)-1 to 176.7 g¡(10 min)-1;meanwhile,the tensile strength of PLA is reduced from 55MPa to 15MPa,and the elongation at break is increased to 125%.When the mass ratio of PLA to TPU is 20:1,the PLA/TPU composite material has the best comprehensive performance.At this time,the tensile strength is 19.6 MPa and the elongation at break is 145.6%.LYM/CNTs hybrid materials were added as modifiers to PLA/TPU composite materials,and the compatibility and interfacial interaction between polymer chains were further studied.The results show that after adding LYM/CNTs hybrid materials,PLA/TPU composite surface "island structure" is significantly reduced,and there are no obvious cracks and deep holes on the surface,interface compatibility is improved effectively.By adding TPU to modify PLA,it complements the defects and deficiencies of PLA itself in a complementary way,as well as improving the performance of PL A products,broadening the scope of PLA application,and promoting the development in the market.After the addition of LYM/CNTs hybrid materials,the interface compatibility of PLA/TPU composites was improved,and the bonding ability between the two was fundamentally strengthened.The interface performance and comprehensive was improved,which may further promote the development in the packaging field. |
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