Preparation Of TiO₂-Ag Mesoporous Microspheres And Study On The Spinability Of TiO₂-Ag/PLA Antibacterial Composite Materials

Polymer materials are closely connected to our human life,but most can not be decomposed,and its waste become into white garbage in the human life,even causing harm to the human survival environment.Therefore,po lylactic acid?PLA?,which is biodegradable polymer material,has become an increasingly impor tant research topic.With the commercialization of melt-blown grade PLA raw materials,the study of PLA melt-blown nonwovens is also popular in the nonwovens industry.However,simple PLA electrode melt-blown materials are widely used in air filtration suc h as masks,medical protection and air conditioning filters,but they have many disadvantages such as high filtration resistance,low efficiency and unsatisfactory antibacterial properties.Therefore,we use porous titanium dioxide which have about 250 nm partice size and can adsorb while reducing resistance,and silver?Ag?composite also can achieve high-performance filtration and antibacterial.In this paper,TiO₂-Ag mesoporous microspheres were prepared by sol-gel method using polyethylene glycol?PEG?as a pore-forming agent,titanate as titanium source and AgNO₃ as silver source.The prepared TiO₂-Ag mesoporous microspheres were characterized by SEM/EDS,TEM,XRD and BET.The experimenta l results show that Ag-TiO₂ nanoparticles prepared by sol-gel method have the best calcination temperature of 500? and the specific surface area of 126.25m2.g-1.Secondly,TiO₂-Ag/PLA composite particles with different content of TiO₂-Ag was prepared by melting and blending the TiO₂-Ag mesoporous microspheres prepared in the second chapter with PLA.The prepared TiO₂-Ag/PLA composite particles,structure morphology,crystal structure,crystallization property were characterized by SEM,FT-IR,XRD and DSC.The results show that TiO₂-Ag mesoporous microspheres are evenly distributed on the PLA matrix.With the increase of the content of TiO₂-Ag,the particle on the cross-section of PLA composite masterbatch increases.Then,the results show that a relatively small amount of TiO₂-Ag mesoporous microspheres can promote the crystallization of PLA matrix,improve crystallinity and thermal stability of TiO₂-Ag/PLA composite particles.The comprehensive performance area of TiO₂-Ag/PLA composite particles decrease with the increase of the content of TiO₂-Ag mesoporous microspheres.The antibacterial effect of TiO₂-Ag/PLA was studied by shaking method.TiO₂-Ag/PLA is a good antimicrobial material for the inhibition of Escherichia coli and Staphylococcus aureus.Finally,the spining-ability of TiO₂-Ag/PLA blends are investigated by TG?MFI?Rheology and nascent fibers evaluation method.Thermal stability of PLA decrease with the increase of the content of TiO₂-Ag mesoporous microspheres,but still satisfies the melt processing conditions.The TiO₂-Ag/PLA blended melt showed a typical "shear thinning" and its melt viscosity is sensitive to changed temperature,so the melt flowing rate of TiO₂-Ag/PLA composite particles can meet the melt-blown non-woven processing requirements.For primary fibers of TiO₂-Ag/PLA composite particles,TiO₂-Ag mesoporous composite particles can be distributed in the fibers and fiber surface is smooth.When the blending ratio is 3/97,the breaking strength and elongation are maximized.