The Construction Of Super Wetted Surface Structure Of Poly(Lactic Acid) Nonwoven Materials

In recent years,Marine oil spills occur frequently.Every year,such incidents have a serious impact on sustainable economic and social development and human life.At the same time,in weaving production,a lot of waste liquid mixed with oil and water will cause serious pollution to the environment,such pollution is easy to cause serious ecological pollution and damage,affecting human health.With the increasing attention to this kind of pollution,more and more researchers focus on the development and application of efficient oil-water separation materials.However,the commonly used polymer-based oil-water separation materials,such as polypropylene,polyurethane,polyvinylidene fluoride and other non-degradable or refractory materials,will cause secondary pollution to the environment after use.Therefore,the development of environmentally friendly biodegradable oil-water separation materials has become an important issue to be solved.Polylactic acid(PLA)is a biodegradable material with great potential due to its stable chemical properties,high mechanical strength,non-toxic and extensive sources.Poly(lactic acid)nonwoven materials have the characteristics of porous structure and are widely used in medical treatment,agriculture and architecture.In this paper,cellulose nanocrystalline(CNC)and PLA nanoparticles were prepared and their morphologies were controlled.The prepared nanoparticles were used to modify the surface of the nonwovens by ultra-wetting,and the PLA nonwovens with super hydrophilic and super hydrophobic properties were obtained.By means of field emission electron scanning microscope(SEM),Fourier infrared spectroscopy(FTIR),video contact Angle test,aperture analysis,Zeta potential and other methods,the structure characterization and performance analysis of the prepared CNC and PLA nanoparticles and PLA nonwoven materials with special infiltrating surface were carried out.Specific research results are as follows:1.CNC particles with different morphologies were prepared by different acid hydrolysis methods.The CNC particles prepared by hydrochloric acid and sulfuric acid hydrolysis were shaped like bars.With the increase of reaction temperature and reaction time,the particle size of spherical CNC decreases gradually.The comparative study found that the size of CNC spherical particles could be controlled at 30?40nm under the condition of reaction regulation at 80? and 12h,and it had better dispersion performance in water.2.The CNC spherical nanoparticles prepared by the above method were adhered to the surface of the PLA nonwovens by dopamine self-polymerization,and the super hydrophilic PLA nonwovens were prepared.After modification,the water contact Angle of the modified nonwoven material is nearly 0°,which meets the requirement of super hydrophilic.At the same time,the water absorption of the material is also greatly improved,which can reach more than 1000%of the dead weight,which is about 4 times higher than that of the pure PLA nonwoven material.The super-hydrophilic PLA nonwoven material can effectively separate the oil-water mixed solution,and the separation efficiency can still maintain above 97%after 100 cycles of use.Compared with the pure PLA nonwovens,the tensile strength of the super hydrophilic PLA nonwovens was increased by 47%,and the mechanical properties hardly decreased after 40 cycles.3.PLA nanoparticles were prepared by solvent volatilization method.By adjusting the concentration and solvent volatilization rate,the size and morphology of the prepared particles were effectively regulated,and the PLA nanoparticles with diameter less than 100nm and uniform morphology were obtained.The prepared PLA nanoparticles were adhered to the surface of the PLA nonwoven material by epoxy resin to form a kind of nano/micron rough structure.The surface energy of the material was further reduced by the surface treatment of hk-560,and the water contact Angle of the material reached about 152°.The special infiltrating PLA nonwoven material is used for oil-water separation experiments.For oils of different densities such as lubricating oil,silicone oil and castor oil,the material has a good selective absorption ability,and the separation efficiency of oil-water mixed liquid can reach more than 96%.