Preparation And Properties Of Nano-copper Oxide/polylactic Acid Composites

With the rapid development of science and technology,the discharge of wastewater is becoming more and more serious,which has caused serious harm to the environment and people’s daily life.The effective remediation of organic dyes in wastewater is more and more valuable in water treatment technology.Photocatalysis is one of the most promising wastewater treatment technologies for the elimination of organic pollutants.This topic uses nano-copper oxide（nCuO）to modify polylactic acid（PLA）polymer materials,and studies the preparation and properties of nano-copper oxide/polylactic acid（nCuO/PLA）composite materials.The advantages of nano-copper oxide and polylactic acid were fully utilized.The prepared new nano-copper oxide/polylactic acid composite film has excellent photocatalytic performance,and at the same time improves the mechanical properties,thermal properties,and hydrophilicity of PLA materials.The thesis first used absolute ethanol as a new template combined with the self-developed reflux-hydrothermal method to successfully prepare mesoporous nCuO.Mainly investigated the morphology,crystallinity,microstructure and influencing factors of nCuO samples.Then,nCuO/PLA composite membrane was prepared by blending-phase conversion method with PLA as the matrix material,nCuO as the reinforcement material and PLA as the matrix material.The morphology,structure,hydrophilic properties,separation and permeability properties,mechanical properties,thermal stability and photocatalytic properties of the composite membrane materials are also explored.The result of research shows that:（1）The mesoporous nano-copper oxide was successfully prepared by using absolute ethanol as a green and environmentally friendly soft template combined with the reflux-hydrothermal method.The prepared monoclinic phase nano-copper oxide has good crystalline properties,showing a flake structure with mesopores under the microscopic view:the diameter is about 100-200nm,the thickness is about 30-50 nm,and the mesopore diameter is about 1-6 nm,the specific surface area is 18.067 m²/g,and the pore volume is 0.078 cm³/g.（2）nCuO/PLA composite membrane was prepared by blending and phase conversion with nanometer copper oxide as the reinforcing agent and polylactic acid as the matrix material.When the added amount of nCuO in the composite membrane is 15%,the pure water flux of the composite membrane reaches 463 L·m^-2·h^-1;When the amount of nCuO added to the composite membrane was 4%,the retention rate of the composite membrane was up to 90%;When the addition of nCuO in the composite membrane reaches 6%,the interception recovery rate reaches 89.47%;when the addition of nCuO reaches 4%,the elongation at break increases to 71.0%,and the contact angle of pure water decreases to 81.4°;The interaction between nCuO and PLA also changed the pore structure of the composite membrane,and at the same time improved the thermal stability of the composite membrane to a certain extent.（3）Research on the catalytic degradation performance of nCuO/PLA composite film on methylene blue light shows:The photocatalytic effect of nCuO prepared under the hydrothermal time of 4 h is the best;When the addition amount of nCuO in the composite film was 6%,and the photocatalytic degradation of 10 mg/L methylene blue solution,the photocatalytic degradation rate reached 95%in 3 hours;The composite film has good photocatalytic recyclability,can be repeatedly used for the photocatalytic degradation of methylene blue,and has good photochemical stability;Among them,the photo-generated holes h⁺and·OH radicals play a more important role in the photocatalytic methylene blue reaction system in the photocatalytic process.