Preparation And Properties Of Oxidized Nanocellulose/Polylactic Acid Composites Materials

Nowadays,white pollution is becoming increasingly serious in the world.The research and application of green and environmentally friendly membrane materials are of great significance for protecting the environment,saving resources,reducing costs,and promoting sustainable development.Among them,the research on green nanomaterials is one of the hotspots in the field of materials science.This article uses oxidized nanocellulose(TOCN)as the reinforcing phase,polylactic acid(PLA)as the matrix,and polyethylene glycol(PEG)as the compatibilizer to successfully prepare a green and environmentally friendly TOCN/PEG/PLA ternary composite membrane material using tape casting method.The composite membrane has good mechanical strength and UV radiation resistance.The main research content and conclusions are as follows:1.TOCN was prepared using waste pulp as raw material using the TEMPO oxidation method.During the oxidation process,the amount of Na Cl O(main oxidant)was controlled,and the highest carboxyl content of oxidized cellulose could reach 1.3mmol/g.High carboxyl content helps to improve the dispersibility of TOCN,thus optimizing the process flow for preparing TOCN.The TOCN membrane was prepared by vacuum filtration method,and its mechanical and hydrophobic properties were studied.The experimental results show that the tensile strength of TOCN film reaches 100 MPa,so TOCN can be used as a reinforcing filler for composite films with a contact angle of47.15 °.The tensile strength of pure PLA film is 9 MPa.2.Three types of TOCN(0.2wt%,0.4wt%,0.6wt%)were selected and added to PLA solution through solution blending.Different ratios of TOCN/PLA composite films were obtained by tape casting method.The effect of TOCN content on the mechanical properties,water resistance,and UV radiation resistance of the composite film was studied.The experimental results show that when the TOCN content is 0.4wt%,the tensile strength of the composite film is the highest,with a tensile strength of 37.5 MPa and a brittle fracture mode;The maximum contact angle is 63.56°;The UV radiation resistance of TOCN/PLA composite membranes was significantly enhanced compared to pure PLA membranes,and the transmittance of the composite membranes in the UV transmittance region was below 20%.3.In order to improve the compatibility between TOCN and PLA,PEG-4000 was used as a compatibilizer to prepare TOCN/PEG/PLA ternary composite films by tape casting.The effects of different TOCN contents(i.e.0.2wt%,0.4wt%,0.6wt%)on the performance of the ternary composite films were studied.The experimental results show that when the TOCN content is 0.6wt%,the tensile performance of the composite film is the highest,with a tensile strength of 52 MPa.The mechanical properties are further enhanced,and the composite film exhibits ductile fracture;The maximum contact angle is 83.72 °,further improving water resistance;The transmittance of the ternary composite material in the ultraviolet region is below 10%,indicating that the ternary composite film has excellent resistance to ultraviolet radiation;The ternary composite membrane material did not exhibit thermal decomposition before 200 ℃ and has good thermal stability.