Preparation And Application Of Particleboard Residue/Polylactic Acid Wood-Plastic Composites In 3D Printing

As a kind of environment-friendly material,researches of natural fibers have received the attention by more and more researchers due to it can replace synthetic fibers.Polymer composite materials are very important attribute to the wide application.Because of low density,high intensity and renewable,natural fibers have been the reinforced material with great potential.In this paper,the particleboards were used act as the source of natural fibers and degrade polylactic acid as a matrix at the same time.The particleboard fiber reinforced polylactic acid composite and its 3D printing wire were prepared by melt extrusion co mixing and injection molding,respectively.Then the mechanical properties of the composites were tested by the universal testing machine.In order to explore the mechanism of enhancement,the micro-interface,crystallization property,thermal properties and processing property were characterized scanning electron microscopy(SEM),thermogravimetric analysis(TGA),and differential scanning calorimetry(DSC).The modification methods of particleboard pretreatment and their effects on mechanical properties of composites were explored.In addition,the effect of nano-silica on the reinforcement and interfacial compatibility of PLA composites was also discussed.(1)In order to improve the interfacial properties of the wood fibers of particleboard surplus and polylactic acid matrix material,the particleboard surplus was modified combined with alkali treatment and oxidation-reduction agent.TGA results indicated that the alkali treatment can remove the pectin effectively,hemicellulose,and lignin in the fibers.In addition,the lignin of wood powder can be removed more thoroughly with the combination of alkali and hydrogen peroxide.It also can effectively reduce the dosage of chemical agents,effectively protect the morphology of cellulose,lead to it has better thermal stability at the same time.The SEM results showed that the surface of modified particleboard fibers have irregular grooves and cracks,fiber bundles become a single fiber,the ratio of length to diameter becomes larger,result polymer matrix easier to infiltrate the fibers,thus to strengthen the interfacial bonding between fibers and matrix.With the increase of particleboard wood flour content,the elongation at break of PLA composites decreased,but the tensile strength and flexural strength increased first and then decreased.When the content of particleboard wood powder is 15%,the maximum tensile strength of the composite is 68.94 MPa,and the maximum bending strength is 75.01 MPa.After alkali treatment of the particleboard wood composite material can reach 73.75 MPa and 102.56 MPa,respectively.Alkali / hydrogen peroxide treatment result in the were better mechanical,tensile strength and bending strength reached 76.66 MPa and 108.19 MPa,which increased by 16.85% and 71.32% compared with pure PLA,respectively.The mechanical properties of the materials are further improved by the addition of nano-silica.(2)Material masterbatch were extruded by melt extrusion of twin screw extruder,and then the particleboard fiber reinforced polylactic acid composites were prepared by using injection molding and 3D printing technology.TG curves showed that the addition of particleboard wood fibers will reduce the thermal stability of the composites.With the addition of a small amount of nano-silica,the mechanical properties of the composites were further improved,and the thermal stability was slightly improved.(3)Comparison of the composites prepared by injection molding and fused deposition manufacturing(3D printing)respectively,although the material obtained by 3D printing technology is not so better as the conventional injection molding material in tensile properties and flexural properties,the elongation at break of the 3D printing materials are higher relatively lead to theirs processing property are much more better.Moreover,the utilization rate of materials is far stronger than that of injection molding,it can be made into components with complex structure,which can be widely applied in furniture manufacturing industry at the same time.