Study On Preparation And Properties Of Wood Flour/PLA Composite 3D Printing Filament

With the development and promotion of the emerging high-tech manufacturing industry 3D printing technology has become a key research field at home and abroad.However,the supply situation of 3D printing materials as one of the core technologies in the current market is more severe,and has gradually become one of the key factors restricting the development of 3D printing technology.Therefore,research and preparation of a new type of green and environmentally degradable 3D printing filament can greatly promote the development of 3D printing technology.As a widely used material at home and abroad,wood-plastic composite materials can not only reduce the cost of 3D printing filament,but also make rational use of wood processing residues to improve resource utilization.In this study,a wood-plastic composite material and 3D printing technology are combined to develop a wood flour/PLA composite 3D printing filament,and the selection of the filament from the formulation,the optimization of the extrusion process parameters and the determination of the filament aging resistance performance are carried out.A comprehensive study was conducted to determine the performance,and the main content and results include:(1)Determination of the type of plasticizer for wood flour/PLA composite 3D printing filamentThe wood flour/PLA composite 3D printing filament was prepared by the melt extrusion method with poplar flour and polylactic acid as the main raw materials,glycerin and tributyl citrate as plasticizers.The effects of different plasticizers on the melt fluidity,interfacial compatibility,mechanical properties,water absorption and thermal stability of wood flour/PLA composite 3D printing filament were studied under the same plasticizer content.Through various performance tests,under the same content of plasticizer,tributyl citrate can better reduce the crystallinity of polylactic acid in the filament and improve the compatibility of the filament,so that the lemon was better than other plasticizers.The tensile strength,water absorption and thermal stability of the tributyl acrylate group were significantly improved compared with the glycerol group.The properties of the filament were determined to be tributyl citrate.(2)Optimization of extrusion process parameters of wood flour/PLA composite 3D printing filamentBased on determining the type of plasticizer,the testing piece prepared with 3D printed filament was taken as the research object.Firstly,the single-screw extruder was used to select the extrusion temperature,wood flour content and plasticizer content as independent variables.The tensile strength of the piece is the response value.The influence of the respective variables and their interaction on the tensile strength of the test piece was studied by the method of central combination design.A quadratic multi-matrix model of tensile strength was established by using response surface analysis method.According to the actual selection response surface equation,the least square method was used to estimate the corresponding coefficient,and the least significant factor was eliminated to establish the final mathematical prediction model.The optimum extrusion temperature,plasticizer content and wood flour content obtained by response surface methodology were 172.6?,4%and 14.1%,respectively;the tensile strength of the specimen was 24.23 MPa,which was optimized.The previous increase was 2.12%.The prediction model can well describe the relationship between the tensile strength of the specimen and the extrusion temperature,wood flour content and plasticizer content,and can analyze and predict the tensile strength of the specimen.(3)UV aging study of wood flour/PLA composite 3D printing filamentThe ultraviolet aging tester was used to study the aging resistance of the wood flour/PLA composite 3D printed filament by the ultraviolet aging under different temperature conditions to determine the chromatic aberration,tensile strength,scanning electron microscope and water absorption.The results showed that with the aging time prolonged,the aging of the filament was more serious.The specific performance is that the tensile strength of the filament after UV aging was reduced by nearly 50%compared with the original;the internal structure of the filament was damaged,the pores appear;the water absorption rate was greatly improved;and the color of the filament changes more obviously;In addition,the temperature was capable of accelerating the rate at which ultraviolet light aging the filament.The higher the temperature,the shorter the time for the wood flour/PLA composite 3D printing filament to be close to its maximum aging degree,and the faster the performance of the filament was changed.The aging time of the filament near the maximum aging degree at 40? was 80H,which was twice the aging time of the filament at 60?.Studying of the aging behavior of wood flour/polylactic acid composite 3D printing filament was the basic basis for inferring the service life and environment of wood flour/PLA composite 3D printing filament,and provides a theoretical reference for the rational application of wood flour PLA composite 3D printing filament.In summary,this study first determines the type of wood flour/PLA composite 3D printing filament plasticizer,and on this basis,optimizes the extrusion process parameters of the filament,and analyzes the aging resistance of the filament,and finally determines a set of relatively complete wood flour/PLA composite 3D printing filament development route.The research results of this thesis not only enrich the types of 3D printing filaments,but also make rational use of wood processing residues,improve the utilization of wood resources;and promote the promotion and application of 3D printing technology,for the future 3D printing filament the research has played a certain guiding role.