Preparation And Properties Of PLA Based Fdm 3D Printing Shape Memory Material

Fused deposition molding(FDM)is a three-dimensional printing technology of extrusion molding for using thermoplastic monofilament through a hot nozzle,which has the advantages of the low cost,high reliability and simple operation and has shown great potential in the fields of medical equipment,daily necessities,food,electronic components and industrial equipment.At the same time,due to the development of shape memory polymers(SMPs),3D printing materials based on SMPs have been attracting more and more attention.The combination of SMPs and 3D printing makes4 D printing possible.At present,polylactic acid(PLA)filaments are the most used FDM 3D printing material.However,the purely PLA has the problem of large brittleness and high shrinkage factor of its 3D printing products.In order to expand the application of PLA in the field of 3D printing,The detailed contents are as follow:(1)The new type of PLA based 3D printing wire was prepared by using PLA and Pebax as main raw materials.In order to solve the problem of the poor interface binding forcebetween PLA and Pebax,we used DCP as the cross-linking agent.The results that DCP not only triggered crosslinking of PLA phase,but also triggered interface grafting reaction of PLA and Pebax which resulted in the formation of PLA-g-Pebax at interface and enhanced the interface binding force.PLA/Pebax printing wire has good printability(2)ENR/GO masterbatch was prepared by in-situ controlled epoxidation.ENR/GO masterbatch was used to toughen PLA to prepare the new type of PLA 3D printing wire.The results that epoxy and hydroxyl groups are introduced into the natural rubber(NR)molecular chains to anchor oxygenous functional groups on the surface of graphene oxide(GO)sheets and therefore enhance the interfacial interaction between GO and rubber.At the same time,the PLA/ENR/GO printing wire has betterprintability.(3)Pure PLA printing wire was prepared.The results that depending on the FDM process parameters,the internalstrains along print direction,thermal-gradient across layers,and anisotropy introduced during layerby-layer build-up can significantly affect the macroscopic properties,dimensional stability,and structural performance of the final part.Conversely,these factors can be optimized to result in unique,controllable thermally actuated shape-transformations.