Preparation And Properties Of Functional Materials Based On Polymer Solution 3D Printing

3D printing is an additive manufacturing(AM)technology used to generate multiple structures and complex geometries from three-dimensional(3D)model data.3D printing manufacturing technology involves three aspects of molding methods,materials and equipment.After years of development,it posseses the ability to change manufacturing and logistics processes.At present,the main printing technologies for polymer materials are melt printing and photocuring,and the corresponding materials are polylactic acid,acrylonitrile-butadiene-styrene copolymer,photosensitive resin and the like.However,the types of polymer materials that can be applied to these two printing technologies are limited,which greatly limits the application of 3D printing technology in the field of polymer material processing.Therefore,the development of a new platform for 3D printing based on polymer-dissolved viscous solution is of great significance for the expansion of the material library of 3D printing,as well as the processing of materials that are difficult to melt and cannot be formed by photocuring.In this context,based on the solution 3D printer,natural cellulose,shape memory polymer and polyurethane are used as raw materials to optimize the 3D printing process to obtain three-dimensional complex controllable shape structure to meet the application of different fields.We carried out the following related research work:(1)Based on the rheological properties of the cellulose solution,the molten printer was modified,and a solution 3D printing platform was established.Multi-layered cellulosic hydrogels have been successfully prepared and are expected to be used in bioengineering.Studies have shown that cellulose concentration and temperature have great influence on the rheological properties of cellulose solution.It is found that the higher the cellulose concentration,the greater the viscosity of the solution and the shear thinning property.At the same time,the higher the temperature,the lower the viscosity of the solution,the less stable the shape after extrusion.3D printing can realize the preparation of cellulose samples of different structural shapes,wherein the prepared hydrogel scaffold has a controllable double-layer pore structure and is expected to be applied to the field of biological tissue engineering.Cellulose hydrogel scaffolds with good mechanical strength and swelling properties can be obtained by cross-linking cellulose hydrogel with MBA.(2)Based on the solution printing system,the solution 3D printing of shape memory polymer matrix composites was studied.The polyurethane/nano-clay composites with shape memory properties were printed and improved,and the shape memory properties and mechanical properties of polyurethane were improved.Studies have shown that with the increase of content,nano-clay gradually agglomerates in the matrix,and is no longer present in the polyurethane in the exfoliated state.With the increase of nano-clay content,the mechanical properties and thermal stability of polyurethane/nano-clay composites increased first and then decreased,and reached the best effect at 1%.By introducing nano-clay into the polyurethane matrix,the shape fixing rate of the material is obviously improved,and the shape memory property of the polyurethane is effectively enhanced.(3)Based on the solution printing system,the composite printing ink of nano-clay and polyurethane was prepared.After printing at room temperature and removing the clay by acid etching,the elastic polyurethane foam was successfully prepared and immersed in the carbon tube dispersion to obtain piezoresistive properties.Studies have shown that the larger the pore size,the lower the foam density and modulus;the higher the clay content,the lower the density and modulus of the foam.The higher the relative content of nano-clay,the higher the viscosity and modulus of the composite ink,and the larger the microscopic pore size obtained by acid etching.As the relative content of nanoclay increases,the compression performance becomes better and better.When the N-T ratio is 2.1:1,the foam has better compressive elasticity and good compression sensitive conduction properties.