Study On Near-Infrared Curing Assisted 3D Printing Porous Materials And Its Performance

Lightweight and porous material has a wide range of applications.Porous materials prepared by traditional methods are difficult to prepare porous structures and control porous morphology on demand.Photopolymerization technology has the characteristics of energy saving,high efficiency,green environmental protection,and time-space controllability.Using3 D printing method based on photopolymerization,customization of porous structure can be realized.However,the ultraviolet light used in traditional ultraviolet photopolymerization has short wavelength,weak penetration in photosensitive materials,and limited 3D printing scale,which easily leads to insufficient porosity and application performance of the prepared porous structural foam.In this thesis,a high internal phase emulsion that can be cured by highpenetration near-infrared light was prepared first,and then a cross-scale hierarchical porous material was successfully prepared by near-infrared assisted ink direct writing(NIR-DIW).In the first part,a high internal phase emulsion ink for NIR-DIW was prepared,and the printing research of porous structural materials was also carried out.Firstly,the rheological properties of high internal phase emulsion ink and its rheological behavior in the process of near infrared light irradiation were measured by rotary rheometer and real-time infrared rheometer.Furthermore,through total reflection infrared spectroscopy,compression test,porosity calculation and droplet aspect ratio calculation,the effect of printing parameter adjustment on the printed porous structure and performance was explored.The research results show that the prepared photosensitive high internal phase emulsion has shear-thinning properties and realizes self-supporting printing under near-infrared light irradiation.The highly penetrating near-infrared light enables NIR-DIW technology to achieve cross-scale printing of lines with a diameter of 0.26 mm to 4 mm,and the double bond conversion rate of the material is between 52 and 60.5%.The 3D printing of multi-scale hierarchical porous structural materials can be achieved by adjusting the printing parameters.The elastic modulus of the prepared porous structural materials is 2.33～2.76 MPa,and the compressive strength is0.34～0.45 MPa.In the second part,in order to further improve the curing speed and mechanical properties of the porous structure,the research on the thio-ene system high internal phase emulsion and its 3D printing porous structure was carried out.First,a series of photosensitive components containing pentaerythritol tetra(3-mercaptobutyrate)(PE-1)and tripropylene glycol diacrylate(TPGDA)in different proportions were prepared.The effects of sulfhydryl components on the oxygen inhibition induced of polymerization,photocuring behavior and properties of cured materials were studied.The stability and rheological properties of the prepared high internal phase emulsion were further characterized.Finally,the effects of thiol content and printing parameters on the properties of the porous structure were investigated.The research results show that the addition of sulfhydryl components significantly reduces the oxygen inhibiton of the system.When the ratio of PE-1 to TPGDA is 2/3,the final double bond conversion rate is about 500% of that without the addition of sulfhydryl components.The prepared high internal phase emulsion containing sulfhydryl group has excellent thermal stability and centrifugal stability,which can meet the requirements of NIR-DIW printing technology.The addition of sulfhydryl components also effectively improves the curing degree and mechanical properties of NIR-DIW printed porous structural materials.When the addition of PE-1 is 20 wt%,the compressive strength of the porous structural material is increased by more than 50% compared with that without the addition of PE-1.