Preparation Of Inorganic-organic Nanocomposites And Their Performance In 3D Printing

3D printing,also known as additive manufacturing,was a bottom-up manufacturing process and has offered great potential for creating sophisticated geometric shapes compared to traditional processing techniques.Up to now,3D printing has found applications in various areas,such as industrial design,architecture,automible,aerospace,dentistry,education,etc,accompanied with higher demands for the quality of products.Therefore,it was urgent issue to develop high performance materials for 3D printing.Aimed at this,this dissertation focused on the preparation of inorganic-organic nanocomposites by tuning the interfacial interaction between inorganic and organic components.1.?-Al₂O₃ nanowire-enhanced acrylate resin for 3D printingOne-dimensional?1D??-Al₂O₃ nano wires were incorporated into acrylate resins to prepare composite resins.Surface modification of ?-Al₂O₃ nanowires was conducted by silane coupling agents to improve the dispersibility of ?-Al₂O₃ nanowires in acrylate resins matrix.After modification,the maximum amount of?-Al₂O₃ nanowires in acrylate resin was improved to 12 wt%without obvious increase of resin viscosity.Meanwhile,the thermal and mechanical properties of nanocomposite resins were improved after incorporation of surface modified ?-Al₂O₃ nanowires.For the application of 3D printing,curing depth studies were conducted on both nanocomposite acrylate resin and neat acrylate resin,which revealed the significant role of ?-Al₂O₃ nanowires in preventing irregular shapes and improving surface quality of cured resins.The enhanced mechanical property of nanocomposite acrylate resin guaranteed the successful 3D printing of helical springs with high dimensional accuracy compared to neat acrylate resin.2.High-strength boehmite-acrylate composites for 3D printing:reinforced filler-matrix interactions?-AlOOH nanowires with a diameter of?10 nm and a length of several micrometers were synthesized by hydrothermal method.Different inorganic-organic interface interactions were obtained by surface modification of ?-AlOOH nanowires with the commonly used silane coupling agent and a new surface modifier ?-CEA.Significant improvement of dispersibility and mechanical properties were achieved by surface modification of ?-CEA nanowires with ?-CEA.The difference in surface modification effect of silane coupling agent and ?-CEA was attributed to the surface condition of y-AlOOH,which made it apt to adsorb hydrogen ions,and consequently,the reaction of silane coupling agent with ?-AlOOH was affected.The excellent mechanical property of acrylate nanocomposite resins with ?-CEA-AlOOH nanowires made it ideal candidate for 3D printing with high dimensional accuracy,high mechanical property and long-term stability.3.High-performance nano-photoinitiators with improved safety for 3D printingThe new polyhedral oligomeric silsesquioxanes-benzophenone?POSS-BP?hybrid nanophotoinitiators were synthesized by coupling of POSS with benzophenone derivatives.The structure of hybrid nanophotoinitiators was confirmed by NMR.The comparison of UV-vis spectra of POSS-BP hybrid photoinitiators and its corresponding parent photoinitiators revealed similar UV-vis absorption properties.Meanwhile,the unique inorganic Si-O-Si core endowed the hybrid nanophotoinitiators superior thermal and mechanical properties.More importantly,the radical stability was enhanced by the presence of POSS structure with obvious steric effect,therefore,the photoactivity of POSS-BP hybrid nanophotoinitiators were significantly higher than their corresponding low molecular weight parent photoinitiators.The improved safety of POSS-BP hybrid nanophotoinitiators was evaluated by cell toxicity and extraction test,which revealed that the migration of POSS-BP hybrid photoinitiators was hindered by large molecular POSS structure.The utility of these hybrid nanophotoinitiators in 3D printing was demonstrated in printing of various 3D structures with high resolution and accuracy.