Synthesis And Characterization Of Reinforced Photosensitive Resin By Functionalized Graphene Oxide Nanosheets

Stereo lithography apparatus rapid prototyping(SLA)as a classical and conventional rapid prototyping technology has been given much focus due to a very short time needed to produce functional parts,no limitations on the product shape and so on.Photosensitive resin as the starting material which determines the curing process parameters,curing velocity and the properties of curing products,plays a very important role in SLA technology.Specified requirements should be met for the photosensitive resin including low viscosity and low volume shrinkage,and high performance of cured products.However,the application of SLA is not practically suitable for producing advanced components due to the high volume shrinkage,the poor mechanical and low thermal property of present photosensitive resins.Photosensitive resins can’t compete with thermosetting resins in dimensional accuracy and performance of cured products.It is still a great challenge for photosensitive resin to satisfy the above requirements simultaneously.In this study,firstly the ingredient of free radical-initiated(FCI),cationic-initiated(CI)and other components are investigated and optimized through the study of viscosity,volume shrinkage and gel rate of the complex of free radical-initiated and cationic-initiated resin(FRCI).During the process of the ingredient study for the FRCI resin,diethylene glycol modified epoxy acrylic resin was synthesized as the component of free radical-initiated resin,the Bis [(3,4-epoxycyclohexyl)methyl] adipate(TTA26)was selected as cationic-initiated resin and Irgacure 250 as the photo initiator.Then the different ingredient content was determined: the mass ratio of free radical-initiated and cationic-initiated ingredient is 3:4,30% diluent,2% the photo initiator,which could make the combination properties best.The photosensitive resins enhanced with 2-hydroxyethyl methacrylate functionalized graphene oxide(HFGN/FRCI)were prepared and the properties of the cured HFGN/FRCI nanocomposites were investigated.2-Hydroxyethyl methacrylate functionalized graphene oxide(HFGN)was firstly synthesized by in situ covalent functionalization of graphene oxide(GO)with 2-hydroxyethyl methacrylate.The structure of HFGN and FGO were characterized with FTIR and TGA and the effects of HFGN and FGO on the photosensitive resins were evaluated through evaluating the variation of viscosity and gel rate.Compared with adding GO,HFGN and FGO of the viscosity doesn’t markedly increase with the addition of HFGN and FGO,the gel rate also doesn’t reduce until the addition amount reaches 0.06 wt%,showing that HFGN and FGO possess the good compatibility with the matrix and the good compensation for the decline of the resin photo sensitivity.The volume shrinkage of the cured HFGN/FRCI and FGO/FRCI nanocomposite decrease with the increase of HFGN and FGO content,and obtain the best result of 3.6% for 0.06% HFGN contained nanocomposite and 3.4% for 0.06% FGO contained nanocomposite.The results of cured HFGN/FRCI and FGO/FRCI nanocomposites indicate the mechanical properties including tensile,bending and impact properties and the thermal property are all greatly improved even with very small HFGN and FGO additions(0.01~0.06 wt%).Furthermore,the behaviors of the cured composites under dynamic thermal conditions were examined with DMA,confirming the excellent interfacial adhesion and the enlarged interface region derived from the HFGN and FGO addition.