Study On Preparation And Properties Of Reactive POSS Modified EA-Based UV-Curing 3D Printing Materials

As a combination of manufacturing and rapid prototyping technology,three-dimensional photocurable printing has become one of the focus of manufacturing industry research.For the particularity of the forming process and the limitation of materials themselves,the mechanical properties of cured 3DP materials were low,which restricted the development of 3DP technology.In this paper,epoxy acrylate(EA)was used as prepolymer,dipropylene glycol diacrylate(DPGDA)as monomer,phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide as photoinitiator,N-vinyl pyrrolidone(NVP)as solvent to prepare one 3DP material,and different ratios of the methacryloxyphenyl sesquisiloxane(MP-POSS)and octamethacryloxy sesquisiloxane(MAP-POSS)were used to enhance the strength of the 3DP material.The study of MP-POSS modified 3DP materials showed that MP-POSS possessed good compatibility in EA-based 3DP materials under the action of NVP.The analysis of infrared and XRD spectra demonstrated that MP-POSS can be introduced into the 3DP matrix by chemical bonding through photo-initiated radical polymerization.Microscopic morphology analysis showed that there was no obvious phase separation when the addition of MP-POSS was less than 3%.When the addition reached 3%,the supersaturated MP-POSS particles appeared and the number and particle size increased with the increase of the addition of MP-POSS.When the addition of POSS reached 5%,the effect of reinforcement and modification was most obvious.The hardness of the material reached93.2HD,the tensile strength reached 48.9MPa,the flexural strength reached 54.9MPa,and the impact strength reached 12.8KJ/m~2,which were 21.3%,50.9%,58.1%and 62.1%higher than the original material respectively.Tensile fracture morphology analysis showed that the addition of POSS resulted in the formation yield cracks and fracture steps.Impact fracture morphology analysis showed that the addition of MP-POSS resulted in dendritic cracks in the flat section,and the crack branching degree became more obvious with the increase of MP-POSS addition.Thermo-gravimetric measurements showed that the addition of MP-POSS significantly reduced the thermal decomposition rate,increased the thermal decomposition residues and improved the thermal stability of the 3DP materialsThe study of 3DP materials modified by MAP-POSS showed that as an oil-like POSS,MAP-POSS possessed better compatibility than MP-POSS in the 3DP material.Infrared and XRD analysis demonstrated that MAP-POSS could be used as a nano-crosslinking center to copolymerize with pre-polymer and monomer by free radical polymerization.When the addition of POSS reached5%,the effect of reinforcement and modification was most obvious.The hardness of the material reached 87.4HD,the tensile strength reached 40.2MPa,the flexural strength reached 57.8MPa,and the impact strength reached 18.7KJ/m~2,which were 13.8%,24.1%,67.9%and 136.1%higher than the original material respectively.The addition of MAP-POSS made dimples and tongue tear cracks appear on the original smooth fracture surface,and the fracture changed from brittle fracture to ductile fracture.Thermo-gravimetric measurements showed that the addition of MAP-POSS reduced the thermal decomposition rate,increased the thermal decomposition residues and improved the thermal stability of the 3DP materials.MP-POSS improved both of the strength and toughness of 3DP materials to a certain extent.In addition,the effect of MAP-POSS on the curing speed of 3DP materials was less than MP-POSS.But MP-POSS had better effect on reducing the volume shrinkage of 3DP materials.