| Rapid prototyping technology(RP,or 3D printing)has the advantages of fast prototyping speed,high precision and friendly environment.It can be widely used in the fields of biology,medicine,machinery and manufacturing.Photosolidification technology is one of the most rapidly developed and widely used technologies.However,most of the photosensitive resin consumables used in the market for photo-curing printing are free radical photosensitive resins,which have the disadvantages of large shrinkage and warping edge,poor mechanical properties and so on.In this paper,on the basis of exploring the formulation of free radical photosensitive resin with good mechanical properties,epoxy compound,cationic photoinitiator and nano-filling powder were added to modify it to prepare hybrid photosensitive resin with high printing accuracy,good mechanical strength and shrinkage.At the same time,the heat treatment in post-curing of the printed product of the photosensitive resin was also carried out,and the effect of heat treatment on the mechanical properties of hybrid photosensitive resin was explored,and the most suitable heat treatment conditions were obtained.The main research contents and results are as follows:(1)Because of the excellent properties of polyurethane acrylic acid,as the oligomer in this paper,the photosensitive resin was prepared by mixing with different monomers on the market and the mechanical properties were tested.The results show that the mechanical properties of ACMO are the best,because the ACMO molecule itself has a cyclic morpholine group.Compared with the straight chain monomer,its glass transition temperature is higher and the molecular chain segment is not easy to spin.Turn.The curing tests of various proportions of polyurethane acrylate and diluent ACMO showed that the best ratio of tensile strength and tensile rate was 30/70.Based on this ratio,the influence of cationic photoinitiator on the free radical photoinitiator resin was discussed.The tensile strength was 25 MPa and the flexural strength was 52 MPa.(2)The hybrid photosensitive resin was prepared by adding 10 % to 40 % epoxy monomer 3,4-epoxy cyclohexyl methyl-3,4-epoxy cyclohexyl hexyl formate and adding 1 % cationic photoinitiator 261.The mechanical properties of the hybrid photosensitive resin were tested and printed.It was found that the best content of epoxy monomer was 10 %,the tensile strength was 28 MPap,and the bending strength was 28 MPap.The bending strength is 56 MPa.(3)The nano-zirconia powder was modified by Kh570,and the pigment carbon black was added into the hybrid resin with different quality.The effect of nano-zirconia powder on the properties of the resin was investigated.TG te st shows that the thermal stability of the composites decreases with the increase of the amount of nano-filled powder.The test results of mechanical properties show that the tensile and bending strength increases with the increase of powder content.The o ptimum properties of modified nano-zirconia are 1 %,tensile strength 37.7 MPa,flexural strength 55.8 MPa,pigmented carbon black 0.05 %,tensile strength 37.8 MPa and flexural strength 65 MPa.(4)Post-treatment of the above-mentioned different hybrid resins-constant temperature heat treatment.By placing the resins at different temperatures and at different time after constant temperature,testing different tensile and bending properties,and comprehensively analyzing the effect of thermal curing on printin g accuracy,it is concluded that in the resin without filling powder,the best thermal curing temperature is 70 o C and the best temperature is 2 hours,which can pull the resins.Strength increases to 46 MPa and flexural strength to 96 MPa. |
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