Preparation And Property Of High-solid Water-dilutable Photosensitive Resin

In recent years,with the pursuit of the concept of healthy life,water-based resins using water as a solvent have been paid more and more attention.Combining water-based resins with efficient and energy-saving UV curing technology has become a major development trend of water-based resins.The traditional linear water-based photosensitive resin has the problems of low solid content and high viscosity,which limits its further development.Compared with the linear resin,the hyperbranched structure has the advantages of low viscosity and more terminal functional groups,which is beneficial to the preparation of water-based photosensitive resins with high solid content.In this thesis,the hyperbranched polyester polyols were synthesized by a solvent-free method using pentaerythritol（PE）and dimethylolpropionic acid（DMPA）,and the structure of the product was characterized.The aggregation-induced emission properties of hyperbranched polyester polyols were explored;secondly,the terminal hydroxyl groups of polyols were modified by succinic anhydride（SAA）and ethyl acrylate（AOI）to insert carboxyl groups and photosensitive groups.The prepared hyperbranched water-based urethane acrylate（WHBPUA）has the characteristics of high solid content and water-dilutable.Finally,a series of 3D printing water-based photosensitive resins were prepared by compounding WHBPUA 8-8 with polyethylene glycol diacrylate（PEGDA400）and acryloyl morpholine（ACMO）.The mechanical properties of the devices prepared by 3D printing were tested.The main work of the thesis is as follows:（1）Different generations of hyperbranched polyester polyols were synthesized by a solvent-free method using dimethylolpropionic acid（DMPA）and pentaerythritol（PE）catalyzed by p-toluenesulfonic acid（P-TSA）.¹³C NMR spectra showed that the degree of branching（DB）of the three-generation hyperbranched polyester polyols were 0.58,0.48,and 0.46,respectively,indicating that the hyperbranched polyester polyols were successfully prepared.（2）Through the influence of polar solvents on UV absorption spectra,the orbital transition types of hyperbranched polyester polyols were determined,which were n–π^*transitions at 230 nm and n–πtransitions at 260 nm,respectively.Oxygen-rich hyperbranched polyester polyols exhibit aggregation-induced emission（AIE）properties due to the steric conjugation（TSC）effect of oxygen atoms.Through the test of fluorescence spectrophotometer,the maximum excitation wavelength in ethanol solution was determined at 260±5 nm,and the maximum emission wavelength was at 285±5 nm;the fluorescence lifetime was 2.06 ns.（3）A series of hyperbranched polyurethane acrylates（WHBPUA）containing different hydrophilic groups and double bonds were prepared by reacting succinic anhydride and ethyl acrylate（AOI）with hyperbranched polyester polyols.It was characterized by FTIR and ~1H NMR.With the increase of the hydrophilic group content,the particle size of WHBPUA decreased gradually,and changed from a multimodal distribution to a unimodal distribution,while the viscosity of WHBPUA decreased rapidly with the addition of water.For the system of WHBPUA,when the concentration of photoinitiator Doracur1173 is 3 wt.%,the double bond conversion rate of WHBPUA 10-6 is about 92%under UV irradiation of 40 m W/cm~2.（4）A series of 3D printing photosensitive resins were prepared by compounding WHBPUA 8-8 with a solid content of 70%with acryloyl morpholine（ACMO）and polyethylene glycol diacrylate（PEGDA400）.Under the irradiation light intensity of 25m W/cm~2,the initiation effect of TPO-L was the best.When the content of TPO-L was 2wt.%,the final double bond conversion of the system was about 95%.The test found that with the addition of PEGDA400,the flexibility of the prepared 3D printed device increased and the slippage between the molecular chains increased,and the elongation at break of the spline increased from 6%to 74%.The glass transition temperature changed from 124℃to79℃,and the storage modulus decreased.