Thiol‐terminated hyperbranched polymer for DLP 3D printing: Performance evaluation of a low shrinkage photosensitive resin

Abstract

In order to lower the volume shrinkage of the DLP 3D printing photosensitive resins during printing, a thiol‐terminated hyperbranched polymer (T‐HBP) was synthesized and introduced into the bisphenol A epoxy acrylate (EA) based photosensitive resin system. The obtained T‐HBP was characterized by FTIR and 1H NMR spectra, and the grafting rate of sulfhydryl was determined. The mechanical properties of the photosensitive resins were measured by tensile and impact strength measurement. The glass transition temperature of the photosensitive resins was analyzed by DSC and the impact fracture surface was observed by SEM. T‐HBP exhibited a much lower viscosity than its linear counterparts, and the addition of thiol improved the curing speed of the photosensitive resins. When the amount of T‐HBP added was 20 wt%, the shrinkage of the photosensitive resins was reduced by about 45.5% and the impact strength increased by 33.9% compared with the control. The macromolecular spherical structure of T‐HBP effectively reduced the functional group density of the photosensitive resins. In addition, the thiol‐acrylate photopolymerization introduced by T‐HBP further reduced the volume shrinkage of the photosensitive resins.

Modified rod‐shaped calcium carbonate with thiols improving UV‐curing 3D printing resin

“…Figure 6b further indicates that the warpage of 3D printed sample is greatly decreased from 3% to 1%, when 0.5 wt% of RCa1‐Si1 is added. The reduction of warpage should be ascribed that the RCa1‐Si1 can fill the interspace generated during 3D printing 31 …”

Lowering the curing shrinkage of epoxy acrylate‐based photosensitive resins through nano‐TiO2 particle with surface grafted by thiol‐terminated hyperbranched polymer

“…Dipropylenene glycol diacrylate (DPGDA), 3‐(Trimethoxysilyl) propyl methacrylate (KH570), toluene, 3‐mercaptopropionic acid were supplied by Shanghai Aladdin Chemicals Co., Ltd. Nano‐TiO 2 was bought from Nanjing Chemical Reagent Co., Ltd, and its particle size was 5–10 nm. Hydroxyl‐terminated hyperbranched polymer (H‐HBP) was provided by Wuhan Hyperbranched Polymers Science &Technology Co., Ltd. Bis(2,4,6‐trimethylbenzoyl)phenylphosphine oxide (Irgacure 819), flatting agent (BYK331), and defoamer (ST108) were supplied by Japanese TCL Co., Ltd. which was synthesized according to the previously researched method 27 …”

“…Hydroxyl-terminated hyperbranched polymer (H-HBP) was provided by Wuhan Hyperbranched Polymers Science &Technology Co., Ltd. Bis(2,-4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819), flatting agent (BYK331), and defoamer (ST108) were supplied by Japanese TCL Co., Ltd. which was synthesized according to the previously researched method. 27 2.2 | Surface modification of nano-TiO 2…”

“…THBP is a thiol‐terminated hyperbranched polymer that can participate in the photocuring process through the click reaction between the hyperbranched thiol structure of THBP and the carbon–carbon double bond of photosensitive resins 27 …”

“…25,26 THBP is a thiol-terminated hyperbranched polymer that can participate in the photocuring process through the click reaction between the hyperbranched thiol structure of THBP and the carbon-carbon double bond of photosensitive resins. 27 In this paper, nano-TiO 2 particles were treated by KH570 in advance and the surface of which were grafted by THBP, then THBP@TiO 2 was obtained. The results of the samples regarding their shrinkage resistance, mechanical properties test, fracture cross-section analysis, thermogravimetric analysis and FTIR were analyzed and discussed.…”