Effect of modified calcium sulfate whiskers on photocuring materials in 3D printing

In the present research, modified calcium sulfate whiskers were prepared and then dispersed in photopolymers to obtain photocuring composites. Methacrylic acid was firstly used to modify calcium sulfate whiskers to improve the interaction between whiskers and photopolymers. Viscosity of photocuring composites with different whiskers content and hardness of its cured resins were measured. Gel content test showed that the hybrid photopolymer had a high curing rate and degree. Dynamic mechanical analysis was carried out to investigate the influence of modified calcium sulfate whiskers on cured specimens. It showed that the modified whiskers had a higher improvement than the unmodified one. The different impact of the two kinds whiskers can also be observed in scanning electron microscopy images. Mechanical performance was tested and it showed the tensile strength was increased by 26.1%, while the impact strength was reduced by 27.6% at the whisker content of 15 wt%. With a relatively good mechanical properties (10 wt% modified whiskers) and a low volume shrinkage (6.62%), an object was fabricated. It showed the dimension accuracy was quite good. This study may open the way to application of photopolymers in 3D printing.