Highly stretchable dual‐cure photosensitive resin for digital light processing printing
Chuanzheng Ren, Yu‐Hao Deng, Jianjun Bao
Abstract
Abstract The two‐stage curing approach is one of the promising strategies to achieve the 3D printing of high‐performance elastomers. Herein, a novel resin formulation that is composed of a photocurable acrylic resin and a mixture of thermocurable isocyanate oligomer/diamine is evaluated by digital light processing technology. Such resin possesses a satisfying viscosity for printing, especially at ambient temperature. For first curing stage, that is, photocurable stage, precisely architectural components with the required shape can be fabricated by a free‐radical photopolymerization. Methyl ethyl ketone oxime that serves as a blocking agent, was employed to ensure the stability of isocyanate resin during this stage. Consecutively, a thermally activated deblocking process is carried out and accompanied by isocyanate/diamine copolymerization, which is the second curing stage. An interpenetrating polymer networks structure in designing resin (25 wt% photocurable resin and 75 wt% thermocurable resin) was formed after thermal curing, which is of significance for achieving excellently comprehensive mechanical properties. Contributed by special structures, it is capable of reaching a 4.67 MPa of tensile strength at 100% strain, while yielding favorable tensile strength of 7.51 MPa as well a maximum elongation at break of 745.3%, which is nearly identical to the initial mechanical performances of pure polyurethane elastomer.