Morphology and Mechanical Properties of Stereolithography-Printed Polymer Networks

Stereolithography (SLA) is a method of 3D printing in which polymer network objects are formed through the repeated curing of photopolymer resin by a computer-controlled UV laser source. Objects that are 3D printed on a SLA platform show a layered morphology on the microscopic scale, and the resolution of the printed object is determined predominantly by the thickness of each layer, typically on the 100 um scale. Layer formation during printing is dependent on laser intensity and decay during the printing process. Printed layers are generally characterized by a strongly crosslinked region that decays gradually into a more loosely crosslinked domain which is adjacent to a highly crosslinked region of the next layer. This pattern of curing is a function of laser intensity and reflects decay of intensity throughout each curing cycle, or layer. The SLA-printed morphology is characterized on the microscopic scale as a function of laser intensity and decay during printing. High resolution optical microscopy techniques will offer a depiction of crosslinking density change across layered 3D printed structure. The layer curing process will also be investigated by real-time FTIR, DSC, and DMA.