Thermal-Expansion and Fracture Toughness Properties ofParts made from Liquid Crystal Stereolithography Resins

Liquid crystal (LC) resins are a new kind ofstereolithography material that can produce parts with structured or ordered morphologies instead ofthe amorphous morphologies that result from standard resins. The LC molecules can be aligned before cure resulting in an anisotropic crosslinked network when the laser induced polymerization "locks-in" the alignment. Previous papers have explored liquid crystal orientation dynamics [1], the effects of orientation on viscoelastic and mechanical properties [2,3], and the processing ofLC resins by stereolithography [4]. This paper considers the effects ofmorphology on fracture toughness and thermal-expansion properties. Both toughness and thermal-stability continue to be important issues for stereolithography parts. The use ofLC resins may provide a way to significantly improve performance in both ofthese areas, and in addition result in parts with high upper use . temperatures.