As one of VAT photopolymerization, Digital light process (DLP) 3D printing has the advantage of high resolution and fast printing speed, and also has easy material development due to using liquid resin for printing. In addition, since carbon nanotubes (CNTs) has excellent physical properties, various application researches are being conducted as additives for resin. Therefore, as a basic study combining DLP, an innovative process, and CNT, a smart material, the curing characteristics of CNT/resin composites were identified. Dispersion is essential because CNTs have a strong tendency to agglomerate. As the degree of CNT dispersion increases, the area where the CNTs block light increases, hindering the curing of the resin. Therefore, in this study, the curing characteristics of the CNT/resin composites according to the CNT concentration and dispersion were theoretically modeled and verified through experiments. The absorbance of the CNT/resin was measured using UV-Vis spectroscopic analysis, and the relationship with the absorbance and curing thickness was identified. It was found that the absorbance of the CNT/resin is a function of dispersion and concentration of CNTs. Moreover, it was found that the curing thickness is the logarithm of the exposure time and is inversely proportional to the absorbance.
광경화성 3D 프린팅 중 하나로, Digital light process(DLP)는 높은 해상도와 빠른 출력 속도를 보유하고 있으며, 액체상태의 레진을 이용하므로 재료 개발이 용이하다. 또한, Carbon nanotube(CNT)는 우수한 물성치를 가진 재료로, 레진의 첨가제로써 응용 연구가 이루어지고 있다. 따라서, 혁신적인 공정인 DLP와 스마트 소재인 CNT를 결합한 기초연구로써, CNT/레진 복합재의 경화 특성을 파악하였다. CNT는 뭉치려는 성질이 강해 분산이 필수적이다. CNT 분산도가 높을수록 CNT가 빛을 가리는 면적이 증가하여, 레진의 경화를 방해한다. 따라서, 본 연구에서는 CNT/레진 복합재의 CNT 농도와 분산도에 따른 경화 특성을 모델링하고, 실험으로 검증하였다. 분광분석을 이용하여 CNT/레진의 흡광도를 측정했고, 경화 두께와의 관계를 파악했다. CNT/레진의 흡광도는 분산도와 농도의 함수이고, 경화 두께는 노출 시간의 로그이며, 흡광도에 반비례함을 밝혔다.
