풍력블레이드가 대형화되면서 유리섬유 복합재료(GFRP)와 탄소섬유 복합재료(CFRP)를 혼용하여 제작하고 있고, 이 때 두 가지 이종재료 간의 접착특성에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 에폭시 접착제 내 탄소나노튜브 함량 및 경화 시 습도의 차이에 따른 접착강도의 변화를 평가하였다. 탄소나노튜브의 함량이 다른 에폭시 접착제를 활용하여 GFRP와 CFRP를 접착하였고, 경화 시 습도에 따른 특성의 변화를 알아보기 위해 접착강도를 평가하였다. 탄소나노튜브 함량에 따른 변화를 알아보기 위해 접착제에 들어가는 탄소나노튜브의 함량을 0, 0.1, 0.3, 0.5, 1 wt%로 나누어 단일랩 전단 시험을 진행하였고, 습도 조건에 따른 변화를 확인하기 위해 항온항습기로 습도를 20, 50, 80% 조건으로 나누어 접착제를 경화시킨 후 단일 랩 전단 시험을 진행하였다. 실험결과 에폭시 접착제에 탄소나노튜브를 넣음으로써 접착특성이 향상됨을 확인하였지만 함량이 과도하게 많을 때에는 접착력이 줄어드는 것을 확인하였다. 또한 습도가 증가할수록 접착특성이 변하지 않음을 확인할 수 있었다.

As the wind blades become larger, they tend to be made by mixing glass fiber and carbon fiber, and it is important to increase the properties of the adhesive which adheres the two materials. The physical properties of the adhesive vary depending on the content of the additive and curing conditions. In this study, the change in adhesion strength with the difference between the CNT (Carbon Nanotube) content of the epoxy adhesive and the humidity during curing was evaluated. GFRP and CFRP specimens were prepared and adhered using an epoxy adhesive, and to examine changes in characteristics with carbon nanotube contents and with the humidity during curing of the epoxy adhesive, adhesion strength was evaluated by dividing the difference between carbon nanotube content and humidity. To find out the change with the CNT contents, the intelaminar shear strength (ILSS) test was performed by dividing the contents of the CNT into 0, 0.1, 0.3, 0.5, and 1 wt%, and to confirm the change with the humidity conditions, the adhesive was cured by dividing the humidity by 20, 50, and 80%. From the result of the experiment, the adhesive force decreased when the content was excessively large, although the adhesive property was enhanced by adding CNT to the epoxy adhesive. In addition, it was confirmed that the adhesion characteristics were not changed as the humidity increased.

본 연구에서는 폴리올의 혼합으로 폴리우레탄의 물성 저하를 보완하고자 하였다. 신발 및 소재 코팅용으로서 자가치유 기능을 가지는 수분산 폴리우레탄 수지를 합성하기 위해 내구성 및 내열성이 우수한 polyether 폴리올과 기계적 물성이 뛰어난 polycarbonate 폴리올을 병용하여 합성하였으며, 자가치유 기능의 부여를 위해 disulfide기를 도입하였다. 합성된 자가치유 기능 수분산 폴리우레탄은 fourier transform-infrared spectroscopy (FT-IR)을 통해 확인되었으며, universial testing machine (UTM)과 scanning electron microscope (SEM) 측정을 통해 물리적 특성 및 자가치유 특성을 확인하였다. Polycarbonate 폴리올을 병용함으로써 인장강도 및 경도가 증가하였고, 신장율은 감소하였다. 또한 열적 특성의 비교 결과, polycarbonate 폴리올의 함량이 증가함에 따라 열 안정성이 증가하였다. 치료효율은 poly(tetramethylene ether)glycol : polycarbonate polyol = 0.75 : 0.25일 때 가장 높은 효율을 보여주었으며, 현미경 및 SEM을 이용한 표면 관찰을 통해 손상 부분이 치유된 것을 확인하였다.

In this study, self-healable waterborne polyurethane (SH-WPU) as shoes and coating materials with self-healable disulfide functionalities was synthesized by mixing polyether polyol to impart excellent durability and heat resistance and polycarbonate polyol to impart excellent mechanical properties. The synthesized SH-WPU was characterized by fourier transform-infrared spectroscopy (FT-IR), and physical and self-healing properties were confirmed through universal testing machine (UTM) and scanning electron microscope (SEM) measurements. Tensile strength and hardness were increased and elongation was decreased by using polycarbonate polyol. In addition, as a result of comparison of thermal properties, thermal stability has been increased as the content of polycarbonate polyol increased. The healing efficiency showed the highest efficiency when poly(tetramethylene ether)glycol : polycarbonate polyol = 0.75 : 0.25, and it was confirmed that the damaged part was healed through surface observation using a microscope and SEM.