To address the need for a suitable thermoplastic resin-based sizing agent for accommodating the increasing demands of carbon fiber-reinforced plastic, in this work, alcohol-soluble polyamide 6 (PA6) and silane were chemically combined in a certain ratio to improve the mechanical interface properties of the carbon fiber/PA6 composite, and the enhancement in the mechanical interface strength of the final composite according to the treatment time was confirmed. Carbon fiber surface properties were analyzed through ultrahigh-resolution field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy, and Fourier transform infrared spectrometry. The tensile strength of carbon fibers before and after hybrid sizing treatment and the mechanical interfacial shear strength of the final composite were analyzed using tensile and universal testing machines, respectively. After the hybrid sizing treatment, the introduction of the sizing agent to the carbon fiber surface was confirmed through FE-SEM, and a simultaneous increase in the surface roughness was observed. Moreover, the interfacial adhesion was confirmed to increase significantly, as compared to that of the desized carbon fiber. Therefore, this modified sizing agent treatment serves as an effective method for improving the mechanical interfacial adhesion between the carbon fiber and the PA6 matrix.

산업분야에서는 다양한 용액을 대상으로 분리, 정제, 농축 등의 공정이 필요하며, 분리막이 그 역할을 잘 수행해 오고 있다. 반면, 처리 대상 용액이 강산을 함유하고 있는 경우, 대부분의 분리막은 산에 취약하기 때문에 사용이 제한적일 수밖에 없다. 현재 내산성 분리막으로 상용화 되고 있는 분리막은 투과속도가 낮은 문제점을 갖고 있다. 이에, 투과속도가 높 은 폴리아마이드 분리막에 내산성을 부여하기 위한 접근 방법을 모색하기 위한 기초 자료로 본 총설에서는 폴리아마이드 분 리막이 산성 용액 노출 시 표면성질 및 투과특성이 변화하는 원인과 기작에 대해 살펴보고자 한다.

In this study, a MWCNT(multi-wall carbon nanotube) was added to polysulfone(PSf) support layer to improve flux of TFC(thin film composite) RO(reverse osmosis) membrane. Two different kinds of MWCNT were used. Surfaces of some MWCNTs were modified hydrophilically through acid treatment, while those of other MWCNTs were modified through heat treatment to maintain their hydrophobicity. MWCNT/PSf support layer was prepared by adding PSf to the NMP mixed solvent containing 0.1 wt% MWCNTs using a phase inversion method. The surface porosity of the MWCNT/PSf support increased by 42~46% while its surface pore size being maintained. The TFC RO membrane made of MWCNT/PSf support layer showed a 20% flux increase while its salt rejection characteristics is sustained. In addition, the MWCNT/PSf support layer has better mechanical stability than the PSf support layer, there resulting in an increased resistance of flux reduction due to physical pressure.