3-Glycidoxypropyltrimethoxy silane(GPTMS)으로 친수성의 실리카 나노입자(SNPs)를 소수화하였으며, 소수화된 SNPs를 폴리우레탄-우레아(PUU) 에멀젼과 혼합하여 SNPs/PUU 나노복합체 필름을 제조하였다. 필름 제조 후 PUU 매트릭스 내 SNPs의 함량, SNPs 표면의 소수화 정도, 에폭시 그룹과의 열경화 반응 여부가 필름의 물성에 미치는 영 향을 분석하였다. SNP 표면에 도입된 GPTMS의 최대 함량은 1.99×10-6 mol/m2로 SNP 표면적 기준으로 약 53% 수준이었다. GPTMS에 의한 소수화로 PUU 매트릭스 내 SNPs의 분산성이 향상되었으며, SNPs 함량이 5 wt%에서 20 wt%로 증가함에 따라 SNPs/PUU 나노복합체 필름의 유연성은 감소하였으나, 열 안정성은 증가하였다. 특히 Young`s modulus와 tensile modulus는 에폭시의 열경화 반응 후에 크게 증가하였다.

Hydrophilic silica nanoparticles (SNPs) were treated by using 3-glycidoxypropyltrimethoxy silane (GPTMS) and then they were blended with polyurethane-urea (PUU) emulsions to obtain SNPs/PUU nanocomposite films. Thermo-mechanical properties of the nanocomposite films were investigated by varying the grafted amount of GPTMS onto SNPs and the contents of SNPs in the PUU matrix. The thermo-mechanical properties of the nanocomposite films were also compared in terms of the dispersibility of SNPs in the PUU matrix and thermal curing of the GPTMS-grafted SNPs, The maximum amount of grafted GPTMS was 1.99×10-6 mol/m2, and which covered ca, 53% of the total SNP surface area, 29Si CP/MAS NMR analyses with the deconvolution of peaks revealed the details of polycondensation degree and patterns of GPTMS in the surface modification of SNPs. The surface modification did not significantly affect colloidal stability of the SNPs in aqueous medium; however, the hydrophobic modification of SNPs offered a favorable effect on the dispersibility of SNPs in the PUU matrix as well as better thermal stability. XRD patterns revealed that GPTMS-grafted SNPs broadened the reduced the characteristic peak of polyol in PUU matrix. The composite films became rigid and less flexible as the SNP content increased from 5 wt% to 20 wt%. Particularly, Young`s modulus and tensile modulus significantly increased after the thermal curing reaction of the epoxy groups in the SNPs.