Abstract

순수 PMMA와 methacryl-polyhedral oligomeric silsesquioxane(Ma-POSS)를 5 wt% 첨가한 PMMA를 박막(~650 nm)과 초박막(~50 nm)으로 제조하였으며, 유리전이온도(<TEX>$T_g$</TEX>)와 등온 물리적 시효에 미치는 박막의 두께에 미치는 POSS의 첨가 효과를 시차주사열량계(DSC)를 이용하여 조사하였다. 초박막화와 Ma-POSS의 첨가로 인해 <TEX>$T_g$</TEX> 감소가 관찰되었다. 또한 등온 물리적 시효에 의한 엔탈피 완화값(<TEX>${\Delta}H_{Relax}$</TEX>)도 초박막화 Ma-POSS를 첨가하였을 때 감소하였다. 시효시간에 따른 <TEX>${\Delta}H_{Relax}$</TEX> 데이터에 KWW(Kohlrausch-Williams-Watts)식을 적용하여 최대 엔탈피(<TEX>${\Delta}H_{\infty}$</TEX>), 이완시간(<TEX>${\tau}$</TEX>) 그리고 이완시간의 분포상수(<TEX>${\beta}$</TEX>)를 결정하였으며 이를 비교 분석하였다. Thin (~650 nm) and ultrathin (~50 nm) films of neat PMMA and PMMA containing 5 wt% of methacryl-polyhedral oligomeric silsesquioxane were prepared in this work. The effects of film thickness and POSS on glass transition temperature (<TEX>$T_g$</TEX>) and isothermal physical aging were investigated by means of differential scanning calorimetry (DSC). <TEX>$T_g$</TEX> depression was observed as film thickness was decreased and Ma-POSS molecules were incorporated. Enthalpy relaxation (<TEX>${\Delta}H_{Relax}$</TEX>) due to the isothermal physical aging was reduced by ultra-thin film thickness and the addition of Ma-POSS. KWW (Kohlrausch-Williams-Watts) equation was used to fit <TEX>${\Delta}H_{Relax}$</TEX> vs. aging time data providing the fitting parameters; maximum enthalpy recovery (<TEX>${\Delta}H_{\infty}$</TEX>), relaxation time (<TEX>${\tau}$</TEX>) and non-exponentiality parameter (<TEX>${\beta}$</TEX>).

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call