신장 광 레오미터와 소각 X선 산란 방법을 이용한 신장 유동계 내의 삼성분 블록 공중합체의 모폴로지 변화 연구신장 유동계 내의 삼성분 블록 공중합체의 모폴로지 변화 연구

초록

The elongational flow-induced morphological change of triblock copolymer melt with cylindrical microdomains is investigated using elongational flow opto-rheometry (EFOR) and small angle X-ray scattering (SAXS). The polymer studied here is a polystyrene-block-poly(ethylene butylene)-block-polystyrene (SEBS) with polystyrene (PS) weight fraction of 30 % (TODT ³ 300 oC). The alignment of the PS cylinder domains in a preferred direction is achieved by roll-processing at 200 oC. In the EFOR measurement, the uniaxial elongation with a Hencky strain rate, , of 0.01 sec-1 and at 180 oC is applied in the direction either parallel or perpendicular to the cylindrical axis. Transient elongational viscosity, , measured during parallel elongation along the cylinder axis displays an initial increase, followed by a gradual decrease to a steady state before rupture. One measured during perpendicular elongation shows three different regions with elongation time: an initial increase, followed by a gradual decrease and a final increase at the end of elongation.