本研究探討聚苯乙烯 -聚 (乙烯 ╱丁烯 )-聚苯乙烯三嵌段共聚物 SEBS Kraton G1652M 在熔融態下被剪的配向為與結構變化。在實驗中以溶液鑄塊法為主，熱壓成型法為輔製作樣品，探討在大振幅剪與單方向剪下柱結構的排為；並藉著改變同的頻、振幅與剪，試圖解在何種條件下柱結構排最好。本研究用 RDAΠ、 SAXS 測柱結構的機械強與排情形； GPC、 DMA 與 TGA 則分別測得 Kraton G1652M 的分子、玻璃轉化溫以及熱解溫。由研究結果發現，在均向樣品上，在大振幅剪是頻越快或振幅越大，對於柱結構的排就越有誘導能；單方向剪上，柱結構均是有效的往速方向排。所以，在配向效果上，單方向剪的效果會比大振幅剪的好。在機械強上，大振幅剪在剪越大共聚物的 G’就會越小；而單方向剪時，剪越大排越迅速， G’也會比大振幅剪的低，這也表示單方向剪是在所探討的剪方式中配向效果最好的方法。經由 RDAΠ與 SAXS 的實驗，我們也確定 Kraton G1652M 在 270℃以下並會發生相轉變的情形。 The purpose of this research is to investigate in the orientation and structure transition of a tri-block copolymer poly(ethy- lene-co-but-1-ene) block polystyrene, Kraton G1652M in the melt flow. Solvent casting and hot pressing were used to prepare samples for the investigation of the orientation behavior of cylindrical structure. The orientation of the cylindrical structure was investigated under different frequencies, strains and shear rates. Measurements of mechanical properties and the orientation of cylinder were done by RDAΠ and SAXS respectively. Results of GPC, DMA and TGA reveal the molecular weight, glass transition temperature and thermal degradation temperature of Kraton G1652M. From the results, it was found that higher frequencies and larger amplitude were more effective in the orientation of the isotropic sample in large amplitude oscillatory shear experiments, though at some low frequencies opposite results was obtained. In steady shear, cylinder structure was aligned rapidly in the direction of velocity, even at a small rate of 0.3s-1. Steady shear has a better efficiency in orientation than the large amplitude oscillatory shear. When the shear rate is higher, faster the orientation and lower storage modulus were observed in the steady shear than in oscillatory shear. The measurements of RDAII and SAXS confirmed Kraton G1652M has no phase below 270.degree.C.
