The effects of crystallization temperature and blend ratio on the polymorphic crystal structures of poly（butylene adipate） （PBA） in poly（butylene succinate） （PBS）/poly（butylene adipate） （PBS/PBA） blends we...The effects of crystallization temperature and blend ratio on the polymorphic crystal structures of poly（butylene adipate） （PBA） in poly（butylene succinate） （PBS）/poly（butylene adipate） （PBS/PBA） blends were studied by means of differential scanning calorimetry （DSC）, wide-angle X-ray diffraction （XRD） and atomic force microscopy （AFM）. It was revealed that the polymorphism of PBA can be regulated by the blend ratio even in a non-isothermal crystallization process. The results demonstrate that high temperature favors fiat-on α crystals, while low temperature contributes to edge-on β crystals. It was also found that the effect of blend ratio on the crystallization mechanism of PBA is well coincident with that of the crystallization temperature. The increment of PBS content in the PBS/PBA blend gives rise to more β-form crystals of PBA. For those PBS/PBA blends with low PBA content, the interlamellar phase segregation of PBA makes its molecular chains so difficult to diffuse from one isolated microdomain to another that high crystallization temperature and sufficiently long crystallization time will be required if the PBA α-type crystals are targeted.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21204045 and 21276151)Natural Science Basic Research Plan in Shaanxi Province of China(No.2011JQ2004)Key Scientific Research Group of Shaanxi Province(No.2013KCT-08)
文摘The effects of crystallization temperature and blend ratio on the polymorphic crystal structures of poly（butylene adipate） （PBA） in poly（butylene succinate） （PBS）/poly（butylene adipate） （PBS/PBA） blends were studied by means of differential scanning calorimetry （DSC）, wide-angle X-ray diffraction （XRD） and atomic force microscopy （AFM）. It was revealed that the polymorphism of PBA can be regulated by the blend ratio even in a non-isothermal crystallization process. The results demonstrate that high temperature favors fiat-on α crystals, while low temperature contributes to edge-on β crystals. It was also found that the effect of blend ratio on the crystallization mechanism of PBA is well coincident with that of the crystallization temperature. The increment of PBS content in the PBS/PBA blend gives rise to more β-form crystals of PBA. For those PBS/PBA blends with low PBA content, the interlamellar phase segregation of PBA makes its molecular chains so difficult to diffuse from one isolated microdomain to another that high crystallization temperature and sufficiently long crystallization time will be required if the PBA α-type crystals are targeted.
