Nishida Masakazu, Tanaka Tomoko, Hayakawa Yoshio, Ogura Takashi, Ito Yoshiaki, Nishida Masahiro
National Institute of Advanced Industrial Science and Technology (AIST) 2266-98 Shimoshidami, Moriyama-ku Nagoya 463-8560 Japan
Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya Aichi 466-8555 Japan.
RSC Adv. 2019 Jan 11;9(3):1551-1561. doi: 10.1039/c8ra10045d. eCollection 2019 Jan 9.
Details of the mechanism underlying the tensile properties of plasticized polyhydroxyalkanoates (PHA) including poly(butylene succinate) (PBS) were investigated by blending with poly(ε-caprolactone) (PCL) as well as the addition of compatibilizers. Multi-scale instrumental analyses employed micro-focus X-ray CT to provide micro-scale morphology information on the order of ten microns while solid-state NMR spectral and relaxation time analyses contributed knowledge of the environment and molecular mobility of each constituent at the molecular to nano-scale. The blend of plasticized PHA with 50% PCL adopted a sea-island morphology to improve elongation at break in a quasi-static tensile test, which was dominated by the tensile properties of the added PCL. However, impact tensile properties were less improved by PCL addition, because its molecular mobility was suppressed by blending. Meanwhile, peroxy crosslinkers changed the sea-island morphology to homogenous in X-ray CT observations. Although the homogenous morphology sharply lowered the elongation at break in a quasi-static tensile test, the homogenous morphology improved impact tensile properties. Furthermore, graft polymers having acrylonitrile-styrene side-chains did not change the sea-island morphology but increased the molecular mobility of PBS in the plasticized PHA. This weak interaction between the plasticized PHA and PCL improved tensile properties in both quasi-static and impact tensile tests.
通过与聚（ε-己内酯）（PCL）共混以及添加增容剂，研究了包括聚丁二酸丁二醇酯（PBS）在内的增塑聚羟基脂肪酸酯（PHA）拉伸性能的潜在机制细节。多尺度仪器分析采用微焦点X射线计算机断层扫描（CT），以提供约十微米量级的微观形态信息，而固态核磁共振光谱和弛豫时间分析则有助于了解各组分在分子到纳米尺度的环境和分子流动性。在准静态拉伸试验中，含50%PCL的增塑PHA共混物呈现海岛形态，以提高断裂伸长率，这主要由添加的PCL的拉伸性能决定。然而，添加PCL对冲击拉伸性能的改善较小，因为共混抑制了其分子流动性。同时，过氧交联剂在X射线CT观察中将海岛形态转变为均匀形态。尽管均匀形态在准静态拉伸试验中大幅降低了断裂伸长率，但改善了冲击拉伸性能。此外，具有丙烯腈-苯乙烯侧链的接枝聚合物没有改变海岛形态，但增加了增塑PHA中PBS的分子流动性。增塑PHA与PCL之间的这种弱相互作用在准静态和冲击拉伸试验中均改善了拉伸性能。
