Difference in Macroscopic Morphologies of Amylosic Supramolecular Networks Depending on Guest Polymers in Vine-Twining Polymerization
Difference in Macroscopic Morphologies of Amylosic Supramolecular Networks Depending on Guest Polymers in Vine-Twining Polymerization
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DOI：
10.3390/polym10111277
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发表时间：
2018-11-01
期刊：
影响因子：
5
通讯作者：
Kadokawa, Jun-ichi
中科院分区：
文献类型：
--
作者：
Orio, Saya;Shoji, Takuya;Kadokawa, Jun-ichi
直链淀粉是一种天然多糖，在合适的客体聚合物(缠绕聚合)的存在下，作为宿主分子在其酶促形成过程中形成超分子包合物，即以α-D-葡萄糖1-磷酸单体和麦芽低聚糖为底物的磷酸酶催化的酶聚合。此外，在麦芽七糖(G7)接枝聚γ-谷氨酸(PGA)等低聚低聚糖引发剂接枝聚合物的缠绕聚合中，在聚己内酯(PCL)的存在下，酶拉长的直链淀粉接枝链与PGA主链之间的PCL形成包合物，构成超分子网络。根据PCL/PRIMER投料比的不同，可以观察到产物的宏观形态为水凝胶或聚集。在这项研究中，我们评估了这种淀粉超分子网络与不同的客体聚合物在葡萄缠绕聚合中的宏观形态，在聚四氢呋喃(PTHF)、聚己内酯(PCL)和聚L-丙交酯(PLLA)的存在下，使用G7接枝的PGA。结果发现，使用PTHF的反应混合物完全变成水凝胶形式，而使用PCL和PLLA的产物在反应混合物中聚集在一起。用粉末X射线衍射仪和扫描电子显微镜对网络进行了表征。宏观形态上的差异可以用不同客体聚合物的稳定性来合理解释。
Amylose, a natural polysaccharide, acts as a host molecule to form supramolecular inclusion complexes in its enzymatically formation process, that is, phosphorylase-catalyzed enzymatic polymerization using the alpha-D-glucose 1-phosphate monomer and the maltooligosaccharide primer, in the presence of appropriate guest polymers (vine-twining polymerization). Furthermore, in the vine-twining polymerization using maltooligosaccharide primer-grafted polymers, such as maltoheptaose (G7)-grafted poly(gamma-glutamic acid) (PGA), in the presence of poly(epsilon-caprolactone) (PCL), the enzymatically elongated amylose graft chains have formed inclusion complexes with PCL among the PGA main-chains to construct supramolecular networks. Either hydrogelation or aggregation as a macroscopic morphology from the products was observed in accordance with PCL/primer feed ratios. In this study, we evaluated macroscopic morphologies from such amylosic supramolecular networks with different guest polymers in the vine-twining polymerization using G7-grafted PGA in the presence of polytetrahydrofuran (PTHF), PCL, and poly(L-lactide) (PLLA). Consequently, we found that the reaction mixture using PTHF totally turned into a hydrogel form, whereas the products using PCL and PLLA were aggregated in the reaction mixtures. The produced networks were characterized by powder X-ray diffraction and scanning electron microscopic measurements. The difference in the macroscopic morphologies was reasonably explained by stabilities of the complexes depending on the guest polymers.