PBS- <i>co</i> - PCL多嵌段共聚物中顺序结晶/熔融诱导的可逆层状周期性结构,Macromolecules

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PBS- co - PCL多嵌段共聚物中顺序结晶/熔融诱导的可逆层状周期性结构
Macromolecules ( IF 5.1 ) Pub Date : 2018-01-22 00:00:00 , DOI: 10.1021/acs.macromol.7b01779
Miaoming Huang _{1,

2} , Xia Dong _{1,

3} , Lili Wang _{1,

3} , Liuchun Zheng ₁ , Guoming Liu ₁ , Xia Gao ₂ , Chuncheng Li ₁ , Alejandro J. Müller _{4,

5} , Dujin Wang _{1,

3}

Affiliation

首次检测到对称的聚丁二酸丁二酯-共-聚（ε-己内酯）（PBS-共-PCL）多嵌段共聚物中的可逆周期性结构。可以在相差光学显微镜下于150°C观察到相分离的结构，但对随后的PBS组分的结晶行为没有明显影响，该结晶行为在较低的温度（例如82°C）下会破裂。在其中包含熔融PCL成分的球晶。在PBS链在82°C结晶的过程中，通过SAXS实验检测到两个峰。高q峰对应于在由PBS薄片和包含PBS和熔融PCL链的无定形区域组成的PBS丰富域内形成的周期性结构。低q峰来自于富含PCL的区域内形成的周期性结构，该区域由PBS薄片和厚的无定形层组成，以容纳82°C的大部分熔融PCL链。当温度降低至36°C时，PCL成分在PBS球晶模板中结晶，并形成PCL和PBS的交替双晶层结构，这导致低q峰强度降低，而pQ强度升高。高q峰。如果温度再次升高，PCL晶体将重新熔化，仍然可以观察到高q峰，而低q峰再次变强，确认了周期性结构的可逆性。基于获得的结果，提出了结晶/熔融过程中可逆周期性结构的示意性形态模型。

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Reversible Lamellar Periodic Structures Induced by Sequential Crystallization/Melting in PBS-co-PCL Multiblock Copolymer

Reversible periodic structures in a symmetric poly(butylene succinate)-co-poly(ε-caprolactone) (PBS-co-PCL) multiblock copolymer have been detected for the first time. A phase-segregated structure can be observed under the phase contrast optical microscope at 150 °C, but it has no significant effect on the subsequent crystallization behavior of the PBS component, which can break out at lower temperatures (i.e., 82 °C) forming spherulites that contain the molten PCL component within them. During PBS chains crystallization at 82 °C, two peaks are detected by SAXS experiments. The high-q peak corresponds to a periodic structure formed within PBS-rich domains consisting of PBS lamellae and amorphous regions containing PBS and molten PCL chains. The low-q peak arises from a periodic structure formed within PCL-rich domains consisting of PBS lamellae and thick amorphous layers needed to accommodate the large fraction of molten PCL chains at 82 °C. When the temperature is decreased to 36 °C, the PCL component crystallizes within the PBS spherulitic template, and an alternating double crystalline layer structure of PCL and PBS forms, which leads to a decreased intensity of the low-q peak and an increased intensity of the high-q peak. If the temperature is increased again, the PCL crystals remelt and the high-q peak can still be observed, while the low-q peak becomes stronger again, confirming the reversibility of the periodic structures. Based on the results obtained, a schematic morphological model of the reversible periodic structures in the crystallization/melting process is proposed.

更新日期：2018-01-22

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