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首页> 美国卫生研究院文献>Polymers >Solid-State Nuclear Magnetic Resonance (NMR) and Nuclear Magnetic Relaxation Time Analyses of Molecular Mobility and Compatibility of Plasticized Polyhydroxyalkanoates (PHA) Copolymers
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Solid-State Nuclear Magnetic Resonance (NMR) and Nuclear Magnetic Relaxation Time Analyses of Molecular Mobility and Compatibility of Plasticized Polyhydroxyalkanoates (PHA) Copolymers

机译：固态核磁共振（NMR）和核磁共振弛豫时间分析的增塑聚羟基链烷酸酯（PHA）共聚物的分子迁移率和相容性

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The molecular mobility and compatibility of plasticized polyhydroxyalkanoates (PHA) were investigated, focusing on changes due to copolymerization using either flexible poly (butylene succinate) (PBS) or rigid poly(lactic acid) (PLA) units. For the case of a poly(3-hydroxybutyrate) (PHB) unit in plasticized PHA, copolymerization of either PBS or PLA decreased 1H and 13C spin-lattice relaxation times in the laboratory frame (T1H and T1C) in the same manner, while PBS produced a lower 1H spin-lattice relaxation time in the rotating frame (T1ρH) than PLA. Both the signals of 1H MAS (magic-angle spinning) and 13C PST (pulse saturation transfer) MAS nuclear magnetic resonance (NMR) spectra were sharpened and increased by copolymerization with PBS. A variable temperature relaxation time analysis showed that the decrease of T1H values was dominated by the 1H spin diffusion via the interface between PHB and the added polyester because of the good compatibility. Meanwhile, the decrease of T1C values was dominated by increasingly rapid molecular motions of PHB because of the lowered crystallinity due to the plasticization. Slow molecular motions (kHz order) were enhanced more by the addition of PBS than PLA, although rapid molecular motions (MHz order) were enhanced by either polyester. Several NMR parameters were beneficial for analyzing the manufacturing process as the indexes of polymer compatibility and molecular motions.
机译：研究了增塑聚羟基链烷酸酯（PHA）的分子迁移率和相容性，重点研究了由于使用柔性聚丁二酸丁二酸酯（PBS）或刚性聚乳酸（PLA）单元而发生的共聚变化。对于增塑的PHA中的聚（3-羟基丁酸酯）（PHB）单元，PBS或PLA的共聚会降低 1 H和 13 C自旋晶格弛豫时间以相同的方式在实验室框架（T1H和T1C）中，而PBS在旋转框架（T1ρH）中产生的 1 H自旋晶格弛豫时间比PLA短。通过共聚作用， 1 H MAS（魔术角旋转）和 13 C PST（脉冲饱和转移）MAS核磁共振（NMR）信号均变尖锐和增强用PBS。可变的温度弛豫时间分析表明，由于良好的相容性，T1H值的下降主要是通过PHB和添加的聚酯之间的界面通过 1 H自旋扩散控制的。同时，由于增塑导致结晶度降低，PHB分子运动越来越快，从而导致T1C值的下降。通过添加PBS，与PLA相比，增加了慢分子运动（kHz级），尽管两种聚酯均提高了快速分子运动（MHz级）。几个NMR参数作为聚合物相容性和分子运动的指标对于分析制造过程是有益的。

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