In this work, the influence of the thermomechanical degradation of poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) during melt processing on the formation of its crystalline structure was investigated by temperature‐resolved small angle X‐ray scattering (SAXS) and complementary techniques, thus combining different tools in the characterization of polymeric structures. PHBV was processed in an internal mixer at 170°C for 7 minutes at four rotation speeds (50, 100, 150, and 200 rpm), in order to obtain samples with molar masses ranging from 125 000 to 64 000 g mol⁻¹. The processing at higher rotation speeds resulted in the formation of thinner, smaller, and/or imperfect crystallites, which melt at lower temperatures. Moreover, the melting curves were broader than those associated with the unprocessed PHBV, suggesting a change in the size distribution of the crystallites. These results were corroborated by lamellar long period values and crystalline and amorphous thickness as determined by SAXS, where the sample processed at 200 rpm presented the most evident effects of the melt processing.

中文翻译：

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通过温度分辨SAXS实验评估了热机械降解对PHBV晶体结构形成的影响

在这项工作中，通过温度分辨小角X射线散射（SAXS）和互补技术研究了聚（羟基丁酸酯-共-羟基戊酸酯）（PHBV）在熔融加工过程中的热机械降解对其晶体结构形成的影响。 ，因此在表征聚合物结构时结合了不同的工具。PHBV在170°C的内部混合器中以四种转速（50、100、150和200 rpm）处理7分钟，以便获得摩尔质量为125 000至64 000 g mol ^-1的样品。在较高转速下的加工导致形成更薄，更小和/或不完美的微晶，它们在较低的温度下熔化。此外，熔解曲线比未加工的PHBV的熔解曲线宽，表明微晶的尺寸分布发生了变化。通过SAXS测定的层状长期值以及晶体和无定形厚度证实了这些结果，其中以200 rpm处理的样品表现出熔体处理的最明显效果。