Development of in situ nanofibrillar poly (lactic acid)/poly (butylene terephthalate) composites: Non-isothermal crystallization and crystal morphology
Development of in situ nanofibrillar poly (lactic acid)/poly (butylene terephthalate) composites: Non-isothermal crystallization and crystal morphology
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DOI：
10.1016/j.eurpolymj.2020.109489
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发表时间：
2020-02-15
影响因子：
6
通讯作者：
Altstaedt, Volker
中科院分区：
文献类型：
--
作者：
Shahnooshi, Mahboobeh;Javadi, Azizeh;Altstaedt, Volker
采用调谐一步熔融纺丝法制备了聚乳酸(PLA)/聚对苯二甲酸丁二醇酯(PBT)共混物，其中PBT的质量分数为1~10wt%，成功地原位诱导出平均直径为23~51.4 nm的PBT纳米纤维。扫描电子显微镜(SEM)显示了聚乳酸基质中PBT纳米纤维的形态，发现PBT纳米纤维的长径比大于400。用偏光显微镜分析了聚乳酸熔融纺丝纤维在PBT-NFS体存在和不存在的情况下的结晶形态。在PBT-NFS存在下，聚乳酸的结晶形态发生了显著的变化。聚乳酸纤维中分散的球晶在聚乳酸/聚对苯二甲酸乙二酯纤维中转变为沿PBT方向取向的非常小的晶体。非等温结晶研究表明，模压法制备的原位纳米纤维复合材料(NFC)的结晶度显著提高(27.5%)，结晶速率显著提高。结晶速率的提高为研究聚乳酸的晶型及其在冷结晶和熔融结晶过程中成核的相对粒子数提供了比较条件。此外，还比较了具有液滴基质形态的聚乳酸/PBT共混物的结晶行为，并与相同PBT含量的NFC样品的结晶行为进行了比较，以强调共混物形态剪裁的巨大作用。
Tuned one-step melt spinning of poly (lactic acid) (PLA)/poly (butylene terephthalate) (PBT) blends containing 1-10 wt% of PBT, was carried out successfully to induce in situ nanofibrils of PBT with average diameter of 23-51.4 nm. Scanning electron microscopy (SEM) images showed the morphology of PBT nanofibrils (NFs) in the PLA matrix and it was found that the aspect ratio of PBT NFs was more than 400. The crystal morphology of the PLA melt spun fibers in the presence and absence of PBT NFs was analyzed using polarized optical microscopy. Dramatic changes in the crystal morphology of PLA were observed in the presence of PBT NFs. Scattered spherulites in the PLA fibers changed to very small crystals oriented in the PBT NFs direction in the PLA/PBT fibers. Non-isothermal crystallization studies of PLA in the in situ nanofibrillar composites (NFCs) prepared by compression molding demonstrated a significant improvement of crystallinity (27.5%) as well as crystallization rate. Enhanced crystallization rate provided comparative conditions to study the crystal forms of PLA and their relative populations nucleated during the cold and melt crystallizations. Moreover, the crystallization behavior of PLA/PBT blend with droplet-matrix morphology was compared with that of the NFC sample at the same PBT content to emphasize the tremendous effect of the morphological tailoring of blends.