相容剂增容聚对苯二甲酸乙二醇酯/聚乳酸共混物的制备及结晶性能与热性能

Preparation and Characterization of Crystallization and Thermal Property of Poly(ethylene terephthalate) and Poly(lactic acid) Blends Promoted by Compatilizer

分别通过扫描电镜(SEM)、差式扫描量热分析(DSC)、X射线衍射(XRD)、热重分析(TG)、核磁共振及红外光谱等研究相容剂种类、含量及聚对苯二甲酸乙二醇酯(PET)/聚乳酸(PLA)配比对PET/PLA共混物的断面形貌、结晶形态及热性能等的影响。SEM和DSC结果表明,相容剂乳酸/丁二醇共聚物(PLLA-g-BDO)及用量对PET/PLA共混物的界面相容影响较大。与未加相容剂比,相容剂使界面从清晰过渡到模糊,界面处未见明显团聚颗粒;相容剂用量为8%时,DSC曲线上仅出现1个熔融峰。DSC和XRD表明,相容剂的引入降低了共混物的结晶度,冷结晶和热结晶过程中分别结晶,结晶的温度范围较宽,热结晶的结晶度大于冷结晶。冷结晶时,柔性链的PLA先结晶,PET后结晶;热结晶时,结晶温度较大组分PET先结晶,PLA后结晶。TG分析表明PET/PLA配比是材料热稳定性的必要条件。

Crystal and phase morphology, thermal properties of poly（ethylene terephthalate） and poly（lactic acid） blends with reactive compatilizer types, contents and different ratio for PET/PLA were investigated by SEM, DSC, XRD, TG, 1H-NMR and FT-IR etc. Results of SEM and DSC show that （PLLA-g-BDO） compatilizer types and contents have better influences on the interface compatibility of PET/PLA blends. With addition of compatilizer, there is a dramatic shift from clear to fuzzy with no obvious reunion particles for the phase, and an unique melting peak in DSC curve appears at the optimum mass of 8% compatilizer. DSC and XRD confirm that they will crystallize individually as cooling from melt, but crystallinity of the latter is more than the former, which reduce the whole crystallinity at a wide range crystallization temperature. When cooled, PLA component with flexible chain will crystallize first; simultaneously, PET component at higher crystallization temperature will crystallize first when melted. TG indicates that the PET/PLA ratio is necessary for thermal stability of materials.