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Abstract：
Polymeric blends are employed in the production of filaments for additive manufacturing to balance mechanical and processability properties. The mechanical and thermal properties of polymeric filaments made of poly (lactic acid) (PLA), polyhydroxyalkanoates (PHA), and its blend (PLA-PHA) are investigated herein and correlated to their measured structural and physicochemical properties. PLA exhibits the highest stiffness and tensile strength, but lower toughness. The mechanical properties of the PLA-PHA blend were similar to those of PLA, but with a significantly higher toughness. Despite the lower mechanical properties of neat PHA, incorporating a small amount (12 wt.%) of PHA into PLA significantly enhances toughness (approximately 50%) compared to pure PLA. The synergistic effect is attributed to the spherulitic morphology of blended PHA in PLA, promoting interactions between the amorphous regions of both polymers. Thermal stability is notably improved in the PLA-PHA blend, as determined by thermogravimetric analysis. The blend also exhibits lower cold crystallization and glass transition temperatures as compared to PLA, which is beneficial for additive manufacturing. Following additive manufacturing, X-ray photoelectron spectroscopic showed that the three filaments present an increase in C-C and C=O bonds associated with the loss of C-O bonds. The thermal process induces a slight increase in crystallinity in PHA due to chain reorganization. The study provides insights into the thermal and structural changes occurring during the melting process of additive manufacturing.
摘要：
聚合物共混物用于生产用于增材制造的长丝以平衡机械和加工性能。由聚乳酸（PLA）制成的聚合物长丝的机械和热性能，聚羟基链烷酸酯(PHA),本文研究了其共混物（PLA-PHA），并将其与测得的结构和物理化学性质相关联。PLA具有最高的刚度和抗拉强度，但韧性较低。PLA-PHA共混物的力学性能与PLA相似，但具有明显更高的韧性。尽管纯PHA的机械性能较低，掺入少量(12重量%。%)的PHA与纯PLA相比显著提高了韧性(约50%)。协同效应归因于PLA中混合PHA的球晶形态，促进两种聚合物的无定形区域之间的相互作用。PLA-PHA共混物的热稳定性显著提高，通过热重分析确定。与PLA相比，共混物还表现出较低的冷结晶和玻璃化转变温度，这有利于增材制造。在增材制造之后，X射线光电子能谱表明，三根细丝的C-C和C=O键增加，与C-O键的损失有关。由于链重组，热过程引起PHA结晶度的轻微增加。该研究提供了对增材制造熔化过程中发生的热和结构变化的见解。
