Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure
Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure
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DOI：
10.3390/app7060579
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发表时间：
2017-06-01
影响因子：
2.7
通讯作者：
Halada, Gary P.
中科院分区：
文献类型：
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作者：
Cuiffo, Michael Arthur;Snyder, Jeffrey;Halada, Gary P.
聚乳酸（PLA）是一种具有生物相容性和免疫惰性的有机聚合物，常用于熔融沉积（FDM）打印和生物医学支架。然而，由于原料质量和化学性质的变化，有必要对灯丝进行表征，并确定由于FDM工艺而发生的化学变化。我们使用了几种光谱技术，包括激光共聚焦显微镜，傅里叶变换红外（FTIR）光谱和光声FTIR光谱，拉曼光谱和x射线光电子能谱（XPS），以表征源材料和印刷样品的体化学和表面化学。用扫描电镜（SEM）和差示扫描量热法（DSC）表征打印后的形貌、冷结晶度、玻璃化转变和熔化温度。分析显示，在打印前后，碳酸钙基添加剂都与有机配体和潜在的微量金属杂质发生了反应。这些添加剂集中在印刷结构的空隙中。这一发现对生物医学应用很重要，因为碳酸盐会影响打印组织支架上的细胞生长。化学分析的结果也提供了源材料的吸湿性和印刷表面氧化的证据，扫描电镜成像显示了微观和亚微米尺度的粗糙度，这也将影响潜在的应用。
Polylactic acid (PLA) is an organic polymer commonly used in fused deposition (FDM) printing and biomedical scaffolding that is biocompatible and immunologically inert. However, variations in source material quality and chemistry make it necessary to characterize the filament and determine potential changes in chemistry occurring as a result of the FDM process. We used several spectroscopic techniques, including laser confocal microscopy, Fourier transform infrared (FTIR) spectroscopy and photoacousitc FTIR spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) in order to characterize both the bulk and surface chemistry of the source material and printed samples. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were used to characterize morphology, cold crystallinity, and the glass transition and melting temperatures following printing. Analysis revealed calcium carbonate-based additives which were reacted with organic ligands and potentially trace metal impurities, both before and following printing. These additives became concentrated in voids in the printed structure. This finding is important for biomedical applications as carbonate will impact subsequent cell growth on printed tissue scaffolds. Results of chemical analysis also provided evidence of the hygroscopic nature of the source material and oxidation of the printed surface, and SEM imaging revealed micro- and submicron-scale roughness that will also impact potential applications.