The properties of 3D printed polymer composites depend significantly on the fiber-matrix bonding, inter-bead bonding between each layer, and process-induced void contents. This study focuses to determine the effects of acid-based oxidation treatment of fibers on fiber-matrix interfacial bonding of fused filament fabrication (FFF) based 3D printed composites. The effects of nozzle geometry and post-manufacturing vacuum annealing on microstructure, inter-bead bonding, and mechanical properties of the composites are also studied. The surface treatment of fibers had a profound impact on the chemical compositions of the fibers. A significant increase in $–\text{C}\text{O}\text{O}\text{H}$ sites from 0.22 $\text{m}\text{m}\text{o}\text{l}/\text{g}$ to 0.98 $\text{m}\text{m}\text{o}\text{l}/\text{g}$ was observed with 30 min oxidation treatment. The energy dispersion spectroscopy (EDS) also showed the evidence of increased oxygen content on the fibers. Such treated fibers were found to improve both the tensile properties, short beam shear strength, and fracture toughness. The vacuum annealing almost doubled the degree of crystallinity of the composite and gave rise to a chain rearrangement in the polymer-crystalline phase, studied through Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The overall increase in tensile strength, tensile modulus, and short beam shear strength were about 20.58 %, 73 %, and 7 %, respectively in comparison to the baseline. The fracture toughness of the vacuum-annealed sample with functionalized fibers was 23 % higher than the un-annealed-untreated fiber-reinforced composite. Such increment in structural properties was further explained through the SEM analysis of the fracture surfaces. Evidence of crack deflection due to increased surface roughness, fiber alignment, pullouts, fiber-matrix debonding, and crystallinity of the matrix was observed from the analysis.

3D打印的聚合物复合材料的性能很大程度上取决于纤维-基体粘结，各层之间的珠间粘结以及工艺引起的空隙含量。这项研究的重点是确定纤维的酸基氧化处理对基于熔丝制造（FFF）的3D打印复合材料的纤维-基质界面粘合的影响。还研究了喷嘴几何形状和制造后的真空退火对复合材料的微观结构，珠间键合和机械性能的影响。纤维的表面处理对纤维的化学组成有深远的影响。显着增加$–\text{C}\text{Ø}\text{Ø}\text{H}$ 网站来自0.22 $\text{米}\text{米}\text{Ø}\text{升}/\text{G}$ 至0.98 $\text{米}\text{米}\text{Ø}\text{升}/\text{G}$用30分钟氧化处理观察到。能量色散谱（EDS）也显示出纤维上氧含量增加的证据。发现这样处理的纤维改善了拉伸性能，短梁剪切强度和断裂韧性。通过傅立叶变换红外（FTIR）光谱，差示扫描量热法（DSC）和扫描电子显微镜（SEM）研究，真空退火几乎使复合材料的结晶度提高了一倍，并导致聚合物晶体相中的链重排。 。与基线相比，抗张强度，抗张模量和短梁抗剪强度的总体增加分别约为20.58％，73％和7％。具有功能化纤维的真空退火样品的断裂韧性比未退火未处理的纤维增强复合材料高23％。通过断裂表面的SEM分析进一步解释了这种结构特性的增加。从分析中可以观察到由于表面粗糙度增加，纤维排列，拉拔，纤维基体剥离和基体结晶性导致的裂纹变形。