To investigate the mechanical properties of fused deposition modeling (FDM) parts, a compatibilizer and nanoparticles were used as additions in Polycarbonate and Acrylonitrile‐Butadiene‐Styrene (PC/ABS) blends, and four PC/ABS composites were used to fabricate the FDM samples in this study. Two simplified deposition modes of the FDM process were proposed and used to investigate the bonding effect and deposition effect. The bonding effects of the four materials were first investigated using model I of the FDM process. Then, a linear relationship between the bonding strength and the porosity was found, and the optimal processing conditions that produced the best bonding strength were determined. These optimal processing conditions were then used in mode II of the FDM process to fabricate four samples. The mechanical properties and structural characterizations of these samples were studied using tensile tests, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). One interesting phenomenon observed from the tensile tests was that the necking of the PC/ABS FDM sample can spread throughout the total gauge length and measure more than 100% of the strain when the compatibilizer and the nanoparticles were added, which can be attributed to a balance between bonding properties and ductility. The results verify the applicability of PC/ABC composites to FDM technology and suggest that compatibilizers and nanoparticles are suitable candidates to improve the bonding strength and the deposition effect of PC/ABS FDM parts. In conclusion, the balance between bonding properties and ductility is key to improving the tensile behaviors of PC/ABS FDM parts by adjusting the compatibility and porosity of blended PC/ABS samples.

Varying the processing conditions of semicrystalline polymers can produce different morphologies of crystallization, which leads to different properties. There have been extensive studies of flow-induced crystallization on isotactic polypropylene (iPP) using predominantly shear flow. A stretching method, deduced from extrusion, was introduced to study the morphological evolution of elongation-induced shish-kebab crystallization. Different morphologies of the resultant samples with different draw ratios (DRs) were carefully investigated and characterized via differential scanning calorimetry, polarizing light microscopy, scanning electron microscopy, atomic force microscopy, and 2D small-angle X-ray scattering. In addition, the degree of orientation of the samples with different DRs was also investigated using the 2D wide-angle X-ray scattering technique. The results indicate that the elongationinduced morphology is strongly dependent on the effective stretching flow expressed in terms of the DR, which is defined

Purpose Although the feasibility and effectiveness of the fused deposition modeling (FDM) method have been proposed and developed, studies of applying this technology to various materials are still needed for researching its applicability, especially with regard to polymer blends and composites. The purpose of this paper is to study the deposition-induced effect and the effect of compatibilizers on the mechanical properties of polypropylene and polycarbonate (PP/PC) composites. Design/methodology/approach For this purpose, three different deposition modes for PP/PC composites with or without compatibilizers were used for the FDM method and tested for tensile properties. Also, parts with the same materials were made by injection molding and used for comparison. In addition, different deposition speeds were used to investigate the different deposition-induced effects. Furthermore, the behavior of the mechanical properties was clarified with scanning electron microscope images of the fracture surfaces. Findings The research results suggest that the deposition orientation has a significant influence on the mechanical behavior of PP/PC composite FDM parts. The results also indicate that there is a close relationship between the mechanical properties and morphological structures which are deeply influenced by compatibilization. Compared with injection molded parts, the ductility of the FDM parts can be dramatically improved due to the formation of fibrils and micro-fibrils by the deposition induced during processing. Originality/value This is the first paper to investigate a PP/PC composite FDM process. The results of this paper verified the applicability of PP/PC composites to FDM technology. It is also the first time that the deposition-induced effect during FDM has been investigated and studied.

It is generally believed that the length, length distribution, and orientation of fibers are important influencing factors on the mechanical properties of fiberreinforced polymer matrix composites. In this study, the length, length distribution, and orientation of fibers with respect to the loading direction of glass fiberreinforced polypropylene (GF-PP) parts were investigated. GF-PP of different initial fiber lengths, 2 mm (SGF-PP) and longer than 2 mm (LGF-PP), were prepared and then molded into parts via conventional injection molding (CIM) and water-foamed injection molding (WFIM). The mechanical performance of samples was determined using tensile and impact tests, the residual fiber length and length distribution were measured, and the fiber orientation was observed by optical camera and scanning electron microscopy (SEM). The experimental results showed that the mechanical properties of LGF-PP WFIM components were better than those of the CIM components, while the SGF-PP parts were worse than the solid ones. The results also suggested that the LGF-PP WFIM samples exhibited the best fiber length and length distribution, and a lesser degree of fiber orientation, along the flow direction, compared with the CIM samples. It was also shown that the fibers in the GF-PP foamed parts that were longer than a critical length, which possibly exceeded that of the solid parts, were more effective in improving the mechanical properties. Thus, it can be concluded that the property enhancements of the LGF-PP parts can be attributed to the effect of cell growth based on an interpretative model of the interaction of long fibers and foamed cells. POLYM. COMPOS., 00:000-000,