In an article titled “Making and Characterizing Poly (butylene succinate) / Polylactide Blends for 3D Printing to Model Enamel Deposition,” a group of researchers discuss how to use a new type of biodegradable material with high strength and toughness FDM 3D have developed printing. A number of poly (butylene succinate) (PBS) based polymer materials were blended with PLA. PLA is a popular and effective 3D printing material, but it is brittle with extremely low elongation at break. Therefore, better, more ductile materials need to be developed. PBS is a semicrystalline aliphatic polymer with excellent processability, thermal stability and biodegradability. It is also very ductile and has a relatively low melting point.
“However, there are few published studies on 3D printing with PBS.” The researchers point out. “One reason for this is that its low melt strength makes it difficult to continuously form monofilaments when extruding, which causes printing to fail halfway. In addition, the distortion caused by the relatively large volume shrinkage during cooling is likely to occur after crystallization, resulting in defective products. Modification of PBS is therefore absolutely necessary in order to solve the disadvantages mentioned above and to make the material suitable for FDM printing. “
Mixing the two materials can combine their advantages and compensate for their weaknesses. Researchers made PBS / PLA blends of various compositions to validate their suitability for 3D printing. The rheological, thermal and mechanical properties of the blends were studied and various samples were 3D printed with the filaments to assess their suitability for FDM 3D printing technology. The interlayer bond strength in the 3D printed samples was also evaluated.
According to the researchers, all mixtures showed excellent processing properties and can be extruded as monofilaments with a diameter of 1.75.
“As the PBS content increases, the elongation at break and the impact resistance of the mixtures arise,” they continue. “However, the distortion of the printed rods increases due to the greater volume shrinkage that results from the higher degree of crystallinity in the mixtures. In addition, the interlayer bond strength improves due to the reduced melt viscosity. If the PLA content in the mixtures is not less than 40% by weight, the FDM printing can proceed smoothly without spatial distortion or detachment from the platform at room temperature. PBS60 / PLA40 and PBS40 / PLA60 are the optimal mix compositions, taking into account both the material toughness and the deformation of the printed rods and the adhesive strength between the layers. “
Models with porous structures can be successfully 3D printed using PBS60 / PLA40 and PBS40 / PLA60 filaments, and good dimensional accuracy and glossy appearance of the printed structures were obtained. Compared to commercially available 3D printing materials, the mixtures showed both high rigidity and excellent ductility.
“In addition, these materials offer the possibility of meeting energy-saving and environmentally friendly requirements at a relatively low printing temperature and without heating the carrier platform,” the researchers conclude. “With a pearlescent sheen and good mechanical properties as well as dimensional accuracy, the bio-based PBS / PLA mixtures are therefore new and promising materials for the production of FDM filaments for applications in many areas, especially for architectural design. In addition, our study is expected to provide methods to evaluate whether or not a thermoplastic polymer material is suitable for FDM printing. “
The authors of the paper include Qing Ou-Yang, Baohua Guo, and Jun Xu.
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