In Situ Emulsion Polymerization Strategy on Basalt Fibers to Enhance the 3D Printability and the Mechanical Property of Polypropylene

3D printing technology is well-known for versatile design, effortless part acquisition, limited waste, and fast manufacturing. However, its large-scale applications have also long been restricted by the high price and the brittleness of commercial filaments. Hence, a novel 3D printing filament of PP modified by basalt fiber with a core-shell structure synthesized through in situ emulsion polymerization of PMMA was developed to generate numerous nanospheres piled up around fibers. It greatly changed the crystallization behavior of PP, enhancing the 3D printability of PP. The maximum warpage degree decreased by 62.75%, while the volume shrinkage rate decreased by 74.63%, which fitted most requirements of 3D printers. Besides that, the synthesized PMMA@BF could also significantly improve the mechanical properties of 3D printed objects. The tensile strength and the compressive strength increased by 66.81% and 14.40%, respectively. This study explored the use of inexpensive PP as raw material to obtain high-performance 3D printing filament, expanding the use range of 3D printed objects, and also expected to be used in other similar crystallinity polymers to broaden the raw material sources for 3D printing.