Polymer Brush Induced Electroless Copper Plating on PA12 Surface for Tensile Strength Enhancement of Selective Laser Sintering Part

Metal particles can be deposited on nylon 12 (PA12) surface with excellent metal/substrate interface and distribution by electroless plating (EP), but the use of noble metal as EP catalyst would enhance the cost of raw materials and restrict its application. In this work, we developed a polymer brush (PB)-induced EP method to prepare Cu particle/PA12 composite powder (CPP) as an enhancing component for improving the strength of the selective laser sintering (SLS) part. The results showed hydrolyzed 3-amino-propyltriethoxysilane attached on the modified PA12 surface, which presented in PB form. The PB effectively reduced the stability of [Cu-EDTA] complex and REDOX barrier, subsequently, PB acted as catalytic site to reduce Cu ion into Cu metal by EP. The deposit consisted of Cu particles (spherical, about 1 μm) and a small quantity of Cu₂O particles (cubic, about 0.3 μm), the ratio of M_{plated particle}/M_{(plated particle+PA12)} is 15%. The PA12 particles were spheroidized firstly, then formed sintered neck during neighboring particles and sintered body in turn under laser action. Based on the excellent Cu/PA12 interface and dispersion, the tensile strength of the SLS part sintered with 10 W laser energy increased by an average of around 26.2% to 53 MPa.