Crystallization and thermal behavior of recycled polypropylene composites containing nonmetallic printed circuit board powder and β-nucleating agents

A recycled packaging material was found to be a PP copolymer after examinations with DSC, FTIR, and TG techniques. It produced 4.39% residue when heated to 800 °C. In addition, SEM microscopic observations revealed some particles dispersed in the recycled PP (recPP) matrix, resulting in a great source for promotion of recPP crystallization temperature. In the present work, NPG, TMB-5, and CaPA were used as β -nucleating agents to modify PP and recPP crystallization behaviors. The results imply that these three nucleating agents are effective for PP to form β crystal in which TMB-5 revealed the best induction and heterogeneous nucleation effects. However, the nucleating effect for NPG decreased when it was added to recPP. The effect of CaPA also weakened, whereas TMB-5 performed well with the optimum content of 0.1%. When CaPA was added together with PCB powder, the β -nucleating effect of CaPA was enhanced, making β crystal as the main form when using only 0.01% CaPA.