PMMA在MlM后续热脱脂过程中的分解行为

金属粉末注射成形(MIM)粘结剂中高分子物质的分解和排除是一个较缓慢的过程，对这一过程进行理论研究，有助于指导粘结剂的设计和脱脂过程优化.为此，当Fe-2Ni粉末的注射成形坯经充分溶剂脱脂后，用热重法对坯块中的PMMA的热分解行为进行了理论研究和实验验证.假设进行一级反应，根据各种升温速率的热重计算结果，得到了喂料中PMMA热分解反应速率的理论计算表达式In(1-α)=1.33×10

Decomposition behavior of PMMA in MIM succession thermal debinding

Thermal degradation of polymer substances in metal injection molding feedstock is a time-consuming step.Theoretical investigation of this process will be helpful for binder design and debinding scheme modification. In this pa-per, feedstock containing polymethyl methacrylate(PMMA) is molded and completely solvent-debinded, and thermal deg-radation of PMMA in the partly debinded part is theoretically calculated and tested by experiments. First, thermogravity(TG) measurement is used to compare degradation of pure PMMA and PMMA in the partly debinded part. PMMA degra-dation rate in the brown sample is obtained out of TG test and one-order reaction hypothesis. The rate can be expressedas: In(1 - α) = 1.33 × 109 t·exp( - 1 479/T). And then, 6.37 mm thick sample is adopted to get the actual debindingtime. It is found that the debinding rates of the samples at 350 ℃ and 400 ℃ are close to the theoretical calculation val-ues. When heating at a rate of 5 ～ 10 ℃/min for the 6.37 mm sample, the debinding process is completed within 2 h.