One key issue restricting semi-crystalline polymers to be widely applied in powder bed fusion (PBF) of polymers is lack of good powder processability, especially a wide sintering window. In this work, a thermal treatment method with mixed dispersant system (TTMS) was developed to modify a common isotactic polypropylene (PP) powder to adapt for PBF. Both sintering window (SW) and particle morphology of the PP powder were improved by the TTMS process. The SW was expanded from 15 °C for the raw PP powder to 51 °C for the TTMS-PP powder, since the TTMS process facilitated the formation of α crystal with larger lamellar thickness as revealed by differential scanning calorimeter and X-ray diffraction measurements. Moreover, the particle size of the TTMS-PP powder was reduced to 60 μm, which was only a third of the raw PP's size. Consequently, the TTMS-PP powder exhibited a lower flow energy compared to the raw PP powder. These improvements contributed to a better laser processability of the TTMS-PP powder, as demonstrated by the single-layer component with reduced part deformation and better dimensional accuracy. This work is believed to provide a useful guideline for the development of semi-crystalline polymer powders for the PBF technology.

限制半结晶聚合物广泛应用于聚合物的粉末床熔合（PBF）的一个关键问题是缺乏良好的粉末加工性能，尤其是宽的烧结窗口。在这项工作中，开发了一种带有混合分散剂系统（TTMS）的热处理方法，以改性一种常见的全同立构聚丙烯（PP）粉末，以适应PBF。通过TTMS工艺可以改善PP粉末的烧结窗口（SW）和颗粒形态。SW由原来的PP粉末的15°C扩展到TTMS-PP粉末的51°C，这是因为TTMS工艺促进了层状厚度较大的α晶体的形成，如差示扫描量热仪和X射线衍射测量所揭示的。此外，TTMS-PP粉末的粒径减小到60μm，仅为原始PP粒径的三分之一。所以，与原始PP粉末相比，TTMS-PP粉末具有较低的流动能。这些改进有助于提高TTMS-PP粉末的激光加工性能，如单层组件所展示的那样，零件变形减少且尺寸精度更高。认为这项工作为开发用于PBF技术的半结晶聚合物粉末提供了有用的指导。