One key issue restricting the rapid application of selective laser sintering (SLS) technique is the lacking of an ideal method in preparing powder materials with good flowability and excellent sintering properties. This work demonstrates that by carefully controlling over material and processing parameters, spherical polymer powders with suitable size which meet the requirements of SLS process can be prepared from immiscible polymer blends with a large viscosity contrast by using a melt blending-extraction (MBE) method. By changing the viscosity of water-soluble poly(ethylene oxide) (PEO) matrix phase via mixing PEO with different molecular weights, the optimal viscosity ratio (p) for producing spherical polyamide 12 (PA12) powder with particle size ranging from 10 μm to 100 μm is determined to be about 50. In contrast, processing parameters such as mixing intensity were found to only have a marginal effect on the particle size. Available empirical or semiempirical equations based on shear flow cannot make a reasonable prediction for the particle size in such high p systems. Instead, the elongational flow presented during melt mixing is suggested to be crucial in determining the particle size. The spherical polymer powders prepared via the MBE method possess a good flowability and a wide sintering window, and can be good material candidates for the SLS technique.

限制选择性激光烧结（SLS）技术快速应用的一个关键问题是缺乏一种理想的方法来制备具有良好流动性和出色烧结性能的粉末材料。这项工作表明，通过仔细控制材料和加工参数，可以通过使用熔融共混萃取（MBE）方法从具有大粘度对比的不混溶聚合物共混物中制备出具有合适尺寸，满足SLS工艺要求的球形聚合物粉末。通过将不同分子量的PEO混合来改变水溶性聚环氧乙烷（PEO）基体相的粘度，最佳粘度比（p）以制备粒径范围为10μm至100μm的球形聚酰胺12（PA12）粉末约为50。相反，发现诸如混合强度之类的加工参数对粒径仅产生很小的影响。基于此类剪切流的可用经验或半经验方程无法对如此高p系统中的粒径做出合理的预测。取而代之的是，建议在熔融混合过程中出现的伸长率流对确定粒径至关重要。通过MBE方法制备的球形聚合物粉末具有良好的流动性和宽的烧结窗口，并且可以作为SLS技术的良好候选材料。