Unger Laura, Fischer Sybille, Sesseg Jens P W, Pfister Andreas, Schmidt Jochen, Bück Andreas
Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstraße 4, 91058 Erlangen, Germany.
EOS GmbH Electro Optical Systems, Robert-Stirling-Ring 1, 82152 Krailling, Germany.
Polymers (Basel). 2023 Apr 19;15(8):1944. doi: 10.3390/polym15081944.
The feasibility of thermally-induced phase separation and crystallization for the production of semi-crystalline polyetherimide (PEI) microparticles from an amorphous feedstock has been reported recently. Here, we investigate process parameter dependencies for designing and control of particle properties. A stirred autoclave was used to extend the process controllability, as the applied process parameters, e.g., stirring speed and cooling rate, were adjusted. By increasing the stirring speed, the particle size distribution was shifted to larger values (correlation factor ρ = 0.77). Although, the enhanced droplet breakup, induced by the higher stirring speed, led to the formation of smaller particles (ρ = -0.68), broadening the particle size distribution. The cooling rate showed a significant influence on the melting temperature, reducing it with a correlation factor of ρ = -0.77, as confirmed by differential scanning calorimetry. Lower cooling rates led to larger crystalline structures and enhanced the degree of crystallinity. The polymer concentration mainly affected the resulting enthalpy of fusion, as an increased polymer fraction enhanced the latter (correlation factor ρ = 0.96). In addition, the circularity of the particles was positively correlated to the polymer fraction (ρ = 0.88). The structure assessed via X-ray diffraction, was not affected.
最近有报道称，利用热致相分离和结晶从无定形原料生产半结晶聚醚酰亚胺（PEI）微粒是可行的。在此，我们研究了用于设计和控制颗粒性质的工艺参数依赖性。使用搅拌高压釜来扩展工艺可控性，因为可以调整所应用的工艺参数，例如搅拌速度和冷却速率。通过提高搅拌速度，粒度分布向更大的值偏移（相关系数ρ = 0.77）。尽管较高的搅拌速度引起的液滴破碎增强导致形成更小的颗粒（ρ = -0.68），但也拓宽了粒度分布。冷却速率对熔点有显著影响，差示扫描量热法证实，冷却速率降低熔点的相关系数为ρ = -0.77。较低的冷却速率导致更大的晶体结构并提高了结晶度。聚合物浓度主要影响最终的熔融焓，因为聚合物分数增加会提高熔融焓（相关系数ρ = 0.96）。此外，颗粒的圆形度与聚合物分数呈正相关（ρ = 0.88）。通过X射线衍射评估的结构不受影响。
