Doubly porous polymeric materials were prepared from 2-hydroxyethyl methacrylate (HEMA) through the double porogen templating approach. One such approach required the use of a macroporogenic agent, i.e., NaCl particles, and a porogenic solvent. To this purpose, sieved NaCl particles of different size ranges were used (125–200 μm, 200–250 μm, and 250–400 μm), either sintered through Spark Plasma Sintering or non-fused, in conjunction with a porogenic solvent, i.e., isopropanol. After removal of both porogens, the resulting biporous scaffolds were finely characterized in terms of porosity by scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), and nitrogen sorption porosimetry. All the obtained results indicated higher porosity ratios and specific surface areas for doubly porous materials prepared from SPS-mediated sintering of macroparticles, thus demonstrating the crucial role of macroporogen packing on the resulting porosity features. Indeed, a higher compaction of NaCl particles generated fewer interstitial voids between adjacent inorganic particles and thus afforded a higher porosity (87% porosity ratio) in the resulting porous material as compared to the corresponding analogue prepared from non-sintered NaCl particles (80% porosity ratio). A complementary 3-D imaging of the microstructure by means of laboratory X-ray computed microtomography (μCT) but also synchrotron μCT analysis qualitatively confirmed these findings. The macroporogen size was also considered to be a crucial parameter regarding the porosity features, as increasing macroporogen sizes were notably associated with increasing porosity ratios. Finally, swelling of those mono- and biporous materials was investigated. The interconnection in the higher porosity level was notably evaluated, and it was observed that the water uptake of biporous PHEMA scaffolds comprising an interconnected higher porosity level can be as high as ~ 2500%.

中文翻译：

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通过双致孔剂模板方法获得的双孔聚合物材料的形态研究

双孔聚合物材料是通过双致孔剂模板方法由甲基丙烯酸 2-羟乙酯 (HEMA) 制备的。一种这样的方法需要使用大孔剂，即NaCl颗粒和致孔溶剂。为此，使用了不同尺寸范围的筛分 NaCl 颗粒（125-200 μm、200-250 μm 和 250-400 μm），通过火花等离子烧结或非熔融烧结，结合致孔溶剂，即, 异丙醇。去除两种致孔剂后，通过扫描电子显微镜 (SEM)、压汞孔隙率 (MIP) 和氮吸附孔隙率测定法对所得双孔支架的孔隙率进行了精细表征。所有获得的结果表明，由 SPS 介导的大颗粒烧结制备的双孔材料具有更高的孔隙率和比表面积，从而证明了大孔原填料对所得孔隙率特征的关键作用。事实上，与由非烧结 NaCl 颗粒（80% 孔隙率）制备的相应类似物相比，NaCl 颗粒的更高压实度在相邻无机颗粒之间产生更少的间隙空隙，从而在所得多孔材料中提供更高的孔隙率（87% 孔隙率）。比率）。通过实验室 X 射线计算机显微断层扫描 (μCT) 和同步加速器 μCT 分析对微观结构进行补充 3-D 成像，定性地证实了这些发现。大孔原尺寸也被认为是关于孔隙度特征的关键参数，因为大孔原尺寸的增加与孔隙率的增加显着相关。最后，研究了这些单孔和双孔材料的溶胀。对较高孔隙率水平的互连进行了显着评估，观察到包含互连较高孔隙率水平的双孔 PHEMA 支架的吸水率可高达~2500%。