Jiao Yixin, Su Tongming, Chen Yongmei, Long Minggui, Luo Xuan, Xie Xinling, Qin Zuzeng
School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
Guilin Zhuorui Food Ingredients Co., Ltd., Guilin 541001, China.
Nanomaterials (Basel). 2023 Sep 17;13(18):2575. doi: 10.3390/nano13182575.
To improve the water absorbency and water-retention rate of superabsorbent materials, a porous calcium carbonate composite superabsorbent polymer (PCC/PAA) was prepared by copolymerization of acrylic acid and porous calcium carbonate prepared from ground calcium carbonate. The results showed that the binding energies of C-O and C=O in the O 1 profile of PCC/PAA had 0.2 eV and 0.1-0.7 eV redshifts, respectively, and the bonding of -COO groups on the surface of the porous calcium carbonate led to an increase in the binding energy of O 1. Furthermore, the porous calcium carbonate chelates with the -COO group in acrylic acid through the surface Ca site to form multidirectional crosslinking points, which would increase the flexibility of the crosslinking network and promote the formation of pores inside the PCC/PAA to improve the water storage space. The water absorbency of PCC/PAA with 2 wt% porous calcium carbonate in deionized water and 0.9 wt% NaCl water solution increased from 540 g/g and 60 g/g to 935 g/g and 80 g/g, respectively. In addition, since the chemical crosslinker ,'-methylene bisacrylamide is used in the polymerization process of PCC/PAA, ,'-methylene bisacrylamide and porous calcium carbonate enhance the stability of the PCC/PAA crosslinking network by double-crosslinking with a polyacrylic acid chain, resulting in the crosslinking network of PCC/PAA not being destroyed after water absorption saturation. Therefore, PCC/PAA with 2 wt% porous calcium carbonate improved the water-retention rate by 244% after 5 h at 60 °C, and the compressive strength was approximately five-times that of the superabsorbent without porous calcium carbonate.
为提高高吸水性材料的吸水能力和保水率，采用丙烯酸与由重质碳酸钙制备的多孔碳酸钙共聚的方法，制备了一种多孔碳酸钙复合高吸水性聚合物（PCC/PAA）。结果表明，PCC/PAA的O 1谱中C-O和C=O的结合能分别有0.2 eV和0.1 - 0.7 eV的红移，多孔碳酸钙表面-COO基团的键合导致O 1结合能增加。此外，多孔碳酸钙通过表面Ca位点与丙烯酸中的-COO基团螯合形成多向交联点，这会增加交联网络的柔韧性并促进PCC/PAA内部孔隙的形成，从而改善储水空间。含2 wt%多孔碳酸钙的PCC/PAA在去离子水和0.9 wt% NaCl水溶液中的吸水能力分别从540 g/g和60 g/g提高到935 g/g和80 g/g。此外，由于在PCC/PAA的聚合过程中使用了化学交联剂N,N'-亚甲基双丙烯酰胺，N,N'-亚甲基双丙烯酰胺和多孔碳酸钙通过与聚丙烯酸链进行双交联增强了PCC/PAA交联网络的稳定性，使得PCC/PAA的交联网络在吸水饱和后不会被破坏。因此，含2 wt%多孔碳酸钙的PCC/PAA在60℃下5小时后保水率提高了244%，抗压强度约为不含多孔碳酸钙的高吸水性聚合物的五倍。
