Sorkhabi Tannaz Soltanolzakerin, Samberan Mehrab Fallahi, Ostrowski Krzysztof Adam, Majka Tomasz M, Piechaczek Marcin, Zajdel Paulina
Department of Chemical Engineering, Ahar Branch, Islamic Azad University, Ahar P.O. Box 5451116714, Iran.
Faculty of Civil Engineering, Cracow University of Technology, 24 Warszawska Str., 31-155 Cracow, Poland.
Materials (Basel). 2022 Jul 8;15(14):4782. doi: 10.3390/ma15144782.
In this paper, novel microgels containing nano-SiO were prepared by in situ copolymerization using nano-SiO particles as a reinforcing agent, nanosilica functional monomer (silane-modified nano-SiO) as a structure and morphology director, acrylamide (AAm) as a monomer, acrylic acid (AAc) as a comonomer, potassium persulfate (KPS) as a polymerization initiator, and N,N'-methylene bis (acrylamide) (MBA) as a crosslinker. In addition, a conventional copolymeric hydrogel based on poly (acrylamide/acrylic acid) was synthesized by solution polymerization. The microgel samples, hydrogel and nanoparticles were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). A FESEM micrograph of copolymeric hydrogel showed the high porosity and 3D interconnected microstructure. Furthermore, FESEM results demonstrated that when nano-SiO particles were used in the AAm/AAc copolymerization process, the microstructure and morphology of product changed from porous hydrogel to a nanocomposite microgel with cauliflower-like morphology. According to FESEM images, the copolymerization of AAm and AAc monomers with a nanosilica functional monomer or polymerizable nanosilica particle as a seed led to a microgel with core-shell structure and morphology. These results demonstrated that the polymerizable vinyl group on nano-SiO particles have controlled the copolymerization and the product morphology. FTIR analysis showed that the copolymeric chains of polyacrylamide (PAAm) and poly (acrylic acid) (PAAc) were chemically bonded to the surfaces of the nano-SiO particles and silane-modified nano-SiO. The particulate character of microgel samples and the existence of long distance among aggregations of particles led to rapid swelling and increasing of porosity and therefore increasing of degree of swelling.
在本文中，以纳米二氧化硅（nano-SiO）颗粒为增强剂、纳米二氧化硅功能单体（硅烷改性纳米二氧化硅）为结构和形态导向剂、丙烯酰胺（AAm）为单体、丙烯酸（AAc）为共聚单体、过硫酸钾（KPS）为聚合引发剂、N,N'-亚甲基双丙烯酰胺（MBA）为交联剂，通过原位共聚制备了含纳米二氧化硅的新型微凝胶。此外，通过溶液聚合合成了基于聚（丙烯酰胺/丙烯酸）的传统共聚水凝胶。采用透射电子显微镜（TEM）、场发射扫描电子显微镜（FESEM）、傅里叶变换红外（FTIR）光谱、热重分析（TGA）和差示扫描量热法（DSC）对微凝胶样品、水凝胶和纳米颗粒进行了表征。共聚水凝胶的FESEM显微照片显示出高孔隙率和三维互连的微观结构。此外，FESEM结果表明，当纳米二氧化硅颗粒用于AAm/AAc共聚过程时，产物的微观结构和形态从多孔水凝胶转变为具有菜花状形态的纳米复合微凝胶。根据FESEM图像，AAm和AAc单体与纳米二氧化硅功能单体或可聚合纳米二氧化硅颗粒作为种子进行共聚，得到了具有核壳结构和形态的微凝胶。这些结果表明，纳米二氧化硅颗粒上的可聚合乙烯基控制了共聚反应和产物形态。FTIR分析表明，聚丙烯酰胺（PAAm）和聚丙烯酸（PAAc）的共聚链化学键合到纳米二氧化硅颗粒和硅烷改性纳米二氧化硅的表面。微凝胶样品的颗粒特性以及颗粒聚集体之间存在长距离导致快速溶胀、孔隙率增加，从而溶胀度增加。
