Preparation of acryl amide/2-acryl amido-2-methyl propane sulfonic acid/silane modified montmorillonite water-soluble nanocomposites: study of thermal and rheological properties

Water-soluble nanocomposites of acrylamide/2-acryl amido-2-methyl propane sulfonic acid/montmorillonite (MMT) were prepared via in situ copolymerization. In order to graft the copolymer chains onto the clay mineral, montmorillonite was modified with a vinyl-containing silane groups (dimethylchlorovinylsilane) through silylation reaction. Furthermore, the polymer nanocomposites (PNCs) containing 1, 3, and 5 wt% modified MMT were synthesized. Also, the PNCs were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The thermal decomposition temperature of the synthesized PNCs increased with the increase in the MMT content. Td10, the 10 % weight loss temperature, increased from 207.87 °C (Td10 of the copolymer) to 279.56 °C (Td10 of the 5 wt% modified nanoclay containing PNC). A dynamic rheology study was used to investigate the effect of clay mineral on the copolymerization and the PNCs. In comparison with the copolymer, the complex viscosity increased about 64 % in PNC containing 5 wt% MMT. The complex viscosities of the PNCs were employed at high frequencies so as to calculate the apparent molecular weights of the copolymer of PNCs through the Maron–Pierce model. The molecular weight of the copolymers, grafted onto the organoclay, increased with the MMT content in the in situ copolymerization. In addition, two rheological models, power law and Carreau, were used to investigate the relationship between the viscosity of the PNCs and shear rate. Ultimately, the morphology of the PNCs changed from exfoliated to intercalated with the increase in the MMT content.