A series of polystyrene (PS)/unmodified Na-montmorillonite (Na-MMT) composites were prepared via in situ radical polymerization. The prepared composites were characterized using various techniques. The presence of various functional groups in the unmodified Na-MMT and PS/unmodified Na-MMT composite was confirmed by Fourier transform infrared spectroscopy. Morphology and particle size of prepared composites was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). According to the XRD and TEM results, the interlayer spacing of MMT layers was expanded. SEM images showed a spongy and porous-shaped morphology of composites. TEM revealed the Na-MMT intercalated in PS matrix. The thermal stability of PS/unmodified Na-MMT composites was significantly improved as compared to PS, which is confirmed using thermogravimetric analysis (TGA). The TGA curves indicated that the decomposition temperature of composites is higher at 24–51°C depending on the composition of the mixture than that of pure PS. The differential scanning calorimetry (DSC) results showed that the glass transition temperature of composites was higher as compared to PS. The moisture retention, water uptake, Brunauer–Emmett–Teller specific surface area, and specific pore volume of composites were also investigated. Water resistance of the composites can be greatly improved.

Abstract:In this study, the mixtures of N-hydroxymethyl acrylamide (HMAm) monomer and Na-Montmorillonite (Na-Mt) were polymerized in different ratios in the presence of benzoyl peroxide (Bz2O2) with in-situ radical polymerization to prepare poly(Nhydroxymethyl acrylamide) (PHMAm)/Na-Mt composites. Purified Na-Mt, and newly prepared composites were characterized with Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal analysis (TGA/DTA) techniques. The moisture retention, water uptake, adsorptive properties of the composites was also searched. The XRD patterns demonstrated that the PHMAm matrix intercalated into Na-Mt layers. The PHMAm/Na-Mt composites had much better thermal stability than the pure PHMAm.