Studies On Poly (Silicone-co-acrylate)/montmorillonite Nanocomposites Emulsion

Cetyl trimethylammonium bromide (CTAB) was intercalated into between Na-MMT layers via ion exchanging. Organic montmorillonite (OMMT) was prepared via ion exchanging. The distance between MMT and OMMT layers was measured by X-ray diffraction (XRD) analysis. XRD analysis result showed that the distance between MMT layers was increased via CTAB intercalating. It can be obtained that organic CTAB has been intercalated between MMT layers.OMMT was dipped in acrylate before monomer was polymerized. Poly (silicone-co-acrylate)/ montmorillonite nanocomposite emulsion were prepared by in situ intercalative emulsion polymerization of acrylate and organosilicone in the presence of OMMT with different OMMT contents (0, 0.5, 1, 1.5, and 2 wt %) and A-151 contents (5,10, and 15 wt %). The emulsion takes on "core-shell" structure.The particle size and the distribution of particle size of the emulsions were measured by laser light scattering. The result obvious showed that the particle size of nanocomposite emulsion was smaller than the non-modified emulsion, and the nanocomposite emulsion containing 1 wt% of OMMT has the smallest particle size. In additional, the particle size distribution of nanocomposite emulsion was narrower.The surface tension was measured using German Du Nouy surface tension equipment. The values of surface tension (25 ℃) of emulsion are enhanced with increase of A-151 content. Again, the surface tension of nanocomposite emulsion was lower in comparison with the non-modified emulsion.The drying speed was measured by weighed the emulsion on microscope slide using an electronic balance. The result showed that the drying speed of the nanocomposite emulsion was faster than that of the non-modified emulsion. Thedrying speed of the nanocomposite emulsion increased 10%~ 15%.The viscosities of emulsion were measured with a NXS-11 rotational viscometer at 20, 25, 30, 35, and 40 (±0.1)°C after the solid contents of emulsion were adjusted to equalize using distilled water. It can be seen that the nanocomposite emulsion is pseudoplastic fluid. The viscosities of emulsion and the flow activation energes (Ea) are increased with increasing the content of OMMT and reached the smallest when the content of OMMT was 1%, meanwhile, both of them are directly proportional to the contents of A-151. Pseudoplasticity of the nanocomposite containing 1 wt% OMMT was the most strong.The viscosities of emulsion were measured after emulsions were laid up for three months. The decreased viscosities of nanocomposite emulsions were less than 5%, and that of the non-modified emulsion were larger than 5%. It showed that the stability of nanocomposite emulsions were better.During the film curing, Fourier Transform Infrared (FTIR) spectrometer, Differential Thermal Analysis (DTA), and Torsional Braid Analysis (TBA) was used for the investigation of the structural changes of the curing system. All above results clearly showed that the curing speed for the nanocomposite emulsion was faster about 2d compared with the non-modified emulsion. The curing reaction of emulsion film was accelerated by heated. The result showed that the curing temperatures of nanocomposite emulsion film were lower.In additional, nanocomposite emulsions also have bigger adhesion, bigger tensile strength, and lower material cost.Therefore, OMMT could improve the properties of emulsion and emulsion film, in other words, the properties of nanocomposite emulsion were better in compared with the non-modified silicone-acrylate emulsion. This is more advantageous in practice.