Structural, thermal and morphological properties of aqueous hybrid emulsion of silylated poly (urethane)/organic modified montmorillonite nanocomposites based on a new silicone and imide ring containing vinylic macromonomer

Abstract

A new silicone and imide ring containing vinylic macromonomer, N trimethylsiloxyethyltrimelli tilimidomethacrylate (TMSETMIM), has been synthesized for the formulation of waterborne polyurethane (PU). A vinyl group containing silicone, the (3 methacryloyloxypropyl) trimethoxysilane (MPTMS) was used for comparison of the effects of silicone type with TMSETMIM on the PU. Then, a series of new sili conized PU hybrid nanocomposites, were successfully synthesized by the emulsion polymerization in the presence of organic modified montmorillonite (OMMT) and an aqueous PU dispersion using ammonium peroxodisulfate (APS) as an initiator. The PU dispersion was synthesized by a polyaddition reaction of hex amethylene diisocyanate (HMDI), on polypropylene glycol (PPG 1000) and dimethylol propionic acid (DMPA) as a chain extender. The obtained NCO chain ends reacted with water (which acts as a further chain extender producing some urea bonds). The structural elucidation of monomer was carried out by FTIR, 1 H NMR, and 13 C NMR spectroscopic techniques. The copolymers were also characterized by using FTIR. Thermal properties of the copolymers were studied by using thermogravimetric analysis (TGA) and differen tial scanning calorimetry (DSC). The morphologies of the copolymers were characterized with scanning electron microscopy (SEM) and transition electron microscopy (TEM) and then the effects of silicone con centrations on the water absorption ratio was examined. The formed film from the hybrid emulsion contain ing TMSETMIM could provide obviously higher water resistance property in comparison with MPTMS. Also, the heat stability increases while the T g decreased.

Preparation and Properties of OMMT/PU Composites

“…The reaction equation was listed in Schemes 1 and 2. As seen in Figure 1(a) few absorption peaks can be found at 3297 cm −1 , 2970 cm −1 , and 1725 cm −1 which can be attributed to -OH and -NH stretching vibration [12,13], stretching vibration absorption peak of -CH, and -C=O stretching vibration, respectively, indicating that the organic modifier has been exchanged into the galleries of the silicate layers. This showed that the urethane groups were generated by the reaction of -NCO and -OH in the system.…”