فهرست مطالب ahmad rabbii

An organic-inorganic hybrid composite includes a silane coupling agent, an organic polymer and inorganic particles on nano or microscales. These compounds are prepared due to their potential applications in different industries. Silane coupling agents are organo-silicon compounds which act as a binder and are widely used to bond organic materials such as rubbers, plastics, adhesives and coatings to inorganic materials like glass fibers, adhesives, minerals and fillers. For preparation of organic-inorganic hybrid composites, first: the surface of inorganic substrates such as metal powders, inorganic particles and fillers in nano or micro dimensions is modified by applying coupling agents of different functional groups through sol-gel method in an aqueous media under acidic condition. In the next step, the surface of modified particles is polymerized with vinyl monomers or monomers with one or more different functional groups by grafting-to or grafting-from methods. In this way, different nano and micro particles such as silicon dioxide, iron oxide, aluminum oxide, titanium dioxide, silver oxide, bismuth oxide and etc are widely used. As a result, silane coupling agents are extensively used to improve the interfacial adhesion in composites and other material systems and to enhance the performance of composites such as their mechanical strength, moisture or chemical resistance and electrical properties to a desirable level. This typically includes the modification of resins, organic compounds and inorganic surfaces, accomplished by adding one or more specific functional groups of one or more organo-silane coupling agents.

Polyacrylamide is prepared by free radical polymerization mechanism in aqueous solution, using ammonium persulphate as initiator. Poly(acrylamide- co-sodium acrylate) or partially hydrolyzed polyacrylamide (PI-IPA) with different degrees of hydrolysis was obtained by alkaline hydrolysis of polyacrylamide using sodium hydroxide as hydrolyzing agent. The intrinsic viscosity of copolymers with different degrees of hydrolysis was measuredwith Ubbelohde capillary viscometer in 0. 2 M sodium sulphate solution and related molecular weights {law) were estimated using Mark-Houwink equation. The results show that the intrinsic viscosity of copolymers increases with increasing the hydrolysis degree. We also found that sodium hydroxide as a hydrolyzing agent influences the M u of parent polymer and causes significant reduction in product My, while slight reduction has been reported. The degrees of hydrolysis of copolymers were determined based on a standard back titration method. In addition to titration method, IR spectra bands identified the carboxyl groups.