Influence of nanoparticle morphology on reaction kinetics, particle size and rheology in acrylic latex
- PDF / 398,791 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 23 Downloads / 185 Views
Influence of nanoparticle morphology on reaction kinetics, particle size and rheology in acrylic latex Mireya L. Hernandez-Vargas1,2 , Angel Romo-Uribe1 and Jamil Baghdachi3 1 Laboratorio de Nanopolimeros y Coloides, Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Cuernavaca Mor. 62210, MEXICO. 2 Departamento de Ingeniería Química Metalúrgica, Facultad de Química, Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510, MEXICO. 3 Coatings Research Institute, Eastern Michigan University, Ypsilanti MI 48197, U.S.A. * To whom correspondence should be addressed: [email protected] ABSTRACT Organic/inorganic (O/I) composite latexes combine the best attributes of inorganic solids with the processability, lightweight and handling advantages of organic polymers. There are common methods to produce polymer nanocomposites: melt compounding, in-situ polymerization and solution mixing. Emulsion polymerization is an unique chemical process widely used to produce waterborne resins with various colloidal and physicochemical properties. This free radical polymerization process involves emulsification of the relatively hydrophobic monomer in water by an oil-in-water emulsifier, followed by the initiation reaction with a water insoluble initiator. This research focuses on the synthesis and reactions kinetics of polyacrylic latex with the incorporation of various nanospheres (SiO2, TiO2, Al2O3 and Fe2O3), and layered silicate (Bentonite nanoclay) nanoparticles via emulsion polymerization. The influence of nanoparticle concentration on reaction kinetics was also investigated. The results showed that the concentration of nanoparticles has significant influence on the monomer conversion, particle size, coagulum content and viscosity of the emulsion. Furthermore, the nanostructured emulsions were shear thinning, exhibiting a power-law behavior, and the viscosity was influenced by the nanoparticle morphology. INTRODUCTION Organic/inorganic nanoparticles are of great interest, as they are expected to have combined properties of both inorganic materials (e.g., high modulus, high temperature and solvent resistance) and organic molecules (easy processability, lightweight, optical properties, fracture toughness) [1, 2, 4]. In recent years, hybrid organic/inorganic nanocomposites have attracted much interest because of their extensive potential applications in various fields of material science, ranging from paints, magnetic fluids, smart polymers, and high-quality paper coating to catalysis, microelectronics, and biotechnology [2, 3]. Heterogeneous polymerization, especially emulsion polymerization, provides an effective way of synthesizing latex microparticles with various architectures and forms [4-6]. Moreover, the emulsion polymerization which utilizes monomers as seeds prior to beginning the reaction is widely utilized in the production of emulsions. This type of chemical reaction is carried out in water, emulsifier, initiator, and a small amount of monomers. In this way, the polymerization starts with a def
Data Loading...
