Surface modification with silane coupling agent

Scheme 12.1.1 Surface modification with silane coupling agent.

Zhao et al. [32] carried out a surface modification of Ti02 nanoparticles with the silane coupling agents 3-aminopropyl trimethoxysilane (APTMS) and 3-Isocyanato propyl trimethoxysilane (IPTMS). The process of nanoparticle surface modification by silane coupling agents is shown in Fig. 2. Various anionic surfactants have been used to disperse nano Ti02 [33],... 

Modification of the surfaces of coUoidal silica spheres with silane coupling agents enables transfer of the particles to nonpolar solvents. With 3-methacryloxypropyltri-methoxysilane bonded to the surface, the particles have been transferred from water to the polymerizable monomer, methyl acrylate. Electrostatic repulsion due to a low level of residual charge on the particle surfaces cause the dilute dispersions of particles to form a non-close packed colloidal crystalline array (CCA). Polymerization of the methyl acrylate with 200 nm diameter silica spheres in a CC fixes the positions of the spheres in a plastic film by the reactions shown in Figure 11.14. The difriaction... 

Many other functional silane coupling agents are available from commercial suppliers, including hydroxyl, aldehyde, acrylate and methacrylate, and anhydride compounds. Substrate modification procedures similar to those discussed above can be used with these reagents to link a biomolecule to an inorganic surface or particle. 

Based on the literature discussed in this chapter, it seems that surface modification of natural fibers is absolutely necessary to improve their thermal stability, dispersion in the polymer matrix, and compatibility with the polymer matrix. Physical and chemical methods reported have significantly modified the surface properties of the fibers as well as polymer matrices to improve the dispersion of the fibers and hence various properties of the polymers. Use of silane coupling agents and acetylation... 

Silane modification of a thermoplastic resin latex, therefore requires only a small amount of silane coupling agent with such solubility characteristics that it will not migrate into the latex particle, but when filmed on a surface will have sufficient compatibility with the polymer film to bond to it. 

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