Silane-grafted silicas

Q. Zhang, Q. Liu, Y. Zhang, H. Cheng, Y. Lu, Silane-grafted silica-covered kaolinite as filler of styrene butadiene rubber. Applied Clay Science, ISSN 0169-1317 65-66 (September 2012) 134-138. http //dx.doi.Org/10.1016/j.clay.2012.04.024. 

Fig. 17 Dependence of the grafted amount of PVFA (yc) on the initial volume fraction of VFA used to graft on vinyl silane-functionalized silica particles (xVfa)...

Functionalization of the polymer has been widely employed in binary nanocomposites to improve the polymer/filler interactions and thus maximize the load transfer. Functionalization also serves to enhance the compatibility between the two components of polymer blend. Many grades of functionalized polymers are now available, including maleated grades and silane-grafted polymers. Examples of functionalized matrices studied in ternary nanocomposite studies include PP-g-MA [41], PP-g-VTEOS [27] and examples of functionalized elastomers include SEBS-g-MA [8,49,65], EPR-g-MA [19,44,65], POE-g-MA [75], and EPDM- -MA [64]. It is also important to note that only nonpolar matrices and elastomers require functionalization, as opposed to polar polymers like PA6, which present natural interactions with polar fillers such as silica particles and clay platelets. 

SILICA GEL, MCM, AND ACTIVATED ALUMINA Table 6.2. Silanes used for grafting silicas ... 

Bauer F, Ernst H, Hirsch D, Naumov S, Peking M, Sauerland V and Mehnert R, Preparation of scratch and abrasion resistant polymeric nanocomposites by monomer grafting onto nanoparticles, 5(a) - Application of mass spectroscopy and atomic force microscopy to the characterization of silane-modified silica surface , Macromol Chem Phys 2004 205(12) 1587-93. 

Structure EANPS = electrostatic agglomerated nonporous substrate, EAWPS = electrostatic agglomerated wide-pore substrate, PGPS = polymer grafted porous substrate, SMPSS = silane modified porous silica substrate, CMS = chemically modified substrate, APCS = adsorbed polymer coated substrate. 

The high acidity of the unique sulfonic acid function of Nafion can also be utilized by tethering perfluoroalkanesulfonic acid groups to the surface of various silicas. Two approaches have been described to prepare such hybrid organic-inorganic materials. The grafted materials 3 have been prepared by reacting preformed silica materials (MCM-41, SBA-15) with sultone 2 [Eq. (2.31)].165 Co-condensation of tetraethoxy-silane with 4 in the presence of dodecylamine template, in turn, furnished the HMS-based material 5 [Eq. (2.32)].166,167... 

---