Hydrophobation of silica surface by silylation with new organo-silanes bearing a polybutadiene oligomer tail

Abstract

To enhance dispersion of silica into styrene-butadiene emulsion copolymer (e-SBR), used in tyres production, two new modifiers, characterized by 3-mercaptopro pyltrimethoxysilane grafted onto polybutadiene oligomers of <Mn> 5 900 (sb1) and 5000 (sb3), were used. Silica was modified with several degrees of the two new silanes. Thermodynamic surface properties of the modified silicas were estimated by inverse gas chromatography as a function of the grafting degree of sb1 and sb3. e-SBR/silica compounds, with silica pre-modified and in situ modified during the mixing, were prepared and characterized using vulcanization tests, dynamicmechanical analysis, and morphological observations by TEM. At degree of silylation lower than 10 wt%, the method of pre-modification allows a better dispersion of the silica within the elastomeric matrix and the best results were obtained using sb3. In particular, the lowest Payne effect, similar to that of a sample containing silica modified with bis-triethoxysilylpropyltetrasulfide, usually used in tyre production, was found for the sample containing silica grafted with about 10 wt% of sb3.

Interfacial interaction modes construction of various functional SSBR–silica towards high filler dispersion and excellent composites performances

“…6 Therefore, the alkoxysilane groups contribute to single covalent bonds with the silanols of silica in the silica/SSBR-g-MPTES composites. 10,33,34 Fig. 3 presents various modes of interfacial interaction of silica/F-SSBR composites.…”

High performances unsaturated polyester based nanocomposites: Effect of vinyl modified nanosilica on mechanical properties

“…Three types of silane coupling agents containing vinyl, methacryloxy and unsaturated fatty acid residues were used for silica functionalization in order to study the influence of silica modification on the mechanical properties of the UPe based nanocomposites. It was proved that modified nanoparticles behave beneficially within polymer matrices in comparison to unmodified ones, e.g., the modified nanoparticles show comparatively better dispersion in polymer, accompanied with covalent bonding, which could significantly improve nanocomposite properties [20,22]. In order to achieve these goals, modification of Aerosil ® 380 was performed by covalent bonding with unsaturated fatty acid residues to silica surface by a two-step method: a) First step; modification with (3-aminopropyl)trimethoxysilane In a dry three-necked glass reactor, equipped with a magnetic stirrer, reflux condenser, thermometer and a nitrogen inlet tube, 1.0 g of silica (Aerosil ® 380) and 120 mL of dry toluene were charged.…”

“…One of the reinforced materials, with a wide range of industrial applications, is unsaturated polyester resin (UPe) loaded with nanofillers such as titanium oxide [12], organochemically modified silicone oxide particles [13][14][15] or inorganic/organic modified multi-walled carbon nanotubes [16]. A significant improvement of mechanical and thermal properties of nanocomposite materials, obtained by the addition of silica in polymer [17][18][19], is caused by strong interactions between silica nanoparticles and strong filler crosslinking [20]. The main application problem of bare silica is hydrophilic surface which reduces compatibility with polymer matrix causing agglomeration, and thus it is recommended to perform appropriate modification of the silica nanoparticles [21].…”

“…The main application problem of bare silica is hydrophilic surface which reduces compatibility with polymer matrix causing agglomeration, and thus it is recommended to perform appropriate modification of the silica nanoparticles [21]. A good filler dispersion, stability and compatibility with the polymer matrix can be obtained by chemical surface modification of hydroxyl groups with organosilanes [20,22], which provides enormous possibility for new functionalities introduction. Kim and White [23] used organosilanes having different aliphatic chain lengths for silica surface chemical treatment.…”

Surface thermodynamics of Efavirenz and a blend of Efavirenz with cellulose acetate propionate by inverse gas chromatography

“…Inverse gas chromatography (IGC) is a powerful technique to investigate the surface characterization of polymers, polymer blends, pharmaceutical materials, excipients, and plasticizers . Nowadays, with the increasing growth and development of pharmaceutical applications, special attention has been focused on understanding the surface behavior of pharmaceutical drugs.…”