Epoxy-functionalized Silane Research Articles

Silicone/Amine Resin Hybrid Materials as Abrasion Resistant Coatings

Hydroxyl organofunctional silicone solutions were prepared by acid-catalyzed hydrolysis and condensation of tetraalkoxysilanes, alkoxysilane modified organic compounds, and hydroxyl functional trialkoxysilanes or epoxy functional silanes. These silicone solutions were mixed with methoxylated urea formaldehyde and methoxylated melamine formaldehyde to form silicone/amine resin hybrids and applied on bisphenol A polycarbonate substrates as coatings. After thermal curing at 100−125 °C for 2−3 h, several optically transparent hard coatings with excellent abrasion resistance were obtained.

The international collaborative programme on organosilane coupling agents: an introduction

Silane coupling agents have great potential in many areas of adhesive bonding and coating. However, there is a need to gain a better understanding of their mode of action and the effects of variations in application conditions. This paper gives a brief overview of an international collaborative research project designed to investigate the fundamental nature of the interactions between epoxy functional silanes and aluminium adherends, how these interactions are affected by the silane application conditions and the resulting effects on bond strength and durability.

Carbonaceous Materials Containing Silicon as Anodes for Lithium-Ion Cells

ABSTRACTGraphite and pregraphitic carbons capable of reversibly reacting with lithium ions are hosts commonly used in Li-ion cells. As a continuation of previous work, we have used chemical vapour deposition of benzene and silicon-containing precursors to prepare carbons containing nanodispersed silicon. The silicon resides within the unorganized regions in the pregraphitic carbons. These materials reversibly react with lithium in electrochemical cells and the reversible specific capacity has been known to increase from -300 mAhg−1, in the absence of silicon, to near 500 mAhg−1 as silicon is added. We also report on Si-O-C materials which have been shown to reversibly react with Li in electrochemical cells with reversible specific capacities as high as 770mAhg−1. These materials have been made by thermal pyrolysis of siloxane polymers and epoxy-silane composites prepared from hardened mixtures of epoxy novolac resin and epoxy-functional silane. These materials all show promise for use as anode materials in advanced rechargeable lithium batteries.

Chemical Reactions of an Epoxy-Functional Silane in Aqueous Solutions

Abstract When the coupling agent is dissolved homogeneously in water, the hydrolysis rate of the alkoxy group is influenced by the pH of the solution, the size of the alkoxy group, and to a lesser extent, the size of the organofunctional group directly attached to the silane atom. We have quantitatively studied the reactions of γ-GPS in aqueous solutions. In a dilute solution, the silanol group slowly condensed to siloxane at pH = 4. The epoxy group reacts with both water and the silanol group. The reaction rate of the epoxy group with water is influenced by the pH of the solution. The reaction of the epoxy group with water proceeds faster than with the silanol group due to the large excess of water present, although the rate constants of these two reactions are comparable.

Reinforcement mechanism of polyester‐fiber‐reinforced rubber—A model study

AbstractThe reinforcement mechanism of polyester tire cord was studied by Fourier‐transform infrared spectroscopy using various model compounds. Three model compounds representing the main chain of polyester and the terminal groups, namely carboxylic acid and hydroxyl groups, were used. Chemical reactions between these polyester models and an epoxy functional silane coupling agent were studied qualitatively as well as quantitatively. Among the many possible reactions, the reaction between the carboxylic acid and epoxy group was found to proceed readily. Kinetic studies of the major reactions also show quantitative differences in their activation energies as well as the rate constants. Based on the quantitative studies, we have estimated the expected rate of interfacial reaction at the heat treating temperature of polyester tire cord.

An elastic theory for rubber

We demonstrate molecular design strategies for engineering the deformation rate sensitivity and fracture resistance of organic-inorganic hybrid films in moist environment. Hybrids with intimate mixing of inorganic and organic molecular networks were synthesized with an epoxy-functionalized silane, (3-glycidoxypropyl) trimethoxysilane and an acetate-stabilized zirconium alkoxide, tetra-n-propoxyzirconium. The highly confined non-hydrolysable organic molecular network connectivity was systematically manipulated by tuning the epoxy ring opening polymerization reaction and the incorporation of carbon bridges of selected lengths. By investigating the corresponding time-dependent crack growth in moist environments, new insights into the fundamental molecular-scale relaxation and cracking mechanisms of the hybrids are provided. These processes were found to be impacted by the confined organic network connectivity which results in significant changes in the deformation rate sensitivity and fracture resistance. With increasing non-hydrolysable organic network connectivity, mechanical behavior that varied from almost perfectly elastic to increasingly viscoelastic could be obtained in a controlled fashion. The related resistance to cracking in moist environments was found to be significantly improved. These findings provide a basis for the rational design of functional hybrids with precisely defined mechanical properties.