Silane coupling agent treatment

Cellulose fillers, with and without silane coupling agent treatment, have been investigated at various levels showing an increase in physical properties and viscosity (53). 

Although the most popular of the processes described above (PAA and CAA) perform very well, there is a continuing need to develop processes that are less hazardous (no chromates, no strong acids or bases) or that are suitable for treatment of repair areas in the field. Two of these treatments are grit blasting coupled with silane coupling agents and sol-gel. 

The hydrophilic SiO substrate)static water contact angle 0=3O°) was prepared by vapor-deposited SiO onto a Formvar substrate[4], with which an electron microscope grid(200-mesh) was covered. The relatively hydrophobic siliconized substrate(0=9O°) was also prepared by surface siliconized treatment a collodion-covered electron microscope grid was dipped into an aqueous solution of silane coupling agent. 

The reaction between MAH, PE, clay and the catalyst must take place essentially simultaneously. If the clay is first reacted with MAH at elevated temperatures, analogous to the treatment of clay with silane coupling agents, a clay maleate half ester or diester is probably formed. The latter does not readily react with PE even in the presence of a free radical catalyst. 

Han [17] has shown that the effect of silane coupling agents on the viscosity of filled thermoplastics is not consistent. Melt viscosity may be decreased or increased depending on the chemical structure of the treatment and the nature of the polymer/filler combination under consideration. These observations probably reflect the effectiveness of the coupling agent in promoting bonding between filler and polymer, and hence the extent of polymer immobilization. 

Similarly, Plueddemann has reported [3c] an optimum silane coupling agent layer thickness of 50-200 A for commercial glass fiber treatment for use in composite materials. On the contrary, optimum adhesion of polypropylene to aluminum was obtained with a silane primer layer between 0.5 and 10 pm thick. In... 

In order to realize, in practice, the coupling effects of silanes, it is necessary to standardize the conditions of application such that the silane is able to provide a molecular bridge without itself becoming a weak interphase between the fiber and matrix. As already mentioned, the principal experimental parameters to be controlled in the application of silane coupling agents on the fibers are the concentration, the solvent, and the treatment time. In order to arrive at the best conditions for each parameter, the IFSS was determined for each set of treatment conditions. Optimization of the conditions of silane application was thus progressively achieved. 

FIGURE 13.12 Raman spectra of unsaturated silane coupling agent (A), silane—PDMS adduct (B), and the adduct after treatment at 350°C for 0.5 min (C). 

Work undergone in this area has looked at tensile and impact properties of a PVC composite filled with hollow glass beads, of three different sizes, and different volume fractions (96). The influence of particle shape and silane coupling agents, for surface treatment of glass beads, on mechanical properties has also been investigated (116, 366). 

We investigated the use of the molding resin powder (<150 m) as a filler for construction materials composed of bisphenol A type epoxy resin and amine type hardener, and compared the material properties with those produced with a silica powder filler (<150 fi m). Furthermore, the effect of surface treatment of the molding resin powder on these properties was examined by using epoxy or amino silane coupling agents, which were added at lwt% to the molding resin powder and heated at 100°C for 1 hr. 

Fig. 6.13. Hydrophobising an oxide surface by treatment with a silane coupling agent (redrawn...

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