Acid-Base Interaction in Filler-Matrix Systems

Abstract

The mechanical properties of solution-cast films of filled polymers are found to be very much enhanced when the polymer is strongly adsorbed on the filler in the casting solution. Acid-base interactions between polymer and filler promote such adsorption, subject to the acidic or basic nature of the solvent. ^-Potential measurements were used as a measure of acid-base interaction between filler and polymer in solvents of low dielectric constant. Thin films containing up to 60 vqI % filler were cast from both acidic and basic solvents. Relative values of Young's modulus and tensile strength were compared for each system using the equations of Kerner and Nielsen as a basis for the cases of good and poor adhesion. In a system with acidic polymer (post-chlorinated PVC) and basic filler (CaC03 or BaTi03) cast from an acidic solvent (CH2Cl2), both adhesion and mechanical properties were improved over the same system cast from a basic solvent (THF); adsorption measurements showed no polymer adsorption from THF, but rapid and strong adsorption from CH2CI2. For the most part, in systems where both polymer and filler were either acidic or basic, brittle films (or none at all) were obtained.

Corrosion Control through a Better Understanding of the Metallic Substrate/Organic Coating/Interface

“…Work on task 3 has not yet been initiated. Details of the results obtained for 1 and 2 are described below.…”

“…The amounts of pyridine adsorbed per unit area were about twice those of triethylamine, so for the pyridine curves the ordinates have been reduced by a factor of two to allow them to fit on the same graph. The ether and sulfide data are too inaccurate at this time to be reported in more detail, but the triethylamine and pyridine adsorption data were very reproducible and were Langmuirian in all details; the graphs of these data according to equation (3) are shown in Figures 29 and 30. The straightness of the lines indicates that the isotherms are indeed Langmuir isotherms; that is, the equilibrium constant K is constant at all surface concentrations, suggesting that all the acid sites are of equal strength and that the adsorbed bases are not tightly crowded together at full coverage.…”

“…The stock solutions of iron(III) chloride were prepared by dissolving about 100g FeC 3 to make up 250 ml solution. After filtration through a 0.2 pm Nucleopore filter, this solution was titrated with standardized KMnO 4 solution after reduction by tin(II) chloride.…”

“…The panels were rinsed in distilled water, immersed for 5-10 min in 5% NaCN solution at room temperature, rinsed in distilled water, dried in acetone, and stored in acetone until ready for application of the coating. "Alkalis e cleaned" panels were immersed for 5-10 min at 80*C in a 200 cm solution containing 6 g NaOH, 4.8 g Na 2 SiO', 0.6 g EDTA, 0.48 g Na CO 3 , and small amounts of the wetting agent, hexadecyl trimethyl ammonium bromide. The panels were thoroughly rinsed in distilled water, dried in acetone, and stored in acetone until ready for the application of the coating.…”

“…When the deposited mass/cm 2 was converted into thickness of coating using a value of 1.186 g/cm 3 for the density of Epon 1001, and the data plotted as a function of time, a set of graphs similar to those given in Figure 69 for deposited mass vs time was obtained. The same linear function on deposition time was observed as expected.…”