Лако-красочные материалы — производство

1. Determination of the Surface Tension Components The wetting of a solid surface by a liquid drop is expressed by Young’s equation Ys — Ysl= УLcos в (18) Combining this equation with Eq. (8) one obtains the Young-Dupre equation for the work of adhesion Wa = Yl(1 + cos в) (19) Combining and rearranging Eqs. […]

There is a plethora of analytical techniques available to assess the acid-base properties of materials. They range from wettability and chromatographic measurements to spectro­scopic approaches and more sophisticated scanning probe microscopic methods [12,13,15-19,59-61]. For the purpose of this contribution, the focus will be on contact angle measurements, inverse gas chromatography, x-ray photoelectron spectroscopy, and atomic […]

van Oss and co-workers [22] introduced the notion of acidic and basic components to the surface energy (у+and у Г, respectively) to characterize the acid-base properties of materi­als and predict WAB: WAB = 2(у+у2-)1/2 + 2(уГу2+)1/2 (16) у+ and уГ for a solid can be determined by contact angle measurements using three reference liquids of […]

This method makes use of AHAB to assess WAB: WAB = —«abAHab (13) where f is a free energy to enthalpy conversion factor and nAB the number of acid-base adducts per unit area. AHAB can be evaluated experimentally, e. g., by microcalorimetry [13], infrared spectroscopy [13,15,55], and contact angle measurements [49,50], or evalu­ated by Drago’s […]

A. The Thermodynamic or Reversible Work of Adhesion In the absence of chemisorption and interdiffusion, the work of adhesion is the sum of the various intermolecular forces involved and can be related to the surface free energies (Dupre’s equation): W = Yi + Y2 — y12 (8) where у 1 and y2 are the surface […]

In the case of organic-inorganic materials interaction (e. g., polymer-metal oxide), Bolger and Michaels [33] suggested a model based on Bronsted acid-base chemistry to account for the strength of the interaction. They defined a parameter A for organic acids and bases: Aa = IEPS(B) — pKa(A) (7a) and Ab = pKa(B) — IEPS(A) (7b) where […]

Gutmann [32] proposed a two-parameter equation for the estimation of AHAB: -AHAB(kcal/mol) = (4) where AN is the acceptor number of the acidic species and DN the donor number of the basic species. DN was defined as the negative of the enthalpy of formation of the Polymers Ca Ea Cb Eb Method Ref. CPVC _ […]

Drago proposed a four-parameter equation to predict the heat of acid-base adduct for­mation [31]: —AHAB — (EaEb + CaCb) (3) where E and C are the susceptibilities of the acid (A) and the base (B) to undergo an electrostatic interaction (E) and a covalent bond (C), respectively. Drago showed that his equation estimated AHab for […]

Pearson [30] proposed qualitative scales of acidity and basicity based on the numerical values of equilibrium constants for nucleophilic substitution reactions. Pearson noted that the stability of the acid-base adducts depended on the size and the charge of the adjacent acids and bases. Pearson identified hard and soft types of acids, and hard and soft […]

The water-water hydrogen bond is, for example, responsible for the anomalously high boiling point of water and contributes to 70% of the surface tension of this liquid at ambient temperature. It is also well known that the hydrogen bonds between complemen­tary base pairs thymine-adenine (two bonds) and cytosine-guanine (three bonds) are the key to the […]