Page 666 - Handbook of Thermal Analysis of Construction Materials

634 Chapter 16 - Paints and Coatings

such as gas chromatography (GC), gel permeation chromatography, high
performance liquid chromatography (HPLC), infrared spectroscopy (IR),
nuclear magnetic resonance spectroscopy (NMR), surface analysis, UV-
visible spectroscopy, microscopy, x-ray diffraction, and thermoanalytical
techniques. This chapter will deal with the applicability of thermoanalytical
techniques for characterizing paints and coatings.
Generally, the basic chemical components of paint and coating
materials can be considered the same regardless of the field of application.
Considerable work has been published on the use of the thermoanalytical
techniques for characterizing coatings and paints for many applica-
tions. [2]–[38] However, these have not been extensively applied to paints and
coatings for construction applications.

2.0 PAINTS

Thermoanalytical techniques are potentially useful in studying
paints for any application. One of the applications of thermoanalytical
techniques, for example, is the use of DSC and DTA to study the influence
of impurities or differences in crystallinity during pigment formation. The
use of these techniques for purity evaluations will depend on the material
and the impurities. [2]
Another important aspect of coatings technology is the heat of
reaction or mixing. This can provide essential information in calculating
heat balance for processing coating materials since the evolution or absorp-
tion of a substantial amount of heat could change the temperature of the
[3]
material enough to interfere with its flow. Odlyha, et al., used DSC to
evaluate the oxidation stability of paint media, particularly as drying oils
represent the main material other than egg yolk which has been used as a
binding medium in paintings from the fourteenth century in Northern
European countries and Italy. The authors studied the effects of age,
composition (e.g., oil, oil-protein), and oil and pigment type on the
oxidative degradation of paint media. They also calculated kinetic param-
eters to determine whether the observed phenomena can be explained by a
classical Arrhenius activation energy approach.
[4]
Odlyha also used DSC to study samples from three paints during
treatment in the Conservation Department of the Tate Gallery. Knowledge
of the type of paint media used is of interest both to the conservator who
needs to select the appropriate material for cleaning and to the art historian