Page 649 - Handbook of Thermal Analysis of Construction Materials

616 Chapter 15 - Roofing Materials

Differential scanning calorimetry (DSC), TG, DTA, TMA, and
DMA have proven to be useful in the characterization of materials. DSC
provides information on the glass transition temperature, vulcanization
reaction, and oxidative stability. Thermogravimetry (TG) is applied for the
quantitative analysis of the material components. The changes in sample
dimensions as a function of time or temperature under a nonoscillatory load
are measured by TMA, whereas DMA or DLMTA measures the rheological
properties. These methods can also provide information about the thermal
stability of polymers, their lifetime or shelf life under particular conditions,
phase changes in the polymer, glass transition, the influence of additives,
kinetics, oxidation stability, and many others. [11]–[20] Thermoanalytical
techniques bridge the gap between the traditional engineering evaluation
and chemistry. Thermoanalytical methods have long been used to charac-
terize construction materials, [21]–[28] but they are not widely used to charac-
terize roof membrane materials.
In 1988, an international roofing committee, working under the
auspices of CIB/RILEM (Conseil International du Bâtiment pour la Recher-
che, l’Étude et la Documentation/Réunion Internationale des Laboratoires
d’Essais et de Recherches sur les Matériaux et les Constructions), [29][30]
recommended that thermoanalytical methods be added to the inventory of test
methods currently used to characterize roof membrane materials.
Since little research had been reported on the application of thermal
analysis (TA) methods to roofing, the committee recommended that more
research be carried out to provide the technical basis for this application.
The recommendation was based on research by Farlling [31] and Backenstow
and Flueler. [32] These authors used TG, DSC, and DMA to characterize
EPDM, PVC, and polymer-modified materials. Backenstow and Flueler
reported the application of torsion pendulum analysis to characterize the
above membrane materials. They concluded that TA techniques were
useful for membrane characterization and should be investigated as meth-
ods for incorporation into standards. Previous work published by Cash [33]
on the use of DSC to characterize neoprene, chlorinated polyethylene
(CPE) and PVC had shown that DSC could be used to identify not only the
components in a single-ply sheet and the manufacturer, but also to differ-
entiate between new and exposed materials.
In 1990, Gaddy, et al., [34] conducted a study to provide data on the
feasibility of using thermoanalytical methods to characterize roofing mem-
brane materials. The authors used TG, DSC, and DMA to analyze white and
black EPDM before and after laboratory exposure to heat, ozone, UV, and
outdoor exposure. The results were compared to changes in load-elongation