ALKALINE HYDROLYSIS OF POLYMERS IN CONTACT WITH CEMENT BASED MATERIALS

Author(s): Wadsö, L. and Karlsson, O. J.
Paper category: Conference
Book title: XIII International Conference on Durability of Building Materials and Components - XIII DBMC
Editor(s): Marco Quattrone, Vanderley M. John
Print ISBN: none
e-ISBN: 978-2-35158-149-0
Publication year: 2015
Pages: 300-303
Total Pages: 4
Language: English

Abstract: Hydrolysis of polymers is a common degradation mechanism under alkaline conditions such as found in contact with humid or wet concretes and mortars. Common building related products that are susceptible to alkaline hydrolysis are flooring adhesives, concrete admixtures, polymeric reinforcement materials and PVC plasticizers. We have developed a method based on isothermal calorimetry – the measurement of heat production rate at constant temperature – that can be used to quantify hydrolysis rates. The method relies on that the heat produced by hydrolysis is close to zero, but that the acid produced by the hydrolysis reaction is neutralized in the alkaline solution, and that the heat produced by this process is high and almost constant (per mol of reaction). With knowledge of this heat (the neutralization enthalpy) it is possible to directly measure the number of hydrolysis events taking place per second, i.e., the true kinetics of the process. Measurements can be made under different pH and temperature conditions, and the result can be used develop kinetic models of hydrolysis. We will in this paper exemplify this with data from calorimetric measurements on flooring adhesives, and discuss the use and limitations of kinetic models developed from such data.

Online publication: 2015
Publication Type: full_text
Public price (Euros): 0.00