Degradation of floor adhesives as a function of pH

Floor adhesives on cement-based substrates may degrade if the pH is high enough and this has in many cases led to emissions of odorous substances and deteriorated indoor air quality. We have used isothermal calorimetry to assess the degradation rate of two floor adhesives as a function of pH. The rate of heat production measured by the calorimeter is proportional to the reaction rate. The degradation rate was similar for a “standard” and a “low emitting” adhesive, but the low emitting adhesive did not release volatile reaction products. The results show that adhesive degradation is strongly pH dependent. A model of alkaline hydrolysis based on two reaction sites is discussed.