Influence of biocide and dispersant additives on the performance and durability of building paints produced with granite waste

Abstract

Several studies aim to develop sustainable paints with performance and durability comparable to commercial ones. These can involve the reuse of waste as a substitute for conventional pigments and the replacement of organic solvents with aqueous bases. This latter approach contributes to reducing emissions of Volatile Organic Compounds (VOCs); however, it makes the paint more susceptible to biodegradation and instability. In this research, we sought to assess the influence of different concentrations of biocide and dispersant additives on the performance and durability of paints produced with granite waste (GW). The experimental program was divided into two phases. In Phase 1, the optimized mixture of basic components was determined based on the results of abrasion resistance (AR) and hiding power (HP). In this phase, the best proportion of GW, water, and polyvinyl acetate (PVA) resin was obtained, respectively, 44.3%, 35%, and 20.7%. In Phase 2, maintaining the optimized mixture from Phase 1, paints were formulated with the incorporation of biocide (0; 0.050; 0.225; and 0.400%) and dispersant (0; 0.02; 0.76; and 1.50%), and they were analyzed for AR, HP, shelf life, and weather resistance. It was found that the biocide additive did not significantly influence the performance properties, while the dispersant additive reduced the AR of the paint film possibly due to an increase in the pH of the medium. Regarding shelf life, samples with 0.225% biocide were considered more economical and sustainable. In the weather resistance test, none of the samples analyzed showed cracks, peeling, or mold. However, the fading of the paint film was more intense for higher concentrations of dispersant. Thus, the results obtained indicate that biocide additives are promising alternatives to improve the durability of paints based on GW.