*3.6. Chemical Attack Resistance*

Table 5 presents the relative weight loss (%) suffered by the specimens ENS-15 and ENS-20 after 24 h or 96 h under chemical attack. The reagents simulate the composition of some substances, such as cleaning products and food or atmospheric acids, that would possibly be in contact with the engineered stone if applied as a coating.


**Table 5.** Relative weight loss after 24 h/96 h of chemical attack of ENS-15 specimens.

After observing the results presented in Table 5, it can be seen that the ENS produced had a smaller weight loss when attacked by basic reagents than when attacked by acidic ones, probably due to the matrix, since epoxy resin has a high resistance to chemical agents, especially alkali [33].

ENS-15 had a small relative weight loss in the face of chemical attacks, which can be attributed to the fact that the glass, quartz, and epoxy resin are materials that present certain chemical stability. Possibly, the glass, as its original application was beverage packaging, had a more chemically inert composition. Quartz at room temperature presents a stable phase of silica and is also, by nature, a chemically stable material [30].

Gomes et al. [16] evaluated the behavior of their AOS artificial stone also agglomerated by epoxy resin under chemical attack with the same agents used in the present work. However, the authors evaluated chemical attack resistance for all reagents for only 24 h, while in this present work, some chemical attack reagents acted for 96 h according to the standard [32]. Still, the reagent that caused the greatest weight loss was HCl, corroborating the conclusions of Gomes et al. [16].
