Water sorption/solubility of ethanol-based adhesives after different solvent evaporation methods

Objectives: This study evaluated the water sorption (W_sp) and solubility (W_sl) of one-bottle, ethanol-based adhesives (Single Bond 2/3M – SB2; Excite/Ivoclar – EX) after different solvent evaporation methods. Methods: The materials were inserted into a truncated cone metallic mold (7mm top diameter x 7.5mm bottom diameter x 2mm height) and divided into seven groups, according to the evaporation method: no treatment (negative control–NC), 20s waiting time at 25șC (G1), 20s air-blowing with air (G2), 20s air-blowing with warm air at 45șC (G3), 20s waiting at 37șC (G4), 20s of suction using a suction apparatus (G5), and 1min under vacuum (positive control–PC). The specimens were photo-activated for 40s and weighed to constant dry mass. W_sp and W_sl were evaluated by weight alteration of samples after storage in distilled water at 37șC for 7 days, according to ISO4049. Data were submitted to two-way ANOVA and Tukey's test (5%). Results: For W_sp (”g/mm³), there were no significant differences for SB2 among the different evaporation methods: NC(23.53), G1(22.70), G2(22.79), G3(24.15), G4(24.10), G5(22.95), PC(21.93). For EX, significant differences were detected: NC(13.98)^ab, G1(15.05)^a, G2(12.67)^abc, G3(10.84)^c, G4(12.46)^bc, G5(12.96)^bc, PC(12.54)^bc. The analyses of W_sl (”g/mm³) showed no significant differences for SB2: NC(4.71), G1(5.31), G2(4.63), G3(4.83), G4(4.78), G5(4.68), PC(3.94). On the other hand, significant differences were observed for EX: NC(7.33)^ab, G1(8.08)^a, G2(6.91)^ab, G3(6.00)^b, G4(6.12)^b, G5(6.59)^ab, PC(6.18)^b. Conclusions: The influence of evaporation method on W_sp and W_sl was material dependent. The evaporation method influenced the results for EX, while no significant differences were detected for SB2. In general, the lowest values for sorption/solubility were detected for the air-blowing procedure using warm air.