The influence of isopropyl alcohol and non-ionic surfactant solutions on the mechanical properties of offset paper

The dynamic mechanical properties of coated offset paper before and after application of isopropyl alcohol and surfactant solutions have been investigated. The mechanical properties of the papers were studied with dynamical mechanical analysis in the tensile mode and the samples were submitted to a uniaxial loading in stress-strain measurements. An increase in the isopropyl alcohol concentration slightly reduced the mechanical strength, while the addition of surfactant clearly made the paper stiffer and weakened the paper strength. As the surface tensions of the liquids were adjusted to the same level, the changes in mechanical properties are ascribed to changes in water-induced wetting and subsequent changes in interfacial properties within the paper constituents. The storage and loss moduli of the paper after application of the surfactant solutions were twice those recorded after isopropyl alcohol treatment. The binder was not affected by the solutions, but there was significant debonding, disrupting the internal or surface structure in the base paper-coating layer interface, especially by surfactant solutions.