Influence of imbibed moisture and organoclay on tensile and indentation behavior of polyamide 66/hectorite nanocomposites

Design with polymeric materials is difficult because moisture absorption during service affects their mechanical properties. Mechanical behavior of polyamide 66/hectorite nanocomposites (PA66CN) with different amounts of imbibed moisture and organoclay was studied using tensile and instrumented micro-indentation tests. PA66CN specimens with imbibed moisture content were obtained by equilibrating in laboratory air and distilled water. The amount of moisture absorbed by the PA66CN samples is decreased with an increase in the amount of organoclay. The imbibed moisture greatly improved the ductility of PA66CN, which was reduced with increase in the amount of organoclay, however with a simultaneous reduction in the tensile modulus and strength. Fractography analysis of failed dry and equilibrated PA66CN specimens showed a clear transition from glassy to rubbery behavior due to absorption of moisture.