Viscoelastic
studies on thermoplastic polyurethane nanocomposites using a nano- hardness
tester
The
The viscoelastic
behaviour of a range of polyurethane thermoplastic elastomer montmorillonite
nanocomposites has been studied using a nanohardness
tester. For softer Shore hardness 80A materials, the introduction of the organo-clay increased the creep strain obtained while the nano-indentor was held at constant load. The increase in
creep strain was greatest for materials containing an organo-clay
modified with a more hydrophilic quaternary alkylammonium
surfactant and with higher loadings of the hydrophilic organo-clay.
This suggested the effect might be due to a plasticising
effect of the excess surfactant. For the harder Shore hardness 55D materials,
the addition of the organo-clays produced only a
small decrease in the creep strain, probably due to the interconnected hard
domains in this material.