IPN's are essentially intimate mixtures of the cross-linked networks with no covalent bonds or grafts between them. For many investigators in the sound and vibration-damping field, IPN's are a new class of polymers capable of exhibiting relatively broadband damping properties.
Whereas homopolymers and statistical copolymers damp effectively over narrow temperature ranges, typically 20-30ºC, IPN's constitute a class of multi-component polymeric materials that are capable of damping over broad temperature ranges of 100ºC. The idea came up as a way to combine the two approaches studied until this moment, i.e. the butyl rubber formulations and the IPN. A methodology was developed to chemically bond to the epoxy resin backbone, liquid polybutadiene chains. The pursued objective is to be able to combine all the good characteristic of the materials tested and put them all together within one single material.
The polymeric material obtained with this type of modified epoxy resin consisted of an IPN of polyurethane and epoxy resin, showed good elasticity and tackiness. The material was analysed by DMA and the spectra obtained showed a rather significant broadening of the tan d peak. Furthermore, the value of tan d is rather high.
This approach is based on the use of optimal blends of different materials polymerised at the same time, which would give rise to a perfect compromise of properties, enlarging the range where they can be used. The main idea would be to obtain a nanocomposite by adding mica as a filler that would enhance the damping performance of the material by introducing the SPADD philosophy within the material matrix itself.