to the UV yellowing associated with polyurethanes and is known to not change the physical, mechanical properties of the foam. There are subtle changes arising from the analysis of the coalesced bubbles, and these could be a result of a depletion event of one or more components in the foam. This information, combined with the information gained in the preceding Chapters enables meaningful analysis of a complete sandwich panels to be evaluated, which begins in the next Chapter. Analysis of foam/coil coating interface Introduction In this Chapter the surface chemistry within the foam/backcoat interfacial region is examined. In previous work, discussed in Chapter 2, Shimizu demonstrated segregation effects when polyurethane was applied to a variety of metallic substrates. In that body of work it was found that this segregation of catalysts could occur and could be found immediately adjacent to the metallic substrate. In order to investigate the chemistry of the adhesion between the foam and the coated surface the technique of ultra-low angle microtomy (ULAM) was chosen for sample preparation followed by analysis by The ULAM technique was established at the University of Surrey as a method of giving a tapered section of the interfacial region by cutting at a shallower angle than is normally achieved in a normal taper section or ball cratering method. This enables a larger region for analysis of the interface. . With these techniques it is important to ensure that the surfaces cut cleanly and that no debris is dragged across the cut section and that no damage occurs due to the energy used to access the interface (such as can occur due to the frictional nature of the ball cratering process). It is of particular
to the UV yellowing associated with polyurethanes and is known to not change the physical, mechanical properties of the foam. There are subtle changes arising from the analysis of the coalesced bubbles, and these could be a result of a depletion event of one or more components in the foam. This information, combined with the information gained in the preceding Chapters enables meaningful analysis of a complete sandwich panels to be evaluated, which begins in the next Chapter. Analysis of foam/coil coating interface Introduction In this Chapter the surface chemistry within the foam/backcoat interfacial region is examined. In previous work, discussed in Chapter 2, Shimizu demonstrated segregation effects when polyurethane was applied to a variety of metallic substrates. In that body of work it was found that this segregation of catalysts could occur and could be found immediately adjacent to the metallic substrate. In order to investigate the chemistry of the adhesion between the foam and the coated surface the technique of ultra-low angle microtomy (ULAM) was chosen for sample preparation followed by analysis by The ULAM technique was established at the University of Surrey as a method of giving a tapered section of the interfacial region by cutting at a shallower angle than is normally achieved in a normal taper section or ball cratering method. This enables a larger region for analysis of the interface. . With these techniques it is important to ensure that the surfaces cut cleanly and that no debris is dragged across the cut section and that no damage occurs due to the energy used to access the interface (such as can occur due to the frictional nature of the ball cratering process). It is of particular