Cross-linking processes with microwave radiation and neutron Compton scattering.

The hardening process of moulding sands on quartz matrices bound by polymer binders containing carboxyl and hydroxyl groups can be carried out by using physical agents (microwave, UV). The highest hardening level obtain moulding sand samples containing binders in a form of the composition of poly(acrylic acid)/carboxymethyl starch within the microwave radiation field. The supplied energy is sufficient for the formation the stable cross-linked structures with the hydrogen bonds. Our previous vibrational spectroscopic work found signatures of the above processes, whereby essentially the hydrogen projected vibrational density of states shifts to higher frequencies. Neutron Compton scattering, being sensitive to the high frequency modes, will be used in this proposal to shed new light on the crosslinking process. Selective deuteration will be used to render the technique site-specific.