Use of contrast matching small-angle neutron scattering to monitor the presence of closed porosity in controlled porosity styrene-divinylbenzene resins

A series of styrene-divinylbenzene resins produced with varying amounts of toluene as a porogen have been investigated using contrast-matching small-angle neutron scattering. The results show the existence of some microporosity in the samples that cannot be accessed by a weakly swelling solvent, ethanol. Also, when the amount of porogen used in the production of the samples is low, a significant amount of the macroporosity is closed. The implications of this for the industrial application of these materials is discussed.