Ester, polymer-bound, degree

Effect of Degree of Esterification on Yields of p-Nitrobenzoylation of a Polymer-Bound Ester... 

Because the components must initially form miscible solutions or swollen networks a degree of affinity between the reacting components is needed. Therefore, most of the investigations into epoxy IPNs have involved the use of partially miscible components such as thermoplastic urethanes (TPU) with polystyrenes [57], acrylates [58-61] or esters which form loose hydrogen-bound mixtures during fabrication [62-71 ]. Epoxy has also been modified with polyetherketones [72],polyether sulfones [5] and even polyetherimides [66] to help improve fracture behavior. These systems, due to immiscibility, tend to be polymer blends with distinct macromolecular phase morphologies and not molecularly mixed compounds. 

Many observations, however, have provided strong evidence that site-site interactions are quite facile. Carboxylic acids bound to polystyrenes of varying degrees of cross-links have been observed to undergo anhydride formation even at low levels of functionalization 140,14I). The observation that cross-Claisen condensation products result from polymers on which two esters are attached also supports the view that intersite reactions can occur in polymer matrices142). Barany and Merrifield U) analysed a number of situations under which intersite reactions occured and found that they usually occur when... 

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