Microwave-assisted PEGylation of Merrifield resins

Modification of insoluble polymers through covalent attachment of short chain soluble polymers can produce hybrids that combine some of the advantages of both types of polymers such as physical stability and solvent-like characteristics. A convenient microwave-assisted PEGylation method of Merrifield resin (MR) was developed using focused microwave irradiation under atmospheric pressure conditions. The effect of molecular weight of PEG, % cross-link and chloride load of MR on the yield of the hybrid polymer was investigated and compared with yields obtained under conventional heating. The data indicated that the yield decreased with increasing the molecular weight of PEG and increasing chloride load of MR and that the highest yield (92.6%) was obtained with PEG molecular weight of 200 and MR (2% cross-link) with 1.25 mequiv./g of chloride. Thermal degradation observed of the grafted PEG increased with increasing heating time under conventional heating conditions.