Effect of Chemical Crosslinking on Properties of Polymer Microbeads: A Review

Cross-link property has been used to improve the insolubility, mechanical strength, stiffness, and rigidity of polymer microbeads having potential applications in solid-phase synthesis, solid-phase extraction, and biomedical fields. Therefore synthesis of polymer with desired cross-linker (hydrophilic/hydrophobic/rigid/flexible) and concentration of cross-linker (cross-link density) is an important. In the present review, chemical cross-linking by free-radical, condensation, UV radiation, and small-molecule cross-linking are discussed in details. Further, effects of cross-linker (type/concentration) on polymer properties like surface area, pore volume, pore size, particle size, thermal degradation, glass transition temperature, and polymer swelling are also discussed. Importantly, present review discusses the influences of rigidity, flexibility, hydrophilicity, and hydrophobicity of a cross-linker on polymer properties.