pH-dependent swelling properties of hydrophilic grafts gels of starch and acrylonitrile

摘要

It has been reported many polyelectrolyte gels, which normally possess pendent ionic groups in their hydrophilic polyeric networks, exhibited a borad transition of equilibrium swelling ratio with a change in the magnitude of pH~([1,2]). It was also been known that charged polymeric networks have been recognized as usful matrices for delivering drugs because of their volume change in response to pH variation~([3]). Therefore, there have been growing interests in hydrogels exhibiting a sharp volume phase transition when an exermanal stimulus such as pH change. However, many synthetic polymer gels so far studied have poor biointermiscibility ahd probably have side effect when they are applied to human body as a biomaterial. On the other hand, starch which is natural polymer, can be graft with a variety of synthetic monomers to form copolymer gels having properties of both the natural and synthetic polymers. Then, starch graft gels can be expected as a novel material like to biopolymer gels.