Chitin is widely distributed in nature and an important renewable resource. However, it has been difficult to provide material applications from chitin, due to poor solubility and processability. We already found that an ionic liquid of 1-allyl-3-methylimidazolium bromide (AMIMBr) swelled chitin. Furthermore, we also reported that self-assembled chitin nanofiber film was obtained by regeneration from the chitin ion gel with AMIMBr using methanol, followed by filtration. In this study, we attempted grafting of a living propagating end of poly(2-methyl-2-oxazoline) to the surface of the chitin nanofibers to obtain poly(2-oxazoline)-grafted chitin nanofibers (Scheme 1). The product formed a gel with DMSO, which was further converted into a hydrogel.<br/>For grafting by the reaction of a living propagating end with reactive groups on the nanofibers, amino groups were first introduced by deacetylation in NaOH aq. Ring-opening polymerization of 2-methyl-2-oxazoline with methyl<i> p</i>-toluenesulfonate as an initiator was performed in DMSO to generate a living propagating end, which was then reacted with the produced amino groups on the nanofibers. With progress of the reaction, the mixture turned into gel form. The IR measurement of the isolated product indicated the progress of grafting of poly(2-methyl-2-oxazoline) on the nanofibers. The SEM images of the products in accordance with reaction times indicated that the chitin nanofibers were gradually disentangled with prolonged reaction times. The hydrogel was obtained by immersing the product in water.

Grafting of polyoxazoline on chitin nanofiber film to form organo- and hydrogels

253rd National Meeting (2017)

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