A simple and fast formation of biodegradable poly(urethane-urea) hydrogel with high water content and good mechanical property

The synthesis of biodegradable hydrogels with both good mechanical properties and high water content is still a great challenge. In this study, a simple and scalable strategy for the preparation of a biodegradable polyurethane prepolymer composed of isocyanate terminated linear polyethylene glycol (L-PEG) and isocyanate terminated three-armed poly(l-lactic acid) (T-PLLA) is described. When mixed with water, the prepolymer forms a poly(urethane-urea) hydrogel in few minutes. The effect of the molecular weight and the feeding ratio of L-PEG and T-PLLA on the mechanical property of the poly(urethane-urea) hydrogel is discussed. The resulting hydrogel shows good mechanical properties with high tensile strength (up to 108 KPa) and recorded elongation rate (4500%), while maintaining high water content (up to 91% mass ratio). Meanwhile, the maximum water retaining capacity of the hydrogel can be up to 38 times of PU prepolymer (in mass), which is equal to 97.4% water content. Its degradation property is analyzed by the loss of tensile strength and cross section morphology through SEM with time. Such a low cost and biodegradable poly(urethane-urea) hydrogel, which combines fast hydrogel formation, high water content and good mechanical properties, might be used as potential candidates for applications in agrological field, such as sand fixing in desertification control. [Display omitted] •Biodegradable hydrogels with both good mechanical properties and high water content were obtained.•A simple and scalable strategy for the preparation of a biodegradable PU prepolymer was described.•The prepolymer forms a poly(urethane-urea) hydrogel in few minutes when mixed with water.•The maximum water retaining capacity of the hydrogel can be up to 38 times of PU prepolymer (in mass).