Quaternized xylan/cellulose nanocrystal reinforced magnetic hydrogels with high strength

Recently, ever-increasing focus has been on the exploration of high-strength and intelligent hydrogels. In this paper, we demonstrate a feasible approach to prepare magnetic hydrogels with high compression strength, elasticity and elongation by a two-step process. Quaternized xylan (QXH) and cellulose nanocrystal (CNC) could form the ionic crosslinking within the network to enhance the mechanical strength of hydrogels. Subsequently, Fe3O4 nanoctahedra was fabricated in situ within the reinforced hydrogel matrix. Properties of prepared hydrogels including the compressive strength, swelling ratio, magnetic performance, thermal stability, surface morphology and adsorption capacity for heavy metal ions from the aqueous solution were investigated. Results showed that QXH and CNC had the significant impact on improving the strength property of hydrogels. The compressive stress of prepared hydrogel was sharply increased to the limit of the measurement (2.5 MPa), when the compressive strain reached 85%. This hydrogel also maintained 90% original strength after compression for 30 times. The maximum tensile elongation of this hydrogel was 2875%, corresponding to the breaking tensile strength of 73.86 kPa. Prepared hydrogels also showed the good absorption capacity for heavy metal ions.