A kind of high-strength and high-toughness cellulose hydrogel with mechanotropic optical anisotropy structure and its preparation method

Abstract

The invention provides a preparation method of high-strength and high-toughness cellulose hydrogel with a force-induced optical anisotropic structure. The preparation method comprises steps as follows: firstly, cellulose gel with low chemical crosslinking density is prepared, and the obtained cellulose gel is put in a non-solvent of cellulose for 0.1-25 min and subjected to rapid physical cross-linking; the obtained cellulose gel is washed with pure water, and the high-strength and high-toughness cellulose hydrogel with the force-sensitive-induced optical anisotropic structure and low chemical crosslinking density is obtained. The prepared cellulose hydrogel is sensitive to externally applied stress, shows remarkable optical anisotropism and is a potential intelligent soft material.

Description

technical field [0001] The invention relates to a preparation method and application of cellulose hydrogel, belonging to the fields of chemical engineering and polymer functional materials. Background technique [0002] Polymer hydrogel is a multi-component system with a three-dimensional cross-linked network structure ( Chem. Soc. Rev ., 2013. 42, 7391-7420 ; Chem. Soc. Rev ., 2013. 42, 7335-7372). However, despite many improvements, the functions of hydrogels have continued to expand. Improving the mechanical strength and toughness of hydrogels has always been a bottleneck for researchers. Some fields such as human bone tissue repair, smart soft matter sensors or membrane filtration applications Hydrogels are required not only to have good toughness and strength, but also to have functionality. At present, the disadvantages of poor mechanical strength of traditional hydrogels have been compensated by a series of studies, the most representative of which are nanocomposit...

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Problems solved by technology

Tests have confirmed that the mechanical strength of this type of hydrogel is much higher than that of a single cross-linked cellulose hydrogel, and the maximum elongation at break is 80%. The disadvantage is that the chemical cross-linking time in the first step of the preparation process and the second The ethanol-induced physical crosslinking takes a long time (up to 24h / 48h respectively), which greatly reduces the efficiency of material preparation and increases the difficulty of industrial application; at the same time, after introducing a large number of physical crosslinking networks, the crystallinity of cellulose is significantly improved, sacrificing The optical transmittance of the hydrogel, and a large number of crystals greatly restrict the movement of cellulose molecular chains, which greatly restricts the improvement of the tensile elongation at break of the material

In addition, this type of cellulose hydrogel exhibits no other functionality due to this alternate chemical-physical double-crosslinking treatment ( Adv. Funct. Mater .,2016. 26, 6279-6287)

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