Method for preparing carboxymethyl cellulose with different substitution degrees from waste soybean straws

Abstract

The invention relates to a method for preparing carboxymethyl cellulose with different substitution degrees from waste soybean straws, wherein a series of carboxymethyl cellulose products with substitution degrees of 0.21-0.60 are prepared by using industrial soybean straws as a raw material through pre-treating crushing, dispersing, soaking, alkalizing, reacting, washing and other steps. According to the invention, the method has advantages of stable and controllable product substitution degree, stable and controllable product solubility, high substitution degree in the same technological process, accessible reaction temperature, reasonable reaction time, simple technological process, cheap and accessible instruments and the like, can utilize the wastes to reduce the environmental burden,obviously lower the cost and widen the application value of soybean straws, and has excellent market popularization value.

Description

technical field [0001] The invention relates to a method for preparing carboxymethyl cellulose with different degrees of substitution from waste soybean stalks. Background technique [0002] Carboxymethyl cellulose is a carboxymethyl group substitution product of cellulose. According to its molecular weight or degree of substitution, it can be a completely soluble or insoluble polymer. The latter can be used as a weak acid cation exchanger to separate neutral or basic proteins. Carboxymethyl cellulose can form high-viscosity colloids and solutions, have the characteristics of adhesion, thickening, flow, emulsification and dispersion, shaping, water retention, protective colloid, film forming, acid resistance, salt resistance, suspension, etc., and is physiologically harmless Therefore, it is widely used in the production of food, medicine, daily chemical, petroleum, paper making, textile, construction and other fields. Carboxymethyl cellulose is a water-soluble cellulose e...

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Problems solved by technology

[0003] In this case, there have been some existing technologies that use low-cost raw materials to prepare carboxymethyl cellulose. For example, Chinese patent CN101463091 discloses a method for preparing carboxymethyl cellulose from plants, which is used in corn, wheat Carboxymethyl cellulose with a high degree of substitution is obtained from straw such as rice and rice. Although the raw material cost has been reduced, the pretreatment process of the raw material is complicated in this method, and the raw material needs to be activated by steam explosion to obtain a relatively high degree of substitution. , and when it is applied to short and thin straws, the degree of substitution is difficult to exceed 0.50 after repeated experiments within the range of open process conditions

Chinese patent CN104086660 discloses a method for preparing carboxymethyl cellulose with bagasse as a raw material. Although the process is simple, the ratio of its dispersion, soaking and reaction reagents is only suitable for sugarcane, which has a high cellulose content and has no stems. Reactive raw materials are wrapped in leather, and the design of process steps and reaction conditions are single, resulting in uncontrollable degree of substitution

Chinese patent CN104761648 discloses a method for preparing nanocellulose with low energy consumption. The reaction time is shortened, but the process requires complex mechanical assistance such as centrifugation and homogenization. Although the energy consumption is reduced, the process complexity is increased.

However, the cellulose, hemicellulose, lignin and other components in soybean straw are very high, but limited by the effect of the above-mentioned existing technology, it has been impossible to use soybean straw as a natural raw material for preparing carboxymethyl cellulose with a low-cost method.

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