| Sodium carboxymethyl cellulose(CMC)is widely used in food,petroleum,natural gas,paper,medicine,daily chemical,construction,paint and other industries due to its excellent properties.It is one of the most important cellulose ethers.The demand for CMC is increasing year by year,and the application fields are constantly expanding.China is the country with the most abundant bamboo resources in the world,and also the country with the most fully developed and utilized bamboo resources in the world.Bamboo shoot shells are wastes from bamboo shoot processing.With the rapid development of bamboo shoot processing industry,the output of waste bamboo shoot shells is huge.Bamboo shoot shells are lignocellulosic resources and ideal raw materials for biocellulose production.Taking the bamboo shoots processing waste bamboo shoots as raw materials,extracting the re-modification of bamboo shoots,can not only broaden cellulose sources,reduce the cost of raw materials,can also solve environmental issues and social problems due to improper waste of abandoned bamboo shoots,Realize the resource utilization of bamboo shoots processing waste dried bamboo shoots.In this paper,the bamboo shoots were processed by waste bamboo shoots as raw materials,and the cellulose of bamboo shoots shells was extracted by ultrasonic-assisted alkali method.After ultrasonic-assisted alkalization and etherification,high-viscosity CMC was obtained.Through the research on influencing factors and process optimization,the research results were as follows :The technology of ultrasonic-assisted alkaline extraction of bamboo shoot shell cellulose was studied.According to the research results of influencing factors,the optimal process parameters were determined as follows: liquid-solid ratio 10:1,mass fraction of sodium hydroxide 8%,extraction temperature 50 ?,extraction time 30 min.Through process optimization,the optimal process parameters were obtained as follows: the ratio of liquid to material was 10.84:1,the mass concentration of sodium hydroxide was 8.60%,the extraction temperature was 49.76 ?,and the cellulose content of bamboo shoot shells was 89.0%.The process of preparing bamboo shoot shell CMC by ultrasonic-assisted double alkali addition method was studied.According to the research results of influencing factors,the optimal process parameters were determined as follows: the mass ratio of sodium hydroxide to cellulose was 1:1,the alkalization time was 40 min,the ratio of two alkali additions was 5:1,the alkalization temperature was 25 ?,the chloroacetic acid The mass ratio to cellulose was 1.2:1,the etherification temperature was 75 °C,and the etherification time was 150 min.Through process optimization,the optimal process parameters were obtained as follows: the ratio of two additions of alkali was 4.94:1,the dosage of chloroacetic acid was 1.24:1,the etherification time was 149.53 min,and the CMC viscosity of bamboo shoot shell was 2164 m Pa·s.Scanning electron microscope results showed that the surface of bamboo shoot shell CMC was rough and loose,showing the characteristics of salt;infrared spectrum results showed that a chemical reaction occurred between cellulose molecules and chloroacetic acid,and part of the hydroxyl hydrogen in cellulose molecules was replaced by carboxymethyl groups,the molecular structure changed;X-ray diffraction results showed that the diffraction peak at 2?=15.6° disappears,and the diffraction peak at 2?=22.4° shifts to the low-angle direction,indicating that its I crystal structure has transformed into II crystal structure.The effect of bamboo shoot shell CMC on acidic milk beverage was studied.The results showed that bamboo shoot shell CMC has a good stabilizing effect on acidic milk beverage and can be used as an excellent stabilizer.When the addition amount was 0.1%,the phenomenon of bridging and flocculation occurred,which made the system unstable.With the increase of the addition amount,the stability gradually improved,and the optimal addition amount was 0.4%. |
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