| We firstly introduce the distribution, use and history, fibre characteristic and performance of Apocynum venetum, and also mention the current degumming methods.Then according to GB/T 5889 -1986 "quantitative analytical method of chemical composition of ramie", we analyze the chemical composition of Apocynum venetum, and find mat Apocynum venetum have large difference in chemical composition with other basts. It contains less cellulose, while its hemicellulose, water-soluble matter, lignin and waxiness are much more man other basts. So it's hard to degum Apocynum venetum. We adopt ultrasonic degumming method which is different from common approach. To satisfy our experiment demand, we invent a multi-frequency ultrasonic device which can produce high frequency and low frequency. It creates convenient condition to our experiments.We mainly study the process of ultrasonic degumming. We pretreat Apocynum venetum with microwave and men with ultrasonic treatment. What's more, we discuss the the functional principle of microwave and ultrasonic and analyze the factors that affect degumming effect. Then we choose the best processing parameters by orthogonal experiment: Temperature is 60℃, microwave pretreating time is 12min, ultrasonic treatment time is 70mm, hydrogen peroxide concentration is 1,5%.Finally, we compare ultrasonic degumming method with chemical method and chemical-bacterial approach. The result indicates mat ultrasonic method can increase degumming efficiency, reduces degumming time and residual gum content The retted Apocynum venetum has better quality in fibre quality and can better remain fibre characteristic. |
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