微波法制备氰乙基化竹粉及其产物的表征

超声活化后的竹粉在微波辐射的作用下与丙烯腈反应制备氰乙基化竹粉,考察最佳用量和反应条件对氰乙基化反应的影响,并用电子显微镜、X-射线衍射分析(XRD)、红外(FTIR)和示差扫描量热分析(DSC)等对竹粉改性前后的微观结构和热塑性进行了初步研究.结果表明,1.5g竹粉在饱和KSCN的NaOH溶液的润胀作用下,超声活化10min后,与8mL丙烯腈微波辐射30min即可获得传统40℃水浴反应3h才能得到的增重率约为40%的氰乙基化竹粉.微波作用使竹粉的氰乙基化反应可以在非常温和的条件下(40℃)短时间内完成,减少了丙烯腈的水解和均聚等副反应.氰乙基化竹粉中竹纤维表面结构变得粗糙,管束结构消失,结晶度降低,并在145～290℃之间出现一个大的吸热峰.

Preparation and Characteristic of Cyanoethylated Bamboo Powder by Microwave Irradiation

The cyanoethylated bamboo powder was prepared with bamboo powder and acrylonitrile by microwave irradiation after ultrasonic activated.The effects of formula and reactive condition on the cyanoethylation were studied and the products were characterized by electro microscope,X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectroscope and differential scanning calorimeter(DSC)etc.The optimal formula and reactive condition were that 1.5 g of bamboo powder was pretreated by ultrasonic for 10 min in saturated KSCN solution contained 1 mol·L-1 of NaOH,then reacted with 8 mL of acrylonitrile by microwave irradiation at the temperature of 40 ℃.The same weight gain ratio(about 40%) could be obtained by conventional water bath method,but the reaction time was prolonged from the primary 30 min to 180 min.Cyanoethylation could be completed at the mild condition and short time which could reduce the side reaction of acrylonitrile as hydrolyzation and homopolymerization.The structure of cellulose of cyaoethylated bamboo powder was distroyed and the surface of product became rough.The bundle of fibre and the crystallinity of cellulose decreased and a new endothermic peak between 145 ℃ and 290 ℃ appeared.