快速界面聚合包覆毫米级海藻酸钙水润珠

通过界面聚合法,采用非溶剂硅油分散毫米级海藻酸钙载水胶囊(水润珠),利用水润珠表面微量水分引发氰基丙烯酸乙酯(ECA)原位聚合,形成聚氰基丙烯酸乙酯包覆水润珠(PECA@水润珠)。研究了ECA的添加量对水润珠结构、形貌、缓释性能和热稳定性的影响。结果表明,水润珠表面形成白色聚合物包覆层,随着ECA添加量的增大,水润珠粒径增大,包覆层厚度增加,失重率降低,PECA@水润珠囊壁的阻隔性能和热稳定性增强。与未包覆的水润珠相比,当ECA的添加量为2mL时,水润珠在24h的失重率降低了57.89%,有效延缓了芯层水分的扩散。该方法全过程绿色无毒、反应迅速且温和,有望实现大粒径水凝胶胶囊表面的均匀包覆及工业化生产,在生物医药领域具有重要的应用价值。

树脂基复合材料固化过程的超声波在线监测研究进展

热固性聚合物复合材料的固化过程是化学交联和物理凝固共同作用的结果。与传统的红外光谱、介电分析法、差示扫描量热法、动态力学热分析和流变测试等离线分析方法相比,超声波在线监测法能够合理预测体系固化过程中的力学行为参数,实现对复合材料固化行为的实时反馈及完整表述。文中介绍了超声波在线监测技术的测试原理,综述了国内外采用超声波在线监测法研究纯树脂及其复合材料体系力学状态转变过程和固化动力学的进展。

Effects of Distiller's Grain Substrate with Acid Regulation on the Growth of Tobacco Seedlings in Floating Breeding System

In order to reduce the use of peat resources and realize the sustainable development of tobacco, the pH of distiller s grain substrate was adjusted with humic acid, and the effects of various distiller s grain substrates on the growth of tobacco seedlings were studied to find out the method of cultivating high-quality tobacco seedlings by using distiller s grain substrate. The results showed that when 60% of humic acid was added to the distiller s grain substrate made from coarse distiller s grains, fine distiller s grains, perlite and vermiculite, both the pH and electrical conductivity decreased significantly and were similar to that of the conventional substrate. Moreover, the emergence rate of tobacco seedlings, the rate of strong tobacco seedlings, leaf number, stem height, root growth and quality of tobacco seedlings were good.