STUDY ON THE SWELLING BEHAVIOUR OF COPOLYMER HYDROGEL

The states of water in poly (N-vinylpyrrolidone-methylmethacrylate) and poly (N-vinylpyrroli-done-2-hydroxyethyl methacrylate) hydrogels have been studied by means of DSC. The effect ofpolmer structure on equilibrium swelling extent of water has been examined. It was found that thestate of water and the water content in different hydrogels were dependent on the kind of monomer used,the component of copolymer, the sequence distribution of the monomer unit and the degree of cross-linking (including chemical and physical) to a great extent. The equilibrium water content of thehydrogel may be regarded as the sum of the different state of swollen water contents of the hydrogel.Based on these, a semiempirical formula used to estimate the equilibrium water content of the copolymerhydrogels was presented.     

大功率LED驱动电路研究设计

根据大功率LED的供能要求,从EMI滤波、功率因素校正、半桥谐振转换三个方面着手,以FAN6961和FSFR2100为控制芯片,设计了一款大功率的高效率LED驱动电路,在90～264VAC的线路输入和满载下,功率因数高于93%,效率高于85%,并具有低输入电流谐波失真和低EMI.     

共聚水凝胶溶胀特性的研究

本文用差示扫描量热法研究了聚[N-乙烯基吡咯烷酮-甲基丙烯酸甲酯] 和聚[N-乙烯基吡咯烷酮-甲基丙烯酸β羟乙酯]两种共聚水凝胶中水存在的状态,考察了聚合物结构对平衡溶胀度的影响。结果表明,共聚单体的种类、共聚物组成、序列分布、化学交联度等结构因素对水存在的状态及各种状态水的含量都有很大影响,平衡吸水率可看作各种状态溶胀的水量的加和,以此为基础,提出了估算共聚水凝胶平衡吸水率的半经验公式。