三聚氯氰与N, N-二烷基荒氨酸钠盐的取代反应研究

采用不同烷基的N,N-二烷基荒氨酸钠盐与三聚氯氰进行取代反应,合成了四个新化合物,产物结构经元素分析,IR,MS和^1HNMR表征。实验结果表明,反应得到的不完全是预想的三嗪的三荒氨酸取代产物,而是具有三种不同结构的产物,并对这一反应可能的机理进行了讨论。     

Ultrasound-Assisted Surface-Modification of Wood Particulates for Improved Wood/Plastic Composites

The combined effects of alkali and ultrasound treatment of wood flour on the mechanical properties of polypropylene-based wood/plastic composites (WPCs) were examined. FT-IR measurements confirmed that the alkali treatment removed both hemicellulose and lignin from the wood, and there was an increase in the number of hydroxyl groups on the cellulose surface. This process was promoted by ultrasound treatment. Mechanical testing of injection-molded WPC samples revealed that alkali treatment improved both composite strength and modulus when polypropylene grafted with maleic acid was used as a coupling agent. The strength increase is due to improved adhesion between the fiber and matrix, while improved modulus is due to the removal of lignin and hemicellulose that are not as stiff as cellulose. Polarized optical microscopy showed the presence of well-defined polymer crystals on the surface of the modified wood, and this is also responsible for the improved mechanical properties. It is conclusively demonstrated that the combination of chemical treatment of wood and ultrasound assistance is more effective in improving the mechanical properties of the composites than the use of chemical treatment alone.     

Silicas modified with amino- and mercaptosilanes - fillers of urethane elastomers

Determination of the optimum composition of a urethane-silica mixture, which would form crosslinked products, presented a significant problem in these studies. The unmodified silica was dosed at various ratios as compared to urethane elastomer: 2.5, 5.0, 7.5 and 10.0 phr. The optimum amount of the filler (precipitated silica) was found to be 5 phr and this amount of silica was subjected to modification with 3 and 5 weight parts of aminosilane U-15 or mercaptosilane A-189, per 100 weight parts of SiO₂.     

二甲基二烯丙基氯化铵反相乳液聚合动力学及机理的研究

研究以异构烷烃混合物为连续相,以丁二酸二(2-乙基)己酯磺酸钠(Sodium-di-2-ethylhexylsulfosuccinate,CH~3CH~2CH~2CH~2CH(C~2H~5)CH~2OCOCH(SO~3Na)CH~2COOCH~2CH(C~2H~5)-CH~2CH~2CH~2CH~3,AOT)和山梨糖醇单油酸酯(SMO)为乳化剂,以偶氮二异庚腈(ADVN)为引发剂的二甲基二烯丙基氯化铵的反相乳液聚合,得到了R~P~,~0=kc^0^.^4~Ⅰ~,~0c^0^.^5~A~O~Tc^-^0^.^4~S~M~Oc^3^.^0~M~,~0的表观动力学表达式。首次提出并研究了反相乳液聚合中单体在单体液滴和胶束中的分配系数对聚合动力学的影响,成功地解释了初始聚合反应速度和单体浓度三次方成正比的原因。通过对胶粒(latex)直径、单体在油相中的溶解度、聚合反应速度与AOT浓度及搅拌速度间的关系的测定,证明聚合反应是通过胶束(micelle)成核机理而进行的。通过对不同单体浓度下的^1H NMR盐效应的研究,证明溶液聚合的速度和单体浓度二次方成正比不是由于生成双分子π配合物,而是由静电屏蔽效应和粘度的改变引起的。     

用TPAC重量法测定钽的新方法

研究了TPAC作为沉淀剂用重量法测定含铌复杂基体中钽的可能性. 结果表明,TPAFTa经分解定量地转化为五氧化二钽, 并以此为称量形式. 对20多种共存离子的吸附或共沉淀的杂以质量均小于万分之四. 随着老化时间的增加晶体明显增大, 吸附或共沉淀的杂质显著减少. 选择了最佳实验条件、详细研究了TPAFTa的物理化学性质. 钽的回收率为98.1-101.8%、镍基高温合金试样分析结果为1.80±0.027%, 可认为TPAC是钽的特效沉淀剂.     

Silicas modified with silane pro-adhesive compounds - active fillers of rubbers

In order to improve filler-polymer interaction, a modification of the silica surface character was indispensable, from a hydrophilic to a partially or fully hydrophobic one. The changes were effected in the course of precipitation by modification of silica surface with silane coupling agents. The modified silicas obtained were tested in SBR rubber and appropriate strengthening parameters of the filled SBR vulcanizates were established.     

Moisture Absorption Behavior of Wood/Plastic Composites Made with Ultrasound-Assisted Alkali-Treated Wood Particulates

The combined effects of alkali and ultrasound treatment of wood flour on the moisture absorption behavior of polypropylene-based wood/plastic composites (WPCs) were examined. FT-IR measurements confirmed that the alkali treatment removed both hemicellulose and lignin from the wood, and there was an increase in the number of hydroxyl groups on the cellulose surface. This process was promoted by ultrasound treatment. Particle size analysis of treated wood fibers revealed that alkali treatment reduced the particle size slightly, and the particle size was further reduced by the assistance of ultrasound. Moisture absorption measurements revealed the interplay between the presence of relative amounts of cellulose, hemicellulose and lignin in the wood and the amount of coupling agent added. It was found that appropriate alkali treatment and an optimum amount of added coupling agent could simultaneously improve composite mechanical properties and reduce both the rate and the maximum amount of moisture absorbed. Further improvements require preferential removal of hemicellulose from the wood and conditions that promote covalent bonding between the coupling agent and the wood reinforcement.     

茴香霉素族中两个新抗生素结构的确定

茴香霉素(Anisomycin,1)是一个抗滴虫属(Trichomonas),变形虫(Entamoeba)和真菌等作用很强的抗生素,用于防治植物真菌病害,其商品名为 Flagecidin.我们曾于1963年分离到此抗生素(508甲).Beereboom 等用化学方法确定了它的结构,但至今尚未见其类似物报道.1968年,Butler 又确定了它的构象.吴淑云等在筛选抗肿瘤的抗生     

丙烯酸氟醇酯的合成

本文用不同方法合成了几种新的含氟醇及其丙烯酸酯和甲基丙烯酸酯RF(CH2)mOC(O)CR[1]=CH2[R1=H,Me;RF=Cl(CF2)2n,n=1,2,3,m=2;RF=CF3(CF2)2OCF(CF3)CF2OCF(CF3),m=1;RF=RfO(CF2)2SO2NR,m=2:Rf=Cl(CF2)8,R=Et;Rf=CF3(CF2)5,R=n-C3H7,Et;Rf=C2F5O(CF2)4,R=Me,Et],这些酯可以和丙烯酸正辛酯共聚,所得乳液是一种表面处理剂,能使织物具有一定防水,防油性能。     

N-取代-α-氨基膦酸酯的不对称合成

本文以手性α-异丙基对氯苄胺为手性诱导试剂和取代苯甲醛生成的席夫碱与亚磷酸酯进行不对称加成反应, 生成具有双手性中心的N-取代-α-氨基磷酸酯。化学产率为40~91%, de%可达到72%。并简单讨论了立体效应对光学诱导能力的影响。