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本文研究了丙烯酸酯共聚物载体对驱蚊剂N,N-二乙基间甲苯酰胺(DETA)慢释放行为的控制,探讨了单体配比、共聚物分子量以及DETA含量对释放速率的影响。结果表明。增加亲水性单体丙烯酸(AA),可提高DETA的释放速率;降低共聚物数均分子量,会减少DETA的释放量;剂型中DETA含量与释放量存在线性正比关系,但DETA的含量增加并不导致释放有效时间的线性增加。本文还就共聚物膜的透湿性和碱溶性作了研究,亲水性单体AA的增加同样导致透湿性和碱溶性的增加。制备的聚合物驱蚊剂经现场应用试验,表明具有良好的长效驱蚊特性。 相似文献
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We have used fluorescence quenching of tryptophan-containing trans-membrane peptides by bromine-containing phospholipids to study the specificity of peptide-lipid interactions. We have synthesized peptides Ac-K2GLm WLnK2A-amide where m = 7 and n = 9 (L16) and m = 10 and n = 12 (L22). Binding constants of L22 for dioleoylphosphatidylserine [di(C18 : 1)PS] or dioleoylphosphatidic acid [di(C18 : 1)PA] relative to dieoleoylphosphatidylcholine [di(C18 : 1)PC] were close to 1. However, for L16, whilst the bulk of the di(C18 : 1)PA molecules bound with a binding constant relative to di(C18 : 1)PC close to 1, a small number of di(C18 : 1)PA molecules bound much more strongly. Assuming just one high affinity binding site on L16 for anionic lipid, the affinity of the site for di(C18 : 1)PS was calculated to be ca. 8 times that for di (C18 : 1)PC. The relative binding constant was little affected by ionic strength and close contact between the anionic headgroup of di(C18 : 1)PS and a lysine residue on the peptide was suggested. The relative binding constant for di(C18 : 1)PS at this high affinity site was less than for di(C18 : 1)PA. Cholesterol interacts with L22 with an affinity about 0.7 of that of di(C18 : 1)PC. The structure of the peptide itself is important. The peptide Ac-KKGYL6WL8YKKA-amide (Y2L14) incorporated into bilayers of dinervonylphosphatidylcholine [di(C24 : 1)PC] whereas L16 did not incorporate into this lipid. It is suggested that thinning of a lipid bilayer around a peptide to give optimal hydrophobic matching is less energetically unfavourable when a Tyr residue is located in the lipid/water interfacial region. 相似文献
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YU Ming XU Qiang School of Materials Science Engineering East China University of Science Technology Shanghai China 《Chinese Journal of Reactive Polymers》2006,(1)
1. INTRODUCTIONThese years, HCFC-141b may be the most used blowing agent for its useful properties. But, because of its high global warming effect leading to the destruction of the ozone layer, production of HCFC141b has been forbidden. However, there are… 相似文献
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本文用广角及准弹性光散射法测定了聚苯醚砜各级分在DMF中和在θ溶剂中25℃时的均才半径R_G,第二维利系数A_2,流体力学半经R_H,扩散系数D_O,扩散系数的浓度依赖性k_F以及这些参数与分子量M的关系。它们的结果如下R_G=0.031MO~(0.55) D_O(θ)=0.906×10~(-4)M~(0.5) D_0=1.445×10~(-4)M~(0.55)A_2=0.033M~(-0.35) k_D(θ)=0.5M~(0.34) k_D=2.3×10~(-6)M~(1.36)α_H=R_H/R_H(θ)=0.63M~(0.05)R_H(θ)=0.0299M~(0.5)R_H=0.0188M~(0.55) 作者讨论了静态与动态两种高分子尺寸之间的关系;三种溶胀因子α_η和、α_H、α_G之间的关系;以及摩擦系数的浓度系数k_F与流体力学体积V_H之间的关系。它们的结果满足下面各关系式: R_H/R_G=[π(v+1)(2v+1)/3]~(1/2)(2-v)(1-v)/2, α_η~3=α_(G)~2α_H, k_F=1.2A_2M+N_AV_H/M,K_F(θ)=N_AV_H/M 相似文献
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The yellowing of white and pastel coloured textiles and garments has been a problem for many years in the textile industry. In the last 15 years much evidence has been published which suggests that a large proportion of storage yellowing is attributable not to the yellowing of fibre substrate or textile finish but to the yellowing of phenolic antioxidants which migrate onto the textiles from polyethylene and polypropylene packaging. These mobile phenolic compounds interact with atmospheric pollutants, particularly oxides of nitrogen, to give yellow compounds. A brief outline of the problems of yellowing is given, together with the identification of the yellow substances produced by BHT (2,6-di-tert-butyl-4-methyl phenol) and possible mechanisms of their formation. Prophylactic measures that can be taken by the garment manufacturer and finisher to prevent or minimise yellowing are also discussed. 相似文献
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A. L. Cimecioglu G. C. East 《Journal of polymer science. Part A, Polymer chemistry》1992,30(2):313-321
The synthesis of poly(methylene sebacate) was carried out via the reaction of cesium sebacate with bromochloromethane in N-methylpyrrolidone over a range of temperatures (55–130°C). A number of polymers having limiting viscosity numbers in the range of 0.29–0.94 dL g?1 (CHCl3; 25°C) were characterized by elemental analyses, 1H- and 13C-NMR, DSC, and GPC techniques. The polymerization was found to be very rapid at 100°C, being complete in ca. 15 min. and was relatively insensitive to the stoichiometric ratio of the monomers. As high molecular weight polymers were produced without the quantitative conversion of the reactants, the polymerization is considered to be occurring by an interfacial mechanism. 相似文献
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Sensitive methods were developed for the analysis of dextromethorphan (I) and two metabolites, (+)-17-methyl-morphinan-3-ol (II) and (+)-morphinan-3-ol (III), in plasma as well as dextromethorphan and three metabolites II, III and (+)-3-methoxymorphinan (IV) in urine using high-performance liquid chromatography followed by detection with a fluorometer. Dextromethorphan and its metabolites were extracted from plasma and urine and separated in the reversed-phase mode. The practical lower limits of determination for I, II, and III in plasma were 0.5, 5, and 5 ng/ml, respectively; for I, II, III, and IV in urine, the limits were 20 ng/ml, 0.6 microgram/ml, 0.5 microgram/ml, and 15 ng/ml, respectively. The linearity of the calibration graphs was excellent (r varied from 0.9994 to 0.9999) over concentration ranges of two orders of magnitude. 相似文献