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The copolymerization of propylene with 1,4divinylbenzene using an isospecific MgCl2supported TiCl4 catalyst yielded polypropylenes containing pendant styrene moieties.


Polystyrenegraftpolydimethylsiloxane (PSgPDMS) copolymers with different PDMS content were synthesized by the radical bulk copolymerization of PDMS macromonomer and styrene.


PS nanoparticles with smaller diameter such as a numberaverage diameter of 18.7 nm and better monodispersity were obtained since the dropped styrene amount was suitable under 20wt% emulsifier amount and 3wt% initiator amount based on the monomer.


The composite microspheres comprised the Fe3O4 magnetic nanoparticles as cores and the copolymer of styrene and acrylic acid as shells.


Polymerization of styrene catalyzed by rare earth Schiff base complexes

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 A sample of butadienestyrene copolymer obtained from emulsion polymerization at 50℃ with 80% conversion has been doubly fractionated into fractions by adding successive amounts of methanol at 25℃ into a 1% solution of the polymer in benzene. From the weight and intrinsic viscosity of each fraction obtained, an integral weight distribution curve was drawn according to the method of Schulz and Dinlinger. The differential distribution curve exhibits a rather sharp maximum around the molecular weight of 50,000,... A sample of butadienestyrene copolymer obtained from emulsion polymerization at 50℃ with 80% conversion has been doubly fractionated into fractions by adding successive amounts of methanol at 25℃ into a 1% solution of the polymer in benzene. From the weight and intrinsic viscosity of each fraction obtained, an integral weight distribution curve was drawn according to the method of Schulz and Dinlinger. The differential distribution curve exhibits a rather sharp maximum around the molecular weight of 50,000, in agreement with many published results including one obtained from ultracentrifuge data. The fractions with [η]>3, i.e., M>500,000 took a couple of weeks to go into solution, indicating an appreciable degree of branching or slight crosslinking of the macromolecules. The viscosity data of the fractions in toluene at 30℃ show that the values of k' snd β of the equations Inη_r/C = [η]  [β] [η]~2C η_(sρ)/C = [η] + k' [η]~2C are constant, k'=0.36, being independent of molecular weight and k' + β = 1/2 for fractions with [η]>3. For fractions with [η]>3, k'>0.36, in conformity with the findings of Cragg and others that k' increases rapidly with the presence of branching or crosslinking. Besides, we found that for these fractions, k'+β>1/2, which relationship can also be used for the detection of branching in butadienestyrene copolymer.  本文報告測定本所合成研究室用乳液聚合在50°時所製備的丁苯橡膠分子量分佈的結果。我們在1％苯溶液中,加入甲醇作沉澱劑經分級沉澱後,用粘度法測定各級份的分子量。所得分子量分佈曲線,在分子量等於50,000處有一個明顯的高峯,與前人的結果相符合。特性粘數[η]>3的級份,從它們的溶解度和在甲苯溶液中的粘度數據,我們認為有顯著的支鏈和交聯的存在,約佔試樣的25％。甲苯溶液的粘度數據指示在[η]<3時,k′=0.36,與分子量無關,而且k′+β=1/2;當[η]>3時,k′值顯著地增大,而且k′+β>1/2。 這些差異的大小,我們認為可以看作丁苯橡膠分子支鏈或交聯程度的一種量度。 從本實驗所得的丁苯橡膠的分子量分佈曲線,我們建議同時用■和■來做橡膠的品質指示。  The molecular weights of nine fractionated samples of butadienestyrene copolymer were determined osmometrically in toluene at 25°. Experimental technique for the use of osmometer and the swelling of cellophane membrane in 5—30 pct NaOH solutions have been described. The change of permeability during repeated use of the membrane and its possible deformation during a determination were discussed.π/C vs C plots for the system studied are nonlinear, while the experimental data permitted linear extrapolation... The molecular weights of nine fractionated samples of butadienestyrene copolymer were determined osmometrically in toluene at 25°. Experimental technique for the use of osmometer and the swelling of cellophane membrane in 5—30 pct NaOH solutions have been described. The change of permeability during repeated use of the membrane and its possible deformation during a determination were discussed.π/C vs C plots for the system studied are nonlinear, while the experimental data permitted linear extrapolation on (π/C)~(1/2) vs C plots to give M_n and A_2 values. The ratio A_2M_n/[η] was found to be a constant, independent of M_n.The[η]M relation obtained is [η]=1.25×10~(4)M~(0.78)dl/g in toluene at 30°. The somewhat higher value of a obtained is explained by the fact that previous workers applied linear extrapolation on π/C vs C plots and the possible branching of the samples used was neglected.  1.本文叙述所用渗透计及测定方法,在实验技术方面,討論半透膜對溶剂的透过性在使用中的變化,和在渗透计上半透膜在测定进行中可能有的变形。 2.又曾用九個丁苯橡膠级份的甲苯溶液在25°時作了渗透壓测定,得到的数據π/C对C是非線性的,但是可用(π/C)~(1/2)對C作线性外推,得到M_n和A_2的数值,且A_2M_n/[η]为一常数。 3.從粘度及渗透壓数據,得到: [η]=1.25×10~(4)M~(0.78)分升/克(甲苯溶液,30°)所得a值较前人测定的为高,并在文中加以詮釋。  Viscosity and osmotic pressure measurements have been carried out intoluene with six well fractionated samples of butadienestyrene copolymerwhich was emulsion polymerized at 5℃. The polymer sample could becompletely dissolved in the solvent. All fractions show normal viscositybehavior with respect to the value of k'. Branching of the polymer moleculesis considered to be negligible. Osmotic pressure data at 25℃ obtainedpermitted linear extrapolation (л/C)~(2/1)C plots to give the values of M_nand A_2,... Viscosity and osmotic pressure measurements have been carried out intoluene with six well fractionated samples of butadienestyrene copolymerwhich was emulsion polymerized at 5℃. The polymer sample could becompletely dissolved in the solvent. All fractions show normal viscositybehavior with respect to the value of k'. Branching of the polymer moleculesis considered to be negligible. Osmotic pressure data at 25℃ obtainedpermitted linear extrapolation (л/C)~(2/1)C plots to give the values of M_nand A_2, which comform to the relation RTA_2= 7.41×10~5M_n~(0.275).The ratio A_2 M_n~/[η] is a constant the value of which is 16% lower thanthe corresponding ratio for the high temperature polymer. The intrinsicviscosity molecular weight relation obtained is [η]= 2.95×10~(2)M~(0.75) ml/g .in toluene at 30℃. When compared to the linear macromolecules polymerizedat 50℃, [η] low temp./[η] high temp. (?)1.24 at the same molecular weight.This difference in [η] is probably due to the difference in the short rangeconfiguration of the copolymer molecule, i. e. difference in the relative amountsof 1, 2 cis and trans1, 4 adducts.  用六个5°时乳液聚合的低温丁苯橡胶级份(M_n=5×10~4—1×10~6),作甲苯溶液的粘度(30°)和渗透压(25°)的测定。试样能全部溶解,粘度性质都很正常,k’值没有异常增大,高分子的支化可以忽略。渗透压数据可用(π/C)~(1/2)对C作线性外推,得到的分子量和第二维利系数依从 RTA_2=7.41×10~5Mn~(0.275)的关系。特性粘数与分子量间的关系为 [η]=2.95×10~(2)M~(0.75)厘米~3/克(甲苯溶液,30°)与高温丁苯橡胶的线型分子相较,当分子量相同时,[η]低温/[η]高温=1.24,此差别可能是由于近程结构(1,2及顺、反式1,4加成)的不同所致。   << 更多相关文摘 
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