星形支化聚苯乙烯模型化合物的合成及表征

本文用阴离子聚合方法,首先合成了线形‘活’的聚苯乙烯大分子阴离子,然后用二乙烯基苯为偶联成核剂,制备了十三个4-80臂较窄分子量分布的等臂长规则星形支化聚苯乙烯的模型化合物,并用GPC—粘度计联用装置对之进行了表征。     

星形SIS热塑性弹性体形态与力学性能研究

本文报导了关于用电镜、电子拉力机、粘弹谱仪研究以多氯代硅烷为偶联剂,用阴离子聚合方法合成的具有臂长相同支化度不同的一组星形SIS热塑性弹性体样品的形态、力学性能与聚合物几何结构的关系。研究结果表明,PS聚集区尺寸随支化度增加而增大,抗张强度、杨氏模量也随文化度显著增加。根据交联橡胶和Kerner方程推导了星形聚合物的模量方程E=[E_(1,0) φ(1-2/f)][(1 15(1-v_1))/(8-10v_1)·φ_2φ_1]     

星形聚苯乙烯的链缠结和松弛过程

本工作用应力松弛仪测定了一组等支链长不同支化度星形聚苯乙烯的松弛谱,探讨了支化结构对松弛谱橡胶平台区粘弹行为的影响,用“管子”模型对松弛谱进行了计算机模拟,从分子运动观点上解释了星形聚合物的粘弹特性:     

GPC普适标定对星形支化聚苯乙烯适用性的实验验证

用GPC-连续型粘度计-小角激光光散射光度计三联用装置研究了GPC普适标定对星形支化聚苯乙烯试样的适用性问题.结果证实:支化度因子g'≥0.131时的所有星形聚苯乙烯级分,普适标定均适用;但对g'<0.131时的星形支化聚苯乙烯高支化级分,普适标定将不能适用.     

星形SIS嵌段共聚物的动态力学性能

本文报导了用粘弹谱仪对组成相同、支链分子量相同而支化度不同的,以及支化度相同、支链分子量不同的系列星形SIS嵌段共聚物的测试结果,实验发现:支链分子量是影响各相玻璃化转变温度和动态杨氏模量E′的主要因素,支化度对各相玻璃化温度影响很小,但是对E′影响是明显的。     

星形聚苯乙烯的玻璃化转变温度和液1-液2松弛

用扭辫仪(TBA)和线膨胀仪测定了一组规则的星形聚苯乙烯的玻璃化转变温度T_g和T_ll松弛。两种实验方法的结果表明:支链分子量相同的星形结构聚合物的T_g随着支化度增加而升高,但也发现星形聚苯乙烯的T_g却低于具有相同分子量的线形聚苯乙烯的T_g·液₁-液₂松弛温度T_ll和损耗峰的强度也依赖其支化度。与以二乙烯基苯为凝胶核的星形结构相比较,证实了后者的双T_g转变。     

以二乙烯苯凝胶为核的星形高聚物的研究(Ⅰ)——星形聚苯乙烯的支化度及支化度分布

本文以二元活性共聚物的模型来处理星形高聚物结合点的二乙烯苯凝胶,参考了活性二元共聚物的统计理论,得到了活性预聚物与二乙烯苯的反应产物的分子量与支化度的分布函数。在活性聚苯乙烯、对位二乙烯苯、正丁基锂与苯的反应体系中,进行了实验验证。结果表明:在配料比不大的情况下,理论分析与实验结果基本一致。在上述理论分析基础上,结合实验数据,得到了两个分布参数以及控制支化度及支化度分布的规律。     

星形聚合物结构的统计分析——不等反应活性和取代效应

本文用全概率公式和概率分布母函数的性质,推导了考虑不等反应活性和取代效应的星形聚合物的分子量分布、平均聚合度、支化度分布和平均支化度等分子结构参数。以三种三官能度偶联剂与活性预聚体的偶联反应作为特例,讨论了不等反应活性和取代效应对星形聚合物分子量分布和分散度的影响,结果指出,当偶联反应不完全时,上述两类效应对星形分子的平均性质有明显影响;当偶联反应接近完全时(反应程度高于90％),不等反应活性和取代效应的影响几乎可以忽略。     

用凝胶渗透色谱测定聚合物中的支化度

本文在Ambler报导的测定聚合物中支化度的工作基础上,提出了支化度的计算方法和电子计算机计算程序,可用ALGOL-60语言在国产DJS-6电子计算机上计算。讨论了支化模型、短链支化和长链支化分布函数等对计算结果的影响,确定了该方法可以相对比较镍系顺式聚丁二烯中的支化度。     

4—臂和7—臂星形支化聚苯乙烯的合成及其溶液性质

本文合成了不同分子量的5个4-臀星形聚苯乙烯和4个7-臂星形聚苯乙烯试样,用GPC粘度计联用装置对之进行了测定。提出了一种用良溶剂中的粘度数据,通过线性外推方法,得到θ条件下的g'_θ因子(=[η]_(b,θ)/[η]_(l,θ))的理论处理方法。对良溶剂中的g'因子(=[η]_b/[η]_l)和g'_θ因子之间的差异以及g'_θ因子与g_θ因子(=S_(b,θ)~z/S_(l,θ)~z)间关系式g'_θ=g'_θ~∈中的∈选值问题进行了详细的讨论,结果证实,∈不仅与支化类型有关,而且与支化程度有关,对4-臂星形聚苯乙烯,∈=1.487,而对7-臂星形聚苯乙烯,∈=1.14。4-臂星形聚苯乙烯的g'和g'_θ因子差别较小;对7-臂星形聚苯乙烯,两者间差别较大,不可忽视。     

The determination of small amounts of vanadium in the presence of large amounts of uranium

To eliminate the color interference of large amounts of uranium in the determination of vanadium by the Hamner method, the vanadium was separated prior to titration by the extraction of vanadium cupferrate with chloroform. The chloroform extract was evaporated with sulfuric acid and the excess cupferron removed by oxidation with nitric acid and perchloric acid. The vanadium was reduced with ferrous ammonium, sulfate solution, the excess ferrous ion oxidized with ammonium persulfate, and the vanadium (IV) titrated with 0.02 N potassium permanganate. As little as 1.02 mg of vanadium in the presence of 5 g of uranium oxide was determined accurately by this method.     

Sites of reaction of pilocarpine

Analysis of the sites of reaction of a biologically important compound, pilocarpine, a molecule with imidazole and butyrolactone rings connected by a methylene bridge, has been accomplished in a quadrupole ion trap with the aim of characterizing its structure/reactivity relationships. Ion-molecule reactions of pilocarpine with chemical ionizing agents, dimethyl ether (DME), 2-methoxyethanol, and trimethyl borate (TMB), along with collision-activated dissociation elucidated the reaction sites of pilocarpine and made possible the comparison of structural features that affect sites of reaction. Based on MS/MS experiments, methylation occurs on the imidazole ring upon reactions with CH3OCH2+ or (CH3OCH2CH2OH)H+ ions but methylation occurs on the lactone ring for reactions with (CH3O)2B+ ions. Bracketing experiments with two model compounds, alpha-methyl-gamma-butyrolactone and N-methyl imidazole, show the imidazole ring to have a greater gas-phase basicity and methyl cation affinity than the lactone ring. The contrast of methylation by TMB ions on the lactone ring is explained by initial addition of the dimethoxyborinium ion, (CH3O)2B+, on the imidazole ring with subsequent collisional activation promoting an intramolecular transfer of a methyl group to the lactone ring with concurrent loss of CH3OBO. Semiempirical molecular orbital calculations are undertaken to further address the favored reaction sites.     

Investigation of the halocyclization of S- and N-allyl derivatives of 2-benzothiazolethione

3-Allyl-2-benzothiazolethione reacts with iodine regiospecifically with annelation of the five-membered ring, while with bromine a mixture of the five- and six-membered rings are formed. 2-Allylthioben- zothiazole reacts with halogens with annelation of the five- and six-membered rings, while 2-(2-methyl-2-propenyl)thiobenzothiazole is annelated at the five-membered ring.     

On the mechanism of the formation of ozonides of the alkali metals

Conclusions A mechanism of the formation of ozonides of alkali metals was proposed on the basis of data obtained in an investigation of the reaction of oxygen-labeled KOH with ozone, the reaction of KOH with atomic oxygen, and the reaction of KOH with ozone; this mechanism is based upon: the catalytic decomposition of ozone on the surface of the solid alkalies into molecular and atomic oxygen, the interaction of the latter with the hydroxide, forming a superperoxide, and an interaction of the superperoxide with ozone, forming the ozonide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1183–1187, June, 1967.     

Study of methods of preparation of 1,4-diglycidyltetrazolone. New synthesis of triglycidylisocyanurate

1,4-Digtycidyltetrazolone was synthesized for the first time by the reaction of tetrazolone and epichlorohydrin with subsequent treatment of the products of addition with a base. The basic directions of the reaction of carbamoyl azide with epichlorohydrin, which yields triglycidylisocyanurate and diglycidylcarbamoyl dude, were investigated. The features of the synthesis and properties of the substances obtained were described.     

Preparation of complexes of sulfoxides of petroleum origin and tributyl phosphate with chlorides of rare-earth elements

Conclusions Conditions were found for obtaining the complexes of petroleum sulfoxides and tributyl phosphate with the chlorides of the rare-earth elements with a coordination number of 9, 7, and 6. It was established that anhydrous trisolvates are obtained by the azeotropic distillation of the water with toluene and subsequent drying of the complexes with zeolites.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2790–2792, December, 1977.     

Enthalpy of formation of thiophene derivatives

The enthalpy of formation in the gas phase has been calculated for 21 carbonyl compounds of the thiophene series with the aid of the PM3, MINDO, AM1, and MNDO semiempirical quantum-chemical methods. Comparison of them with experimental data showed that the best linear correlation was achieved with the PM3 method. The latter in conjunction with a developed linear regression equation has been used to predict the enthalpy of formation of 22 carboxylic acids and ketones of the thiophene series.     

Hybridization of DNA at the surface of phospholipid monolayers. Effect of orientation of oligonucleotide chains

We studied the properties of lipid monolayers formed at the air-water interface composed of dioleoylphosphatidylcholine (DOPC) with incorporated short (19-mer) oligonucleotides. These oligonucleotides were modified by oleylamine at both (3' and 5') terminals or only at one (3') terminal. Interaction of single-stranded (19-mer) oligonucleotides without oleylamine with DOPC monolayers resulted only in slight increase of surface pressure and the area per phospholipid molecule, while more substantial and significant increase of these values were observed following incorporation of oligonucelotides modified by oleylamine. This influence is similar for both types of oligonucleotide modifications. However, considerable differences in changes of monolayer properties took place after hybridization with complementary oligonucleotides. The hybridization of oligonucleotides with the DNA modified by oleic acid at both 3' and 5' terminals at the surface of lipid monolayer resulted in further increase of surface pressure and in the increase of the area per phospholipid molecule, while decrease of both the surface pressure and the area per phospholipid molecules were observed for hybridization with DNA modified by oleic acid at 3' terminal. It is possible that in latter case, the hybridization caused the loss of hybridized molecules from monolayers. Interaction of noncomplementary chains with DOPC monolayers with incorporated oleyl acid-modified DNA also influenced the properties of monolayers, but the effect was weaker in comparison with that observed for complementary chains.     

原子荧光光谱法测定褪黑素治疗组兔肝脏硒含量

为探讨褪黑素对实验性动脉粥样硬化兔肝脏组织中硒含量的影响,用高脂饮食复制兔动脉粥样硬化,然后给予褪黑素建立治疗组模型,获取肝脏,用硝酸、过氧化氢混合液微波消解样品,采用原子荧光光谱法测定肝脏组织中硒的含量。结果表明,正常组、高脂组和褪黑素治疗组硒在肝脏组织中质量分数分别为3.31、2.14和1.34 mg/kg。提示给予褪黑素治疗后,褪黑素治疗组的硒平均含量比高脂组的平均含量降低37.4%,所以褪黑素对肝脏硒的吸收具有明显的抑制作用。     

Chemistry of heteroanalogs of isoflavones

Thiazole analogs of isomeric isoflavones were synthesized from -(2,4-dimethyl-5-thiazolyl)-2-hydroxyacetophenones, and their reaction with hydrazine hydrate and alkylating and acylating agents was studied. The reaction of thiazole derivatives of 7-hydroxychromone with hydrazine hydrate proceeds with opening of the pyrone ring and subsequent cyclization of the intermediate to o-hydroxyphenylpyrazole derivatives. The reaction of hydrazine hydrate with thiazole derivatives of 5-hydroxychromone, which proceeds with retention of the pyrone ring, leads to hydrazones. The structures of the new compounds were confirmed by the PMR spectra.See [1] for communication 6.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 25–28, January, 1979.