水溶性高分子链中磺酸盐基团含量的电导滴定测定法

研究了N ,N ,N 三甲基十六烷基溴化铵 (CTAB)与丙烯酰胺 (AM) 2 丙烯酰胺基 2 甲基丙磺酸钠盐(NaAMPS)二元共聚物P(AM co NaAMPS)的复合作用 .在复合作用过程中 ,由于不断释放出高导电性的无机盐小离子 ,故随着表面活性剂的加入 ,聚电解质水溶液的电导率不断增大 .当采用较低浓度 (0 0 0 1mol·L- 1 )且使二者的离子等摩尔量发生复合作用时 ,体系的电导率会发生明显的转折 .利用电导率的这一转折性变化 ,建立起了复合作用电导滴定法测定共聚物P(AM co NaAMPS)分子链中磺酸盐单体NaAMPS含量的新方法 .与元素分析进行比较的结果表明 ,上述复合作用电导滴定法可作为测定水溶性大分子链中磺酸盐单体含量的方便而又准确的方法 ,而且预计还可用作为测定水溶性大分子链中其它离子性基团含量的简捷方法     

Horseradish peroxidase-catalyzed polymerization of<Emphasis Type="Italic"> p</Emphasis>-hydroxycinnamic acid for synthesis of reactive microspheres

In this article, we report the experimental synthesis of reactive polymer microspheres of poly(p-hydroxycinnamic acid). Enzyme-catalyzed polymerization of poly(p-hydroxycinnamic acid) using horseradish peroxidase as a catalyst and hydrogen peroxide as an oxidant took place in a mixture solution of methanol and phosphate buffer solution; it was found that the fraction of methanol in the mixture solution strongly affected the yield of powdery polymer materials. The chemical structure of the polymers was characterized by ¹H-NMR and FT-IR spectroscopies, and the molecular weight was measured by gel permeation chromatography. The ¹H-NMR chart of the obtained polymer was almost the same as that of the monomer; FT-IR spectra indicated the existence of carboxyl groups. The weight-average molecular weight of the soluble part in tetrahydrofuran was found to be 1,451. Dispersion polymerization of p-hydroxycinnamic acid was carried out in a mixture solution of methanol and phosphate buffer solution by adding a dispersion stabilizer. Of the several such polymers tested, poly(vinyl alcohol) was found to be the most effective in producing reactive poly(p-hydroxycinnamic acid) microspheres.     

含硅芳香二酐的合成及其聚酰亚胺

从4-溴-l，2-二甲苯出发，经过三步反应合成了双-（3，4-苯二甲酸酐)二甲基硅烷单体，总产率为24．7％；由该单体与4，4′-二氨基二苯醚共聚合，经环化脱水反应得含硅聚酰亚胺，并对该共聚物进行了初步表征。     

Radical polymerization of methyl trans-β-vinylacrylate

Methyl trans-β-vinylacrylate (MVA) undergoes radical polymerization with α,α′-azobis(isobutyronitrile) (AIBN) in bulk and solution. The polymer obtained consists of 85% trans-1,4 and 15% trans-3,4 units. Poly(MVA) (PMVA) is readily soluble in common organic solvents, but insoluble in n-hexane and petroleum ether. PMVA exhibits a glass transition at 60°C, and loses no weight up to 300°C in nitrogen. The kinetics of MVA homopolymerization with AIBN was investigated in benzene. The rate of polymerization (R_p) can be expressed by R_p = k[AIBN]^0.5[MVA]^1.0, and the overall activation energy has been calculated to be 94 kJ/mol. The propagation radical of MVA at 80°C was detected by ESR spectroscopy, which indicated that the unpaired electron of the propagating radical was completely delocalized over the three allyl carbons. Furthermore, the steady-state concentration of the propagating radical of MVA at 60°C was determined by ESR spectroscopy, and the propagation rate constant (k_p) was calculated to be 1.25 X 10² L/mol ·s. Monomer reactivity ratios in copolymerization of MVA (M₂) with styrene (M₁) are r₁ = 0.16 and r₂ = 4.9, from which Q and e values of MVA are calculated as 4.2 and -0.32, respectively. © 1995 John Wiley & Sons, Inc.     

Fluorescence Evaluation of Scavenging Efficiency of Antioxidants Against Reactive Oxygen Species (ROS) in Cigarette Smoke

Cigarette smoke can cause cellular oxidative stress that contributes to various adverse health effects associated with smoke exposure, partially due to reactive oxygen species (ROS) present in cigarette smoke. Reduction of abundant ROS in the cigarette mainstream smoke (MSS) is of importance for human health. In this work, a simple, rapid, and reliable fluorescence evaluation of scavenging efficiency of antioxidants as potential filter additives against ROS in cigarette smoke is reported. This method was based on the combination of model glass reactor and a fluorescence assay of ROS in cigarette smoke using dihydrorhodamine 6 G (DHR-6 G). The antioxidant was added into a glass reactor attached to cigarette filter, which simplified the preparation of combined filter containing additives. The ROS scavenging efficiency of antioxidants was then determined using spectrofluorimetry by the change in fluorescence intensity of whole smoke-bubbled solutions before and after addition of antioxidants into the glass reactor. The proposed method was successfully applied to the determination of ROS scavenging efficiency of several potential additives, such as tert-butylhydroquinone (TBHQ), vitamin C, β-carotene, grape seed extract, and Ginkgo biloba extract. Moreover, the relationship between MSS ROS scavenging efficiency and antioxidant activities (DPPH radicals scavenging efficiency and Fe²⁺ reducing power) of these compounds was also investigated.     

以混旋邻氯扁桃酸为模板的分子印迹聚合物的制备及拆分性能研究

以混旋邻氯扁桃酸为模板分子和合成的(S)-(1-萘乙基)-丙烯酰胺为手性功能 单体制备分子印迹聚合物作为色谱固定相，对混旋邻氯扁桃酸有较好的拆分能力， 分离因子α达到1.36。但对模板分子的类似物混旋扁桃酸和对氯扁桃酸没有拆分能 力。用Hyperchem软件模拟了(S)-邻氯扁桃酸与(S)-(1-萘乙基)-丙烯酰胺形成的复 合物的结构模型，其在聚合物母体中留下的具有立体构型和作用力双重识别的S-S 型空穴，对(S)-邻氯扁桃酸有较强的保留作用，从而达到对混旋物拆分的目的。     

毛细管气相色谱法测定炼厂气中单体烃组分的含量

采用PLOT／Al2O3石英毛细管气相色谱柱和氢火焰离子化检测器，建立了炼厂气中单体烃组分含量测定的毛细管气相色谱法，当炼厂气中单体烃组分的含量大于或等于2．1％时，RSD≤0．95％，当炼厂气中单体烃组分的含量为0．5％－2．1％时，RSD为0．95％－10．0％，当炼厂气中单体烃组分的含量为0．2％－0．5％时，RSD为10．0％－25．0％，该方法对单体烃组分的测定结果与行业标准SH／T0230－92《液化石油气组成测定法》的测定结果基本一致。     

Ring-opening polymerization of cyclic carbonates by alcohol–acid catalyst

Ring-opening reactions of 1,3-dioxepan-2-one ( 1 ) and 1,3-dioxan- 2 -one (2) with several alcohols were examined. The reactions proceeded without trifluoroacetic acid (TFA) in low conversions, while they proceeded smoothly with TFA to afford the ring-opened adducts and oligomers. Ring-opening polymerizations of 1 and 2 were also carried out by alcohol–acid catalysts to afford the corresponding polycarbonates (M _n = 2500−6800). The molecular weights increased with increase of the conversions of 1 and 2. The observed polymerization rates of 1 and 2 were determined as 24.4 × 10⁻⁶ and 0.8 × 10⁻⁶ s⁻¹, respectively. Mechanistic aspects were studied by NMR spectroscopy. The methylene protons α and β to the carbonate moieties shifted to lower fields in 0.06–0.11 ppm in the ¹H-NMR spectra by the addition of TFA. Downfield shifts of the carbonyl carbon signals of 1 and 2 were observed in 3.94–4.15 ppm in the ¹³C-NMR spectra. These results strongly suggest that the cyclic carbonates are activated by TFA. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2463–2471, 1998     

Spacer effect of novel bifunctional organophosphorus monomers in metal-imprinted polymers prepared by surface template polymerization

The interfacial activity and the molecular structure of functional monomers are critical factors that determine the success of synthesizing metal-imprinted polymers by surface template polymerization. From this point of view, first we prepared three distinct novel bifunctional organophosphorus monomers that are interspaced, in each case, by an alkyl spacer having a specific length. Each monomer carries two phosphonic acid groups and two aromatic groups in its molecular structures. Further, by using the synthesized bifunctional monomers, we prepared highly selective Zn(II)-imprinted polymers by the surface template polymerization initiated from a water-in-oil emulsion. To evaluate the template effect, we conducted diagnostic adsorption studies on Zn(II)-imprinted and unimprinted polymers with zinc ions. A high interfacial activity was found to be required for the functional monomers to create the predominant template effect. It became clear that Zn(II)-imprinted polymers having bifuctional monomers with 12-length alkyl chains (1,12-dodecanediol-O, O′-diphenyl phosphonic acid: DDDPA) yielded the best results. Moreover, analysis results of adsorption behavior supported a high-performance of the Zn(II)-imprinted polymers with DDDPA. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2727–2734, 1998     

新型大颗粒离子交换树脂的表征和催化活性

用红外、核磁及热分析技术表征由溶胶-凝胶法制备、具有离子交换性能的大颗粒树脂催化剂，证实了树脂催化剂由含苯基及含硅的化合物构成，热稳定性高于商品离子交换树脂近100℃。对该树脂催化剂进行磺化反应的最佳条件为：温度，25℃；浓度，氯磺酸：三氯甲烷-1：4（Vo1）；时间，12h。其缩醛化反应的催化活性与商品大孔离子交换树脂相当。