The petentiometric determination of peroxide hydrogen and glucose on the glassy electrode modified by the calix[4]arene

A new petentiometric method to determine peroxide hydrogen and glucose had been studied. This method had been applied on the petentiometric determination of peroxide hydrogen and glucose in the total ionic strength adjustment buffer (TISAB) (pH 7.5) solution with the glassy electrode modified by the calix[4]arene. The glassy carbon electrode covered with the calix[4]arene depended on the H₂O₂ concentration in the range of log[H₂O₂] from −3.3 to −1.2 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 65.6 ± 3 mV and the detection limit of peroxide hydrogen was 4.0 × 10⁻⁵ mol L⁻¹. The glassy carbon electrode covered with the calix[4]arene depended on the glucose concentration in the range of log[glucose] from −3.6 to −2.8 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 50.2 ± 2 mV and the detection limit of glucose was 2.0 × 10⁻⁵ mol L⁻¹. The electrode had the good selectivity, sensitivity, stability and repeatability.     

中性红褪色光度法测定蒙药铜灰体系中产生的过氧化氢含量

在 p H=3.5的乙酸 -乙酸钠缓冲溶液中 ,用中性红褪色光度法测定了蒙药铜灰体系中产生的过氧化氢的含量。过氧化氢在 0— 5 0μg/ 2 5 m L范围内与 lg(A0 / A)值呈线性关系 ,线性回归方程为 lg(A0 / A) =2 .5× 10 -3+1.0 5× 10 -2 C双氧水 (μg/ 2 5 m L) ,r=0 .9999     

La-O小团簇上超氧物种与过氧物种间的连接途径

采用密度泛函理论方法考察了La-O团簇上超氧物种与过氧物种间转化的连接途径. 单重态下, 团簇上单个超氧物种可通过一系列臭氧物种转化为过氧物种, 且转化能垒较高;三重态下, 单个超氧物种则并无与过氧物种间连接的途径. 然而, La-O团簇上两超氧物种间的相互作用及其转化也具单重态和三重态两条途径. 三重态下, 超氧物种可很容易地转化为过氧物种(O₂^- + O₂^-↔O₂^2- + O₂), 超氧物种与过氧物种处于快速的交换状态之中;单重态下, 超氧物种转化为过氧物种则需较高的活化能垒, 表明在单重态下这些氧物种具有较高的稳定性.     

Allylic monomers as reactive plasticizers of polyphenylene oxide. Part III – Rheological and mechanical properties

The chemorheology of blends of diallyl ortho-phthalate (DAOP) as reactive plasticizer of polyphenylene oxide (PPO) were monitored during their cure with either dicumyl peroxide (DCP) or tert-butyl hydroperoxide (TBHP), and their mechanical properties and morphology were studied. The steady shear and dynamic rheology behaviour was consistent with chemical gelation of DAOP in blends with low concentrations of PPO but the gelation behaviour at higher PPO concentrations was more complex. Dynamic mechanical thermal analysis of the blends of PPO:DAOP cured with either DCP or TBHP indicated a two phase structure. For PPO:DAOP/DCP, the lowest transition (between 150 °C and 200 °C) was attributed to a DAOP-rich phase and its T_g was higher than that for pure DAOP/DCP due to the presence of PPO in the DAOP-rich phase. The smaller damping shoulder near 250 °C was caused by a PPO-rich phase with a T_g that was lower than pristine PPO due to the presence of unpolymerized or polymerized DAOP. In contrast, the glass transition region of the PPO:DAOP/TBHP system was very broad due to an overlap of the transitions for DAOP-rich and PPO-rich phases caused by higher levels of unpolymerized DAOP. SEM observations of the blends revealed a two phase morphology with PPO-rich particles in a poly-DAOP matrix for blends with ?30 wt% PPO, a co-continuous morphology for blends with 40 wt% PPO, and a phase inverted morphology with more than 50 wt% PPO. These SEM observations agree with studies of the swelling, disintegration or dissolution of matrix of the blends in solvent.     

The Influence of Peroxide on Bubble Stability and Rheological Properties of Biobased Poly(lactic acid)/Natural Rubber Blown Films

This study investigated the effects of natural rubber(NR)and an organic peroxide on the rheological properties,mechanical properties,morphology,and bubble stability during film blowing of poly(lactic acid)(PLA).The NR and peroxide contents were varied from 0 wt%to 25 wt%and 0 wt%to 0.5 wt%,respectively.The results confirmed that the presence of well-dispersed NR could significantly improve the toughness,elongation at break,and processability of PLA films,where the optimal amount of NR was 15 wt%.For the reactive blending with peroxide,a suitable peroxide content for good film toughness and clarity was 0.03 wt%,while the higher content of 0.1 wt%could provide slightly higher processability.These contents are considered much lower than that in the PLA system(without NR),which required up to 0.5 wt%peroxide.The rheological studies indicated that the melt strength,the storage modulus(G’)and complex viscosity(η*)at low frequency could be correlated with good film blowing processability of the PLA/NR films at low gel contents.These parameters failed to correlate in the films having high gel contents as the deformation rate experienced by each test was different leading to the different levels of response to the type and amount of gels.     

纺粘法聚丙烯无纺布专用料的研制

介绍了以聚丙烯通用料为基础料，通过添加降温母料研制出适用于纺粘法的PP无纺专用料，经应用试验表明，此专用料生产平稳，可降低纺丝温度，改善了产品的加工性，提高了产品的力学性能及手感。     

过氧化氢氧化溴邻苯三酚红催化光度法测定痕量钴

在 NH3 · H2 O- NH4Cl体系中 ,痕量钴与 EDTA协同催化 H2 O2 氧化溴邻苯三酚红 ,据此建立了测定痕量钴的新方法。质量浓度的线性范围为 0— 1.3μg/ m L,检出限为 2 .6× 10 -10 g/ m L。可用于人体尿液、维生素 B12 注射液、百合中痕量钴的测定。