ASA/SEBS/paraffin composites as phase change material for potential cooling and heating applications in building

Phase change material (PCM) is able to melt and crystalize with a high heat of phase change at constant temperature, which provides new and green cooling and heating strategies for buildings. In this work, PCMs for buildings composed of acrylonitrile‐styrene‐acrylate copolymer (ASA), polystyrene‐b‐poly(ethylene/butylene)‐b‐polystyrene triblock copolymer (SEBS) and paraffin were fabricated by melt blending. The results of the accelerated leakage test indicated an excellent ability of PCMs to keep paraffin from leakage. Thermal properties suggested that the phase change enthalpy of PCMs increased with the increasing content of paraffin and their phase change temperature was close to the comfortable sensible temperature of human body, which made it quite suitable for building cooling and heating. Besides, PCMs presented excellent stability and reusability after several thermal cycling tests. The temperature test conducted with self‐designed cylindrical devices gave a more sufficient and direct demonstration of the cooling and heating effect. Remarkably, excellent cooling and heating performance (both as high as 15°C) of the composites could be obtained with the addition of paraffin. And the time span of the cooling and heating process was as long as 5 and 7.5 hours, respectively. Owing to its excellent cooling and heating capabilities, the ASA/SEBS/paraffin composites are of great potential to be applied in building temperature control.     

Transport properties of crosslinked acrylonitrile butadiene rubber/poly(ethylene‐co‐vinyl acetate) blends

The diffusion and transport of organic solvents through crosslinked nitrile rubber/poly(ethylene‐co‐vinyl acetate) (NBR/EVA) blends have been studied. The diffusion of cyclohexanone through these blends was studied with special reference to blend composition, crosslinking systems, fillers, filler loading, and temperature. At room temperature the mechanism of diffusion was found to be Fickian for cyclohexanone–NBR/EVA blend systems. However, a deviation from the Fickian mode of diffusion is observed at higher temperature. The transport coefficients, namely, intrinsic diffusion coefficient (D*), sorption coefficient (S), and permeation coefficient (P) increase with the increase in NBR content. The sorption data have been used to estimate the activation energies for permeation and diffusion. The van't Hoff relationship was used to determine the thermodynamic parameters. The affine and phantom models for chemical crosslinks were used to predict the nature of crosslinks. The experimental results were compared with the theoretical predictions. The influence of penetrants transport was studied using dichloromethane, chloroform, and carbon tetrachloride. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1815–1831, 1999     

Ring‐banded spherulite surface structure of poly(ε‐caprolactone) in its miscible mixtures with poly(styrene‐co‐acrylonitrile)

The surface structure of the ring‐banded spherulites in polymer blends PCL/SAN (90/10) was studied by optical microscopy, SEM, and TEM, respectively. It is interesting to find that the surface structure of the ring‐banded spherulites in polymer blends PCL/SAN (90/10) is made up of the convex bands. The landscape of the convex bands on the surface has been little emphasized before. Radial fibrils are arranged on the bands. Details of the radial fibrils on the bands can be observed by TEM. The landscape of the convex bands on the surface and twisting of lamellae in the convex bands for PCL/SAN blends may be useful to explain the formation mechanism of the ring banded spherulites in polymer blends or even in homopolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2682–2691, 1999     

Complex‐radical terpolymerization of acceptor–donor–acceptor systems: Maleic anhydride (n‐butyl methacrylate)–styrene–acrylonitrile

Some features of radical ternary copolymerization of maleic anhydride (MA)–styrene (St)–acrylonitrile (AN) and n‐butyl methacrylate (BMA)–St–AN acceptor–donor–acceptor monomer systems have been revealed. The terpolymer compositions and kinetics of copolymerizations were studied in the initial and high conversion stages. The considerable divergence in the copolymer compositions was observed when a strong acceptor MA monomer was substituted with BMA having comparatively low acceptor character in the ternary system studied. Obtained results show that terpolymerization proceeded mainly through “complex” mechanism in the state of near binary copolymerization of St…MA (or BMA) and AN…St complexes only in the chosen ratios of complexed monomers. The terpolymers synthesized have high thermal stabilities (295–325 °C), which is explained by possible intermolecular fragmentation of AN‐units through cyclization and crosslinking reactions during thermotreatment in the isothermal heating conditions. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2652–2662, 2000     

离子液体催化丙烯腈氯化合成2,3-二氯丙腈

 Ionic liquids formed by imidazolium and pyridinium cations with Cl-, Br-, BF-4, and PF-6 anions were used for the catalytic synthesis of 2,3-dichloropropionitrile by the chlorination of acrylonitrile. The ionic liquids containing Cl- and Br- show good catalytic properties. The Cl- and Br- ions act as strong Lewis bases and molecular chlorine is activated by the induction effect of Cl- and Br-. Due to the stronger steric hindrance effect of the BF-4 and PF-6 anions, the chlorination of acrylonitrile is limited in the ionic liquids containing BF-4 and PF-6 anions.     

气相色谱法测定环境空气中的微量丙烯腈

 建立了测定环境空气中丙烯腈的Tenax GC吸附-热解吸气相色谱法。方法的回收率为85.6%～105.4%,RSD为4.5%～6.2%。当采样体积为2 L时,最低检测限为0.01 mg/m3 。     

铽-芳香羧酸-丙烯腈三元配合物的合成及发光性能

铽-芳香羧酸-丙烯腈三元配合物的合成及发光性能;铽;芳香羧酸;丙烯腈;三元配合物;发光性能     

气相色谱-质谱法测定化妆品中的丙烯腈

建立了化妆品中丙烯腈的气相色谱-质谱分析方法.不同类型的化妆品样品中加入甲醇超声提取,经高速离心处理浓缩后,采用Oasis HLB固相萃取柱净化,1 mL 20%甲醇溶液淋洗,3 mL 80%甲醇溶液洗脱,收集洗脱液,浓缩后经无水硫酸钠脱水,进行气相色谱-质谱定性及定量分析.选用HP-INNOWax(60 m×0.25...     

钒化合物引发丙烯腈聚合──高分子场效应

研究了酸性介质中五价钒氧离子（VO）、强碱性阴离子交换树脂负载钒（V）（BAEV）、硫酸氧钒（VOSO4）、杨梅形聚羧酸氧钒（IV）（APCV）、杨酸形聚亚氨二乙酸氧钒（IV）（APIV）、杨梅形聚得偕亚氨二乙酸氧钒（IV）（APOV）、笼形聚羧酸氧钒（IV）（CPCV）和笼形聚肟偕亚氨二乙酸氧钒（IV）（CPOV）等与硫脲（TU）配住生成活性种并引发丙烯腈（AN）聚合反应。表观聚合速度（Rp）分别是：VO-TU:Rp=2.8X105e-14200/RTC2.2'(AN)c.20(HNO3)c0(V5+)c1.3(TU)BAEV-TU:Rp=1.9X104e-6860/RTc1.2(AN)c1.0'(HNO3)c0.44(PV)c1.0(TU)VOSO4-TU:Rp=0APCV-TU:Rp=2.3X104e-4100/Rtc1.5(AN)c1.5(HNO3)c0.5(PV)c2.0(TU)APIV-TU:RP=2.2X105e-6860/RTc1.0(AN)c2.0(H2SO4)c0.5(PV)c1.5(TU)APOV-TU:RP=1.9X108e-10800/RTc.10(AN)c1.0(HNO3)c0.6(PV)c1.5(TU)CPCV-TU:Rp=9.7X105e-10500/RTc1.0(AN)c1.5(HNO3)c0.5(PV)c0.76(TU)CPOV-TU:Rp=1.0X108e-10500/RTc1.0(AN)c3.0(HNO3)c1.0(PV)c1.5(TU)根据实验结果,认为：（一）钒化合物与硫脲在酸性介质中通过“逐步配位—质子转移”机理产生引发种;（二）钒络合物及其活化后所产生的阳离子自由基（i＝0,1,2,…,n）处于大分子引力场内进行链引发,在某些情况下,原地进行键增长反     

Rapid detection of compositional drift of polydisperse copolymers using thermal field-flow fractionation and multi-angle light scattering

Summary The use of thermal field-flow fractionation (ThFFF) with multi-angle light scattering (MALS) for the rapid detection of compositional heterogeneity in random copolymers is demonstrated. Soret coefficients were directly calculated from the ThFFF retention times while the MALS detector provided the polymer's radius of gyration (R _g) distribution. FromR _g, the diffusion coefficient (D) could be calculated and this allowed, in combination with the Soret coefficient, the calculation of the thermal diffusion coefficient (D _T). It was shown that theD _T distribution can serve as a measure for the chemical composition distribution of random styrene acrylonitrile copolymers. Comparison of ThFFF-MALS results with literature data from ThFFF-hydrodynamic chromatography (HDC) cross-fractionation experiments showed a fair agreement.