火灾场景中细水雾幕对玻璃保护效果实验研究

在火灾环境中,玻璃极易受到过量热流的影响而发生破裂,从而增加火灾房间的通风,导致火势急剧增长,甚至跨区域蔓延。研究防止玻璃在火灾条件下破裂与脱落技术手段对火灾防控具有重要意义。基于此,提出了一种采用细水雾幕阻隔火焰热辐射保护玻璃的方法。实验通过改变细水雾幕工作压力及其在火灾不同阶段的启动,并与传统水膜法进行对比,研究各工况下的保护效果。结果发现火源与保护装置同时启动,细水雾幕与水膜都可以将玻璃首次破裂时间延长。流量为0.38 L/min时,在细水雾幕保护下玻璃首次破裂时间比水膜保护下延长361 s。细水雾幕工作压力越大,保护效果越好,但当压力超过1.0 MPa持续提高细水雾幕压力,保护效果变化不明显。当延迟到玻璃表面温度达到90℃时,启动这两种保护装置,细水雾幕对窗玻璃保护效果不受影响,但水膜法玻璃首次破裂时间会缩短。     

电子辐照Kapton/Al薄膜力学性能退化规律与机理研究

目的为航天器用Kapton/Al薄膜材料的选用提供数据支撑和高性能Kapton/Al薄膜材料的研制提供理论支持。方法用综合辐照试验装置对Kapton/Al薄膜材料进行电子辐照,用拉力试验机对Kapton/Al薄膜材料开展力学性能拉伸试验,用XPS对其成分和微观结构进行测试分析。结果Kapton/Al薄膜材料的抗拉强度和断裂伸长率随着拉伸速度的增加而降低,随着电子辐照注量的增加呈指数减小,在电子辐照下,薄膜材料分子键发生断裂和交联,C—CO和C—N键断裂发生脱氧和脱氮反应,C—H基团相对含量增大。结论电子辐照将造成Kapton/Al薄膜材料力学性能降低,薄膜材料分子价健的断裂和交联是薄膜力学性能降低的主要原因。     

Bi_2MoO_6薄膜电极光电催化氧化处理氰化物的研究

本文采用非晶态配合物法及浸渍提拉法在导电玻璃基底上制备了Bi2MoO6薄膜电极,采用此电极在可见光(λ420 nm)照射下进行了光电催化氧化处理氰化物的研究.通过场发射扫描电子显微镜和X射线衍射对电极的晶体结构进行了表征,发现导电玻璃基底上充分而平均地覆盖着黄色的纳米Bi2MoO6颗粒,形成了γ-Bi2MoO6相.在Bi2MoO6电极处理络合态氰化物Cu(CN)2-3实验中,总氰化物的去除率和Cu的回收率大致是随着电压的升高而增大,当电压为2.0 V,反应时间为120 min时,处理效果最好,剩余总氰化物和Cu的含量分别为30%和35%.破络合后的Cu2+一部分以Cu(Ⅱ)形式沉积在阳极上,一部分转化为Cu单质沉积在阴极上.在Bi2MoO6电极处理自由态氰化物NaCN实验中,总氰化物的去除率大致也是随着电压的升高而增大,当电压为2.0 V,反应时间为120 min时,剩余总氰化物含量为5%.     

Adsorptive removal of iron and manganese ions from aqueous solutions with microporous chitosan/polyethylene glycol blend membrane

Microporous chitosan (CS) membranes were directly prepared by extraction of poly(ethylene glycol) (PEG) from CS/PEG blend membrane and were examined for iron and manganese ions removal from aqueous solutions. The different variables affecting the adsorption capacity of the membranes such as contact time, pH of the sorption medium, and initial metal ion concentration in the feed solution were investigated on a batch adsorption basis. The affinity of CS/PEG blend membrane to adsorb Fe(II) ions is higher than that of Mn(II) ions, with adsorption equilibrium achieved after 60 min for Fe(II) and Mn(II) ions. By increasing CS/PEG ratio in the blend membrane the adsorption capacity of metal ions increased. Among all parameters, pH has the most significant effect on the adsorption capacity, particularly in the range of 2.9-5.9. The increase in CS/PEG ratio was found to enhance the adsorption capacity of the membranes. The effects of initial concentration of metal ions on the extent of metal ions removal were investigated in detail. The experimental data were better fitted to Freundlich equation than Langmuir. In addition, it was found that the iron and manganese ions adsorbed on the membranes can be effectively desorbed in 0.1 mol/L HCl solution (up to 98% desorption efficiency) and the blend membranes can be reused almost without loss of the adsorption capacity for iron and manganese ions.     

Removal of phenol by activated alumina bed in pulsed high-voltage electric field

A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe^2＋. The removal rate of phenol could reach 72.1% when air aeration flow rate was 1200 ml/min, and 88.2% when 0.05 mmol/L Fe^2＋ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.     

EG填充无卤阻燃型LDPE复合薄膜阻燃性能研究

为了改善聚合物低密度聚乙烯(LDPE)薄膜的阻燃性能,通过向其中添加膨胀型阻燃剂聚磷酸铵(APP)/季戊四醇(PER)和可膨胀石墨(EG),制备了无卤阻燃型低密度聚乙烯复合薄膜.实验研究了膨胀阻燃剂填充聚合物LDPE作为阻燃复合薄膜的性能,分析了膨胀阻燃剂的加入对复合膜阻燃性能、残重率和力学性能的影响机理.研究发现,该新型配方中的EG和APP/PER对复合薄膜的阻燃性能具有协同作用,当配方中APP/PER/EG的填充量达到30%质量分数(APP∶PER∶EG∶LDPE质量比16∶8∶6∶100)时,薄膜材料的氧指数可达到27.5%;与纯LDPE薄膜相比,阻燃薄膜的氧指数提高了10.3%,改善了阻燃效果.     

Role of Hydrophilic and Hydrophobic Interactions in Structure Development of Zein Films

Zein has been studied for its potential as a biobased polymeric material. Due to the fact that films made exclusively from zein are brittle, composites of zein and oleic acid were prepared in our lab and formed into flexible films. Film properties were believed related to their structure. X-ray scattering measurements on zein films suggested the formation of layers along the plane of the film. Oleic acid seemed to play an important role in layer formation. However, X-ray measurements could not yield information on the nature of the interface between oleic acid and zein. Surface plasmon resonance (SPR) was used to further investigate interaction between zein and oleic acid. Dynamic adsorption of zein from alcoholic solutions onto hydrophilic and hydrophobic surfaces generated by self-assembled monolayers of 11-mercaptoundecanoic acid or 1-octanethiol was monitored by SPR. It was observed that zein had a greater affinity for hydrophilic than for hydrophobic surfaces under the prevalent experimental conditions. A mechanism for structure development of zein-oleate films was proposed based on these results and previous X-ray measurements. It is suggested that the structure development involves hydrophilic adsorption of fatty acids onto the zein surface followed by hydrophobic associations leading to a layered film structure organization.     

A spectrophotometric method for detection of enzymatic degradation of thin polymer films

An assay method has been developed for monitoring the enzymatic degradation of thin films of translucent polymers. The method was based on the observation that when a solution-cast film of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was exposed to a solution of a depolymerase fromPseudomonas lemoignei, the surface of the film roughened and the film became visibly turbid. This increase in turbidity could be measured spectrophotometrically and was reproducible during the initial stage of degradation. Turbidity correlated very closely with film weight loss early in the degradation but reached a maximum value before extensive degradation had taken place. For a given set of films, this correlation was independent of the concentration of the enzyme used, although it did vary with the mode of enzyme exposure. The turbidity was associated with the exposure of crystalline domains due to the removal of amorphous material from the film surface. The increase in crystallinity at the surface was verified by attenuated total reflectance infrared spectroscopy (ATRIR). In conjunction with SEM, weight loss, and ATRIR, the film turbidity assay provided much semiquantitative insight into the mechanism of the enzymatic degradation reaction. This assay was used to study the enzymatic degradation of films of PHBV solution blended with cellulose acetate esters (CAE). The presence of only 25% of CAE of degree of substitution 2.9 severely hampered the enzymatic degradability of PHBV, a result which is consistent with the environmental degradation of these same samples exposed to activated sludge.     

Physical properties and biodegradability of blends containing poly(ε-caprolactone) and tropical starches

In order to assess feasibility of tropical starches (sago and cassava starches) as biodegradable plastic materials, blending with poly(-caprolactone) (PCL), a biodegradable polymer, was carried out. It was confirmed that the physical properties (tensile strength and elongation) of PCL/sago and PCL/cassava blends were similar to those of PCL/corn blend, suggesting that sago and cassava starches can also be blended with PCL for production of biodegradable plastic. However, the properties of all PCL/starch blends were still low compared with those of polyethylene. Enzymatic degradability evaluation showed that lipase degradation of PCL and-amylase degradation of starch increased as the starch content in the blend increased. Burial test of the blends for 1, 3, and 5 months was carried out and the rate of degradation of the PCL/sago blend was confirmed to be slower than those of PCL/corn and PCL/cassava blends. Observation of the film blends structure by scanning electron microscope revealed that the starch was dispersed in a PCL continuous phase. Furthermore, changes in the film surface before and after enyzme treatments were observed.     

光催化氧化法降解有机磷农药的研究

本研究采用负载型TiO2膜作为催化剂降解有机磷农药敌敌畏，探讨了光催化反应时间、溶液的初始浓度对敌敌畏降解率的影响。试验表明，不同初始浓度的敌敌畏在经过90minUV／TiO2处理后，降解率都能达到90％以上，而且降解率随光照时间的增长而增加，随初始浓度的增加而降低。本研究采用毛细管柱气相色谱检测敌敌畏的剩余浓度，检出效果较好，并通过色谱图探讨敌敌畏的降解过程。