SO_2改性活性炭催化PS降解对氯苯酚的研究

采用SO_2高温焙烧法对活性炭进行了掺硫改性,并以掺硫活性炭(ACS)为催化剂,研究了对氯苯酚(4-CP)在ACS活化过硫酸盐(ACS/PS)体系中的降解规律和机理。结果表明,ACS比表面积有所降低,同时表面掺杂的含硫官能团以砜基和噻吩基为主。ACS的催化活性有明显提升,尤其在酸性环境和较高反应温度时。在反应温度为55℃时,反应210 min,ACS/PS体系4-CP几乎完全降解,相对改性前提高30.9%。基于中间产物测定数据,初步推断了4-CP在ACS/PS体系中的降解机理和过程。     

无卤阻燃ACS/PC合金的制备及性能

以聚碳酸酯(PC)为耐热树脂,磷酸酯为阻燃剂制备无卤阻燃丙烯腈-氯化聚乙烯-苯乙烯塑料(ACS)/PC合金,研究了ACS与PC的质量比、磷酸酯用量、增容剂用量等因素对阻燃ACS/PC合金综合性能的影响。结果表明,当ACS与PC的质量比为75∶25时综合性能最优;增容剂马来酸酐接枝(丙烯腈/苯乙烯)共聚物(AS-g-MAH)可以有效提高缺口冲击强度;磷酸酯与ACS存在协同增效作用,相对于阻燃丙烯腈-丁二烯-苯乙烯塑料/PC合金,阻燃ACS/PC合金的磷酸酯用量大幅下降。     

MMP-9、IL-6与急性冠脉综合征相关性的研究

目的观察急性冠状动脉综合征(ACS)中基质金属蛋白酶-9(MMP-9)、白细胞介素-6(IL-6)的水平变化,探讨二者之间的关系。方法选ACS患者50例,其中不稳定性心绞痛患者28例,急性心肌梗死患者22例及正常对照组50例,采用酶联免疫吸附试验(ELISA)测定血浆MMP-9、IL-6水平,分析MMP-9与IL-6的相关性。结果ACS患者血浆MMP-9水平显著高于对照组(P<0.01),ACS患者血浆IL-6水平显著高于对照组(P<0.01)。ACS患者血浆MMP-9与IL-6呈显著的正相关(r=0.55,P<0.01)。结论ACS患者血浆MMP-9、IL-6水平明显升高,与不稳定粥样斑块破裂密切相关,两者共同作用促使ACS发生。     

ACS树脂的结构与热性能

通过相差显微图片和红外光谱分析ACS树脂[丙烯腈(AH)-氯化聚乙烯(CPE)-苯乙烯(S_t)]的结构,利用差热分析(DTA)和热失重(TG)曲线剖析ACS树脂的热性能。结果表明,ACS树脂系CPE、CPE-g-AS和AS以分散的橡胶相(CPE相)与连续的塑料相(AS相)共存的多相抗冲体系。CPE和ACS的热解聚机理均为脱氯化氢,氧化降解。ACS热稳定性明显优于CPE。     

ACS用量对CPVC-ACS复合材料的性能影响

采用机械共混法制备了氯化聚氯乙烯(CPVC)、丙烯腈-氯化聚乙烯-苯乙烯(ACS)二元共混复合材料(CPVC-ACS),研究了共混复合材料的组成与材料力学性能、耐热性能、阻燃性能和抗老化性能的关系。结果表明,ACS加入到CPVC中,可达到良好的增韧效果,但ACS用量的增加使CPVC的拉伸强度和维卡软化点温度降低;ACS对CPVC的阻燃性能影响不大,改性CPVC均可达到难燃级;用ACS改性CPVC的抗老化性能明显优于CPVC-ABS。     

PVC/ACS彩色共挤异型材的研究

制备了聚氯乙烯(PVC)/丙烯腈-氯化聚乙烯-苯乙烯塑料(ACS)彩色共挤异型材,研究了耐候层配方中的ACS含量对PVC/ACS彩色共挤异型材制品的力学性能及耐候性能的影响,考察了加工温度对所得共挤异型材耐候性能的影响,并与PVC/丙烯腈-苯乙烯-丙烯酸酯塑料(ASA)彩色共挤异型材进行对比.结果表明,ACS的耐老化性...     

微氧反应器和好氧对照系统负荷效应对比研究

为了探讨负荷效应对微氧污泥床反应器运行特征的影响,研究比较了上升流式微氧污泥床反应器(UMSB)和好氧对照系统(ACS)在3种不同负荷水平下的运行特征。结果表明,负荷较低时,UMSB和ACS的COD去除率没有显著性差异,而UMSB的TP去除率显著高于ACS。负荷较高时,UMSB和ACS的COD去除率存在显著性差异,而UMSB和ACS的TP去除率不存在显著性差异。有机负荷对UMSB中COD和TP的去除具有较大影响。     

新型ACS树脂的研制

从乙烯—丙烯共聚物弹性体(EP)出发,通过氯化反应生成氯化乙丙共聚物弹性体(CEP),然后与丙烯腈(A)、苯乙烯(S)进行接枝共聚,合成新型ACS树脂。研究了EP组成,CEP的氯含量,A、C、S 3种组份比例等条件对ACS树脂性能的影响。     

应用化学发光免疫分析法测定CA125

目的 评价化学发光免疫分析法测定CA125辅助诊断卵巢癌的临床应用价值。方法 分别用Lumiassay~(TM)与ACS:180试剂测定卵巢癌61例,非卵巢癌21例。正常对照67例,并与RlA进行对照。结果 Lumiassay~(TM)、ACS:180与RIA测定CA125的灵敏度分别为86.9％、86.9％和80.3％;特异度分别为95.5％、97.0％和92.5％;阳性预测值分别为94.6％、96.4％和90.7％;阴性预测值分别为88.9％、89.0％和83.9％;准确度分别为91.4％、92.2％和86.7％。Lumiassay~(TM)与ACS:180有高度的一致性和相关性;Lumiassay~(TM)、ACS:180与RIA一致性与相关性略低。结论 化学发光免疫分析法测定CA125辅助诊断卵巢癌具有较高的灵敏度、特异度与临床价值,在3种方法的对比中,Lumiassay~(TM)ACS:180有着高度的相关性,优于RIA。     

访问美国化学文摘社纪实

我们应美国化学学会(以下简称ACS)的邀请,在参加了9月11～17日在密苏里州堪萨斯城举行的ACS184次年会之后,用了一天半的时间参观访问了其下属的化学文摘社(以下简称CAS)。美国《化学文摘》(以下简称CA)是当今世界上最有威信的一种化学、化工文摘刊物。它创刊于1907     

阻燃ACS树脂的制备及应用

采用熔融挤出法制备阻燃ACS树脂,研究了环保溴系阻燃剂、增韧剂种类及用量对阻燃ACS综合性能的影响.结果表明,低分子量溴化环氧树脂/三氧化二锑复配阻燃ACS树脂的综合性能损失较小,耐候性良好.ABS高胶粉的增韧效果优于氯化聚乙烯(PE-C),但所得增韧阻燃ACS的拉伸性能、弯曲性能降幅较大.PE-C具有协效 阻燃作用,...     

ACS/Sb2O3复合材料制备方法对性能的影响

对采用原位悬浮聚合制备的苯乙烯一氯化聚乙烯一丙烯腈（ACS）共聚物／Sb2O3复合树脂、原位聚合苯乙烯一丙烯腈（SAN）共聚物／Sb2O3复合树脂与ACS树脂的共混物和ACS树脂／Sb2O3的直接共混物的力学性能和阻燃性能进行了研究比较。结果发现：原位聚合法制备的ACS／Sb2O3复合材料的性能优于其它两种方法制备的复合物；三种复合材料的冲击性能都劣于纯ACS材料；采用原位聚合方法，Sb2O3质量分数小于7％时，Sb2O3对复合材料有增强作用；当Sb2O3质量分数大于10％时，直接共混ACS／Sb2O3复合物的阻燃性能劣于其它两种方法制备的ACS／Sb203复合材料。     

Dynamic rheological behavior and mechanical properties of PVC/ACS blends

In order to increase the processability and mechanical properties of poly(vinyl chloride) (PVC), the terpolymer of acrylonitrile-chlorinated polyethylene-styrene (ACS) is used to modify the PVC. The plasticizing, rheological, and dynamic mechanical properties of PVC/ACS blends are investigated by means of torque rheometer, oscillation rheometer, and dynamic mechanical analyzer. The measurements of torque rheometer showed that both plasticizing time and stabilization torque are decreased with increasing ACS content. The PVC/ACS melts displayed larger dynamic storage modulus (G′), loss modulus (G′′), and complex viscosity (η*) than that of pure PVC, and these values reached maximum for the blend with 10 wt% ACS. When ACS content was below 10 wt%, PVC and ACS showed good compatibility in the blends by displaying a single T _g; however, when ACS content was more than 15 wt%, the phase separation phenomena occurred in the blends. PVC/ACS blends showed larger storage modulus (E′) and loss modulus (E′′) than that of pure PVC, but these values decreased with increasing ACS content. ACS can enhance both tensile and impact strength of PVC, and the impact strength reached maximum with 15 wt% ACS content which is higher 2.5 kJ/m² than the pure PVC. These results suggested that ACS is an efficient processing aid and toughening modifier for PVC at appropriate content.     

Effects of added aluminum chromium slag on the structure and mechanical properties of colored zirconia ceramics

Colored zirconia ceramic samples were prepared via pressureless sintering with yttria-stabilized zirconia as a raw material and aluminum chromium slag (ACS) as an additive. Then, the effects of added ACS (0-15.0 wt%) on the microstructure, phase composition, and mechanical properties of the ceramic were investigated. The addition of ACS changed the apparent color of zirconia ceramics from white to pink, and the color deepened as the ACS content increased. In addition, more pores appeared in the sintered ceramic substrate as the content of ACS increased, and the relative density of samples declined from 97.7% to 91.1% with an increase in ACS content. However, the microhardness and bending strength each reached their maximum values (1887.2 HV and 433.5 MPa, respectively) when the content of ACS was 5.0 wt%. Fracture surface analysis of the samples showed that intergranular fractures were the main features of sintered samples with no added ACS, whereas numerous transgranular fractures occurred in sintered samples to which ACS had been added. The XRD results revealed that the prepared mainly composite ceramics were composed of t-ZrO₂, m-ZrO₂, and chromium-corundum, and the content of the t-ZrO₂ gradually increased as the ACS content increased.     

Theoretical and experimental testing of a scaling rule for air current segregation of alumina powder in cylindrical silos

Air current segregation (ACS) is one segregation phenomenon that has been identified to contribute significantly to the separation of fines (particles < 42 µm) from coarse material during the filling of industrial silos. This paper describes investigations of ACS for alumina powder based on experiments conducted in an industrial silo, in the laboratory and by computation, using the commercial computational fluid dynamics code Fluent.For the industrial silo, the extent of ACS has been measured using the accumulation of fine material at the wall as an indicator. Based on these results, modifications to the feeding system were undertaken which showed that ACS is promoted if the material is fed in a dilute form. Experiments in the laboratory confirmed this effect visually. In order to be able to compare numerically the extend of ACS, a segregation index has been developed. It was found that a dilute particle jet leads to more ACS than dense particle jet.The effects of solids feeding rate and air extraction rate on ACS have been investigated in the laboratory silo and the results clearly show that low solids feeding rates promote ACS. It was further found that an increase in the air extraction rate has a mild effect in suppressing ACS. These effects were confirmed by the Fluent simulations, which showed an unexpectedly good agreement with the experiments.     

Preparation of bimodal mesoporous silica containing cerious salt and its application as catalyst for the synthesis of biodiesel by esterification

A kind of bimodal mesoporous silica catalyst modified with ammonium cerous sulfate (ACS/BMMS) was synthesized and applied in the esterification of free fatty acid and alcohol. The characterization results including XRD, N₂ adsorption and desorption, FTIR, ²⁹Si-NMR and TEM showed that ACS/BMMS has orderly arranged bimodal mesopores, the small mesopore diameter is about 4.0–6.0 nm and the large mesopore diameter is in the range of 7.0–9.0 nm. The chemical interaction existed between silica group Si (OH)₂(OSi)₂ and the NH₄ ⁺, SO₄ ^2? and Ce-O groups of cerious salt. When the loading is not more than 10%, cerious salt dispersed finely on the supports. Oleic acid and methanol were used as the raw material of probe reaction; ACS/BMMS had significantly better activity than the ACS/SBA-15, ACS/SBA-16, ACS/MCM-41, BMMS and bulk ACS. The optimum loading of ACS is 10%, the optimum reaction conditions are reaction temperature 140 °C, reaction time 2 h, mole ratio of methanol to oleic acid 2.0 and the dosage of catalyst 4.0%, in above situation the conversion of oleic acid is about 94.0%, the reusability of ACS/BMMS is much better than bulk ACS. The kinetic study showed that the esterification of oleic acid and methanol on ACS/BMMS match Eley–Rideal model very well.     

ACS树脂合成条件对其化学结构及性能影响

研究了氯化聚乙烯(CPE)含量、单体比例、溶胀温度及反应时间对丙烯腈-氯化聚乙烯-苯乙烯(ACS)树脂的接枝率、摩尔质量及其分布、拉伸性能及微观结构的影响。研究结果表明,当CPE质量分数为30%、单体St/AN质量比为2 1∶、溶胀温度为40℃、反应时间为8 h时,能够得到微观结构均匀、拉伸性能较好的ACS树脂,其拉伸强度可达31.33 MPa。     

SYNTHESIS,RHEOLOGICAL BEHAVIOR,AND MECHANICAL PROPERTIES OF GRAFT-TYPE ACS RESIN

Graft-type ACS resin and α-methylstyrene (α-Mst)-containing ACS were synthesized by suspension polymerization. The effect of concentration of initiator and polyvinyl alcohol (PVA) on reaction was discussed. The graft efficiency (GE) increased with the increasing concentration of initiator in the first stage, but it began to decrease when the initiator concentration exceeded 3.3–3.5×10^?4mol L^?1. The GE decreased gradually with the increasing concentration of PVA. The rheological behavior, mechanical properties, and morphological structure of resins were studied. The rheological behavior became worse with the increasing content of chlorinated polyethylene and the melt is a pseudo-plastic liquid. The impact strength of graft-type ACS resin increased as the content of chlorinated polyethylene increased. The rheological behavior and impact properties of α-Mst-containing ACS resin got better because of the introduction of α-Mst, and the comprehensive properties was the best at the 5% α-Mst content of ACS resin.