Radical scavenging activity of canola hull phenolics

Possible use of canola hulls as a source of natural anti-oxidants was explored. Cyclone canola hulls were extracted with methanol (30 to 80%, vol/vol) and acetone (30 to 80%, vol/vol). The free radical-scavenging activity of phenolic extracts so prepared was evaluated using the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical ion (ABTS^o−), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and chemiluminescence assays. The total content of phenolics in prepared extracts from canola hulls ranged from 15 to 136 mg sinapic acid equivalents per gram of extract. Higher levels of condensed tannins were detected in the acetone extracts than in the corresponding methanolic counterparts. Seventy and 80% (vol/vol) acetone extracts displayed markedly stronger antioxidant activity than any of the other extracts investigated. Statistically significant linear correlations were found between TEAC (Trolox equivalent antioxidant capacity) values (expressed in mM of Trolox equivalents per gram of extract) and total pehnolics, TEAC and total condensed tannins (i.e., determined using the modified vanillin and pronthocyanidin assays), as well as TEAC and protein precipitation activity of phenolic extracts (i.e., measured using the dye-labeled assay). The antioxidant activities of extracts as determined by the ABTS^o− radical ion assay correlated highly with those of the chemiluminescence and DPPH radical assays.     

酚醛环氧乙烯酯树脂研究

本文以酚醛环氧树脂F-51与甲基丙烯酸合成出酚醛环氧乙烯酯树脂,并对此树脂的耐热性、耐化学溶剂性能进行了研究.     

以环己酮为原料合成十二烷二酸二甲酯的气相色谱分析法

以环己酮为原料合成十二烷二酸二甲酯粗品,含量测定采用气相色谱法:内标物选用癸二酸二甲酯,色谱柱选用大口径毛细柱FFAP(25m×0.53mm×1.0um)。结果表明:本方法具有简单、快速、准确、可靠。     

青霉素G亚砜对-硝基苄酯的合成工艺研究

以青霉素G钾为原料制备青霉素G亚砜对-硝基苄酯.氧化反应的条件为:青霉素G钾与过氧乙酸的投料比(mol)为1:1.15,氧化温度＜5℃,反应时间2h,青霉素G亚砜收率为93.5%;酯化反应最佳反应条件为:DMF的用量为4.28ml/1g青霉素亚砜,青霉素亚砜与对一硝基溴苄的投料比(mol)为1:1.15,反应温度为室温,反应时间为24小时,酯化收率为83.36%,反应总收率为77.92%.此方法可控制产品质量,确保操作安全简便,对工业化生产具有参考意义.     

碱金属盐对低氢酯比下苯甲酸甲酯加氢催化剂的修饰

为了考察了Mn与Zn摩尔配比以及不同碱金属盐修饰制得的锰锌复合氧化物催化剂对苯甲酸甲酯气固催化加氢合成苯甲醛反应活性和选择性的影响,在氢酯比为1.5的条件下,进行苯甲酸甲酯催化加氢反应,发现以5%LiCl修饰的活性组分负载量为25%、n(Mn)/n(Zn)为1.14的MnO-ZnO/γ-Al2O3催化剂,在常压、430℃、空时为1.84 h时,苯甲酸甲酯的转化率为97.71%,苯甲醛的选择性为84.80%.     

双亚磷酸酯类抗氧剂626合成的工艺

摘要以新工艺合成了双（2，4-二叔丁基苯基）季戊四醇二亚磷酸酯（抗氧剂626）。先以三氯化磷与2，4-二叔丁基苯酚反应合成出中间体（2，4-二叔丁基苯基）二氯亚磷酸酯，再将其与季戊四醇反应合成出产品。探索了反应条件，溶剂及催化剂的种类等因素对产品收率和质量的影响，筛选出最佳的合成工艺条件为：以甲苯或二甲苯为熔荆，体系保持负压至常压，第一步反应温度40—50℃，反应2h，第二步反应温度50—130℃，反应6h，反应收率为86％。     

N,N,N-三甲基-2,3-二(硬脂酰氧基)丙基氯化铵(CDESA)的生物降解性

采用活性环氧中间体失水甘油基三甲基氯化铵合成了一种阳离子双酯表面活性剂——N,N,N-三甲基-2,3-二(硬脂酰氧基)丙基氯化铵(CDESA),来代替传统的难降解的表面活性剂型柔软剂,如目前国内仍在大量使用的双十八烷基二甲基氯化铵(D1821)。对CDESA的好氧降解性能进行了研究:以天然环境中的生活沉降污泥作为微生物源,用河水稀释,经培养、驯化后用于测试降解时间和半衰期,并与D1821的好氧降解性能作了对比。结果表明,CDESA的半衰期为3 d,容易降解,而D1821半衰期为7 d,较难降解,CDESA生物降解性能优于D1821。     

Study on the structure and properties of cyanate ester/bentonite nanocomposites

Cyanate ester (CE)/bentonite (BT) nanocomposites were prepared by melt blending of CE with NH₄⁺‐BT. The nanostructure of CE/BT nanocomposites was studied by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that partially intercalated and partially exfoliated structures coexisted in CE/BT nanocomposites containing 2.5 wt % BT with respect to that of bulk CE. Below 2.5 wt % BT content, a totally exfoliated and disordered structure was formed in the nanocomposites. The exfoliated BT enhanced the toughness of CE/BT nanocomposites. The impact strength showed a maximum of 7.1kJ/m² at 1 wt % BT, compared to 3.8kJ/m² of pure CE. Furthermore, results of thermogravimetric analysis (TGA) suggest that CE/BT nanocomposites have higher thermal stability. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 632–637, 2005     

基于动态硼酸酯键改性黄原胶的性能

基于苯硼酸聚合物可以与存在于黄原胶糖环单元结构中的伯、仲醇羟基通过硼酸酯键形成动态共价微交联结构的性质对黄原胶进行改性。以偶氮二异丁基脒二盐酸盐（AIBA）为引发剂，通过水相自由基聚合，制备了不同共聚比的丙烯酰胺（AM）、N-(3-二甲氨基丙基)丙烯酰胺（DMAPAM）和3-丙烯酰胺基苯硼酸（AMBB）的三元共聚物P(AM-co-DMAPAM-co-AMBB)。通过1H NMR、FTIR、元素分析和光散射对聚合物结构及相对分子质量进行了表征，并对其与黄原胶复配体系的增黏性、流变性、抗老化性及抗干扰性进行了评价。结果表明：P(AM-co-DMAPAM-co-AMBB)与黄原胶复配后对黄原胶溶液具有明显的增黏性，其中苯硼酸单体的摩尔比为1.0 mol%的聚合物对黄原胶溶液的增黏幅度达43.8%，在8074 mg/L的矿化水中增黏幅度高达56.4%，且复配体系具有良好的抗老化降解性，对乙二醇和1,3-丙二醇具有较强的抗干扰性。     

Viscoelastic, Thermal and Mechanical Properties of Dicyclopentadiene Bisphenol Diyanate Ester / Epoxy Co-polymers

Summary Dicyanate ester containing dicyclopentadiene cycles and epoxy co-polymers were prepared by copolymerization between epoxy and dicyclopentadiene bisphenol cyanate esters (DCPDCE). Viscoelastic properties of the co-polymers were characterized by the technique of dynamic mechanical analysis (DMA), which indicated that the introduction of E51 in the co-polymers would effectively improve the toughness of DCPDCE, while the thermal dimensional stability would be weakened. Results from thermogravimetric analysis (TGA) are in good accordance with the T_g values from DMA curves. Mechanical testing of the cured co-polymers shows that E51 can improve the mechanical properties of the co-polymers while its usage is controlled among 5% to 15%.