纸塑铝复合包装材料各组分共热解行为研究

以用甲酸分离枕型利乐包所得的纸、聚乙烯、铝作为实验材料,采用热重红外联用(TG-FTIR)分析技术,研究了各组分在热解过程中的协同作用,以探索纸塑铝复合包装各组分共热解机理,为实现废弃利乐包材料的资源化利用提供科学参考和实验依据。结果表明:共热解时纸和聚乙烯之间存在协同作用,在失重峰位置表现得尤为明显;铝在共热解时具有一定的催化作用,在反应的不同阶段起到了相应的促进或者抑制热解的作用。     

Synergism in the wetting properties of ternary surfactant mixtures

It has been shown that ternary surfactant synergism can be predicted on the basis of nonideality parameters of binary subsystems derived from advancing contact angles. Studies with appropriate surfactant mixtures of glucamides, ether sulfates, secondary alkane sulfonates, and alkylamidopropyl betaines were performed on substrates of different polarity.     

Solvent extraction of nickel from acidic solutions using synergistic mixtures containing pyridinecarboxylate esters. Part 3. Systems based on arylsulphonic acids

The solvent extraction of nickel and calcium from acidic solutions by mixtures of dinonylnaphthalene sulphonic acid (DNNSA) and different pyridinecarboxylate esters (2-, 3- and 4-C₅H₄.CO.OR, where R = n-octyl, 2-ethylhexyl and 2-octyl) in xylene was investigated. In contrast to extraction systems employing DNNSA alone, these mixtures permit the separation of nickel and calcium to be carried out, especially when an excess of the ester is used. The extractability of base metals from sulphate solutions by mixtures of DNNSA (0·25 M ) and isodecyl 3-pyridinecarboxylate (0·25 M ) in Shellsol K decreases through the series Cu > Ni > Al > Co > Ca > Zn > Fe(III) > Mg. Mixtures containing the 2- or 4-ester showed a slightly different selectivity series: Cu > Ni > Co > Zn > Al > Fe(III) ≥ Ca > Mg. In a batch countercurrent experiment, a simulated leach liquor containing Ni 2·15, Mg 5·05 and Ca 0·42 g dm⁻³ (initial pH 3·0) was extracted with the mixed reagent (0·25 M DNNSA plus 0·25 M 4-ester) in four stages at unit phase ratio, without any pH adjustment. The recovery of nickel was 91%, with co-extractions of calcium and magnesium of 14 and 8%, respectively. When the concentration of the 4-ester was increased to 0·50 M , the recovery of nickel increased to 95%, whilst the co-extractions of calcium and magnesium decreased to 4 and 3%, respectively. © 1998 SCI.     

Flavonoids quercetin,myricetin, kaemferol and (+)‐catechin as antioxidants in methyl linoleate

The antioxidant effect of the flavonoids quercetin, myricetin, kaemferol, (+)‐catechin and rutin on methyl linoleate oxidation was investigated. In addition, the synergistic effects of flavonoids and α‐tocopherol were studied. Oxidation was monitored by conjugated diene measurement and by determining the formation of hydroperoxide isomers by HPLC. The antioxidant activity of flavonoids in non‐polar methyl linoleate differ from that previously reported in water‐containing systems, such as LDL and liposome systems. The activity of antioxidants (10–1000 μM ) measured by hydroperoxide formation decreased in the order: myricetin>quercetin>α‐tocopherol>(+)‐catechin >kaemferol=rutin. The antioxidant activity of flavonoids increased as the number of phenolic hydroxyl groups increased. In addition to the number of hydroxyl groups, other structural features such as the 2,3 double bond in the C‐ring and a glycoside moiety in the molecule had an effect on the antioxidant activity. Myricetin and rutin, especially had a synergistic effect with α‐tocopherol. Myricetin, quercetin and rutin protected α‐tocopherol from decomposition, myricetin being the most protective. The relative hydrogen‐donating activity measured by the ratio of cis,trans‐ to trans,transhydroperoxide isomers formed during oxidation decreased in the order: α‐tocopherol >myricetin>quercetin. Hydroperoxide isomeric distribution of the samples containing kaemferol or rutin did not differ from the control. Thus, although α‐tocopherol was the most effective hydrogendonor, myricetin and quercetin were more effective antioxidants in inhibiting the hydroperoxide formation in methyl linoleate. © 1999 Society of Chemical Industry     

A new electrochemical technique to study tribocorrosion at the micrometric scale

A new method to investigate the tribocorrosion properties of metals and alloys has been developed with which the current density of a metal probe in an electrolyte under rubbing conditions can be measured. The electrochemical microcell consists of a microcapillary (inner diameter 0.84 mm); the rubbing partner is an Al₂O₃ tube which rotates inside the microcapillary. Rotational speed, load and applied electrical potential can be varied, so that it is possible to analyse the corrosion rate during rubbing under various controlled conditions. With conventional tribocorrosion machines (e.g., pin-on-disc, ball-on-plate rig) and also with single-scratch test machines, the current measured also derives from surface areas which are not undergoing mechanical wear. In the present method, the activation of specific surface areas under rubbing conditions, and subsequent repassivation, can be studied separately.     

The solvent extraction of nickel from acidic solutions using synergistic mixtures containing pyridinecarboxylate esters. Part 2: Systems based on alkylsalicylic acids

The synergistic solvent extraction of nickel and cobalt by pyridinecarboxylate esters (2-, 3- or 4-C₅H₄N.CO.OR) in admixture with 3-bromo- or 3-nitro-derivatives of 5-alkylsalicylic acids was studied. Nickel is extracted more strongly than cobalt in all cases and, for systems containing a given pyridinecarboxylate, the pH₅₀ values (pH values for 50% extraction) of both metals decrease in the order: alkylsalicylic acid > bromo-derivative > nitro-derivative. For systems containing a given salicylic acid, the separation between the pH₅₀ values for nickel and cobalt was found to increase in the order: pyridine 2-ester < 4-ester ≈ 3-ester. The extractability of divalent base metals from sulphate solutions by mixtures of isodecyl 3- or 4-pyridinecarboxylate and 3-bromo- or 3-nitro-5-nonylsalicylic acid in Shellsol K decreases through the series: Cu > Ni > Co ≈ Zn > Ca > Mg. In single-stage batch extraction experiments with a simulated leach liquor containing Ni 2·2, Cu 0·5, Ca 0·4 and Mg 5·0 g dm⁻³ (and smaller amounts of other base metals), adjustment of the equilibrium pH value to between 3·3 and 4·0 with magnesium oxide gave extractions of nickel and copper of 97–100%, with co-extractions of calcium and magnesium of <0·5 and <0·1%, respectively. Amongst the metals present in lower concentrations, manganese (2–5%) and lead (5–10%) were extracted only slightly whereas cobalt (40–80%), zinc (15–65%) and iron (100%) were more strongly extracted.     

迷迭香在油香椿制品储藏过程中的抗氧化效果研究

选用TBHQ、迷迭香和茶多酚等作为抗氧化材料,研究几种抗氧化剂对油香椿制品储藏过程中油脂氧化效果的影响.采用烘箱加热进行加速试验,定期测定油脂过氧化值(POV)的变化情况来研究不同浓度天然抗氧化剂迷迭香和添加维生素C、植酸或柠檬酸等增效剂的迷迭香抗氧化效果.实验结果显示:天然抗氧化剂迷迭香的抗氧化效果优于茶多酚,比TBHQ的抗氧化效果稍差,0.02%迷迭香能有效阻遏油脂中POV值的升高,它与维生素C、植酸或柠檬酸混合使用,能显著增强抗氧化作用.     

Evaluation of Combined Antibacterial Effects of Eugenol, Cinnamaldehyde, Thymol, and Carvacrol against E. coli with an Improved Method

ABSTRACT:  In this study, the antibacterial activities of eugenol, cinnamaldehyde, thymol, carvacrol, and their combinations against  E. coli  were investigated separately. First, broth macro-dilution assay was adopted to determine the minimal inhibitory concentration (MIC) of the 4 components. Second, the combination testing was performed using chequerboard method. Finally, the combined effects were evaluated with an improved method, which was based on the indices of fractional inhibitory concentration (FIC) and Effect of the Combination (EC) jointly. The results indicated that MICs of the 4 components were 1600, 400, 400, and 400 mg/L, respectively; treatments with cinnamaldehyde/eugenol, thymol/eugenol, carvacrol/eugenol, and thymol/carvacrol revealed synergistic effects according to the 2 indices. By means of combination, MICs of eugenol, cinnamaldehyde, thymol, and carvacrol decreased to 400, 100, 100, and 100 mg/L, respectively. Consequently, the negative impacts of unpleasant smell of these 4 components could be minimized, making it possible to add them to foods as preservatives. In addition, this improved evaluation method provided a more accurate and comprehensive way to evaluate combined effects.     

界面相容剂对PE-HD/木粉复合材料力学性能的影响

用不同的界面相容剂对高密度聚乙烯(PE-HD)/木粉复合材料进行界面处理,研究了界面相容剂的含量、种类对复合体系力学性能的影响.结果表明,界面相容剂的加入使复合体系的力学性能有不同程度的改善,其中MAPE的加入,对体系的拉伸、弯曲强度提高最大,在MAPE含量为10%时,复合体系的力学性能达到最大值;经EPDM-MA处理的复合材料,其冲击韧性有明显提高;EVA-MA的加入,使复合材料的性能有所提高;SBS对体系界面粘接力的影响不明显;但MAPE和弹性体SBS复配处理的复合体系,其冲击强度的提高尤为显著,这可能是由于MAPE和SBS在复合体系中发生了协效作用,形成具有柔韧性的中间相所致.     

磺酸盐与磺酸盐表面活性剂协同作用研究

为获得具有性能优良的表面活性剂,研究了磺酸盐与磺酸盐表面活性剂在降低油水界面张力方面的协同作用。选取了十二烷基苯磺酸钠(C12ΦS)与4-(7'-十四烷基)苯磺酸钠(7C14ΦS)、4-(8'-十八烷基)苯磺酸钠(8C18ΦS),绘制了磺酸盐及复配体系的烷烃扫描曲线,考察了表面活性剂的亲水亲油性能、复配比例对协同作用的影响及磺酸盐及复配体系降低原油界面张力的能力。证实了磺酸盐与磺酸盐复配协同作用源自亲水亲油性能的改善,亲油性磺酸盐8C18ΦS与亲水性磺酸盐C12ΦS、7C14ΦS复配,可以获得具有适中亲水亲油性能的复配体系,实现协同降低界面张力作用,通过适当的磺酸盐表面活性剂复配可使长庆油田原油与1%Na Cl水溶液的界面张力降低至超低值。