凝固条件对纤维素/丝素蛋白纤维相形态及性能的影响

蛋白质纤维具有光滑柔顺、透气吸湿等优点,然而天然蛋白纤维产量有限。再生蛋白纤维的制备通常采用与其它成纤高分子接枝或共混的方法,有利于提高再生蛋白纤维的断裂强度。选用同为天然高分子的纤维素为基体,以共溶剂溶解纤维素与蛋白质,进而纺丝成形制得力学性能满足要求的纤维素/丝素蛋白共混纤维。为了探究凝固剂组成对纤维素/丝素蛋白共混纤维相形态及性能的影响,选用水、乙醇、乙醇/1-丁基-3-甲基咪唑氯盐([BMIM]Cl)等作为凝固剂。研究发现:乙醇作为凝固剂时,纤维素与丝素蛋白能很好地同时凝固;而当在乙醇凝固浴中加入适量的[BMIM]Cl径向均匀分散。通过对凝固剂组成的调控能有效提升纤维的力学强度。     

Production of antimicrobially active silk proteins by use of metal‐containing dyestuffs

The work presented here discusses a new technique for preparing silk fibers and films with persistent antimicrobial activity through use of metallic dyestuffs during the fiber dyeing process. The length of the silk fibers investigated contracted when the fibers were immersed in concentrated neutral salt solutions, such as calcium or potassium nitrate, at elevated temperature levels. The birefringence and molecular orientation of the silk fibroin molecules became less ordered by the action of the neutral salt solutions, resulting in increased dyestuff absorption. Subsequently, contracted silk fibers were dyed with metallic dyestuffs containing Cr or Cu for the purpose of obtaining silk fibers with antimicrobial activity. Silk fibers dyed with metallic dyestuffs showed significant antimicrobial activity against the plant pathogen Cornebacterium and the human pathogen Coli bacillus. Tensile strength of the silk fibers after the salt shrinking and dyeing processes did not show a significant change, whereas the elongation at break was increased slightly. The techniques described here for preparing significantly active antimicrobial silk fibers are effective and economic ways of providing new materials for industrial and biomedical applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1181–1188, 2002     

Polymorphic stability of some shortenings as influenced by the fatty acid and glyceride composition of the solid phase

A number of North American vegetable and animal fat shortenings, which had been analyzed previously for their physical and textural characteristics, were analyzed also for their chemical composition. The fatty acid and triglyceride composition of the solids were calculated by analyzing the composition of the original product and the liquid phase, and by determination of the solid fat content (SFC) of the fat. The solids were also isolated by isopropanol (IP) separation, and the high melting glycerides (HMG) by acetone crystallization at 15°C. There was not much difference in total saturates andtrans content between vegetable and animal fat shortenings. Changing formulations from soy-palm to soy-cottonseed does not change the total saturates plustrans content. The solids of the vegetable shortenings in the β form contained about 20% of 16:0, those in the β′ form 30% or more. The animal fat shortenings were mainly in the β form, their solids contained 30% or more of 16:0. C54 triglyceride content of the solids of β vegetable shortenings (calculated and IP-separated) was >45%, that of all animal fats was <25%. Solids of animal fat shortenings contain high levels of C52. The C54 triglycerides are β-tending and should be kept low in vegetable shortening. In the HMG the C54 should not exceed 30%. This can only be achieved by incorporation of a β′ hard fat, preferably palm hard fat. Animal fat, especially lard, crystallizes in the β form because the palmitic acid in the glyceride molecule is located in the 2-position, whereas those of vegetable fats are in the 1- and 3-position.     

A rapid test to measure performance,emission and wear of a diesel engine fueled with palm oil diesel

Results of performance, emission and tribological evaluations of palm oil methyl ester and its blends with conventional diesel in an automobile diesel engine test bed are presented. Polymerization and carbon deposits on the fuel injector were monitored. CO, CO₂, O₂, combustion efficiency and temperature of exhaust gases were also measured. Palm oil methyl ester and its blends have great potential as alternative diesel fuel. Performance and exhaust gas emission for palm oil methyl ester and its blends with conventional diesel are comparable with those of conventional diesel fuel. Palm oil methyl ester does not pose a severe environmental problem and will not deteriorate engine and bearing components.     

Properties of palm-oil-in-water emulsions: Effect of mixed emulsifiers

Palm-oil-in-water emulsions were prepared with mixtures of Tween 40 and Span 40 in various proportions. Stability and droplet-size distribution of the emulsions were monitored. Interfacial tensions of the palm oil/water interface were also determined in the presence of these emulsifier mixtures. Emulsifying efficiency of the emulsifier mixtures was assessed. No synergistic effect of Tween 40 (sorbitan monopalmitate with 18–22 moles of ethylene oxide) and Span 40 (sorbitan monopalmitate) was found on interfacial tension. Tween 40 alone (hydrophilic-lipophilic balance value 15.6) at 1.0% w/w gave palm oil emulsions that were stable for more than 30 d at 60°C. Emulsifier mixtures of Tween 40 and Span 40 with hydrophilic-lipophilic balance values in the range of 8.0–8.6 produced stable emulsions only at much higher emulsifier-mixture concentrations. The inherent nature of the oil and the accompanying natural surface-active materials present in the oil can influence the prevailing conditions at the oil/water interface and alter composition of the interfacial film and hence its stability.     

利用腈纶废丝合成絮凝剂PAN—DCD

本文以腈纶废丝为原料与双氰双胺在碱性溶液中反应，成功地制得含有多种活性基因的聚合物ＰＡＮ－ＤＣＤ，并用于染料废水脱色及炼油厂废水除油，除酚的处理研究，与常规使用的几种絮凝剂进行处理结果对照，实验结果表明：该产品单独使用处理效果明显优于其他絮凝剂，与聚铝复合使用处理效果更为理想。     

Synthesis of 2‐monoglycerides by alcoholysis of palm oil and tuna oil using immobilized lipases

Commercial immobilized lipases were used for the synthesis of 2‐monoglycerides (2‐MG) by alcoholysis of palm and tuna oils with ethanol in organic solvents. Several parameters were studied, i.e., the type of immobilized lipases, water activity, type of solvents and temperatures. The optimum conditions for alcoholysis of tuna oil were at a water activity of 0.43 and a temperature of 60 °C in methyl‐tert‐butyl ether for ～12 h. Although immobilized lipase preparations from Pseudomonas sp. and Candida antarctica fraction B are not 1, 3‐regiospecific enzymes, they were considered to be more suitable for the production of 2‐MG by the alcoholysis of tuna oil than the 1, 3‐regiospecific lipases (Lipozyme RM IM from Rhizomucor miehei and lipase D from Rhizopus delemar). With Pseudomonas sp. lipase a yield of up to 81% 2‐MG containing 80% PUFA (poly‐unsaturated fatty acids) from tuna oil was achieved. The optimum conditions for alcoholysis of palm oil were similar as these of tuna oil alcoholysis. However, lipase D immobilized on Accurel EP100 was used as catalyst at 40 °C with shorter reaction times (<12 h). This lead to a yield of ～60% 2‐MG containing 55.0‐55.7% oleic acid and 18.7‐21.0% linoleic acid.     

Preparation of silk fibroin and polyallylamine composites

Composite films made of silk fibroin (SF) and polyallylamine (PAA) are prepared that contain various compositional ratios. These materials are analyzed to elucidate the resulting physical properties and to assess their potential toward advanced applications as industrial materials. The composite films are obtained from a SF and PAA binary system by dry casting from aqueous solution. These composite films exhibit excellent processability such as film forming capabilities, and the elongation at break is increased in the wet state. The differential scanning calorimetry (DSC) curves of the composites suggest that a mutual interaction takes place between the SF and PAA. This interaction is believed to occur because the endothermic peak, corresponding to the individual polymer, shifts with increasing SF content. The random coil conformation of the SF is present, regardless of the PAA blending, as confirmed by FTIR and DSC measurements. Additionally, living cells from Antheraea pernyi and Bombyx mori insect tissues are shown to grow effectively on the composite films. Maximum growth levels occur when the cultivation flask is coated with the material in SF/PAA ratios of 75:25 to 25:75. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1963–1970, 2002; DOI 10.1002/app.10491     

Supercritical CO2‐assisted synthesis of poly(acrylic acid)/Antheraea pernyi SF blend

Monomer acrylic acid (AA) and initiator azo‐bis(isobutyronitrile)were carried into Antheraea pernyi silk fibroin (SF) fibers using supercritical CO₂ as a solvent and carrier, followed by free radical polymerization at a suitable temperature, resulting in PAA/SF blends. The binary system of CO₂/AA and the ternary system of CO₂/AA/AIBN systems were studied. Different impregnation conditions, such as time, pressure, and concentration of AA in the fluid phase on mass uptake, were studied. Fourier transform infrared spectroscopy and X‐ray diffraction results confirmed that PAA was indeed present in the silk and that there were intermolecular hydrogen bonds between PAA and SF. According to thermogravimetry and DTG, blending with PAA could enhance the thermal stability of SF slightly. The water retention values indicated that the hydrophilic nature of the fibers was improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 864–868, 2005     

双活性基活性染料真丝绸染色工艺研究

双活性基活性染料用于真丝绸染色有诸多影响因素：缚酸剂用碳酸氢钠比碳酸钠的固色率高用量在2％～4％，pH为8～9时最为合适：染色温度从60℃升到85℃时固色率提高3％～8％，超过85℃时易造成“灰伤”．当元明粉的用量从30g／l升到60g／l时上染率和固色率提高10％。随着浴比的增加，其固色率会有不同程度的降低，在实验条件下，浴比为1：40最好。通过上染曲线，讨论了染色过程的控制。