正交试验优选木薯淀粉接枝醋酸乙烯酯的工艺条件

以过硫酸铵引发木薯淀粉与醋酸乙烯酯接枝共聚反应,对影响淀粉与醋酸乙烯酯接枝反应的4个因素:原料配比、引发剂浓度、反应温度及反应时间进行了研究.以转化率、接枝率及接枝效率为考查对象,利用SAS软件统计分析得到适宜的工艺条件:引发剂浓度18.0 mmol/L,反应温度60℃,反应时间3 h,原料配比为2.0.并用Srectrum One红外光谱对接枝物的化学结构进行分析,证实了木薯淀粉-醋酸乙烯酯接枝共聚物的存在.     

丙稀酸甲酯在天然胶乳硫化胶膜表面的接枝共聚

采用氩等离子体激发及紫外辐射引发技术可以使丙稀酸甲酯接枝共聚到天然橡胶硫化胶膜表面。接枝处理硫化胶膜表面接触角测定结果表明,随着接枝反应的进行,较多的聚丙烯酸甲酯接枝到硫化胶膜表面,使硫化胶膜表面接触角显著下降。采用等离子体激发 2 min,紫外光照射 16 min 的处理条件,可使硫化胶膜表面与水的接触角由 105°下降至约 60°。接枝处理硫化胶膜表面形态分析结果表明,接枝后的聚丙烯酸甲酯分子链在硫化胶膜表面互相叠加,使胶膜表面变得粗糙,从而使天然橡胶硫化胶膜表面亲水性能得到改善。     

Graft copolymerization of granular allyl starch with carboxyl-containing vinyl monomers for enhancing grafting efficiency

Graft copolymerization of granular allyl starch with carboxyl-containing vinyl monomers using H₂O₂/Fe²⁺ initiator in aqueous dispersion was investigated for enhancing grafting efficiency of the copolymerization. The graft copolymerization was evaluated in terms of grafting efficiency, grafting ratio, and conversion of monomer to polymer. Influences of both allyl etherification of starch and structures of vinyl monomers used on the copolymerization were revealed. Variables such as molar ratio of Fe²⁺ to H₂O₂, initiator concentration, monomer concentration, polymerization temperature, and time of the graft copolymerization were also studied. It was found that allyl etherification of starch enhanced the grafting efficiency and grafting ratio evidently. Acrylic acid exhibited the greatest grafting efficiency and ratio for the copolymerization after starch was allyl-etherified. The copolymerization should be carried out under the protection of nitrogen gas at 30–35 °C for 3 h by using H₂O₂/Fe(NH₄)₂(SO₄)₂ as initiator. Preferred molar ratio of H₂O₂/Fe(NH₄)₂(SO₄)₂/anhydroglucose was in a range of 20/1/1000 to 60/3/2000.     

Studies on electro-conductive fabrics prepared by in situ chemical polymerization of mixtures of pyrrole and thiophene onto polyester

This article reports on development, characterization, and performance of electro-conductive textiles prepared by in-situ chemical polymerization of mixtures of pyrrole and thiophene onto a polyester fabric. It was observed that a mixture of pyrrole and thiophene at 4:1 molar ratio resulted in the lowest surface resistivity among all the mixtures and the individual monomers studied. This electro-conductive fabric exhibited exponential voltage-current relationship. Further, it showed substantial fall in surface resistivity under the exposure of ultra-violet radiation. Under the application of DC voltage across it, an exponential rise in surface temperature was observed and the coefficient of rise in temperature was found to be directly related to the duration of voltage applied. Further, when subjected to mechanical straining, it displayed a decrease in resistivity followed by an increase of resistivity.     

A comparative study of wool fibre surface modified by physical and chemical methods

The wool scale present on the fibre surface gives rise to certain unwanted effects such as felting and poor wettability in textile wet processing. In general practice, the removal of scale was done either by surface modification through physical/chemical degradation of scale or by deposition of a polymer on the scale. In modern treatment, combination of both methods is usually carried out. Since the deposition of a polymer on the fibre surface depends much on the surface characteristic of the fibre, therefore, the surface property of modified fibre is an important factor for polymer application. On the other hand, the surface modification methods may also result in improved hydrophilicity of fibre. The present paper investigated the surface physico-chemical properties of wool fibre under the influence of different surface modification treatments: (i) low temperature plasma (LTP) treatment with nitrogen gas and (ii) chlorination. The surface physico-chemical properties of the LTP-treated and chlorinated wool fibres were studied which included contact angle measurement with different solvents, determination of critical surface tension and surface free energy. Experimental results showed that these selected properties were altered after the surface modification treatments. In addition, a polymer was deposited in the treated wool fabrics and scanning electron microscope was used for assessing the surface morphology.     

Protein content and protein quality of tuberous roots of some legumes determined by chemical methods

Chemical data regarding the protein content and quality of the tuberous roots of four grain legumes suited to cultivation in the humid tropical lowlands are presentend. Crude protein was estimated as a product of % nitrogen in the meals extracted with 70% (v/v) ethanol x 6.25 and the amino acid composition of the proteins was estimated by analysis of meals after extraction with ethanol. The crude protein value for the meals ranged between 3.9% and 14.1% on a dry weight basis and the amino acid profiles were nutritionally acceptable in comparison with that of the FAO reference protein, except for the sulpho-amino acids. Nodulating and mineral nitrogen regimes during plant growth did not change the nutritional value of the tubers.     

Forage yield and chemical composition of canola (Brassica napus L.) as affected by sowing methods

The sowing method of spring‐type canola (Brassica napus L. var. oleifera) for forage has a major influence on its productivity and agronomic management. A field experiment was conducted in Matamoros, Coahuila, Mexico, during two growing seasons (2008–2009 and 2009–2010) to determine dry matter (DM), crude protein (CP) and net energy for lactation (NE_L) yields, as well as canola forage chemical composition as a function of six sowing methods. The treatments assessed were broadcast sowing and five different row spacings: 0·19, 0·38, 0·57, 0·76 and 0·95 m (double row, 0·20 m apart). In the first year, with a mean growing season temperature of 17·2°C, sowing methods did not affect DM yield, but CP and NE_L content and yield were higher in 0·19‐m row spacing. The mean temperature in the second year (13·5°C) was slightly lower than the long‐term mean (14·8°C) in the region, resulting in the highest DM (8840 kg ha^?1), CP (2486 kg ha^?1) and NE_L yields (51 103 MJ ha^?1) with 0·19‐m row spacing. In row‐sowing methods with over 0·19‐m row spacing, DM, CP and NE_L yields decreased by 19·3–39·7, 20·4–42·1 and 21·2–42·7% respectively. Results indicate that sowing methods significantly affected canola forage productivity.     

自由基聚合法合成天然橡胶接枝共聚物的研究综述

通过聚合物接枝改性天然橡胶(NR)是改善NR性能和扩展其应用范围的重要方法之一。目前,人们主要通过自由基聚合(freeradical polymerization,FRP)法合成NR接枝共聚物,本文就其反应机理和反应工艺进行了综述,并从接枝共聚物的结构可控性和可控/“活性”自由基聚合的角度对NR接枝共聚物的合成方法进行了展望。     

UV-induced coloration of cotton fabrics by photografting of acrylamido dyes using acrylamide as a comonomer

Formulations of acrylamido dyes containing comonomers can be photografted onto cotton fabric upon UV irradiation at room temperature without neutral salts, which makes it a novel coloration process of excellent environmental friendliness. The photografting of the dyes can be assisted by the copolymerization of the acrylamide comonomer which may reduce the steric hindrance of the bulky dyes. About 90 % of the dyes and 94 % of the acrylamide are photopolymerized in the solution and the degree of polymerization is estimated to be 13.2 according to ¹H-NMR and MALDI-TOF mass analyses. The optimal K/S values of the grafted cotton fabrics showed 13.3 and 12.3 for red and yellow dyes, respectively. The optimal UV-grafting coloration can be achieved when a UV energy of 25 J/cm² was irradiated on the padded fabrics with a formulation of 0.65 mole ratio of acrylamide to the dyes, 7 wt% acetophenone photoinitiator (Irgacure 2959) based on the dye weight under pH 6. Furthermore, the color fastness properties of the grafted fabric were superior to those of conventional reactive dyeing of the dyes due to higher molecular weight of the polymerized dyes.     

Relative efficiency of three methods for chemical control of Pacific coast wireworms in potatoes

Data from six experiments with registered, nonpersistent chemical compounds for control of Pacific coast wireworm (Limonius canus Le-Conte) were combined to elucidate the relative efficiency of three types of treatments. The treatments were soil fumigation and band or broadcast applications of granular organophosphorus insecticides. Band treatments gave less effective and more variable control than broadcast treatments. Fumigation treatments were more effective than, and about equally as variable as, broadcast treatments. All treatments became progressively less effective and less dependable as the population of wireworms increased. It was not economical to treat infestations of less than 0.12 wireworms/ft². Band treatments were usually adequate for populations up to 0.4/ft² and broadcast treatments for populations up to 1.6/ft². However, it was considered most economical to broadcast for infestations between 0.15 and 0.7/ft². For heavier infestations, either fumigation or a combination of treatments appeared prudent. Because all treatments performed rather inconsistently, precautions to avoid underestimating an infestation are justified.     

不同耕作方式麦子病虫发生规律及其药剂防治技术探讨

近年来,稻套麦是阜宁县三麦播种的主要方式,而耕翻麦面积大大减少,这种耕作制度的实施不失为农业生产的重大技术变革,不仅节约了耕作开支,缩短了农忙时间,而且提高了耕作效率,解放了大批劳动力。然而,这种耕作方式的改变也带来了一些新的问题,因为农田免耕保护了某些病菌和害虫     

A comparison of chemical and physical methods for treating French fries to produce an acceptable microwaved product

Frozen par-fries were processed in January and February using BelRus and Russet Burbank potatoes which were obtained from the same source and held under the same storage conditions. Prior to par-frying the raw potato slices were treated chemically or physically in order to increase the amount of bound water, or to remove water. At each processing date total solids of the raw and treated tissue were determined. Par-fries were analyzed for fat content. Treated samples were microwave heated and evaluated for sensory qualities as compared to frozen par-fries heated in a conventional oven. In no cases were the microwaved fries superior to the oven-heated fries in color, flavor, or texture. Drying the blanched fries in an oven for 10 min. prior to par-frying produced a microwaved product that was quite similar to the oven-heated fries, particularly in the case of the BelRus potatoes. In all cases BelRus potatoes absorbed less fat on par-frying than did Russet Burbank potatoes.     

中国甘蔗辐射诱变育种研究概述

本文对中国近50多年来在甘蔗辐射诱变方面所作的研究及取得的成果进行了概述,并对甘蔗辐射诱变育种提出了展望。     

Polyol production by chemical modification of date seeds

Polyol production from chemical modification of date seeds has been investigated through oxypropylation and liquefaction techniques (using organic solvents in the presence of a catalyst). The obtained products were characterized using infrared spectroscopy analysis, ¹H NMR, thermogravimetric analysis and other parameters such as hydroxyl number (I_OH) and viscosity. Results showed that 93% of the solid substance was converted into polyol in the oxypropylation reaction at the date seeds/propylene oxide ratio of 0.25 and 10% potassium hydroxide at 160 °C. The oxypropylated product has I_OH of 779 mg KOH/g and viscosity of 6.9 Pa s. Regarding the liquefaction technique, results show that a yield of 95% was obtained at the date seeds/liquefying solvent ratio of 0.25 in 60 min of reaction at 160 °C. The liquefied product shows I_OH of 336 mg KOH/g and viscosity of 0.9 Pa s.     

Quality of stored potatoes improved by chemical treatment

A combination spray of CIPC, thiabendazole, and chlorine applied to potatoes at time of storage negated the detrimental effect of CIPC when applied to freshly harvested tubers. It also prevented sprouting and reduced the incidence of pressure bruise. The application of thiabendazole and chlorine reduced Fusarium tuber rot and the degree of tissue degradation around wounds, thereby increasing tuber quality.     

Synergistic UV-curable flame-retardant finish of cotton using comonomers of vinylphosphonic acid and acrylamide

While ‘Pyrovatex’ and’ Proban’ processes have been widely used for durable flame-retardant finishing of cotton, the flame retardants could release formaldehyde inevitably during or even after the finishing process, which is not environmentally compatible. As a new formaldehyde-free flame retardant and finishing process, the comonomers of vinylphosphonic acid (VPA) and acrylamide (AAm) can be in situ copolymerized upon LED-UV irradiation and impart excellent flame retardancy to the cotton. The increasing AAm addition enhanced fixation, flame retardancy effectivity and synergistic effectiveness by reducing the steric hindrance between the VPA monomers during the copolymerization. Also the multifunctional crosslinkers of either methylene bisacrylamide or triacryloylhexahydro triazine significantly improved the laundering durability of the finished fabrics. The increased char formation and residue number after pyrolysis indicated the solid-phase retarding mechanism of the synergistic VPA and AAm combination.     

Kinetics on the copolymerization of acrylonitrile with itaconic acid or methyl acrylate in dimethylsulfoxide by NMR spectroscopy

The free radical solution polymerization of acrylonitrile (AN) with itaconic acid (IA) or methyl acrylate (MA) was carried out in dimethylsulfoxide (DMSO) using 2 2'-azobisisobutyronitrile (AIBN) as the initiator. Based on the monomer conversion versus time data, the copolymerization rate was retarded by IA but promoted by MA. The monomer sequence distribution was characterized by ¹³C NMR to explain the significant difference in the copolymerization kinetics of the ANIA and AN-MA copolymers. The results of the copolymer composition curves and ¹³C NMR spectral analysis illustrated that the penultimate model was suitable for describing the copolymerization behavior of AN-IA, and the terminal and penultimate models were adequate for AN-MA. The penultimate reactivity ratios, r _MA , were ~2 times higher than r _IA , indicating that the reactivity of AN-terminated radical having MA as the preceding group was higher than that with IA. Then, the corresponding content of triads sequence AN-AN-AN (AAA) in the AN-MA copolymers was higher than those in the AN-IA copolymers. The appearance of new resonance signals of the quaternary and methyl carbon indicated a higher content of IA in copolymers. The higher IA concentrations the lower viscosity-average molecular weight of the polymers. The decrease in the molecular weight was correlated to the formation of the oligomers.     

Comparison of different rice flour- and wheat flour-based butter cookies for acrylamide formation

Acrylamide (AcA) contents of different rice flour- and wheat flour-based butter cookies baked at 130 °C for 20, 55, or 90 min were investigated. AcA contents of different flour-based cookies increased with baking time. Color parameters in terms of CIE L*, b*, C*, and ΔE values showed significant opposite correlation to the AcA formation in each of the raw flour cookie. The cookies based on white rice flour had the lowest AcA contents ranging from not detectable (ND) to 204 μg/kg, followed by cookies based on brown rice flour (ND to 450 μg/kg), white wheat flour (155 μg/kg to 661 μg/kg), and whole wheat flour (306 μg/kg to 982 μg/kg). Considerably lower AcA levels were found in the rice flour-based cookies than in the wheat flour-based cookies, as well as in the milled flour-based cookies than in the whole-grain cookies. Although the flour source was considered to play a primary role in determining the AcA content, AcA content was apparently not dependent on the quantities of reducing sugars and free asparagine in the starting raw flour and cookies during baking. In summary, given its reducing potential for AcA formation, rice flour could be used in the production of cookies safe from heat-induced contaminants.     

Fabrication and characterization of oat flour processed by different methods

The properties of oat flour can be manipulated by processing to suit various consumption and product development needs. In this work, three different processes typically used on oat flour, namely the extrusion, drum drying and enzyme-treatment spray drying process were evaluated with respect to how each process changes the quality of the oat flour. Results showed that the extrusion process produced oat flour with the best flow ability while the enzyme-treated spray drying process led to the lowest flowability. The color of enzyme-treated spray-drying oat flour was the brightest while the oat flours turned darker after extrusion and drum drying. In addition, drum dried oat flour had the highest capability to hold water. In terms of particle size distribution, the extruded and drum dried oat flour showed smaller particle size and the particle had less complete and irregular surfaces. On the other hand, the enzyme-treated spray-drying samples showed the best particle uniformity and sphericity. The viscosity of all the treated oat flour decreased with increasing shear rate, indicating the shear thinning behavior, and a weak gel-like behavior with very high viscosity was obtained via drum drying. The results reported here can be useful and provide a baseline to fully understand how the oat flour properties changes with different processing methods to offer a wider opportunity in using oat flour for food product fortification and design.