Edible hydrogel from gelatin and alginate as functional low-calorie noodle

There is an urgent need to develop edible hydrogels that can be served as a main dish with low-calorie content and high satiety value, yet are easy to digest. However, the development of such hydrogels remains challenging. In this study, low-calorie edible hydrogels were prepared from gelatin and sodium alginate (gel/SA hydrogels) through a facile acid soaking-drying method. These gel/SA hydrogels exhibited excellent mechanical properties with texture characteristics similar to that of Liangpi. The sensitivity of gelatin and acidified sodium alginate to pH resulted in a high swelling ratio of the hydrogels, contributing to weight retention in a simulated stomach environment and rapid degradation in a simulated intestinal environment. These properties indicate that these gel/SA hydrogels have a good prospect of being used as low-calorie food with high satiety value and are easy to digest. Konjac glucomannan can also be incorporated into the gel/SA hydrogels to further improve their biological functionality.     

硫氰酸钠法明胶改性腈纶的研究

采用丙烯腈对明胶接枝改性 ,然后与聚丙烯腈共混纺丝的方法 ,制备了明胶改性腈纶 ,研究了改性比 (明胶 /丙烯腈 ,质量比 )和明胶含量对明胶改性腈纶机械性能、吸湿保水性能的影响。研究结果表明 ,当改性比为 0 .7～ 2 .0 ,明胶含量不超过 5 .0 %时 ,改性腈纶具有良好的机械性能 (断裂强度大于 3 .1c N/dtex) ,可以满足后纺加工的需要 ;改性腈纶纤维亲水性能良好 ,随着改性比的减小、明胶含量的增加 ,其回潮率和保水率都逐渐增大。     

Effect of Curing Agent on Sodium Alginate Blends Using Barium Chloride as Crosslinking Agent and Study of Swelling,Thermal, and Morphological Properties

Sodium alginate and lignosulfonic acid blends were prepared in various ratios (100/0, 80/20, and 60/40), in order to test the suitability of these blends for controlled drug delivery in variable pH medium using barium chloride as crosslinking agent. The blends were characterized by TGA and DSC, in order to study thermal degradation properties and glass transition temperature. Thermal analyses of blends were found to be degrading in multiple steps compared to their pure polymers. Crystallization characteristics are investigated using the DSC curves. Further, miscibility of blends was investigated for morphological studies by SEM.     

海藻酸钠明胶协同固定化黑曲霉脂肪酶

以海藻酸钠明胶为复合载体,采用包埋法制备固定化黑曲霉脂肪酶,考察了海藻酸钠、明胶浓度等因子对固定化效果的影响,比较固定化酶和游离酶对温度、pH等条件的稳定性。结果表明,制备固定化黑曲霉脂肪酶的最优条件为:海藻酸钠、明胶浓度分别为1.25%和0.5%,CaC l2浓度为10%,给酶量为450 IU/g;固定化酶最适温度为35℃,最适pH为9.0,常见有机溶剂和金属离子对固定化酶的活力影响较小。     

明胶一海藻酸钠复合纤维的研制及性能表征

明胶（Gel）与海藻酸钠（sA）溶液共混得到不同配比的纺丝原液,通过黏度法,从热动力学角度对两种高分子材料的相容性及分子间作用力进行表征,结果表明,当SA：Gel比例为3：1时最优,此时共混液中两种高分子间存在较为强烈的分子间作用力,并辅以红外光谱分析,再对各种比例条件下共混液的膜材料进行了力学性能的检测,结果显示在该比例时膜材料具有最强的抗张强度。采用正交试验方法对SA—Gel共混纤维的后处理条件进行优化,结果表明,对共混纤维的断裂强度和断裂伸长率影响最大的因素,分别是热处理温度和拉伸率,而共混纤维的线密度和吸湿性均受拉伸率的影响最大。     

海藻酸钠-明胶协同固定化S-腺苷甲硫氨酸合成酶的研究

以海藻酸钠和明胶为载体,对S-腺苷甲硫氨酸合成酶进行固定化。再用戊二醛对其进一步交联,增强固定化酶的稳定性。考察了海藻酸钠和明胶质量分数、CaCl2质量分数、酶和载体比例以及交联剂戊二醛体积分数等因素对固定化酶的影响。结果表明,最佳固定化条件为:海藻酸钠质量分数2.0%、明胶质量分数1.0%、CaCl2质量分数4.0%、固定化酶量为2.5 g/L凝胶、戊二醛体积分数0.6%。交联固定化酶热稳定性得到大幅度提高,在50℃下保温5 h仍保留72%的活力,而游离酶则完全失活。交联固定化酶在碱性溶液中的稳定性较高,在pH=8.0～9.0的缓冲液中4℃保温10 h酶活性仍保留87%以上。将交联固定化酶用于S-腺苷甲硫氨酸的合成,连续反应8批次后酶活性仍保留65%。     

明胶-海藻酸钠复合纤维的研制及性能表征

明胶(Gel)与海藻酸钠(SA)溶液共混得到不同配比的纺丝原液,通过黏度法,从热动力学角度对两种高分子材料的相容性及分子间作用力进行表征,结果表明,当SA∶Gel比例为3∶1时最优,此时共混液中两种高分子间存在较为强烈的分子间作用力,并辅以红外光谱分析,再对各种比例条件下共混液的膜材料进行了力学性能的检测,结果显示在该比例时膜材料具有最强的抗张强度。采用正交试验方法对SA-Gel共混纤维的后处理条件进行优化,结果表明,对共混纤维的断裂强度和断裂伸长率影响最大的因素,分别是热处理温度和拉伸率,而共混纤维的线密度和吸湿性均受拉伸率的影响最大。     

添加海藻酸钠对椰子水体系合成细菌纤维素的影响

以椰子水为培养体系,向培养基中添加海藻酸钠,利用木醋杆菌(Ax.)静态培养合成细菌纤维素(BC)。研究发现,培养体系中添加少量海藻酸钠,能显著提高产物的产量,添加量为4 g/L时,产量最大(8.35 g/L),是其他条件相同情况下不添加海藻酸钠时BC产量(3.47 g/L)的2.4倍。采用FTIR、XRD、TGA、SEM对产物进行了表征;并测试了产物的含水率及力学性能。结果表明,海藻酸钠的添加,对产物化学结构无改变,但一定程度降低了细菌纤维素结晶指数;降低了产物含水率和产物干膜的拉伸强度及断裂伸长率。     

Encapsulation of Plant Biocontrol Bacteria with Alginate as a Main Polymer Material

One of the most favored trends in modern agriculture is biological control. However, many reports show that survival of biocontrol bacteria is poor in host plants. Providing biocontrol agents with protection by encapsulation within external coatings has therefore become a popular idea. Various techniques, including extrusion, spray drying, and emulsion, have been introduced for encapsulation of biocontrol bacteria. One commonly used biopolymer for this type of microencapsulation is alginate, a biopolymer extracted from seaweed. Recent progress has resulted in the production of alginate-based microcapsules that meet key bacterial encapsulation requirements, including biocompatibility, biodegradability, and support of long-term survival and function. However, more studies are needed regarding the effect of encapsulation on protective bacteria and their targeted release in organic crop production systems. Most importantly, the efficacy of alginate use for the encapsulation of biocontrol bacteria in pest and disease management requires further verification. Achieving a new formulation based on biodegradable polymers can have significant effects on increasing the quantity and quality of agricultural products.     

水基液压介质多功能添加剂的研制

水基液压系统不但可以节省大量的石油资源 ,降低运行成本 ,而且有利于环境保护 ,但系统存在腐蚀、结垢、菌藻繁殖、泄漏和摩擦磨损等一系列问题。针对以上问题 ,研制出了一种多功能的水介质液压系统添加剂 ,该药剂具有优良的防锈、润滑性能以及良好的防垢、杀菌性能 ,能有效地解决以水作传动介质的液压系统的腐蚀、摩擦磨损等问题     

煤浆磁化对水煤浆性质影响的研究

研究了磁化对蒸馏水、自来水和工业废水配制的水煤浆性质的影响,磁化对水煤浆添加剂吸附量的影响。结果表明:较强的磁场强度和较短的磁化时间可以显著地降低水煤浆的粘度,磁化会使水煤浆添加剂的吸附量增加,并对水煤浆的磁化机理进行了初步探讨。     

阳离子聚合物固墨剂及其对喷墨记录介质性能的影响

两步法合成了二甲基二烯丙基氯化铵(DMDAAC),并将DMDAAC进行聚合,得到聚二甲基二烯丙基氯化铵(PDMDAAC),以其作为阳离子聚合物固墨剂应用于喷墨记录介质的涂层中,研究了它对几种喷墨记录性能的影响。结果表明:当颜料与亲水性聚合物的比例为90/10,阳离子聚合物固墨剂PDMDAAC的添加量为6%时,喷墨记录介质涂层的记录性能达到最佳,吸墨速度为6.2 s,清晰度为1.0015,耐水性能达到a级。     

The Smectic Rheology of a Polysiloxane Side Chain Liquid Crystalline Polymer

The rheology of a side chain liquid crystalline polymer (SLCP) with a polysiloxane backbone was investigated. The dynamic shear moduli of the SLCP in a smectic phase did not show the normal terminal behavior as the homogenous polymeric melts did, and instead, they tended to level off in the low frequency terminal zone. Time–temperature superposition failed for both dynamic moduli in the low frequency terminal zone and the departure from the superposition became more evident in the vicinity of smectic/isotropic transition. The plateau-like moduli in the terminal zone indicated the layer structure of the smectic phase. The steady shear viscosities of the smectic phase exhibited a shear thinning behavior over the shear rates investigated. The shear thinning was lost at low shear rates when the temperature passed the smectic/biphasic border. The shear viscosity and the dynamic moduli showed a divergence in the neighborhood of the smectic/isotropic temperature. The activation energies of the shear viscosity and the moduli were smaller than that of the SLCP with polymethacrylate backbone. The rheological behavior of the SLCP at low frequencies and low shear rates was dominated by the smectogen.     

海藻酸钠及其共混溶液的流变性研究

研究了海藻酸钠溶液,海藻酸钠与羟甲基纤维素、丙三醇、明胶、粒子填充剂等共混溶液的流变性能。结果表明:海藻酸钠溶液属于切力变稀的非牛顿流体;随溶液浓度的提高,粘流活化能增加;海藻酸钠相对分子质量增大,其溶液的结构粘度指数增大。海藻酸钠共混溶液的表观粘度随羟甲基纤维素的加入而增大;随明胶和丙三醇的加入而减小;随粒子填充剂的加入,先增加后减小。     

聚丙烯纤维及胶粉对聚合物改性砂浆失水率的影响

为了解纤维、胶粉对聚合物改性砂浆塑性收缩开裂的影响机理,本试验采用改进过的滤纸法研究了纤维掺量及长度、胶粉掺量、纤维与胶粉复掺环境下对聚合物改性砂浆失水率的影响.研究结果表明:PP纤维对聚合物改性砂浆有一定的保水性,纤维掺量和长度对聚合物改性砂浆失水率均有不同程度的影响,且两因素之间相互影响;胶粉对聚合物改性砂浆也有一定的保水作用,且随着胶粉掺量的增加(掺量小于3％),砂浆失水率逐渐减小;复掺与单掺规律有所不同,通过调整纤维和胶粉的掺量,得到了较优的复掺组合:0.4％ PP和3％ 328胶粉,这个组合下的失水率最低.     

Development of a robust hydrogel system based on agar and sodium alginate blend

BACKGROUND: As part of an ongoing research and development programme of our laboratory on functional modification of seaweed polysaccharides for preparing hydrogels with improved properties, we report herein the preparation of a robust hydrogel system based on grafting of agar and sodium alginate blend (Agar/Na‐Alg) with acrylamide (AAm) to obtain the copolymer Agar/Na‐Alg‐graft‐PAAm. RESULTS: A robust hydrogel system with superior absorbency and pH resistance has been developed based on a PAAm‐grafted seaweed polysaccharide blend of Agar/Na‐Alg. The blend (Agar/Na‐Alg) and grafted product (Agar/Na‐Alg‐graft‐PAAm) were evaluated using Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, swelling capacity, rheology and scanning electron microscopy. The swelling capacity of the grafted copolymer exhibited an enhancement over that of the blend from 14 to 24 g g^?1 in acidic medium. The blend and grafted copolymer produced hydrogels with lower gelling points of 31 and 29 °C and gel strengths were 170 and 120 g cm^?2, respectively. CONCLUSION: This study constitutes an example of value addition of seaweed polysaccharides targeting new applications. The copolymer hydrogel may be useful in health, personal care and agricultural applications. Copyright © 2007 Society of Chemical Industry     

On Liquid Water Isothermic Segregation in a Medium of Highly Elastic Hydrophobic Polymers Such as Polymethyl Methacrylate

Abstract

Deglassifying the films of plasticized polymethyl methacrylate (PMMA) in heated water causes the spontaneous segregation of water drops of micrometer and larger radius. This process which is accompanied by a change in the film size is impossible in structureless hydrophobia systems. The phenomenon indicates a structural organization of polymer chains, which are responsible for adsorption of a certain amount of molecular water by hydrophobic PMMA. From a thermodynamic standpoint, “structural hydrophily” is of entropic nature and is provided by the micropore generation caused by fluctuations. The micropores are stabilized through the capture of water molecules. When the polymer transforms to the highly elastic state, zones of a dynamically active microporous sponge are formed with the participation of moisture. In these zones, the fluctuation results in the formation and destruction of hydrophobic slits, which ensure the appearance of the water interlayers and drops of critical size that merge into the stable water phase. A thermodynamic model of the process is considered.     

The Effect of Gap Distance between a Pin and Water Surface on the Inactivation of Escherichia coli Using a Pin-to-Water Plasma

Atmospheric plasmas have been applied for the inactivation of microorganisms. Industrials demand to investigate the relation of the key reactive species induced by plasmas and the operating parameters including boundary conditions in order to control plasma treatment processes. In this study, we investigated the effect of gap distance between a pin-electrode and water surface on inactivation efficacy. When the gap distance decreased from 5 mm to 1 mm, the reduction of Escherichia coli (E. coli) was increased to more than 4 log CFU/mL. The reactive oxygen species measured optically and spectrophotometrically were influenced by gap distance. The results from electron spin resonance (ESR) analysis showed that the pin-to-water plasma generated hydroxyl radical (OH•) and singlet oxygen (¹O₂) in the water and superoxide radical (O₂⁻•) served as a precursor of OH•. The inactivation of E. coli was significantly alleviated by sodium azide (¹O₂ scavenger), indicating that ¹O₂ contributes the most to bacterial inactivation. These findings provide a potentially effective strategy for bacterial inactivation using a pin-to-water plasma.     

Ternary Gels of a Polymer Blend and a Recycled Oil: Their Use as Bitumen Modifiers

A blend of random ethylene‐vinyl acetate copolymer (EVA) and triblock styrene‐butadiene‐styrene copolymer (SBS) was dissolved in a recycled engine oil to obtain ternary thermoreversible gels. As the temperature was increased, first a network associated with EVA disappeared, and a second one associated with SBS dominated, maintaining the elastic response of the system. The principal advantage of these ternary systems is that their mechanical properties and thermal stability are better than that of binary gels. These gels, made from waste, can be used as bitumen modifiers to obtain binders of improved properties and good stability, which are useful for road surfacing.

Temperature sweeps of elastic modulus performed at a frequency of 1 Hz.     

超临界水中硫酸钠溶解度研究

研究硫酸钠在超临界水中的溶解度。在实验范围内 (4 0 0 5 0 0℃ ,2 2 .5 30MPa)测得溶解度均小于40× 10 -6g/g。随温度降低和压力升高 ,硫酸钠溶解度增大。关联了溶解度模型 ,表明同一温度下的硫酸钠溶解度对数与水密度对数呈线性关系。