Soy protein biopolymers cross-linked with glutaraldehyde

Biopolymers from soy protein isolate (SPI) crosslinked with glutaraldehyde (GA) were prepared. Surface hydrophobicities of SPI-GA biopolymers and SPI were 4.4 and 11.5, respectively. The solubility profile of SPI was slightly higher than that of SPI-GA biopolymers. Foaming capacities of SPI-GA biopolymers (23 mL) were higher than that of SPI (19 mL), but similar to egg white (22 mL). Foaming stabilities of SPI-GA biopolymers (120 min) were significantly higher than those of SPI (40 min) and egg white (98 min). The emulsifying properties of SPI-GA biopolymers were lower than those of SPI and bovine serum albumin (P>0.05). Tensile strength (TS) and elongation at break (ETB) of SPI-GA biopolymer films were significantly higher than those of glycerol-plasticized soy protein films. TS and ETB of SPI-GA biopolymer films increased with increasing GA concentrations. GA treatment intensified yellowness of SPI-GA biopolymer films. SPI-GA biopolymers may have potential use for biodegradable packaging materials.     

Interaction of soy isolate with polysaccharide and its effect on film properties

When soy isolate was mixed with sodium alginate, the two polymers interacted to form electrostatic complexes. They also formed varying degrees of covalent bonding, depending on reaction time and the presence or absence of the reducing agent sodium cyanoborohydride. On the other hand, soy isolate and propyleneglycol alginate (PGA) formed mostly covalent complexes at alkaline pH. The interaction of soy protein with polysaccharide maintained or improved its solubility and emulsifying activity, particularly when covalent bonds were involved. The alkylated complexes also showed better film-making properties. However, protein-PGA films were more readily formed and had greater stability in water than the protein-alginate films.     

大豆分离蛋白的性质测定与改性研究

采用POCl3对大豆分离蛋白进行改性.通过正交实验,得到影响蛋白质溶解性、乳化性、起泡性等的最佳工艺条件.     

大豆蛋白酶解产物的分子量分布与其发泡性能关系的研究

研究木瓜蛋白酶水解大豆蛋白所得到的酶解产物的分子量分布与其发泡性能的关系。酶解产物经过分离纯化,根据标准曲线的回归方程得到,大豆多肽的分子量分别为大于5000 Da和1148 Da、501 Da三个级分,其中第二个为主要成分。通过泡沫性能测试,结果表明,分子量在2000 Da以下的酶解产物的发泡性能最好,依次为分子量在3000~5000 Da之间的产物、2000~3000 Da之间的、5000~10000 Da之间的,分子量10000 Da以上的产物的发泡性能最差。     

Biodegradable and Multifunctional Polymer Micro-Tubes for Targeting Photothermal Therapy

We describe an innovative form of polymer micro-tubes with diverse functions including biodegradation, magnetic manipulation, and photothermal effect that employs and activates photothermal therapy to target cancer cells. The micro-tube comprised soybean protein isolate, poly-l-glutamic acid, magnetite nanoparticles, plus gold nanoparticles. Through electrostatic force, these components, with opposite charges, formed pairs of layers in the pores of the template, various bilayers of soybean protein isolate and poly-l-glutamic acid served as the biodegradable building wall to each micro-tube. The layers of magnetite nanoparticle functionalized micro-tubes enabled the micro-tube manipulate to target the cancer cells by using an external magnetic field. The photo-thermal effect of the layer of gold nanoparticles on the outer surface of the micro-tubes, when under irradiation and when brought about by the near infrared radiation, elevated each sample’s temperature. In addition, and when under the exposure of the near infrared radiation, the elevated temperature of the suspension of the micro-tubes, likewise with a concentration of 0.2 mg/mL, and similarly with a power of 2 W and as well maintained for 10 min, elevated the temperature of the suspension beyond 42 °C. Such temperatures induced apoptosis of target cancer cells through the effect of photothermal therapy. The findings assert that structured micro-tubes have a promising application as a photothermal agent. From this assertion, the implications are that this multifunctional agent will significantly improve the methodology for cancer diagnosis and therapy.     

聚硫橡胶对环氧树脂固化动力学及力学强度的影响

用红外光谱分析了在环氧树脂中加入聚硫橡胶的固化及增韧过程,通过差示扫描量热法研究了增韧体系的反应动力学,探讨了聚硫橡胶用量对固化产物力学强度的影响,并对试样断口形貌进行了扫描电镜观察。结果表明,聚硫橡胶的加入降低了环氧树脂的表观活化能而没有改变反应级数,使得固化反应的总放热量减少、放热过程更加平均。聚硫橡胶对环氧树脂的增韧效果明显,二者通过化学键结合,韧性撕裂的冲击断面形貌验证了这种活性增韧。当聚硫橡胶用量为30份(质量)时,环氧树脂固化物的冲击强度可达到未增韧者的896%。     

噁唑烷酮改性环氧树脂的性能

采用4,4-二苯基甲烷二异氰酸酯(MDI)对双酚A环氧树脂和脂肪族环氧树脂进行噁唑烷酮化共改性,研究了MDI及作为活性稀释剂的脂肪族环氧用量对改性产物黏度及树脂固化物力学性能、耐热性的影响。结果表明,低改性比和稀释剂可以有效降低唑烷酮改性环氧树脂黏度,当改性比为4∶1时,树脂固化物拉伸强度、弯曲强度达到75.4 MPa和158.2 MPa,分别比环氧树脂固化物提高了64%和57%,断裂延伸率和冲击强度有较大提高,具有高强高韧的特点。稀释剂含量对Tg影响较小,各改性树脂Tg在108～118℃之间,与纯环氧树脂的耐热性相当。     

大豆分离蛋白及其与丙烯酸接枝产物在不同pH值水相中的动态光散射研究

利用动态光散射技术,研究了大豆分离蛋白及其与丙烯酸接枝共聚物在水相体系中对pH值的响应性。结果发现,大豆分离蛋白和接枝产物对水相pH值都具有很高的响应性。大豆分离蛋白平均流体力学半径在等电点附近(pH=4~5)达到最大值。接枝率为27.5%的丙烯酸的接枝共聚物的平均流体力学半径在pH为2~3范围内最大。随着接枝率增加,丙烯酸的接枝共聚物在水相体系中的溶解性能越好。对接枝产物不同pH值水溶液进行研究具有很大的理论指导意义。     

Hygrothermal effects on tensile and fracture properties of epoxy filled with inorganic fillers having different reactivity to water

The study investigated the effects of ageing on the tensile properties and fracture behaviour of an epoxy filled with inorganic fillers having different reactivity to water, such as fly ash, calcium carbonate (CaCO₃), and Portland cement. CaCO₃ is insoluble in water, whereas fly ash and cement are reactive to water; however, fly ash is less reactive than cement. The water absorption, tensile properties, and mode-I fracture toughness of the epoxy containing 7?wt% of filler were compared after ageing the composites in distilled water at 50?°C. Gravimetric analyses showed that compared to neat epoxy, CaCO₃ slightly decreased the equilibrium water uptake of the filled epoxy, whereas fly ash and cement increased the equilibrium water uptake. Compared to the other fillers, the tensile strength of CaCO₃-filled epoxy was inferior in both dry and wet conditions. However, in dry condition, the elastic modulus of CaCO₃-filled epoxy was slightly higher. Overall, the fly ash-filled epoxy showed better tensile and fracture properties in both dry and wet conditions although it absorbed more water than the other fillers did. Scanning electron microscopy revealed that crack deflection played a dominant role in the toughening of filled epoxies in both dry and wet conditions.     

导电银胶在电磁屏蔽材料上的研究与应用

以片状银粉作为导电介质,以环氧树脂、固化剂、促进剂混合为成膜剂制备出可用于电磁屏蔽,具有良好力学性能的导电银胶。讨论了银粉在银胶中质量分数为75％、81％时,固化后银胶在100kHz～18GHz波段的电磁屏蔽性能,银含量越高对15M～18GHz高频率波段电磁屏蔽效能越好,可达到17～51dB。分析了银胶导电性与电磁屏蔽功效之间的关系;通过扫描电镜的观察,从微观上进一步验证其电磁屏蔽作用;当银含量为81％时其拉伸强度为1．20MPa。     

Processing,tensile, and fracture properties of injection molded Hdpe‐Al2O3‐HAp hybrid composites

The aim of this study is to characterize the physical and mechanical properties of HDPE‐alumina‐HAp composites prepared by injection molding techniques and to demonstrate their superiority over unreinforced HDPE. Composites with up to 30 vol. % of filler, composed of equal volumes of HAp and alumina, were successfully processed by injection molding. On the basis of the analysis of processing results, i.e., melt viscosity, volume flow rate, shear rate, mixing torque, the critical ceramic loading was determined. Tensile tests done at varying crosshead speeds confirm that an increase in ceramic loading results in an increase in strength, as well as a simultaneous decrease in the total elongation at failure. A maximum strength of 20 MPa and a maximum tensile modulus of around 1 GPa was achieved with 30 vol % ceramic loading in semicrystalline HDPE matrix. SEVNB test results demonstrate an improvement in toughness at 20 vol %. The fracture properties are discussed in terms of interfacial bonding between ceramic fillers and the semicrystalline HDPE matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Functional properties of soybean and lupin protein concentrates produced by ultrafiltration-diafiltration

Ultrafiltration followed by diafiltration (UF-DF) was evaluated for the production of protein products from partially defatted soybean meal or undefatted lupin (Lupinus albus L.2043N) meal. This study determined the effects of UF-DF on functional properties of the extracted proteins and compared the results with those of protein prepared by acid-precipitation (AP). UF-DF produced only protein concentrates (73% crude protein, dry basis, db), while AP produced protein isolates (about 90% crude protein, db). Soybean protein produced by UF-DF showed markedly higher values for solubilities up to pH 7.0, surface hydrophobicity index, emulsion activity index, and foaming capacity than did the AP soybean protein. UF-DF soy protein was also the most heat-stable among all protein samples tested. With lupin proteins, only the surface hydrophobicity and emulsion activity indices were significantly improved by using UF-DF. UF-DF generally had no adverse effects on, and in most cases even improved, the functional properties of soy protein concentrate produced by this method. UF-DF did not produce a comparable improvement in functional properties of lupin proteins as it did for soybean protein.     

Creation of Hydrophobic Materials Fabricated from Soy Protein and Natural Rubber: Surface,Interface, and Properties

Hydrophobic materials were successfully prepared from SPI and NR by blending via freezing/lyophilizing. The interfacial interaction, surface properties, hydrophobicity, and mechanical properties, biodegradability as well as the biocompatibility were investigated. The blend sheets exhibited good interface adhesion and good optical transparency. Their hydrophobicity was significantly improved compared with pure soy protein sheets. XPS results proved the NR surface enrichment. Flexibility and toughness of the blend sheets were enhanced and phase inversion phenomena were observed. Furthermore, the blend sheets exhibited good biodegradability and biocompatibility capable of supporting cell adhesion and proliferation.

     

Structure and properties of PP/POE/HDPE blends

This work was aimed to counteract the effect of ethylene‐α‐olefin copolymers (POE) by reinforcing the polypropylene (PP)/POE blends with high density polyethylene (HDPE) particles and, thus, achieved a balance between toughness and strength for the PP/POE/HDPE blends. The results showed that addition of HDPE resulted in an increasing wide stress plateau and more ductile fracture behavior. With the increase of HDPE content, the elongation at break of the blends increased rapidly without obvious decrease of yield strength and Young's modulus, and the notched izod impact strength of the blends can reach as high as 63 kJ/m² at 20 wt % HDPE loading. The storage modulus of PP blends increased and the glass transition temperature of each component of the blends shifted close to each other when HDPE was added. The crystallization of HDPE phase led to an increase of the total crystallinity of the blend. With increasing HDPE content, the dispersed POE particle size was obviously decreased, and the interparticle distance was effectively reduced and the blend rearranged into much more and obvious core‐shell structure. The fracture surface also changed from irregular striation to the regularly distant striations, displaying much obvious character of tough fracture. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

超声波改性大豆蛋白乳液凝胶的制备、性能及应用

采用超声波改性的大豆蛋白作为乳化剂和凝胶基质制备葡萄糖酸内脂（GDL）诱导乳液凝胶,研究超声波处理对大豆蛋白乳液和乳液凝胶特性,以及槲皮素运载性能的影响。通过乳液凝胶分子间作用力和质构特性的分析,确定超声波改性的最佳条件,为超声波功率400 W,温度55 °C,时间30 min。结果表明,超声波改性导致乳液的平均粒径下降、Zeta-电位绝对值上升、界面蛋白含量上升、表观粘度下降。乳液凝胶的最终G’值提高,形成了更趋近于弹性性质的凝胶材料;低场核磁共振中驰豫时间降低,峰比例分布改变,乳液凝胶的水合特性上升;微观结构观察发现,改性大豆蛋白乳液凝胶具有更加均匀的多孔结构,油滴更好地嵌入在凝胶的网络结构中。此外,超声波处理改善了大豆蛋白乳液凝胶的运载性能。实验结果表明,超声波改性大豆蛋白槲皮素乳液凝胶的包封率、生物利用率和脂肪分解率显著提高。     

Performance of protein-based wood bioadhesives and development of small-scale test method for characterizing properties of adhesive-bonded wood specimens

A small-scale test method to measure the tensile strength of adhesive-bonded wood strip specimens was developed by simple modification of commercially available binder clips. As bioadhesives, soy protein concentrate (SPC) and gelatin resins were prepared and were evaluated for shear and tensile bond strengths of bamboo and maple wood-bonded specimens. Titebond-II (TB-II), a commercially available wood glue was also tested to compare its bonding property to SPC and gelatin-based bioadhesives. TB-II glue showed the highest shear and tensile bond strengths with both bamboo and maple wood strips. Hot-pressing increased the shear and tensile bond strengths of SPC resin with wood specimens by 500% while the increase for gelatin resins was up to 200%. Roughness profile and surface properties were also characterized with an optical interferometric profiler and a scanning electron microscope. The results indicated that rougher surface significantly increased the bond strengths in both shear and tensile modes.     

竹材与高密度聚乙烯界面相容性的研究

以竹片、竹粉、竹纤维和高密度聚乙烯(PE–HD)为研究对象,采用液体石蜡油、质量分数为5%的H_2O_2、甲基丙烯酸甲酯、质量分数为5%的NaOH水溶液、质量分数为5%的邻苯二甲酸酐乙醇溶液、热处理等方式对其进行预处理,通过对不同处理方法所得试样的平面拉伸强度和胶合强度的考察分析,发现具有合适比表面积的竹纤维与PE–HD具有更好的界面相容性,并且经过预处理后竹纤维与PE–HD的相容性改善效果更加明显。另外,质量分数为5%的H_2O_2和质量分数为5%的邻苯二甲酸酐乙醇溶液,对竹材与PE–HD的界面相容性改善效果更明显。     

Tensile strength and toughness of acetylated pine and lime flakes

Thin strips of pine, Pinus sylvestris, and lime, Tilia vulgaris, were acetylated with acetic anhydride to various levels of acetyl weight gains. Increase in thickness, due to the bulking effect of acetylation, and increase in equilibrium moisture content at 65% relative humidity were determined. Equilibrium moisture content decreased as the degree of acetylation increased for both pine and lime. Finite span tensile strength was determined on thin control and acetylated pine and lime strips. No significant loss of tensile strength was found in either species due to acetylation. Total work expended in fracturing the specimens (work-to-failure) was slightly decreased for acetylated pine but remained essentially unchanged for acetylated lime as compared to controls. This indicates that the toughness of the material is only slightly reduced by the acetylation process.