可生物降解大豆蛋白材料的研究进展

介绍了可生物降解材料的定义和降解机理,阐述了可生物降解大豆蛋白材料的研究概况,从物理改性、化学改性、共混改性三方面对近年来大豆蛋白材料的改性进行了综述,并对其发展前景进行了展望。     

Effect of expanded graphite and modified graphite flakes on the physical and thermo-mechanical properties of styrene butadiene rubber/polybutadiene rubber (SBR/BR) blends

The aim of the present research work is to develop expanded graphite (EG) and isocyanate modified graphite nanoplatelets (i-MG) filled SBR/BR blends, which can substitute natural rubber (NR) in some application areas. The present study investigated the effect of i-MG on the physical, mechanical and thermo-mechanical properties of polybutadiene rubber (BR), styrene butadiene rubber (SBR) and SBR/BR blends in the presence of carbon black (CB). Graphite sheets were modified to enhance its dispersion in the rubber matrices, which resulting in an improvement in the overall physical and mechanical properties of the rubber vulcanizates. Compounds based on 50:50 of BR and SBR with ∼3 wt% nanofillers with CB were fabricated by melt mixing. The morphology of the filled rubber blends was investigated by wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analyses. The intercalated and delaminated structures of the nanofiller loaded rubber blends were observed. Scanning electron microscopic (SEM) analysis of the cryo-fractured surfaces of the rubber compounds showed more rough and tortuous pathway of the fractured surfaces compared to the fractured surfaces of the only CB loaded rubber composites. Filled rubber compounds exhibit increase in the ΔS (torque difference) value, reduced scorch and cure time compared to their respective controls. Dynamic mechanical thermal analysis (DMTA) of the filled rubber compounds shows an increase in the storage modulus compared to the controls. Isocyanate modified graphite nanoplatelets (i-MG) containing rubber compounds in the presence of CB showed an increase in the mechanical, dynamic mechanical, hardness, abrasion resistance and thermal properties compared to the alone CB filled rubber vulcanizates.     

油酸酰胺对SBR/BR汽车橡胶衬套性能的影响

将油酸酰胺以不同份数分别加入到丁苯橡胶/顺丁橡胶(SBR/BR)共混胶中,并通过硫化特性、力学性能和摩擦系数等测试方法来表征胶料的性能。结果表明,随着油酸酰胺份数的增加,硫化胶的摩擦系数明显降低,断裂伸长率和屈挠性能明显提高。当硫化胶中油酸酰胺用量为10份时,与未添加油酸酰胺组相比,拉伸强度降低19.84%,断裂伸长率增大36.14%,硬度减小9.21%,静摩擦系数减小45.51%,动摩擦系数减小37.54%。通过橡胶加工性能分析和扫描电镜(SEM)等测试方法对胶料进行研究,发现油酸酰胺可使填料分散得更均匀。     

Effect of grafting cellulose acetate and methylmethacrylate as compatibilizer onto NBR/SBR blends

Compatibilizer is used for improving of processability, interfacial interaction and mechanical properties of polymer blends. In this study acrylonitrile butadiene rubber (NBR) and styrene-butadiene rubber (SBR) blends were compatibilized by a graft copolymer of acrylonitrile butadiene rubber (NBR) grafted with cellulose acetate (CA) i.e. (NBR-g-CA) and acrylonitrile butadiene rubber (NBR) grafted with methylmethacrylate i.e. (NBR-g-MMA). Compatibilizers were prepared by gamma radiation induced grafting of NBR with cellulose acetate (CA) and methylmethacrylate (MMA) were added with different ratios to NBR/SBR (50/50) blend. The compatibilized blends were evaluated by rheometric characteristics, physico-mechanical properties, swelling behavior, scanning electron microscope (SEM) and thermal analysis. The results showed that, the blends with graft copolymer effect greatly on the rheological characteristics [optimum cure time (Tc₉₀), scorch time (Ts₂), and the cure rate index (CRI)]. The physico-mechanical properties of the investigated blends were enhanced by the incorporation of these graft copolymers, while the resistance to swelling in toluene became higher. SEM photographs confirm that, these compatibilizers improve the interfacial adhesion between NBR/SBR (50/50) blend which induce compatibilization in the immiscible blends. The efficiency of the compatibilizer was also evaluated by studying the thermogravimetric analysis.     

大豆分离蛋白与小麦面筋蛋白共混的可食性复合包装膜研究

采用正交实验方法制备加入丙酸钙的大豆分离蛋白(SPI)与小麦面筋蛋白(WGP)复合薄膜,从力学性能、透水性、透氧性理化指标方面来比较蛋白质复合膜性能的优劣,结果发现,SPI-WGP复合膜性能比较优异,从中找出最优化的水平组合.     

大豆分离蛋白与明胶蛋白复合膜的制备与性能研究

以大豆分离蛋白为基质,添加明胶蛋白,用溶液铸膜法制备复合膜.研究了成膜液的溶液性能;复合膜的各种性能,包括表观性能、力学性能、阻隔性能.通过扫描电子显微镜观察了膜的微观结构.结果表明,当明胶含量为30%(质量分数)左右,两种蛋白的相容性最佳,复合膜的各项性能达到较佳值,拉伸强度达到31.59MPa,断裂伸长率达到65.96%,并且对氧气和水都有良好的阻隔性.     

Freeze–thaw stability of emulsions with soy protein isolate through interfacial engineering

In this paper, we examined to the influence of interfacial composition on freeze–thaw stability of oil in water emulsions. An electrostatic layer-by-layer deposition method was used to create the multilayered interfacial membranes with different compositions of primary emulsion (Soy protein Isolate); secondary emulsion (Soy protein Isolate – octenyl-succinate starch); tertiary emulsion (Soy protein Isolate – octenyl-succinate starch – Chitosan). The primary, secondary and tertiary emulsions were subjected to from one to two freeze–thaw cycles (−20 °C for 24 h, +25 °C for 18 h) and then their stability was assessed by ζ-potential, particle size, microstructure and creaming stability measurements. The crystallization behaviour of emulsions was studied by differential scanning calorimetry (DSC). Primary and secondary emulsions were unstable to droplet flocculation when the water phase crystallized, whereas tertiary emulsions were stable, which was attributed to the relatively thick biopolymer layer surrounding the oil droplets. These results showed the interfacial engineering technology used in the study could therefore lead to the creation of food emulsions with improved stability to freezing and thawing.     

改性淀粉/聚乳酸共混物的制备

采用接枝共聚-共混法,制备了乳酸接枝淀粉/聚乳酸复合材料.实验表明,淀粉和乳酸进行接枝反应的最佳温度为90℃,最佳反应时间为3h,在此条件下所得接枝共聚物的接枝率最高为31.62%.共混物的形貌分析和性能研究表明,相对于未经改性的淀粉/聚乳酸复合材料,改性淀粉/聚乳酸复合材料的相容性和机械性能得到明显改善.     

Biodegradable green composites made using bamboo micro/nano-fibrils and chemically modified soy protein resin

Micro/nano-sized bamboo fibrils (MBF) and a modified soy protein resin were used to fabricate environmentally friendly composites. With the incorporation of MBF the fracture stress and Young’s modulus of the soy protein concentrate (SPC) increased significantly. With the addition of 30 parts of MBF (SPC is 100 parts, based on weight), the fracture stress and Young’s modulus were increased from 20.2 MPa to 59.3 MPa and from 596 MPa to 1816 MPa, respectively. The addition of MBF, however, did not show significant decrease in the fracture strain of the specimens. As a result, the toughness of the MBF reinforced SPC increased. The toughness of the SPC based composites containing 30 parts of MBF was 6.0 MPa compared to 2.7 MPa for SPC without MBF. MBF reinforced SPC was then cross-linked using a silane, (3-isocyanatopropyl)triethoxysilane (ITES). Although the fracture strength and Young’s modulus did not show significant increase, the modification using ITES showed significant increase in the fracture toughness. SPC containing 30 parts of MBF, 10 parts of ITES and 2 parts of glycerol showed fracture stress of 82 MPa, Young’s modulus of around 3.2 GPa and toughness of 4.3 MPa. The environment-friendly, fully biodegradable green composites, based on MBF and modified SPC resins, have excellent properties and great potential to replace the traditional petroleum-based materials in many applications.     

大豆分离蛋白可食膜的制备及微波处理对性能的影响

制备了大豆分离蛋白可食性膜.为了提高大豆分离蛋白膜的性能,通过微波进行处理,考察微波对蛋白膜性能影响.结果表明:由于微波处理作用,蛋白膜机械性能增加显著,蛋白膜的阻水性能也得到提高.通过溶胀实验进一步考察蛋白膜交联程度,结果表明:微波处理大豆分离蛋白可食性膜,交联程度提高.     

Physicochemical properties of soy protein isolate/carboxymethyl cellulose blend films crosslinked by Maillard reactions: Color, transparency and heat-sealing ability

Soy protein isolate (SPI) films have many potential applications in the biomaterial field as surgical dressings for burns, films for reduction of wound inflammation, and facial masks. The appearance and the sealing ability are important physicochemical properties that greatly influence consumer acceptance of such protein-based films. The aim of the present work was to investigate the chemical structure and the physical properties associated with color, transparency and heat-sealing ability for SPI/carboxymethyl cellulose (CMC) blend films prepared by solution casting, with weight proportions 90/10, 80/20, 70/30 and 60/40. Fourier transform infra-red (FTIR) and solid-state ¹³C nuclear magnetic resonance (NMR) spectra confirmed that Maillard reactions occurred between SPI and CMC. The Hunter color value (L, a, b) and transparency of films were affected by varying the proportions of SPI and CMC. With increasing degree of crosslinking of SPI and CMC, the yellow color of the films was diluted and transparency was improved. Peel strength and tensile strength measurements showed that the Maillard reactions had the main effect of enhancing the heat-sealing ability above the melting temperature. These results indicated that the structure and properties of SPI-based films could be modified and improved by blending with CMC.     

Effects of plasticization and shear stress on phase structure development and properties of soy protein blends

In this study, soy protein concentrate (SPC) was used as a plastic component to blend with poly(butylene adipate-co-terephthalate) (PBAT). Effects of SPC plasticization and blend composition on its deformation during mixing were studied in detail. Influence of using water as the major plasticizer and glycerol as the co-plasticizer on the deformation of the SPC phase during mixing was explored. The effect of shear stress, as affected by SPC loading level, on the phase structure of SPC in the blends was also investigated. Quantitative analysis of the aspect ratio of SPC particles was conducted by using ImageJ software, and an empirical model predicting the formation of percolated structure was applied. The experimental results and the model prediction showed a fairly good agreement. The experimental results and statistic analysis suggest that both SPC loading level and its water content prior to compounding had significant influences on development of the SPC phase structure and were correlated in determining the morphological structures of the resulting blends. Consequently, physical and mechanical properties of the blends greatly depended on the phase morphology and PBAT/SPC ratio of the blends.     

Characterization of interfacial and mechanical properties of “green” composites with soy protein isolate and ramie fiber

Environment-friendly fiber-reinforced composites were fabricated using ramie fibers and soy protein isolate (SPI) and were characterized for their interfacial and mechanical properties. Ramie fibers were characterized for their tensile properties and the parameters for the Weibull distribution were estimated. Effect of glycerol content on the tensile properties of SPI was studied. Interfacial shear strength (IFSS) was determined using the microbond technique. Based on the IFSS results and fiber strength distribution, three different fiber lengths and fiber weight contents (FWC) were chosen to fabricate short fiber-reinforced composites. The results indicate that the fracture stress increases with increase in fiber length and fiber weight content. Glycerol was found to increase the fracture strain and reduce the resin fracture stress and modulus as a result of plasticization. For 10% (w/w) of 5 mm long fibers, no significant reinforcement effect was observed. In fact the short fibers acted as flaws and led to reduction in the tensile properties. On further increasing the fiber length and FWC, a significant increase in the Young's modulus and fracture stress and decrease in fracture strain was observed as the fibers started to control the tensile properties of the composites. The experimental data were compared to the theoretical predictions made using Zweben's model. The experimental results are lower than the predicted values for a variety of reasons. However, the two values get closer with increasing fiber length and FWC.     

天然大豆蛋白的功能性及其化学改性策略

综述了近年来国内外对大豆蛋白化学改性方法的研究状况,探讨了各种化学改性方法对大豆蛋白功能性的影响及其应用,指出经过合适的化学改性,将大豆蛋白用于制备绿色可降解功能材料是一条符合环境与生态要求的有效路径.     

聚己内酯改性聚乳酸/淀粉共混材料的性能研究

将热塑性淀粉(TPS)与聚己内酯(PCI)、聚乳酸(PLA)共混后,采用溶剂挥发法制备出完全生物降解的聚己内酯改性聚乳酸/淀粉共混材料.测试了材料的力学性能、共混形态、疏水性能和降解性能等.结果表明:甘油和水能够很好增塑淀粉,当淀粉:甘油:水为4:1.2:10时,拉伸强度最高达44.84MPa,断裂伸长率达93%,共混材料具有较好的力学性能;FT-IR和SEM显示聚己内酯的加入提高了共混材料的相客性;随着淀粉含量的增加,吸水率增大;土埋70天后,共混材料最高降解率达42.41%.     

非离子丁苯胶乳改性乳化沥青性能研究

采用自主研发生产的非离子丁苯胶乳作为改性剂,对不同基质沥青进行改性,考察改性乳化沥青的各项性能.并在高速公路进行推广应用,取得较好效果,为非离子丁苯胶乳改性乳化沥青在路面上的应用提供借鉴.     

The significance of carbon nanotubes on styrene butadiene rubber (SBR) and SBR modified mortar

A New approach is introduced to incorporate multi-walled carbon nanotubes (MWCNTs) in cementitious materials. The MWCNTs are dispersed in styrene butadiene rubber (SBR) matrix before mixing the matrix with cement. Surfactants have been successfully applied to enhance the dispersion and functionalization of MWCNTs in SBR. The significance of using this MWCNTs–SBR nanocomposite on the mechanical characteristics including compressive and tensile strengths and microstructural features of latex modified mortar (LMM) were examined. Subsequently, the significance of the functionalized MWCNTs on surface chemistry, microstructure and thermal stability of SBR were characterized. MWCNTs were found to be a useful additive for enhancing the mechanical response and thermal stability of SBR. MWCNTs–SBR nanocomposite was observed to be able to bridge micro-cracks in the LMM which helped enhancing its mechanical properties. The ability of MWCNTs to enhance the mechanical response of SBR polymer matrix might be attributed to chemical bond that functionalized MWCNTs can establish with the SBR polymer matrix. The enhanced MWCNTs–SBR nanocomposite gave rise to improved microstructural features of the LMM. Microstructural investigations showed MWCNTs were well dispersed in and bonded to the SBR matrix.