纤维素纳米晶体/聚苯乙烯复合薄膜的制备及性能研究

通过Pickering乳液法一步实现亲水性纤维素纳米晶体（CNC）和疏水性聚苯乙烯（PS）的高效复合,经溶液浇筑成膜与热压耦合制得力学性能优异的CNC/PS复合薄膜。结果表明,尽管CNC的添加会降低PS薄膜的透明度,但当CNC添加量≤10%时,CNC/PS复合薄膜仍能保持良好的透明度。当CNC添加量为8%时,CNC/PS复合乳液中的乳滴尺寸和乳滴分布均一性最佳,此时CNC/PS复合薄膜的力学性能最佳,其拉伸强度为33.8 MPa,远优于纯PS薄膜（18.9 MPa）,韧性和杨氏模量分别为408.1 kJ/m3和1.9 GPa,是纯PS薄膜的1.8倍和1.5倍。当CNC添加量增至20%时,CNC/PS复合薄膜出现发白现象,透光率显著下降,但仍具有与纯PS薄膜相当的力学性能（拉伸强度为20.9 MPa,杨氏模量为1.6 GPa）。     

木质纤维聚合度对高透光率纤维素薄膜力学性能的影响

以氢氧化钠-亚硫酸盐-蒽醌-甲醇（ASAM）法制备的高聚合度针叶木浆为原料,通过调控漂白时间和漂白剂用量制得形态相近、聚合度不同的4种木质纤维;随后,通过浸渍法将羧甲基纤维素钠（CMC）与上述纤维抄造的原纸复合,制得高透光率木质纤维/CMC纤维素薄膜（以下简称薄膜）,并研究纤维聚合度对薄膜力学性能的影响。结果表明,在不显著改变纤维形态和结晶度的条件下,提高纤维聚合度可以显著提高薄膜的力学性能（抗张强度、韧性、耐折度、撕裂指数、耐破指数）,而其光学性能无明显的变化规律,透光率介于87.9%～89.8%,雾度介于53.6%～64.1%。     

MgO纳米颗粒增强壳聚糖复合薄膜及其抗菌性能研究

采用聚甲基丙烯酸甲酯（PMMA）/碳酸镁预聚物原位合成方法制备球形氧化镁（MgO）纳米颗粒,与壳聚糖复合制备壳聚糖/MgO复合薄膜,研究其力学性能、热稳定性、阻隔性能及抗菌性能。MgO纳米颗粒添加量为5 wt%时,壳聚糖/MgO复合薄膜获得最佳的力学性能,拉伸应力及弹性模量分别较壳聚糖薄膜提高64%及50%。傅里叶红外光谱（FT-IR）结果表明,壳聚糖/MgO复合薄膜力学性能的提升主要是由于壳聚糖的羟基和胺基与MgO形成了氢键。此外,添加5 wt% MgO纳米颗粒后,复合薄膜的氧气透过常数降低了约18%,该薄膜在12 h内可使46%的大肠杆菌结构破坏或死亡,具有优异的抗菌效果。     

聚乳酸/乙酰化纳米纤维素薄膜制备及性能研究

为改善聚乳酸(PLA)薄膜的力学及阻隔性能,采用纳米纤维素(NCC)对其进行改性。以微晶纤维素(MCC)为原料,用硫酸法制备NCC,进而制备乙酰化纳米纤维素(ANCC),然后将PLA与ANCC按不同比例混合后制备复合薄膜。采用透射电子显微镜(TEM)、傅里叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)对其微观结构和形态进行观测。采用拉伸仪和氧气透过率仪对其力学和气体阻隔性能进行分析。结果表明,使用酸法制备的纳米纤维素长度为100~200 nm,直径范围为10~20 nm。乙酰化处理对纳米纤维素的外观形态没有明显改变。与纯聚乳酸膜相比,ANCC添加量为1%时制备的复合薄膜的拉伸强度增加了29.09%,进一步增加ANCC含量则会导致复合薄膜力学性能下降。添加ANCC有效降低了复合薄膜的氧气透过量,ANCC添加量为0.5%时,薄膜的氧气透过率与纯PLA薄膜相比降低42%。添加ANCC对于薄膜的透光率和雾度没有明显影响。     

芳纶纳米纤维/壳聚糖绝缘复合薄膜力学及绝缘性能研究

以芳纶纳米纤维（ANFs）为基体,壳聚糖（CS）为增强剂,采用真空辅助过滤技术制备了ANFs/CS复合薄膜,并通过热压法提高薄膜的致密性,以增强其力学和绝缘性能。结果显示,当壳聚糖负载量为0.02 g时,ANFs/CS复合薄膜的性能最优,其最大拉伸强度可达208 MPa,特征击穿强度62 kV/mm。对ANFs/CS复合薄膜进行热压处理后,复合薄膜的致密性明显提高,其最大拉伸强度和击穿强度分别为253 MPa和109 kV/mm,相较于热压前分别提升了21.6%和75.8%。     

丝素/海藻酸钠复合薄膜的制备与性能

丝素与海藻酸钠共混溶液经过碳二亚胺交联后,采用流延法制备的复合薄膜具有良好的相容性,改进了单一膜材的力学性能、吸湿性及其稳定性。通过对复合薄膜进行红外光谱和扫描电镜分析不同共混比例复合薄膜的微观结构和聚集态结构;通过拉伸断裂测试、热水溶失率、溶胀率及水蒸气传递速率的测试,研究了复合薄膜的基本性能。结果表明:经过碳二亚胺交联后,复合薄膜两相相容性提高,无明显的相分离现象,并在丝素和海藻酸钠之间形成了稳定的共价键交联点,薄膜稳定性明显提高,与单一成分薄膜相比,复合薄膜的柔韧性明显增加。海藻酸钠加入有效提高了薄膜的吸湿性能。     

热处理温度对玻璃纤维表面氧化锡薄膜光电性能的影响

 为在玻璃纤维表面制备透明导电薄膜,使其具有导电性的同时保持良好的透光性,采用溶胶凝胶法制备纳米SnO2溶胶,利用浸渍提拉法在玻璃纤维表面涂覆纳米SnO2溶胶,经过热处理后在纤维表面形成纳米SnO2薄膜。本文利用X射线衍射仪（XRD）、场发射扫描电镜（SEM）、原子力显微镜（AFM）、四探针法和紫外可见分光光度计分别来表征纤维表面薄膜的物相、表面形貌、纤维电阻率以及薄膜透光率。分析了热处理温度对薄膜结构、玻璃纤维导电性能以及薄膜透光率的影响。结果表明,采用溶胶凝胶法制备的溶胶稳定性好,最佳热处理温度是550℃,得到的薄膜晶粒平均大小可达17.18nm,纤维电阻率可达5×10-5Ω·m,同时纤维表面薄膜透光率在88%左右。     

CMC/木质纤维复合纸的制备及性能

以羧甲基纤维素(CMC)和桉木浆为原料,将桉木浆抄造成纸张后浸渍CMC溶液制备CMC/木质纤维复合纸。探讨了CMC的浸渍量对复合纸的光学性能(透光率和雾度)、力学性能(拉伸强度和耐折度)的影响规律。结果表明:当CMC的浸渍量为65%时,CMC/木质纤维复合纸具有优异的光学性能和力学性能,其透光率为91%,雾度为82%,拉伸强度达142 MPa,耐折次数为1516次。     

纳米微晶纤维素/石墨烯柔性导电薄膜的制备与表征

以微晶纤维素为原料,采用酸水解法制备纳米微晶纤维素(NCC)悬浮液,基于真空抽滤法获得NCC薄膜。然后,以NCC为分散剂,并改变其加入量,制备石墨烯/NCC复合涂料液。最后,基于旋涂法将不同配方的石墨烯/NCC涂料液施涂在NCC膜的表面,获得NCC/石墨烯柔性导电薄膜。实验结果表明:添加NCC可有效地提高石墨烯的水相分散性;相比于纯NCC薄膜,NCC/石墨烯复合薄膜的电导率和力学性能均有所增强,但复合薄膜的透光率和热稳定性有所下降;与NCC薄膜相比较,NCC/石墨烯导电薄膜的抗张强度和弹性模量分别增加了207.1%和128.3%,NCC/石墨烯导电薄膜的电导率最大值可达到2.25 s·cm^-1。     

增强剂对大豆蛋白/聚乙烯醇复合薄膜性能的影响

以薄膜拉伸强度、断裂伸长率、透光率、吸水率为评价指标,通过隶属度函数综合评分方法,研究了增强剂对大豆蛋白/聚乙烯醇复合薄膜性能的影响。实验结果表明:与对照组相比,添加可溶性淀粉,薄膜吸水率显著降低,透光率明显增大,但薄膜拉伸强度和断裂伸长率略有减小;添加羧甲基纤维素钠(CMC-Na),薄膜拉伸强度和吸水率明显增大,断裂伸长率明显减小,透光率几乎没有变化;加入明胶,薄膜的拉伸强度增大不明显,断裂伸长率和透光率均有显著提高,吸水率明显减小,当明胶浓度为0.200%时,薄膜综合性能最佳,拉伸强度为4.69MPa,断裂伸长率为45.65%,透光率为13.78%,吸水率为47.21%。     

Gelation,thermal and pasting properties of pigeon pea (Cajanus cajan L.), dolichos bean (Dolichos lablab L.) and jack bean (Canavalia ensiformis) flours

This study evaluated the rheological, thermal and pasting properties of pigeon pea (PP), dolichos bean (DB) and jack bean (JB) legume flours and gels. Starch and protein contents were also measured and its molecular weight distribution was determined by electrophoresis. PP and DB showed the highest viscosities while JB had the highest pasting temperature. The minimum flour concentrations for gel formation were estimated at 6–8% for DB and PP and 10% for JB. Above these concentrations all flour suspensions heated to 95 °C led to gels with a solid-like behavior. Differential scanning calorimetry showed two endothermic peaks in all flours at 80–89 °C and 96–100 °C. Avrami model was successfully fitted to the hardening kinetics of PP and DB gels stored at 4 °C. The half-life times were 22 and 6 h for PP and DB respectively. PP and DB flours were able to form self-supporting gels and could be applied in the formulation of gel-like foods.     

Determination of some chemical and physical properties of Sakız faba bean (Vicia faba L. Var. major)

In this study, some chemical and physical properties of faba bean (Vicia faba L. Var. major) grown up in Antalya region have been determined. Chemical properties such as dry matter, total energy, crude protein, crude cellulose, crude oil, mineral elements––Ca, P, K, Na, S, Al, Ba––and physical properties such as dimensions, weight, thickness, geometric mean diameter, sphericity, bulk density, volume, porosity, projected area, 1000 grain mass, terminal velocity and the rupture strength of grains involved in the study.

The total energy, crude protein, crude cellulose and crude oil contents (as percentage in dry matter) of faba bean are found as 18.87 MJ/kg, 29.63%, 6.39% and 1.06% respectively, and all elements determined in the research are listed in the text. The values of length, width, thickness, weight, geometric mean diameter and sphericity of faba bean are determined as 20.39, 14.54, 7.86 mm, 1.31 g, 13.25 mm and 0.651 for 10.90% moisture content, respectively. In the some moisture content, projected area, volume, 1000 grain mass, bulk density, kernel density, porosity and terminal velocity were measured as 2.79 cm², 1210 mm³, 1349.34 g, 608.17 kg/m³, 1248 kg/m³, 51.48%, 4.94 m/s respectively. In addition, the rupture strength values of faba bean grains were varied between 310.83 and 542.38 N.     

Comparison of properties of native and extruded amaranth (Amaranthus cruentus L. - BRS Alegria) flour

The aim of this study was to compare some of the properties of native and extruded amaranth flour obtained under mild and severe extrusion conditions. The chemical composition of the flours was similar. Flours obtained by both extrusion processes presented high solubility in water, low values of L∗ (luminosity) and an absence of endothermic peak on the DSC method. Water absorption, retrogradation tendency, final viscosity and the viscous behavior by rheology analysis were also studied. The results indicate that extruded flours have a good potential as an ingredient for food exposed to heat treatment at a high temperature and mechanical shear, for use in instant meal products. On the other hand, original flour properties are comparable to those of amaranth starch, which exhibits similarly high quality paste stability, low solubility in water, and elastic behavior, and could be used as a substitute for raw flour in a range of food formulas.     

Chitosan/clay films' properties as affected by biopolymer and clay micro/nanoparticles' concentrations

Blends of chitosan (from Cuban lobster) and clay micro/nanoparticles were prepared by dispersion of the clay particles in the film matrix and the films obtained were characterized in terms of water solubility, water vapor, oxygen and carbon dioxide permeability, optical, mechanical and thermal properties using an Instron universal testing machine, differential scanning calorimetry, thermogravimetric analyses and scanning electron microscopy (SEM). The water vapor barrier properties of the films were significantly improved by incorporation of clay in their composition, while the water solubility decreased as the clay concentration increased (for a constant chitosan concentration). The tensile strength of chitosan/clay films increased significantly with increasing chitosan and clay concentrations, while the values of elongation decreased slightly for high values of chitosan concentration. T_m increased with the increase of chitosan concentration, but the changes in T_m with the addition of clay were not significant.Polynomial models were fitted to the experimental data in order to facilitate future design of chitosan/clay film systems.     

Effects of lipid,PET/PE and PA/PE with high-pressure processing

The mutual effects between food components and packaging materials under high-pressure processing was investigated. Pouches made of Polyethylene terephthalate/Polyethylene and Polyamide/Polyethylene packaging olive oil and glycerol trioleate were subjected to different pressures and holding times, and then stored at 23 ± 2^oC for 40 days. The results proved that there were significant effect between lipid and packaging under high-pressure processing treatment. High pressure would be beneficial to extend food shelf life and affect the enthalpy of fusion of packaging materials, especially when making contact with olive oil which probably acted as a plasticizer to change the polymer structure.     

大麻／棉迷彩印花织物的开发

为提高军用服装的舒适性,开发了一种大麻/棉防红外迷彩织物,对织物的色牢度和基本物理机械性能、舒适性和伪装性等进行了测试分析。结果表明,这种混纺织物在吸湿、散湿性方面比纯棉织物有一定提高,能达到改善服装舒适性的目的,且能满足伪装的要求;但断裂强力和柔韧性有所下降,仍需进一步改进。     

小麦阿拉伯木聚糖对鲜湿面条品质的影响

从小麦麸皮中提取阿拉伯木聚糖,将其添至鲜湿面条中,通过测定面筋蛋白的流变特性,淀粉的糊化特性,面条的蒸煮及质构特性等,分析添加不同质量分数的小麦阿拉伯木聚糖(WBAX)对鲜湿面条品质的影响.结果表明:添加WBAX对面筋蛋白形成有弱化作用,随着WBAX添加量的增加,面粉中淀粉糊化的峰值黏度和终值黏度增加,糊化过程的崩解值...     

Ultrastructural and rheological changes during the gelation of giant squid (Dosidicus gigas) muscle

The giant squid or dosidicus (Dosidicus gigas) is normally shipped frozen from the coasts of America. During the period prior to freezing-when conditions are not always optimum-and during frozen storage, the functional capacity of the muscle proteins declines, rendering the material useless for certain processes such as conversion to gel. This paper examines the reasons for the lack of a good gel-forming capacity as measured both rheologically (breaking force, breaking deformation and gel strength) and in terms of ultrastructure (scanning microscopy). The study was carried out at four different temperatures known to be critical for fish muscle protein gel formation, and at two salt concentrations. At 35°C the structure was spongier in gels made with 1.5% NaCl, although a true gel was still not formed, as shown by rheological measurements. Above 30°C, the ultrastructure became more cellular, particularly in samples made with 2.5% NaCl, at which concentration gel strength values were higher. However, at neither salt concentration nor at any of the experimental temperatures was the mesh as spongy as in other fish gels reported in the literature. The values of rheological analysis and folding test were correspondingly low.     

The effect of starch isolation method on physical and functional properties of Portuguese nut starches. II. Q. rotundifolia Lam. and Q. suber Lam. acorns starches

A new starch was isolated from fruits of two acorn species, Quercus rotundifolia and Quercus suber by alkaline (A3S) and enzymatic (ENZ) methods and physical and functional properties were studied. The isolation method induced changes in most of those properties in the isolated starches, mainly in resistant starch content, syneresis, pasting, thermal and rheological properties. Isolated acorn starches presented high amylose content (53–59%) and resistant starch content (30.8–41.4%). Acorn starches showed limited and similar solubility values and swelling power values, showing a gradual increase from 60 °C to 90 °C. The pasting temperatures ranged from 67.5 to 72.0 °C and pastes did not present breakdown, which is suggestive of a high paste stability of acorn starches during heating. At ambient temperature the turbidity and syneresis values were low, but when held at freezing temperatures the syneresis significantly increased. Thermal analysis revealed that the acorn starches easily undergo transition phenomena as shown by the low T_o and enthalpy values (4.1–4.3 J/g), these effects were more evident in starches isolated by ENZ method. Pastes are more elastic than viscous and form strong gels after cooling. Q. suber starch was shown to be more sensitive to the effect of isolation method. Generally, starch isolated by enzymatic method presented less interesting functional properties, since this isolation procedure greater affected the raw structure of starches.     

不同糯性谷物淀粉性质的比较研究

本研究选取圆糯米、血糯米、糯小麦、糯玉米、糯小米(糜子)、糯高梁和糯薏米为原料提取淀粉,比较研究了7种糯性谷物淀粉的性质,为其应用提供一定的参考。结果表明:透光率以糯玉米和糯高粱淀粉最大,为20%左右;糯薏米和糯小麦淀粉较易凝沉;50℃下圆糯米、血糯米和糯玉米淀粉的膨胀势较大;圆糯米淀粉的冻融稳定性最差,而糯小麦、糯玉米、糯小米(糜子)和糯高粱淀粉的较好;糊化温度以糯小米(糜子)淀粉最大,为67.8℃,而圆糯米、血糯米和糯玉米淀粉的糊化温度最小,均为60℃;7种糯性谷物淀粉的峰值粘度、保持粘度和最终粘度以糯小麦、糯高粱和糯薏米淀粉的最大,糯玉米淀粉的最小;由回升值/峰值粘度的大小可知,糯玉米淀粉最不易老化,糯薏米淀粉最易老化;糯高粱、糯小麦和糯薏米淀粉的抗剪切作用较弱,而血糯米和糯玉米淀粉在剪切过后有变稠的趋势。