甘油含量对 MC/WG可食性复合膜性能的影响

采用流延法制备了不同甘油含量的MC/WG复合膜,并研究了甘油含量对该复合膜性能的影响。实验结果表明:MC/WG复合膜的抗拉强度随着甘油含量的增大而降低;断裂伸长率、水蒸气透过率随着甘油含量的增大而增大;透光率则先增后减,在甘油体积分数为1.25%时达到最大。综合比较,MC/WG甘油所占体积分数为1.25%时复合膜性能最优。     

乳清蛋白添加量对交联羧甲基玉米淀粉可食膜阻隔性能的影响

以交联羧甲基玉米淀粉(CCMS)为原料,辅以增强剂、增塑剂、脱泡剂及脱膜剂等,通过流延方法制备了交联羧甲基玉米淀粉/乳清蛋白可食性复合包装膜。实验考察了乳清蛋白粉的添加量对交联羧甲基玉米淀粉可食性膜阻隔性能的影响。结果表明:乳清蛋白添加量为15%(质量分数)时,可食性复合膜的阻隔性最好,其透氧系数为0.312×10-15cm3.cm/(m2.s.Pa),水蒸气透过系数为2.89 g.mm/(m2.d.kPa),吸水稳定性好。     

Use of antimicrobial methylcellulose films to control Staphylococcus aureus during storage of Kasar cheese

Olive leaf extract (OLE) (Olea europaea L.) is a natural product that has antimicrobial effect on many food pathogens. In this study, methylcellulose (MC) based antimicrobial films containing 0.5–3% (w/v) OLE and glycerol (1.6%, v/v) were produced. The effects of OLE amount on the water vapour permeability (WVP), mechanical and antimicrobial properties of the films were investigated. The films were effective against Staphylococcus aureus (ATCC 25923). The OLE in the film solution caused a decrease in WVP and elongation (E), and an increase in tensile strength (TS). The MC films containing 1.5% (w/v) OLE were applied on Kasar cheese slices inoculated with S. aureus. The count of S. aureus decreased 0.68 and 1.22 log cycle at the 7th and 14th days, respectively. Copyright © 2009 John Wiley & Sons, Ltd.     

Surface evaluation of whey protein films by atomic force microscopy and water vapour permeability analysis

The atomic force microscopy (AFM) technique is a powerful tool for studying surfaces and has been used to provide qualitative and quantitative information about nanometer‐scale matter properties that are often inaccessible by any other experimental technique. In this work AFM was used to evaluate the surfaces of edible films produced with whey protein concentrate (WPC). The morphology and the roughness of the films were analysed. The effects of WPC and plasticizer concentration were characterized in terms of water vapour permeability (WVP) and roughness parameters. Roughness was calculated through the images captured with AFM. AFM can be useful to identify structural changes of the film resulting from sample preparation. The results showed a relation between water vapour permeability and area roughness, through different sample preparation. The analyses of topography through roughness obtained with AFM, demonstrated the correlation between the morphology of the film, obtained with nanometer resolution and WVP. Copyright © 2004 John Wiley & Sons, Ltd.     

负载桑葚花青素的葛根淀粉/壳聚糖复合膜的制备与表征

目的 研究桑葚花青素（Mulberry Anthocyanins, MA）添加量对葛根淀粉/壳聚糖复合膜理化性质及功能活性的影响。方法 以葛根淀粉和壳聚糖为成膜基材，MA为指示剂，采用流延法制备一种新型可食pH指示膜，测定葛根淀粉/壳聚糖复合膜的物理性能、抗氧化性、pH指示等性质，并将指示膜用于猪肉保鲜及新鲜度检测研究。结果 通过对添加不同MA含量的复合膜进行性能测试，发现MA和葛根淀粉之间氢键的形成，极大地改善了复合膜的拉伸强度。MA的加入使得成膜厚度、不透明度、拉伸强度（Tensile Strength,TS）、水蒸气透过率（Water Vapor Permeability,WVP）显著提高，断裂伸长率（Elongation At Break,EAB）显著降低。此外，MA增强了复合膜的抗氧化性和pH敏感性，MA-4的DPPH自由基清除率达到最大值85.24%。将复合膜应用于猪肉新鲜度检测，与对照组相比，负载MA的复合膜可抑制猪肉pH值和TVB-N值，并产生肉眼可辨的颜色变化，其中MA-3的颜色变化最为敏感。结论 加入一定量MA的复合膜能够改善其拉伸强度、不透明度、pH敏感性和抗氧化...     

Monte Carlo study of quantitative analysis method of trace elements in thin aluminum films

We have suggested a quantitative analysis method for the determination of trace elements (100–1200 mass ppm) in thin Al films. One of the features of this method is to use calibration curves (K-ratio vs mass ppm in bulk targets) obtained using a Monte Carlo (MC) simulation of electron scattering. First, we verified the calibration curves using bulk standard Al-Cu alloys. As a result, good agreement was obtained with chemical analysis results. Consequently, we confirmed that the MC simulation correctly expressed the electron trajectories in the targets. Here the X-ray generation ratio was defined as the ratio between the X-ray production from an element in a film and the X-ray production by the same element in the same bulk sample. After that, using this MC simulation, we investigated the relation among the X-ray generation ratio, the trace element concentration and the Al film thickness. As a result, we found that the X-ray generation ratio is in relation to the film thickness, however it is not in relation to the concentration of trace element. Namely, if the thickness of unknown samples is known, using the X-ray generation ratio we can transfer from relative X-ray intensity of the film into the relative X-ray intensity of the bulk sample. Also, from the relation that the K-ratio is corresponding to the relative X-ray intensity, using the calibration curves (K-ratio vs mass ratio in bulk targets), we can obtain the concentration (mass ppm) in thin films. Further, in this study, we provided the X-ray generation ratios and the calibration curves of trace elements such as Mg, Si, Ti, Cr, Mn, Fe, Ni, Cu, Zn in the bulk Al matrix.     

壳聚糖和乳清分离蛋白在食品包装中的应用

综述了壳聚糖和乳清分离蛋白最新研究进展.壳聚糖薄膜是优良的抗菌性包装材料,乳清分离蛋白薄膜对氧气、芳香类和脂类物质的阻隔性非常好.壳聚糖涂层复合薄膜用于活性包装具有巨大的潜力.乳清分离蛋白涂层复合薄膜具有取代日前阻氧性合成包装材料的潜力.     

Preparation,characterization and photocatalytic activity of TiO<Subscript>2</Subscript> / Methylcellulose nanocomposite films derived from nanopowder TiO<Subscript>2</Subscript> and modified sol–gel titania

TiO₂—methylcellulose (MC) nanocomposite films processed by the sol-gel technique were studied for phocatalytic applications. Precalcined TiO₂ nanopowder was mixed with a sol and heat treated. The sol suspension was prepared by first adding titanium tetra isopropoxide (Ti(OPr)₄ or TTP) to a mixture of ethanol and HCl (molar ratio TTP:HCl:EtOH:H₂O = 1:1.1:10:10) and then adding a 2 wt.% solution of methylcellulose (MC). The TiO₂ nanopowder was dispersed in the sol and the mixture was deposited on a microscope glass slide by spin coating. Problems of film inhomogeneity and defects which caused peeling and cracking during calcinations, because of film shrinkage, were overcome by using MC as a dispersant. Effect of MC on the structure evaluation, crystallization behavior and mechanical integrity with thermal treatment up to 500 °C are followed by SEM, XRD and scratch test. XRD Scanning electron microscopy (SEM) showed that the composite films with MC have much rougher surface than films made without MC. Composite films heat treated at approximately 500 °C have the greatest hardness values. For the composite thick film, the minimum load which caused the complete coating removal was 200 g/mm², an indication of a strong bond to the substrate. Photocatalytic activities of the composite film were evaluated through the degradation of a model pollutant, the textile dye, Light Yellow X6G (C.I. Reactive Yellow 2) and were compared with the activity of (i) a similar composite film without MC, and (ii) a TiO₂ nanopowder. The good mechanical integrity make this composite film an interesting candidate for practical catalytic applications.     

小麦醇溶蛋白膜力学性能与吸湿性研究

采用小麦醇溶蛋白的乙醇/水(70/30(v/v))溶液制备了醇溶蛋白膜,分析了交联剂用量与pH值对膜的拉伸性能、吸水性及透湿性的影响.结果表明,适度交联的醇溶蛋白膜具有最大拉伸强度与较高的断裂伸长率.随交联剂用量增加,膜的吸水率稍有下降,而透湿性显著增大.酸碱处理能显著提高膜的拉伸强度,但使吸水性稍有增大.     

Effects of plasticizers on the properties of oat starch films

Oat starch films were prepared by casting using glycerol, sorbitol, glycerol–sorbitol mixture, urea and sucrose as plasticizers. The effects of these plasticizers on the microstructure, moisture sorption, water vapor permeability (WVP) and mechanical properties were investigated using films stored under a range of relative humidities. The plasticizer type did not affect significantly (p ≤ 0.05) the equilibrium moisture content of films, except at 90% relative humidity (RH). Films without plasticizer adsorbed less water and showed higher WVP than plasticized ones, indicating the antiplasticizing effect observed in this work. In general, a decrease in stress at break and Young's modulus and an increase in strain at break were observed when RH increased in all film formulations. Films without plasticizer showed higher stress at break values than the plasticized ones and presented stable strain at break under a range of RH. Sucrose films were the most fragile at low RH while glycerol films were the most hygroscopic.     

Antimicrobial and in vitro wound healing properties of novel clay based bionanocomposite films

The present study investigates the development of methyl cellulose (MC)–sodium alginate (SA)–montmorillonite (MMT) clay based bionanocomposite films with interesting wound healing properties. The differential scanning calorimetry analysis of the composite films revealed presence of single glass transition temperature (T_g) confirming the miscible nature of the ternary blended films. The increase in MMT ratio in the composite films reduced the mobility of biopolymer chains (MC/SA) which increased the T_g of the film. Thermogravimetric analysis showed that dispersion of clay (MMT) at nano level significantly delayed the weight loss that correlated with higher thermal stability of the composite films. It was observed that the developed films were able to exhibit antimicrobial activity against four typical pathogenic bacteria found in the presence of wound. The developed films were able to significantly inhibit (10 mg/ml) the growth of Enterococcus faecium and Pseudomonas aeruginosa. In vitro scratch assay indicated potential wound closure activities of MC-2–4 bionanocomposite films at their respective highest subtoxic doses. In conclusion, these ternary bionanocomposite films were found to be promising systems for wound healing applications.     

Orientation of J-aggregate molecules in Langmuir film and Langmuir-Blodgett films of merocyanine dyes mixed with arachidic acid and n-octadecane and irradiation effect of visible light

Langmuir (L) film and Langmuir-Blodgett (LB) films of a merocyanine dyes (MC) containing C₁₈ alkyl chain mixed with arachidic acid (AA) and n-octadecane (OD) were fabricated. Surface-pressure-area isotherms of an L film and absorption spectra of LB films deposited on a substrate were measured. Amphiphilic molecular orientation in the L film and the built-up proportion of MC J-aggregates to monomer and H-aggregates in MC-LB films mixed with AA and OD were controlled by altering the molar ratio of AA and OD to MC. The built-up proportion of MC J-aggregates in LB films decreased and the J-aggregates decayed to monomer and H-aggregates by increasing the exposure power of a 608-nm monochromatic light.     

Effects of film forming and hydrophobic properties of starches on surface sized packaging paper

The effect on mechanical and barrier properties upon addition of glycerol to temperature‐responsive hydrophobically modified (HM) potato starch was studied on free films. The addition of glycerol lowered the glass transition temperature, the storage modulus, and the water vapor permeability (WVP) for the HM starch films. The HM starch phase separates upon cooling below an upper critical temperature into a solid and a liquid phase. Adding glycerol to the warm starch solution had an inhibiting effect on the particulate precipitation. Substrates surface sized with HM starch with various amounts of glycerol were investigated with respect to barrier properties; WVP, contact angle and Cobb values. Hydroxypropylated starch was used as a reference. Cobb values and WVP results on surface‐sized substrates indicated that the film formation properties of the starches were of great importance for the final surface properties. Good film formation properties were essential for the gas barrier and water resistance while they were less important for high contact angles. The WVP decreased as the glycerol content of the sizes increased, but no sufficient water vapor barrier could be obtained. The HM starches investigated in this work provided good oxygen barrier and the contact angles indicated a hydrophobic character of the surface. The role of the precipitate was investigated, and surface sizing with the precipitate gave low WVP and high contact angles despite its poor film‐forming properties under the experimental conditions. Cobb60 values were slightly improved for HM starch with increasing glycerol content over glycerol‐free sizing. Copyright © 2007 John Wiley & Sons, Ltd.     

Deposition of Cu–Mn alloy film from supercritical carbon dioxide for advanced interconnects

Cu–Mn alloy films for microelectronic interconnects were deposited by H₂ reduction of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)-copper(II) [Cu(tmhd)₂] and bis(penta-methylcyclopentadienyl)-manganese [Mn(pmcp)₂] in supercritical carbon dioxide (scCO₂). 20-nm thick and continuous Cu–Mn films with a smooth surface were deposited at the temperature of 210 °C. Manganese was found to be segregated to film surface and its content on the surface increased with increasing Mn precursor concentration in scCO₂. Mn addition by supercritical fluid deposition could improve surface quality of the Cu film. And electrical resistivity of the Cu–Mn films increased with the Mn contents in the film.     

Thermoplastic starch/polyester films: Effects of extrusion process and poly (lactic acid) addition

Biodegradable films were produced using the blown extrusion method from blends that contained cassava thermoplastic starch (TPS), poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) with two different extrusion processes. The choice of extrusion process did not have a significant effect on the mechanical properties, water vapor permeability (WVP) or viscoelasticity of the films, but the addition of PLA decreased the elongation, blow-up ratio (BUR) and opacity and increased the elastic modulus, tensile strength and viscoelastic parameters of the films. The films with 20% PLA exhibited a lower WVP due to the hydrophobic nature of this polymer. Morphological analyses revealed the incompatibility between the polymers used.     

Leaching of water-soluble plasticizers from polymeric films prepared from aqueous colloidal polymer dispersions

The leaching of water-soluble plasticizers from polymeric films prepared by casting and drying of plasticized colloidal polymer dispersions was investigated with respect to the type and concentration of plasticizer (triethyl citrate or triacetin), film thickness, type of colloidal polymer dispersions (acrylic: Eudragit RS30D, RL30D, or L30D; cellulosic: Aquacoat), Eudragit RS30D/RL30D ratio, and method of film preparation (solvent- or pseudolatex-casting). The leaching increased with increasing level of plasticizer as indicated by an increase in the release rate constant while the release rate constant was independent of the film thickness. The leaching was more rapid from Aquacoat films than from Eudragit RS30D films at all plasticizer concentrations. Increasing the amount of the more hydrophilic polymer dispersion, Eudragit RL30D, in mixed Eudragit RS/RL films increased the rate of leaching. The incorporation of propranolol HCl into the polymeric films significantly increased the leaching rate constant when compared to drug-free films. The leaching from pseudolatex-cast films was faster when compared to the leaching from solvent-cast films due to the denser structure of the solvent-cast films.     

Preparation of Zn(In)Se films from alloyed precursors

Single-phase cubic Zn(In)Se thin film growth by Se vapor selenization of Zn(In) alloy precursors films is described. Depositing the Zn(In) precursor film at higher substrate temperatures changes the In/Zn composition and also yields highly crystalline Zn(In)Se films. The In/Zn ratio in the selenized film is higher in comparison to that of the precursor due to differential selenization kinetics and the complex In-Se and Zn-Se reaction chemistry. The resistivity of the Zn(In)Se film depends on the In/Zn ratio. Initially, the resistivity increases with increased indium incorporation due to increased defect concentration and then decreases at higher In/Zn ratios because of lower grain-boundary effects and reduced trap density owing to improvement in film crystallinity. Treatment with vapor-phase Zn compensates for Zn vacancies in the film, reduces electrically inactive defects, and increases doping efficiency, thereby lowering the resistivities to ∼1 Ω cm. Hot-probe and thermoelectric power measurements show that all low resistive ZnSe films are n-type.     

Leaching of water-soluble plasticizers from polymeric films prepared from aqueous colloidal polymer dispersions

Abstract

The leaching of water-soluble plasticizers from polymeric films prepared by casting and drying of plasticized colloidal polymer dispersions was investigated with respect to the type and concentration of plasticizer (triethyl citrate or triacetin), film thickness, type of colloidal polymer dispersions (acrylic: Eudragit RS30D, RL30D, or L30D; cellulosic: Aquacoat), Eudragit RS30D/RL30D ratio, and method of film preparation (solvent- or pseudolatex-casting). The leaching increased with increasing level of plasticizer as indicated by an increase in the release rate constant while the release rate constant was independent of the film thickness. The leaching was more rapid from Aquacoat films than from Eudragit RS30D films at all plasticizer concentrations. Increasing the amount of the more hydrophilic polymer dispersion, Eudragit RL30D, in mixed Eudragit RS/RL films increased the rate of leaching. The incorporation of propranolol HCl into the polymeric films significantly increased the leaching rate constant when compared to drug-free films. The leaching from pseudolatex-cast films was faster when compared to the leaching from solvent-cast films due to the denser structure of the solvent-cast films.     

Europium incorporated barium titanate thin films for optical applications

BaTiO₃:Eu (BT:Eu) thin films were deposited onto quartz substrates by RF magnetron sputtering. The effect on structural, morphological, optical and photoluminescence (PL) properties in the films with different Eu concentrations (0–5 wt%) were investigated. The X-ray diffraction (XRD) pattern of the undoped BT thin film revealed a tetragonal (T) phase with orientations along (101) plane. From XRD pattern, the crystallinity of the films increased with increase in Eu concentration. The SEM images revealed that the films exhibited tetragonal shape, crack free and good adherence to the substrate. Atomic force microscopy studies showed an increase of grain growth with doping concentration. The rms roughness value increased with increase in Eu concentration and the film surface revealed positive skewness and high value of kurtosis which make them suitable for tribological applications. X-ray photoelectron spectroscopy revealed the presence of barium, titanium, europium and oxygen in BT:Eu film. An average transmittance of >80 % (in visible region) was observed for all the films. Optical band gap of Eu doped BT films decreased from 3.86 to 3.53 eV. Such films with optical properties such as high transparency, decrease in band gap and high refractive index are suitable for optoelectronic applications. PL properties showed a sharp line at 625 nm and a broad line at 552 nm due to europium (Eu³⁺) transitions. PL phenomena were observed, owing to the electronic structure of Eu³⁺ ions as well as BT nanocrystallites in the films. The sharp and intense red luminescence is useful for photoelectric devices and optical communications.     

POSS对壳聚糖膜的阻湿与拉伸性能的影响

目的研究以四甲基铵基笼形聚倍半硅氧烷(Octa TMA POSS)为填料,制备壳聚糖基复合膜,对壳聚糖薄膜的水蒸气阻隔性能和力学性能进行改善。方法采用溶液共混流延法制备复合膜,测定其水蒸气透过系数、表面接触角、溶胀度、溶解度、吸附等温曲线、拉伸性能、成膜液流变性能、微观形貌和X射线衍射等。结果笼形聚倍半硅氧烷的加入可提高复合膜对水分子的阻隔性,尤其是质量分数为3%时,其水蒸气透过系数下降了15.9%。同时,壳聚糖薄膜的力学性能也得到改善,在质量分数低于5%时,壳聚糖薄膜的抗拉强度、弹性模量可同时得到提高。结论四甲基铵基笼形聚倍半硅氧烷的加入可改善壳聚糖薄膜的阻湿性能和力学性能,可大大提升其在食品包装领域的应用潜力。