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Influence of the relative amounts of crystalline and amorphous phases on the mechanical properties of polyamide-6 nanocomposites

Gargalaka Jr., Joao; Couto, Ricardo A. A.; Constantino, Vera Regina Leopoldo; Toma, Henrique Eisi; Araki, Koiti
Fonte: WILEY-BLACKWELL; MALDEN Publicador: WILEY-BLACKWELL; MALDEN
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.08%
The relative amounts of amorphous and crystalline ?- and a-phases in polyamide-6 nanocomposites, estimated from the deconvolution of X-ray diffraction peaks using Gaussian functions, correlates with their mechanical, thermomechanical, and barrier properties. The incorporation of organoclay platelets (Cloisite 15A and 30B) induced the crystallization of the polymer in the ? form at expense of the amorphous phase, such that 12 wt % of Cloisite is enough to enhance the mechanical and the thermomechanical properties. However, higher nanofiller loads were necessary to achieve good barrier effects, because this property is mainly dependent on the tortuous path permeation mechanism of the gas molecules through the nanocomposite films. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)

Cassava starch biodegradable films: Influence of glycerol and clay nanoparticles content on tensile and barrier properties and glass transition temperature

Souza, A. C.; Benze, R.; Ferrão, E. S.; Ditchfield, C.; Coelho, A. C. V.; Tadini, C. C.
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.2%
In this this study, glycerol content and its incorporation method on tensile and barrier properties of biodegradable films (BF) based on cassava starch were analyzed. ANOVA showed that the glycerol incorporation method did not influence the results (P > 0.05), however the glycerol content influenced significantly the tensile and barrier properties of the films (P < 0.05). Films prepared with lower glycerol content presented better tensile and barrier properties than films with higher content. Films were then prepared with addition of clay nanoparticles and their tensile and barrier properties and glass transition temperature were measured. ANOVA indicated that both glycerol and clay nanoparticles influenced significantly the tensile and barrier properties (P < 0.05), diminishing film permeability when clay nanoparticles were present, while the glass transition temperature was not influenced (P > 0.05). (C) 2011 Elsevier Ltd. All rights reserved.; FAPESP (The State of Sao Paulo Research Foundation); CAPES (Brazilian Committee for Postgraduate Courses in Higher Education)

Influence of ethanol and glycerol concentration over functional and structural properties of zein-oleic acid films

Pena-Serna, Carolina; Lopes-Filho, José Francisco
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 580-585
ENG
Relevância na Pesquisa
55.96%
This study was performed in order to determine the effect of the addition of different concentrations of glycerol and ethanol over functional and structural properties of zein-oleic acid films. Films were prepared from zein and oleic acid formulations, containing: 0, 10, 20 and 30% (w/w) of glycerol as plasticizer and 75, 80, 85, 90 and 95% (v/v) of ethanol as zein solvent. Water vapor permeability (WVP) at 4 and 24 C, opacity, water solubility and structural behavior of the film were assessed. The film water barrier properties, WVP and water solubility, were increased when higher ethanol concentration and lower glycerol concentration were used. Furthermore, WVP at 4 C was lower than WVP at 24 C due to the crystalline solid state of oleic acid at lower temperatures. Likewise, opacity, homogeneity and structure of the composite film were improved as ethanol increased and glycerol lowered. © 2013 Elsevier B.V. All rights reserved.

Propriedades mecanicas e de barreira, solubilidade e microestrutura de filmes de farinha de amaranto modificada com epicloridrina ou misturada com poli (vinil alcool).; Mechanical and barrier properties, solubility and microstructure of amaranth flour films crosslinked with epicholorohydrin or blended with poly (vinyl alcohol).

Nadiarid Jimenez Elizondo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/03/2007 PT
Relevância na Pesquisa
56.09%
O amaranto apresenta-se como uma matéria prima interessante para a elaboração de filmes biodegradáveis por seu conteúdo em amido, proteína e lipídeos. Embora o amaranto não seja nativo do Brasil, seu cultivo está sendo desenvolvido nos solos dos cerrados brasileiros com bons resultados. Isto incentiva o desenvolvimento de alternativas para o uso comercial do amaranto. Filmes elaborados a partir de amaranto da variedade caudatus (TAPIA-BLÁCIDO, 2003) resultaram em materiais com excelentes propriedades de barreira, entretanto apresentaram propriedades mecânicas pobres. Estudos desenvolvidos com a variedade que está sendo implantada no Brasil (Amarantus cruentus) com adição de ácido esteárico apresentaram as mesmas características (COLLA, 2004). Assim, o objetivo desta pesquisa foi o estudo do processo de elaboração de dois tipos de filmes biodegradáveis: (1) filmes de farinha de amaranto (A.cruentus) reticulados com epicloridrina e (2) a partir de blendas de farinha de amaranto (A.cruentus) com poli (vinil álcool) (PVA); assim como a avaliação do efeito das duas estratégias (reticulação e PVA) sobre as características mecânicas e de barreira dos biofilmes. O efeito da reação de reticulação (concentração de epicloridrina (1...

The effect of argon plasma treatment on the permeation barrier properties of silicon nitride layers

Majee, Subimal; Cerqueira, M. F.; Tondelier, D.; Geffroy, B.; Bonnassieux, Y.; Alpuim, P.; Bourée, J. E.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em 03/08/2013 ENG
Relevância na Pesquisa
56.09%
In this work we produce and study silicon nitride (SiNx) thin films deposited by Hot Wire Chemical Vapor Depo- sition (HW-CVD) to be used as encapsulation barriers for flexible organic photovoltaic cells fabricated on poly- ethylene terephthalate (PET) substrates in order to increase their shelf lifetime. We report on the results of SiNx double-layers and on the equivalent double-layer stack where an Ar-plasma surface treatment was performed on the first SiNx layer. The Ar-plasma treatment may under certain conditions influences the structure of the interface between the two subsequent layers and thus the barrier properties of the whole system. We focus our attention on the effect of plasma treatment time on the final barrier properties. We assess the encapsulation barrier properties of these layers, using the calcium degradation test where changes in the electrical conductance of encapsulated Ca sensors are monitored with time. The water vapor transmission rate (WVTR) is found to be ~3 × 10−3 g/m2·day for stacked SiNx double-layer with 8 min Ar plasma surface treatment.; FCT - CNRS PICS (French–Portuguese no: 5336) project; Direction des Relations Extérieures, Ecole Polytechnique

Effect of glucose oxidase incorporation in chitosan edible films properties

Lopes, M. I.; Martins, Joana; Fonseca, L. P.; Vicente, A. A.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 ENG
Relevância na Pesquisa
56.03%
Demand for biodegradable and environmentally friendly packaging has draw attention into the development of biodegradable, polymer based edible packaging films. Edible films’ functionality can be enhanced by incorporating active substances such as biocatalysts. The main objective of this work was to evaluate the effect of GOx incorporation in the mechanical and barrier properties of chitosan edible films. Films were prepared by the casting method using 2% (w/v) chitosan with 25% (w/w) glycerol, containing 1.1% (v/v) of a glucose oxidase solution (0.02% (w/v)). Water vapor, oxygen and carbon dioxide permeabilities were evaluated and Fourier Transform InfraRed (FTIR) analysis was performed. The results of the mechanical tests showed that tensile strength and elongation-at-break values of chitosan films increased with the incorporation of glucose oxidase (from 9.6 to 10.6 MPa and from 65.5 to 71.6 %, respectively), however no significant (p<0.05) changes were observed. From permeability tests it was observed that the barrier properties of chitosan films were not affected by the enzyme incorporation. FTIR analysis showed a specific chemical interaction between functional groups of glucose oxidase and bioactive groups of chitosan. These results suggest that chitosan films with incorporated GOx could be used as active packaging as a strategy for extension of food’s shelf-life.

Preparation and evaluation of the barrier properties of cellophane membranes modified with fatty acids

Tomé, Liliana C.; Gonçalves, Carla M. B.; Boaventura, Marta; Brandão, Lúcia; Mendes, Adélio M.; Silvestre, Armando J. D.; Neto, Carlos Pascoal; Gandini, Alessandro; Freire, Carmen S. R.; Marrucho, Isabel M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.08%
Cellophane (regenerated cellulose) membranes with tailored properties regarding hydrophobic character and barrier effects were prepared by their controlled heterogeneous esterification with two fatty acid derivatives (hexanoyl and dodecanoyl chlorides) The characterization of the modified membranes was performed by FUR spectroscopy X-ray diffraction and thermogravimetry confirming the success of the heterogeneous modification reaction while keeping cellophane membranes structural properties Contact angle measurements clearly confirm the enhanced hydrophobic character displayed by the modified cellophane membranes The evaluation of their barrier properties was carried out by determining the permeability towards water vapor at different relative humidities and the permeability towards nitrogen oxygen and carbon dioxide using the time-lag method in both wet and dry states A decrease in both the water permeation and the permeability towards these gases in the wet state was observed for the modified membranes No significant differences in behavior were found between the membranes prepared with hexanoyl and dodecanoyl chloride regarding hydrophobicity but the different lengths of the chain allowed a fine tune of the permeability The obtained cellophane membranes are a good example of the development of new bio-based materials with improved surface and barrier properties (C) 2010 Elsevier Ltd All rights reserved; FCT - PTDC/QUI/68472/2006

Plastic packages for personal care products: evaluation of light barrier properties

Coltro,Leda; Borghetti,Joyce
Fonte: Associação Brasileira de Polímeros Publicador: Associação Brasileira de Polímeros
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2007 EN
Relevância na Pesquisa
55.93%
The use of transparent packages has great marketing appeal since they allow consumers to actually see the product they wish to buy. However, the light that passes through the packaging material may catalyze oxidation reactions in photosensitive products and reduce their shelf life. The use of UV absorbers in packages for personal care products is an increasing tendency in the market due to growing consumer preference for more natural, non-additive products. UV absorbers prevent photo-degradation of the product as a result of the UV light barrier properties of the packaging, which protect the product against UV rays in the wavelength range of 200-380 nm. Although a number of studies indicate the need for the use of UV absorbers, they do not mention any technical reference data that could be used as quality parameters for packaging systems. Therefore, the objective of this study was to evaluate the effectiveness of UV absorbers as light barriers in plastic packages of personal care products in order to generate technical data required to establish specifications for these packaging systems.

Water barrier properties of starch-clay nanocomposite films

Slavutsky,Aníbal Marcelo; Bertuzzi,María Alejandra; Armada,Margarita
Fonte: Instituto de Tecnologia de Alimentos - ITAL Publicador: Instituto de Tecnologia de Alimentos - ITAL
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
Relevância na Pesquisa
66.04%
The functional properties of corn starch based films were improved by incorporating nanoclay (Montmorillonite). Nanoclay was incorporated in the polymer matrix using two different methodologies and the films were formed by casting. The effect of film preparation methodology and of the nanoclay concentration on the physicochemical properties of the films was studied. Depending on film preparation method used, intercalated or exfoliated nanocomposite films were obtained. The FTIR spectra showed a strong interaction between the montmorillonite and the starch molecules. Opacity was dependent on the nanoclay dispersion method used. Water vapor solubility and permeability decreased with increasing montmorillonite content and were affected by the dispersion method. Water diffusion was only dependent on the nanoclay content due to the increase in tortuosity of the diffusion path, caused by the nanoparticles. The results showed that the incorporation of 5% of montmorillonite using an adequate dispersion method, improved the water resistance and barrier properties of corn starch based films. Nanoparticles reduced the damage caused to the properties of these hydrophilic films by the increase in moisture content.

Barrier properties of testis microvessels.

Holash, J A; Harik, S I; Perry, G; Stewart, P A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/12/1993 EN
Relevância na Pesquisa
46.06%
The blood-testis barrier is believed to be constituted by tight junctions between Sertoli cells in seminiferous tubules and possibly by myoid cells that encircle these tubules. We now show that testis microvessels are endowed with several markers of barrier properties of brain microvessels, such as the glucose transporter, P-glycoprotein, and gamma-glutamyl transpeptidase. Quantitative EM studies show that the endothelium in testis, as in brain, is continuous and has long junctional profiles and few vesicles. However, a small proportion of testis capillaries have expansions in their junctional clefts suggestive of patent paracellular channels, which may explain their higher permeability. Because barrier features are thought to be induced and/or maintained in brain microvessels by astrocytes, we assessed whether astrocyte-like cells exist in the testis. We found that the intertubular Leydig cells, adjacent to microvessels, express the astrocyte markers: glial fibrillary acidic protein, glutamine synthetase, and S-100 protein. We suggest that the testis endothelium contributes to the blood-testis barrier and that these endothelial barrier features are influenced by Leydig cells. We believe that the endothelial and the epithelial (Sertoli) components of the blood-testis barrier are "in series" and complement each other in achieving a stable milieu for spermatogenesis.

Effect of Surfactant Mixtures on Skin Structure and Barrier Properties

James-Smith, Monica A.; Hellner, Brittney; Annunziato, Nancy; Mitragotri, Samir
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.08%
We investigated the effect of two commonly studied surfactants, sodium dodecyl sulfate (SDS) and dodecyl trimethylammonium bromide (C12TAB), on skin barrier properties. Using skin conductivity, FT-IR of stratum corneum samples, and penetration of radiolabelled SDS, we determined that addition of C12TAB lowers the ability of SDS to perturb skin’s barrier properties. Ultrafiltration experiments revealed that addition of C12TAB serves to decrease the concentration of monomers and sub-micellar aggregates. None of the measured skin properties including enhancement of skin conductivity, perturbation of lipid structure and skin concentration of SDS correlated with the total SDS concentration in the donor compartment (i.e., the total SDS concentration). However, all these parameters correlated well against the concentration of monomers and sub-micellar aggregates. These findings provide the evidence of the importance of monomer and sub-micellar components in altering skin barrier properties.

Impedance-based cell monitoring: barrier properties and beyond

Benson, Kathrin; Cramer, Sandra; Galla, Hans-Joachim
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 10/01/2013 EN
Relevância na Pesquisa
46.08%
In multicellular organisms epithelial and endothelial cells form selective permeable interfaces between tissue compartments of different chemical compositions. Tight junctions which connect adjacent cells, control the passage of molecules across the barrier and, in addition, facilitate active transport processes. The cellular barriers are not static but can be deliberately modulated by exposure to specific external stimuli. In vitro models representing the essential absorption barriers of the body are nowadays available, thus allowing investigation of the parameters that control permeability as well as transport processes across those barriers. Independent of the origin of the barrier forming cells, techniques are needed to quantify their barrier integrity. One simple assay is to measure the permeability for given hydrophilic substrates possessing different molecular weights like sucrose or dextrans. However, this technique is time-consuming and labor-intensive. Moreover, radioactive or fluorescently-labeled substrates are needed to allow easy analytical detection. Finally, if transport processes are investigated, the standard permeant may interfere with the transport process under investigation or might even alter the barrier integrity by itself. Thus...

The stratum corneum comprises three layers with distinct metal-ion barrier properties

Kubo, Akiharu; Ishizaki, Itsuko; Kubo, Akiko; Kawasaki, Hiroshi; Nagao, Keisuke; Ohashi, Yoshiharu; Amagai, Masayuki
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 25/04/2013 EN
Relevância na Pesquisa
46.08%
The stratum corneum (SC), the outermost barrier of mammalian bodies, consists of layers of cornified keratinocytes with intercellular spaces sealed with lipids. The insolubility of the SC has hampered in-depth analysis, and the SC has been considered a homogeneous barrier. Here, we applied time-of-flight secondary ion mass spectrometry to demonstrate that the SC consists of three layers with distinct properties. Arginine, a major component of filaggrin-derived natural moisturizing factors, was concentrated in the middle layer, suggesting that this layer functions in skin hydration. Topical application of metal ions revealed that the outer layer allowed their passive influx and efflux, while the middle and lower layers exhibited distinct barrier properties, depending on the metal tested. Notably, filaggrin deficiency abrogated the lower layer barrier, allowing specific metal ions to permeate viable layers. These findings elucidate the multi-layered barrier function of the SC and its defects in filaggrin-deficient atopic disease patients.

Structure, wettability, and barrier properties of self-assembled monolayers on metallic surfaces

Srivastava, Piyush
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
46.17%
Self-assembled monolayers (SAMs) offer a convenient approach for fabricating molecularly tailored interfaces with well-defined compositions, structures, and thicknesses. SAMs have been suggested for use as corrosion barriers, antifouling coatings, and as components of molecular electronics and lithography. Still, researchers lack the molecular description of the interfacial properties, structural features, and barrier properties of SAMs that would be useful for optimizing and tailoring the behavior of SAMs. This dissertation makes connections between the molecular level structural features of SAMs and macroscopic properties such as wettability and barrier properties using molecular dynamics (MD) simulations and experimental techniques. MD simulations were performed to explain the unexpected experimental observation that the wetting properties of some liquids on SAMs prepared using alkanethiols (CnSH) depend on whether the chain length (n) is odd or even. The difference in near-surface structure of the liquid (and not that of reorganization events by the monolayer) appears responsible for the high sensitivity of hexadecane and the general insensitivity of water to the structural differences expressed by odd- and even-chained monolayer surfaces. MD simulations were also performed to investigate the influences of molecular structure on the ability of n-alkanethiolate SAMs on gold and copper to act as barrier films against through-film oxygen transport as relevant to the uses of these films in corrosion inhibition. The barrier resistances offered by these films towards oxygen transport...

PLA/PHBV Films with Improved Mechanical and Gas Barrier Properties

BOUFARGUINE, Majdi; GUINAULT, Alain; MIQUELARD-GARNIER, Guillaume; SOLLOGOUB, Cyrille
Fonte: WILEY Publicador: WILEY
EN
Relevância na Pesquisa
55.93%
Blending poly(lactic acid) (PLA) with a small amount of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV; 10 wt%) using a custom multilayer co-extrusion process increases both ductility and gas barrier properties of extruded films compared with neat PLA and classical blending methods. The co-extrusion process allows multiplication of the number of alternate layers of PLA and PHBV within a film. It was observed that for a critical number of theoretical layers, PHBV layers are broken into lamellas. A well-developed lamellar morphology, with thin and long lamellas of highly crystalline PHBV in PLA matrix was obtained. A balance between aspect ratio and crystallinity of the lamellas, and their dispersion within the PLA matrix was needed to obtain films with improved permeability and mechanical properties.

Propriedades de barreira e solubilidade de filmes de amido de ervilha associado com goma xantana e glicerol; Barrier properties of films of pea starch associated with xanthan gum and glycerol

MATTA JR, Manoel D. da; SARMENTO, Silene B. S.; SARANTÓPOULOS, Claire I. G. L.; ZOCCHI, Silvio S.
Fonte: Associação Brasileira de Polímeros Publicador: Associação Brasileira de Polímeros
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
66.06%
O objetivo do trabalho foi avaliar as propriedades de barreira e a solubilidade de biofilmes obtidos a partir de amido de ervilha de alto teor de amilose em associação à goma xantana e glicerol. Soluções filmogênicas (SF) com diferentes teores de amido de ervilha (3, 4 e 5%), goma xantana (0, 0,05 e 0,1%) e glicerol (proporção glicerol-amido de 1:5 P/P) foram estudadas. As SF foram obtidas por ebulição (5 minutos), seguida de autoclavagem por 1 hora a 120 ºC e os filmes foram preparados por casting. O aumento da concentração de amido e de glicerol na composição causou aumento da espessura e da solubilidade dos filmes em água. O plastificante gerou ainda elevação dos coeficientes de permeabilidade ao vapor d'água e ao oxigênio. O aumento da concentração da goma xantana não interferiu nas propriedades estudadas. Os biofilmes obtidos a partir de amido de ervilha verde, associado ou não à goma xantana e glicerol, se comparados com filmes de amido de ervilha amarelas e outras fontes de amido, apresentaram boa barreira ao oxigênio e ao vapor d'água e baixa solubilidade em água.; The aim of this work was to evaluate the barrier properties and solubility of biofilms made from wrinkled pea starch with high amylose content in association with xanthan gum and glycerol. Filmogenic solution (FS) with different levels of pea starch (3...

Effect of the type of clay organo-modifier on the morphology, thermal/ mechanical/ impact/barrier properties and biodegradation in soil of polycaprolactone/clay nanocomposites

Ludueña, Leandro Nicolas; Vazquez, Analia; Alvarez, Vera Alejandra
Fonte: John Wiley & Sons Inc Publicador: John Wiley & Sons Inc
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
Relevância na Pesquisa
56.03%
The effect of addition of unmodified (CNaþ) and modified (C30B and C20A) montmorillonites on the performance of polycaprolactone (PCL) based nanocomposites prepared by melt intercalation was studied. The study covers morphological and thermal aspects, mechanical and barrier properties and also biodegradability, which are important for packaging applications. Particular effort was made to find the main characteristics of the clays responsible for the final clay dispersion degree inside the nanocomposite. The most hydrophobic reinforcement (demonstrated by water adsorption tests) also showed the strongest thermal stability (shown by thermogravimetrical analysis) and the larger basal spacing (calculated by X-ray diffractometry (XRD)), which were the main characteristics that led to the best clay dispersion degree inside the PCL matrix (demonstrated by XRD and Transmission Electron Microscopy (TEM)). The findings demonstrate that a biodegradable polymer/clay nanocomposite with enhanced mechanical, impact, and barrier properties was obtained.; Fil: Ludueña, Leandro Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina; Fil: Vazquez...

Comparative performance and barrier properties of biodegradable thermoplastics and nanobiocomposites vs. PET for food packaging applications

Cava, David; Giménez, Enrique; Gavara, Rafael; Lagarón Cabello, José María
Fonte: Society of Plastics Engineers Publicador: Society of Plastics Engineers
Tipo: Artículo Formato: 235434 bytes; 2459 bytes; application/pdf; text/plain
ENG
Relevância na Pesquisa
66.11%
This article reports on preliminary studies of several comparative packaging properties between polyethylene terephthalate (PET) packaging films and biodegradable biopolymers such as polycarpolactone (PCL), polylacticacid (PLA), amorphous PLA (aPLA), and polyhydroxyalcanoates copolymer with 8 mol% valeriate (PHBV) and of some nanobiocomposites, in terms of thermal and retorting resistance (thermal humid processes) and oxygen, water vapor, aroma, and solvent barrier by means of time-resolved synchrotron radiation, FT-IR and direct permeation methods. This work suggests that while PHBV can easily withstand retorting and shows excellent water and aroma (limonene and linalool) barriers compared with PET, its solvent resistance (toluene and ethanol) and oxygen barrier properties are poorer. First trials with compression molded food contact complying nanobiocomposites of PCL and aPLA show enhanced oxygen barrier but not sufficient, as yet, to outperform high-oxygen-barrier grades of PET film.

Edible films and coatings for cheese; Filmes e revestimentos comestíveis para queijos

Orosa, Maria Inês Franco
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
46.07%
Over the last years there has been an increasing interest to replace synthetic materials by biodegradable ones, due to the ecological problems. Edible and biodegradable films can be produced using polysaccharides, lipids, proteins and composites, and act as a package without damaging the environment. By choosing a suitable coating composition it is possible to preserve several desired properties of a certain food product. Important properties should be considered, such as mechanical, functional and barrier properties. The main goal of this study was to evaluate edible films and coatings from plant proteins (pea, soy), with incorporated natural antimicrobial and antioxidant agents, to potentially protect cheese from physico-chemical and microbial deterioration and to preserve the organoleptic characteristics, especially of sliced cheeses. The work performed focused mainly on the preparation and characterization of pea protein films, with added chitooligosaccharides (COs) (0.5%, 1% and 2%) and two types of essential oils at 1%, bay and thyme oils. Films with 0.5% of COs showed the highest values of Young’s modulus, tensile strength and elongation. Regarding the barrier properties, the film with 1% of COs showed the lower permeability value. Addition of small amounts of COs may be advantageous to improve the mechanical properties of the PPI films...

Effect of cellulose nanofibers concentration on mechanical, optical, and barrier properties of gelatin-based edible films

Andrade-Pizarro,Ricardo David; Skurtys,Olivier; Osorio-Lira,Fernando
Fonte: DYNA Publicador: DYNA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
66.01%
The effect of gelatin, glycerol, and cellulose nanofiber (CNFs) concentrations on the mechanical properties, water vapor permeability, and color parameters of films was evaluated. The results indicate that the color is only affected by the gelatin concentration. Mechanical tests indicated that with increasing concentration of gelatin and CNFs, there is an increase in tensile strength, whereas an increase in glycerol concentration causes an increase in elongation, making the films more flexible. An increased concentration of gelatin and glycerol makes the film more permeable to water vapor, while an increase in the concentration of CNFs reduces this property. Finally, the addition of CNFs to gelatin-based films improves their mechanical and barrier properties (water vapor) without affecting the appearance (color) of the films.