scholarly journals Preparation and Physicochemical Properties of Modified Corn Starch–Chitosan Biodegradable Films

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4431
Author(s):  
Enrique Javier Jiménez-Regalado ◽  
Carolina Caicedo ◽  
Abril Fonseca-García ◽  
Claudia Cecilia Rivera-Vallejo ◽  
Rocio Yaneli Aguirre-Loredo
Keyword(s):  
Water Vapor ◽  
Corn Starch ◽  
Low Cost ◽  
Composite Films ◽  
Hydroxyl Groups ◽  
Biodegradable Films ◽  
Amino Groups ◽  
Gas Barrier ◽  
Starch Films ◽  
The Impact

Starch is a biopolymer with enormous potential for generating new biodegradable packages due to its easy availability and low cost. However, due to its weak functional properties, limitation of its interaction with some hydroxyl groups and evaluation of blends with other polymers are necessary in order to improve its performance. Glycerol-plasticized acetylated corn starch films were developed using the casting method, and the impact of incorporating chitosan (TPS:CH) in various proportions (75:25, 50:50, and 25:75 v/v) was studied in the present research. The effect of chitosan ratios on the physical, mechanical, water-vapor barrier, and thermal properties of the film was studied. Chitosan-protonated amino groups promoted the formation of intermolecular bonds, improving tensile strength, thermal stability, hydrophobicity, water adsorption capacity, and the gas barrier of starch films. The results show that the film composed of TPS25-CH75 proved to be the best barrier to water vapor; thus, these composite films are excellent choices for developing biodegradable packaging for the food industry.

scholarly journals Preparation and Physicochemical Properties of Modified Corn Starch – Chitosan Biodegradable Films

2021 ◽  
Author(s):  
Enrique Javier Jiménez-Regalado ◽  
Carolina Caicedo ◽  
Abril Fonseca-García ◽  
Claudia Cecilia Rivera-Vallejo ◽  
Rocio Yaneli Aguirre-Loredo
Keyword(s):  
Water Vapor ◽  
Corn Starch ◽  
Composite Films ◽  
Biodegradable Films ◽  
Amino Groups ◽  
Gas Barrier ◽  
Starch Films ◽  
The One ◽  
The Impact ◽  
Wide Potential

Starch is a biopolymer with wide potential for the generation of new biodegradable packages due to its high availability and low price. However, due to its weak functional properties, it is necessary to limit the interaction of some hydroxyl, and to evaluate blends with other polymers to improve their performance. Glycerol plasticized acetylated corn starch films were developed by the casting method, and the impact of incorporating chitosan (TPS:CH) at various proportions (75:25, 50:50, and 25:75 v/v) was studied. The effect of the chitosan ratios on the films' physical, mechanical, water vapor barrier, and thermal properties was evaluated. Chitosan protonated amino groups promote the formation of intermolecular bonds, improving the tensile strength, the thermal stability, the water adsorption capacity, and the gas barrier of starch films. Where the film composed of TPS25-CH75 was the one that presented the best barrier to water vapor. These composite films are a good option for development of biodegradable packaging.

scholarly journals Flexible Thermoplastic Starch Films Functionalized With Copper Particles for Packaging of Food Products

2020 ◽  
Author(s):  
Olivia López ◽  
María E. Villanueva ◽  
Guillermo J. Copello ◽  
Marcelo A Villar
Keyword(s):  
Inhibitory Concentration ◽  
Corn Starch ◽  
Composite Films ◽  
Thermoplastic Starch ◽  
Biodegradable Films ◽  
Melt Mixing ◽  
Elongation At Break ◽  
Copper Particles ◽  
Starch Films ◽  
Fresh Products

Abstract Biodegradable films based on thermoplastic corn starch (TPS) and copper particles with antimicrobial capacity were developed. Copper nanoparticles (Cu) and silica coated copper microparticles (Si-Cu) in the range of 0.25 to 5 % were used. Composite films were obtained by melt-mixing and subsequent thermo-compression. Particles distribution within TPS matrix and the presence of some pores and cracks, induced by Si-Cu particles, was evaluated by SEM. The presence of both fillers gave to composite films a brown pigmentation and decreased their transparency; these effects were more pronounced at higher particles concentrations. Regarding mechanical properties, copper particles at 1 and 5 % acted as reinforcing agents increasing the maximum tensile strength but their presence lead to a decrease in elongation at break, affecting films ductility. Composites inhibited the growth of Gram+ and Gram- bacteria, demonstrating their antimicrobial capacity. Copper effectively migrated to a simulant of aqueous foods and naked particles concentration in the simulant medium resulted higher than the minimum inhibitory concentration for bacteria. The characteristics and properties of developed composite films make them an interesting material for food primary packaging, mainly for meat fresh products.

scholarly journals Flexible Thermoplastic Starch Films Functionalized With Copper Particles for Packaging of Food Products

2020 ◽  
Author(s):  
Olivia López ◽  
María E. Villanueva ◽  
Guillermo J. Copello ◽  
Marcelo A Villar
Keyword(s):  
Inhibitory Concentration ◽  
Corn Starch ◽  
Composite Films ◽  
Thermoplastic Starch ◽  
Biodegradable Films ◽  
Melt Mixing ◽  
Elongation At Break ◽  
Copper Particles ◽  
Starch Films ◽  
Fresh Products

Abstract Biodegradable films based on thermoplastic corn starch (TPS) and copper particles with antimicrobial capacity were developed. Copper nanoparticles (Cu) and silica coated copper microparticles (Si-Cu) in the range of 0.25 to 5 % were used. Composite films were obtained by melt-mixing and subsequent thermo-compression. Particles distribution within TPS matrix and the presence of some pores and cracks, induced by Si-Cu particles, was evaluated by SEM. The presence of both fillers gave to composite films a brown pigmentation and decreased their transparency; these effects were more pronounced at higher particles concentrations. Regarding mechanical properties, copper particles at 1 and 5 % acted as reinforcing agents increasing the maximum tensile strength but their presence lead to a decrease in elongation at break, affecting films ductility. Composites inhibited the growth of Gram+ and Gram- bacteria, demonstrating their antimicrobial capacity. Copper effectively migrated to a simulant of aqueous foods and naked particles concentration in the simulant medium resulted higher than the minimum inhibitory concentration for bacteria.The characteristics and properties of developed composite films make them an interesting material for food primary packaging, mainly for meat fresh products.

scholarly journals Flexible Thermoplastic Starch Films Functionalized With Copper Particles for Packaging of Food Products

2020 ◽  
Author(s):  
Olivia López ◽  
María E. Villanueva ◽  
Guillermo J. Copello ◽  
Marcelo A Villar
Keyword(s):  
Inhibitory Concentration ◽  
Corn Starch ◽  
Composite Films ◽  
Thermoplastic Starch ◽  
Biodegradable Films ◽  
Melt Mixing ◽  
Elongation At Break ◽  
Copper Particles ◽  
Starch Films ◽  
Fresh Products

Abstract Biodegradable films based on thermoplastic corn starch (TPS) and copper particles with antimicrobial capacity were developed. Copper nanoparticles (Cu) and silica coated copper microparticles (Si-Cu) in the range of 0.25 to 5 % were used. Composite films were obtained by melt-mixing and subsequent thermo-compression. Particles distribution within TPS matrix and the presence of some pores and cracks, induced by Si-Cu particles, was evaluated by SEM. The presence of both fillers gave composite films a brown pigmentation and decreased their transparency; these effects were more pronounced at higher particles concentrations. Regarding mechanical properties, copper particles at 1 and 5 % acted as reinforcing agents increasing the maximum tensile strength but their presence lead to a decrease in elongation at break, affecting films ductility. Composites inhibited the growth of Gram+ and Gram- bacteria, demonstrating their antimicrobial capacity. Copper effectively migrated to a simulant of aqueous foods and naked particles concentration in the simulant medium resulted higher than the minimum inhibitory concentration for bacteria. The characteristics and properties of developed composite films make them an interesting material for food primary packaging, mainly for meat fresh products.

Real-time and near real-time ZTD from a local network of low-cost dual-frequency GNSS receivers.

2021 ◽  
Author(s):  
Tomasz Hadas ◽  
Grzegorz Marut ◽  
Jan Kapłon ◽  
Witold Rohm
Keyword(s):  
Water Vapor ◽  
Real Time ◽  
Low Cost ◽  
Weather Prediction ◽  
Local Network ◽  
System Component ◽  
Dual Frequency ◽  
Lower Accuracy ◽  
Gnss Receivers ◽  
The Impact

<p>The dynamics of water vapor distribution in the troposphere, measured with Global Navigation Satellite Systems (GNSS), is a subject of weather research and climate studies. With GNSS, remote sensing of the troposphere in Europe is performed continuously and operationally under the E-GVAP (http://egvap.dmi.dk/) program with more than 2000 permanent stations. These data are one of the assimilation system component of mesoscale weather prediction models (10 km scale) for many nations across Europe. However, advancing precise local forecasts for severe weather requires high resolution models and observing system.   Further densification of the tracking network, e.g. in urban or mountain areas, will be costly when considering geodetic-grade equipment. However, the rapid development of GNSS-based applications results in a dynamic release of mass-market GNSS receivers. It has been demonstrated that post-processing of GPS-data from a dual-frequency low-cost receiver allows retrieving ZTD with high accuracy. Although low-cost receivers are a promising solution to the problem of densifying GNSS networks for water vapor monitoring, there are still some technological limitations and they require further development and calibration.</p><p>We have developed a low-cost GNSS station, dedicated to real-time GNSS meteorology, which provides GPS, GLONASS and Galileo dual-frequency observations either in RINEX v3.04 format or via RTCM v3.3 stream, with either Ethernet or GSM data transmission. The first two units are deployed in a close vicinity of permanent station WROC, which belongs to the International GNSS Service (IGS) network. Therefore, we compare results from real-time and near real-time processing of GNSS observations from a low-cost unit with IGS Final products. We also investigate the impact of replacing a standard patch antenna with an inexpensive survey-grade antenna. Finally, we deploy a local network of low-cost receivers in and around the city of Wroclaw, Poland, in order to analyze the dynamics of troposphere delay at a very high spatial resolution.</p><p>As a measure of accuracy, we use the standard deviation of ZTD differences between estimated ZTD and IGS Final product. For the near real-time mode, that accuracy is 5 mm and 6 mm, for single- (L1) and dual-frequency (L1/L5,E5b) solution, respectively. Lower accuracy of the dual-frequency relative solution we justify by the missing antenna phase center correction model for L5 and E5b frequencies. With the real-time Precise Point Positioning technique, we estimate ZTD with the accuracy of 7.5 – 8.6 mm. After antenna replacement, the accuracy is improved almost by a factor of 2 (to 4.1 mm), which is close to the 3.1 mm accuracy which we obtain in real-time using data from the WROC station.</p>

scholarly journals Preparation and Properties of Corn Starch/Chitin Composite Films Cross-Linked by Maleic Anhydride

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1606
Author(s):  
Peng Yin ◽  
Jinglong Liu ◽  
Wen Zhou ◽  
Panxin Li
Keyword(s):  
Maleic Anhydride ◽  
Corn Starch ◽  
Composite Films ◽  
Water Vapor Permeability ◽  
Contact Angles ◽  
Vapor Permeability ◽  
Water Contact ◽  
Elongation At Break ◽  
Shrimp Shell ◽  
Starch Films

To improve the functional properties of starch-based films, chitin (CH) was prepared from shrimp shell powder and incorporated into corn starch (CS) matrix. Before blending, maleic anhydride (MA) was introduced as a cross-linker. Composite CS/MA-CH films were obtained by casting-evaporation approach. Mechanical property estimation showed that addition of 0–7 wt % MA-CH improved the tensile strength of starch films from 3.89 MPa to 9.32 MPa. Elongation at break of the films decreased with the addition of MA-CH, but the decrease was obviously reduced than previous studies. Morphology analysis revealed that MA-CH homogeneously dispersed in starch matrix and no cracks were found in the CS/MA-CH films. Incorporation of MA-CH decreased the water vapor permeability of starch films. The water uptake of the films was reduced when the dosage of MA-CH was below 5 wt %. Water contact angles of the starch films increased from 22° to 86° with 9 wt % MA-CH incorporation. Besides, the composite films showed better inhibition effect against Escherichia coli and Staphylococcus aureus than pure starch films.

Preparation and Characterization of Corn Starch-Nanodiamond Composite Films

2013 ◽  
Vol 469 ◽  
pp. 156-161 ◽  
Author(s):  
Hong Pan ◽  
Dan Xu ◽  
Qin Liu ◽  
Hui Qing Ren ◽  
Min Zhou
Keyword(s):  
Water Vapor ◽  
Food Packaging ◽  
Corn Starch ◽  
Composite Films ◽  
Water Vapor Permeability ◽  
Nanocomposite Films ◽  
Vapor Permeability ◽  
Ft Ir ◽  
Loading Amount ◽  
Physical Blending

Starch-based nanocomposite films were fabricated by the incorporation of different amounts of nanodiamond (ND) particles. These films were characterized by SEM, FT-IR, TGA, tensile testing and water vapor permeability measurement. It was observed that at low loadings, ND dispersed well in starch matrix. However, as the loading amount increased, aggregates as large as several micrometers appeared. The physical blending of ND with starch didnt change the thermal degradation mechanisms of starch films, only increased the char residues. As the ND loading increased, the tensile strength of composite films increased but the elongation at break decreased. However, the water vapor permeability increased as the loading of ND increased due to the increased microspores in films. With further modifications, ND may be considered as a novel of biocompatible nanofillers for reinforcement of biopolymers for food packaging applications.

The Method of Introduced Amino Group for Preparation of Thermo-Responsive Textiles

2015 ◽  
Vol 671 ◽  
pp. 267-272
Author(s):  
Ju He ◽  
Yue Lin Jiang ◽  
Jin Dan Wu ◽  
Ji Ping Wang
Keyword(s):  
Low Cost ◽  
Water Storage ◽  
Cotton Fibers ◽  
Hydroxyl Groups ◽  
Amino Groups ◽  
Temperature Changes ◽  
Responsive Polymers ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Hydrophilicity And Hydrophobicity

Thermo-responsive textile is a widely studied smart material, which finds wide application in self-adjustment, water-storage and medicine control releasing etc. Cotton is one of the mostly researched textiles due to its low cost and easy-preparation. However, it is difficult to graft thermal responsive polymers on cotton because the hydroxyl groups on the surface are not reactive enough. In this study, a dye mediate, 2-Chloro-4,6-diamino-1,3,5-triazine (CDATA) was used to introduce amino groups onto cotton fibers. NIPAAm was then grafted onto cotton by atom transfer radical polymerization (ATRP), which was measured by infrared and contact angle measurements. The obtained cotton-PNIPAAm exhibited an efficient thermal responsive performance, which was indicated by transitions between hydrophilicity and hydrophobicity reversibly according to the temperature changes.

Development of Biodegradable Films Based on Durian Seed Starch

2012 ◽  
Vol 506 ◽  
pp. 311-314 ◽  
Author(s):  
W. Pimpa ◽  
C. Pimpa ◽  
P. Junsangsree
Keyword(s):  
Mechanical Properties ◽  
Water Vapor ◽  
Food Processing ◽  
Corn Starch ◽  
Water Vapor Permeability ◽  
Cassava Starch ◽  
Raw Material ◽  
Vapor Permeability ◽  
Biodegradable Films ◽  
Durian Seed

Fresh durian seed consists largely of starch and can be considered such a suitable raw material for producing biodegradable films. The aim of this work was to develop biodegradable films based on durian seed starch (DSS) and to characterize their water barrier, microscopic and mechanical properties. DSS films were prepared by casting with glycerol as plasticizer. Corn starch and cassava starch, commonly used in food processing, were chosen to prepare films and compare their properties to the DSS-based films. Using a second biopolymer, carboxymethyl cellulose (CMC), in the DSS based composite has been studied as a strategy to improve their important properties. Water vapor permeability and elongation values were improved significantly (p<0.05) when 5% (w/w DSS) CMC was incorporated. Therefore, preparing biodegradable films from DSS is a new alternative for using this raw material which is sometimes much cheaper than commercial starches

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