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1.
Foods ; 13(12)2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38928856

RESUMO

Non-biodegradable plastic materials pose environmental hazards and contribute to pollution. Arabinoxylan (AX) films have been created for applications in food packaging to replace these materials. The water interaction characteristics of biodegradable AX films were assessed following the extraction of AX from dry-milled corn bran (DCB), wet-milled corn bran (WCB), and dried distiller's grains with solubles (DDGS). Films were prepared with laccase and sorbitol before surface modification with lipase-vinyl acetate. Water solubility of the modified DCB films was significantly reduced (p < 0.05); however, the water solubility of modified WCB films decreased insignificantly (p > 0.05) compared to unmodified films. Water vapor permeability of the modified AX films from WCB and DDGS was significantly reduced (p < 0.05), unlike their unmodified counterparts. The biodegradation rates of the modified WCB AX and DDGS films increased after 63 and 99 days, respectively, compared to the unmodified films. The hydrophilic nature of AX polymers from WCB and DDGS enhances the biodegradability of the films. This study found that the modified WCB AX film was more hydrophobic, and the modified DDGS AX film was more biodegradable than the modified DCB AX film. Overall, surface modifications have potential for improving hydrophobicity of biopolymer films.

2.
Int J Biol Macromol ; 268(Pt 2): 131660, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38636766

RESUMO

The synergistic effects of phosphorylated zein nanoparticles (PZNP) and cellulose nanocrystals (CNC) in enhancing the wetting and barrier properties of chitosan hydrochloride (CHC)-based coating are investigated characterized by Fourier Transform Infrared Spectra (FTIR), X-ray Diffraction (XRD), atomic force microscopy and by investigating the mechanical properties, etc., with the aim of reducing cherry rain cracking. FTIR and XRD showed dual nanoparticles successfully implanted into CHC, CHC-PZNP-CNC combined moderate ductility (elongation at break: 7.8 %), maximum tensile strength (37.5 MPa). The addition of PZNP alone significantly improved wetting performance (Surface Tension, CHC: 55.3 vs. CHC-PZNP: 48.9 mN/m), while the addition of CNC alone led to a notable improvement in the water barrier properties of CHC (water vapor permeability, CHC: 6.75 × 10-10 vs. CHC-CNC: 5.76 × 10-10 gm-1 Pa-1 s-1). The final CHC-PZNP-CNC coating exhibited enhanced wettability (51.2 mN/m) and the strongest water-barrier property (5.32 × 10-10 gm-1 Pa-1 s-1), coupled with heightened surface hydrophobicity (water contact angle: 106.4°). Field testing demonstrated the efficacy of the CHC-PZNP-CNC coating in reducing cherry rain-cracking (Cracking Index, Control, 42.3 % vs. CHC-PZNP-CNC, 19.7 %; Cracking Ratio, Control, 34.6 % vs. CHC-PZNP-CNC, 15.8 %). The CHC-PZNP-CNC coating is a reliable option for preventing rain-induced cherry cracking.


Assuntos
Quitosana , Nanopartículas , Molhabilidade , Quitosana/química , Nanopartículas/química , Celulose/química , Chuva/química , Zeína/química , Resistência à Tração , Água/química , Prunus avium/química , Permeabilidade
3.
Food Chem ; 450: 139352, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-38640532

RESUMO

Gelatin (GL) and carboxymethyl cellulose (CMC) are common natural components for edible films, but their water barrier performance are finite as hydrophilic polymers. In this study, a GL/CMC water barrier film was prepared, characterized and applied. The microstructure results showed that complex coacervation at pH 2.0 and cross-linking effect of sodium benzoate resulted in strong interaction forces and dense structure of this film. Compared with pure GL or CMC film, this novel composite film decreased water vapor permeability by approximately 90%, and possessed applicable water solubility (51.5%) and stronger barrier to oxygen and UV light. Acidic environment and sodium benzoate endowed antibacterial activity. Furthermore, the water barrier coating film decreased water loss by 47.8% and improved overall quality of fresh strawberries stored at 25 °C for 6 d. Therefore, the novel water barrier film based on complex coacervation and cross-linking is promising to control the postharvest quality of perishable berries.


Assuntos
Carboximetilcelulose Sódica , Embalagem de Alimentos , Conservação de Alimentos , Fragaria , Gelatina , Permeabilidade , Água , Fragaria/química , Fragaria/efeitos dos fármacos , Gelatina/química , Carboximetilcelulose Sódica/química , Embalagem de Alimentos/instrumentação , Água/química , Conservação de Alimentos/métodos , Conservação de Alimentos/instrumentação , Eletricidade Estática , Frutas/química , Frutas/efeitos dos fármacos , Solubilidade
4.
Int J Biol Macromol ; 261(Pt 2): 129821, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38286371

RESUMO

Chitosan (CT) is extensively applied in developing food packaging films due to its non-toxic, biodegradable, and good film-forming properties. But CT-based single polymer film has issues with poor physico-mechanical, thermal, and light barrier properties. Therefore, this study aimed to incorporate natural berry wax (BYW) at various concentrations (5 %, 10 %, 15 %, 20 %, and 25 %, wt%) into CT to improve the quality characteristics of CT film. The microstructure of the film matrix was effectively proven to be compatible with BYW through the utilization of SEM, XRD, and FTIR spectroscopy. The results demonstrated that the quality parameters of CT/BYW composite film were significantly affected by the increasing concentration of BYW. The integration of BYW with a concentration of 5 % to 20 % to CT substantially improved the film characteristics by reducing moisture content, swelling power, solubility, and water vapor permeability, increasing the film's opacity, thermal stability, and tensile strength as well as enhancing the biodegradable potential. Furthermore, CT/BYW films showed higher thermal stability and UV and visible light resistance compared to pure CT film. Taken together, the CT film with 20 % berry wax showed the best film characteristics and biodegradable potential, which could be promising for enhancing the shelf-life of various food products.


Assuntos
Quitosana , Quitosana/química , Frutas , Embalagem de Alimentos/métodos , Resistência à Tração , Solubilidade , Permeabilidade
5.
Int J Biol Macromol ; 259(Pt 1): 129061, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38161028

RESUMO

Polyvinyl alcohol (PVA) film, a promising alternative to non-biodegradable plastic packaging films for food and medical packaging, is limited by poor water resistance. In this work, a simple solvent evaporation self-assembly was used to construct a nanophase separation structure to establish dense interfacial hydrogen bonding, covalent bonding and iron metal ion coordination interactions between lignin-containing cellulose nanofibers (LCNFs) and PVA matrix to improve the interfacial force and solve the problem of poor compatibility of LCNFs in PVA. The iron ion (Fe3+) coordination tended to combine with the more active lignin phenolic hydroxyl group to construct the nanophase separation structure. Covalent crosslinking of glutaraldehyde (GA) improved the interfacial compatibility of PVA/LCNF films, enhanced the interfacial bonding and formed a homogeneous structure. The multi-nanophase structures improved the strength and elastic modulus of the PVA/LCNF film and provided the films with extremely low water absorption, water vapor transmission rate and excellent UV-shielding. Compared with pure PVA film, PVA-10L-5Fe-3GA film had about 106.9 % higher tensile strength, 93.9 % lower water absorption and 93.4 % lower mass loss, 69.8 % lower water vapor transmission coefficient, and was able to shield UV at 200-400 nm, which is highly expected to be used in packaging films.


Assuntos
Celulose , Nanofibras , Celulose/química , Lignina/química , Álcool de Polivinil/química , Nanofibras/química , Vapor , Ferro
6.
Int J Biol Macromol ; 245: 125486, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37355060

RESUMO

A million tonnes of plastic produced each year are disposed of after single use. Biodegradable polymers have become a promising material as an alternative to petroleum-based polymers. Utilising biodegradable polymers will promote environmental sustainability which has emerged with potential features and performances for various applications in different sectors. Seaweed-derived polysaccharides-based composites have been the focus of numerous studies due to the composites' renewability and sustainability for industries (food packaging and medical fields like tissue engineering and drug delivery). Due to their biocompatibility, abundance, and gelling ability, seaweed derivatives such as alginate, carrageenan, and agar are commonly used for this purpose. Seaweed has distinct film-forming characteristics, but its mechanical and water vapour barrier qualities are weak. Thus, modifications are necessary to enhance the seaweed properties. This review article summarises and discusses the effect of incorporating seaweed films with different types of nanoparticles on their mechanical, thermal, and water barrier properties.


Assuntos
Nanocompostos , Alga Marinha , Polissacarídeos , Carragenina , Polímeros , Verduras
7.
Chemosphere ; 313: 137189, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36379432

RESUMO

Since graphene possesses distinct electrical and material properties that could improve material performance, there is currently a growing demand for graphene-based electronics and applications. Numerous potential applications for graphene include lightweight and high-strength polymeric composite materials. Due to its structural qualities, which include low thickness and compact 2D dimensions, it has also been recognized as a promising nanomaterial for water-barrier applications. For barrier polymer applications, it is usually applied using two main strategies. The first is the application of graphene, graphene oxide (GO), and reduced graphene oxide (rGO) to polymeric substrates through transfer or coating. In the second method, fully exfoliated GO or rGO is integrated into the material. This study provides an overview of the most recent findings from research on the use of graphene in the context of water-barrier applications. The advantages and current limits of graphene-based composites are compared with those of other nanomaterials utilized for barrier purposes in order to emphasize difficult challenges for future study and prospective applications.


Assuntos
Grafite , Polímeros , Grafite/química , Polímeros/química , Águas Residuárias , Água
8.
Front Chem ; 10: 926364, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35958229

RESUMO

Chitosan-based hybrid nanocomposites, containing cellulose nanocrystals (CNCs), graphene oxide (GO), and borate as crosslinking agents, were successfully prepared by solution-casting technique. The synergistic effect of the two fillers, and the role of the cross-linker, in enhancing the structural and functional properties of the chitosan polymer, was investigated. XPS results confirm the chemical interaction between borate ions and hydroxyl groups of chitosan, GO, and CNCs. The morphological characterization shows that the GO sheets are oriented along the casting surface, whereas the CNC particles are homogenously distributed in the sample. Results of tensile tests reveal that the presence of graphene oxide enhances the elastic modulus, tensile strength, elongation at break, and toughness of chitosan, while cellulose and borate induce an increase in the elastic modulus and stress at the yield point. In particular, the borate-crosslinked chitosan-based sample containing 0.5 wt% of GO and 0.5 wt% of CNCs shows an elongation at a break value of 30.2% and a toughness value of 988 J*m-3 which are improved by 124% and 216%, respectively, compared with the pristine chitosan. Moreover, the water permeability results show that the presence of graphene oxide slightly increases the water barrier properties, whereas the borate and cellulose nanocrystals significantly reduce the water vapor permeability of the polymer by about 50%. Thus, by modulating the content of the two reinforcing fillers, it is possible to obtain chitosan-based nanocomposites with enhanced mechanical and water barrier properties which can be potentially used in various applications such as food and electronic packaging.

9.
Polymers (Basel) ; 14(8)2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35458339

RESUMO

Biocomposite films were prepared using corn starch (CS), sorbitol as a plasticiser, and multi-scale kenaf fibre as reinforcing filler. The microstructure and the physical, tensile, and water barrier properties of corn starch reinforced with kenaf fibre were characterised and investigated. The biocomposite films were developed via the solution casting technique using 10 g of CS with 0 to 8% kenaf fibre as filler treated with 30% (w/w, starch basis) of sorbitol. The increased amount of kenaf fibre introduced contributed to improvements in film thickness, weight, and density. Conversely, slight reductions in the biocomposite films' moisture content, water absorption, and solubility rating were 9.86-5.88%, 163.13-114.68%, and 38.98-25.17%, respectively. An X-ray diffraction (XRD) test revealed that the films were amorphous and that there was no effect on the crystallinity structure of films with kenaf fibre reinforcement. Fourier transform infrared (FT-IR) and rheological analysis indicated that kenaf fibre could weaken the molecular interaction of the film matrix. Field emission scanning electron microscope (FESEM) revealed the arrangement and uniform distribution of kenaf fibre at 0.2-0.8%. The incorporation of kenaf increased the tensile strength, Young's modulus, and elongation at break until (6% wt) of fibre. With the kenaf fibre incorporation, the optimal tensile strength, Young's modulus, and elongation at break of the films reached 17.74 MPa, 1324.74 MPa, and 48.79%, respectively. Overall, the introduction of kenaf fibre as filler enhanced the physical and mechanical properties of CS films.

10.
Food Chem ; 384: 132482, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35189439

RESUMO

Biodegradable packaging is more eco-friendly compared with the synthetic plastics. To improve the physical properties of the zein films, poly(lactic acid) (PLA) was mixed with zein to make a biodegradable blend film. The composition of the film with the best properties was the one with zein and PLA in the mass ratio of 1:1 with the addition of 20% poly(ethylene glycol) as the plasticizer. The incorporation of PLA significantly increased the elongation, reduced the tensile strength, and decreased the water vapor and gas permeabilities of zein films. The antimicrobial agent eugenol added in the film significantly inhibited the growth of both S. aureus and E. coli. The migration tests were conducted to confirm the safety of the blend films. This is the first-time report of zein-PLA blend film. The antimicrobial zein-PLA-eugenol film with enhanced mechanical and barrier properties has a high potential as active biodegradable food packaging.


Assuntos
Zeína , Escherichia coli , Eugenol/farmacologia , Embalagem de Alimentos , Poliésteres/farmacologia , Staphylococcus aureus , Resistência à Tração , Zeína/farmacologia
11.
Int J Biol Macromol ; 191: 956-963, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34571125

RESUMO

Synergistic combinations of pullulan, agar, montmorillonite (MMT) clay, and quaternary ammonium silane (QAS)-based (Pullulan/agar/MMT clay/QAS) active nanocomposites were prepared by a simple, cost-effective method. The Pullulan/agar/MMT clay/QAS nanocomposites were studied via Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analyses. The concentration of MMT clay played a very important role in the properties of the nanocomposites. However, the transparency of the composite was not significantly affected by the addition of MMT clay. The ultraviolet (UV) transmittance of Pullulan/agar/MMT clay/QAS was in the range of 91.4-79.8 at 600 nm. The thermal and mechanical properties were significantly improved by the MMT clay. The tensile strength and elongation at break of the composites were in the range of 23.8-39.7 MPa and 37.2-26.9%, respectively. The long alkyl chain in QAS significantly improved the hydrophobic nature of the Pullulan/agar/MMT clay nanocomposites, impacting the contact angle (66.2-71.2°), water vapor permeability (3.17-2.20 × 10-9 g/m2 Pa·s), and swelling ratio (1837-836%). The combination of Pullulan/agar/MMT clay/QAS had a synergistic effect on the rheological properties. MMT clay and QAS significantly increased the viscosity, storage, and loss modulus of the hydrogel composites. With the addition of QAS, the Pullulan/agar/MMT clay nanocomposites showed good antimicrobial activity against gram-positive and gram-negative pathogens.


Assuntos
Ágar/química , Bentonita/química , Filmes Comestíveis , Glucanos/química , Nanocompostos/química , Compostos de Amônio Quaternário/química , Silanos/química , Embalagem de Alimentos/métodos , Resistência à Tração
12.
Foods ; 10(7)2021 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-34359524

RESUMO

This study aimed to develop edible monolayer emulsion-based barriers with polysaccharides as film-forming components (chitosan and sodium alginate), soy lecithin as a surfactant and olive oil as a hydrophobic barrier. Monolayer barriers in the form of films were prepared by casting filmogenic emulsions composed of 2% w/v chitosan (dissolved in lactic acid 1% v/v) or 1% w/v sodium alginate, with different lipid contents (25, 50 and 100% w/w biopolymer basis) and different surfactant concentrations (5, 10 and 25% w/w, lipid basis). Glycerol was used as a plasticizer (25 % w/w, biopolymer basis). After the emulsion drying process, the obtained stand-alone films were sprayed with a crosslinking solution, achieving an optimized crosslinker content of 3.2 mgCa2+/cm2 alginate film and 4 mg tripolyphosphate/cm2 chitosan film. The effect of oil and lecithin contents, as well the presence of crosslinking agents, on the film's water vapour permeability (WVP), water vapour sorption capacity, mechanical properties and colour parameters, was evaluated. The results have shown that the lowest WVP values were obtained with formulations containing 25% lipid and 25% surfactant for chitosan films, and 100% lipid and 25% surfactant for alginate films. The application of the crosslinking agents decreased even further the WVP, especially for chitosan films (by 30%). Crosslinking also increased films' resistance to deformation under tensile tests. Overall, the films developed present a good potential as polysaccharide-based barriers with increased resistance to water, which envisages the use of the designed formulations to produce either edible/biodegradable films or edible coatings.

13.
Polymers (Basel) ; 13(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34372125

RESUMO

The aim of the study was to characterize and compare films made of cellulose nanocrystals (CNC), nano-fibrils (CNF), and bacterial nanocellulose (BNC) in combination with chitosan and alginate in terms of applicability for potential food packaging applications. In total, 25 different formulations were made and evaluated, and seven biopolymer films with the best mechanical performance (tensile strength, strain)-alginate, alginate with 5% CNC, chitosan, chitosan with 3% CNC, BNC with and without glycerol, and CNF with glycerol-were selected and investigated regarding morphology (SEM), density, contact angle, surface energy, water absorption, and oxygen and water barrier properties. Studies revealed that polysaccharide-based films with added CNC are the most suitable for packaging purposes, and better dispersing of nanocellulose in chitosan than in alginate was observed. Results showed an increase in hydrophobicity (increase of contact angle and reduced moisture absorption) of chitosan and alginate films with the addition of CNC, and chitosan with 3% CNC had the highest contact angle, 108 ± 2, and 15% lower moisture absorption compared to pure chitosan. Overall, the ability of nanocellulose additives to preserve the structure and function of chitosan and alginate materials in a humid environment was convincingly demonstrated. Barrier properties were improved by combining the biopolymers, and water vapor transmission rate (WVTR) was reduced by 15-45% and oxygen permeability (OTR) up to 45% by adding nanocellulose compared to single biopolymer formulations. It was concluded that with a good oxygen barrier, a water barrier that is comparable to PLA, and good mechanical properties, biopolymer films would be a good alternative to conventional plastic packaging used for ready-to-eat foods with short storage time.

14.
ACS Appl Mater Interfaces ; 13(28): 33464-33476, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34241991

RESUMO

Encapsulation materials play an important role in many applications including wearable electronics, medical devices, underwater robotics, marine skin tagging system, food packaging, and energy conversation and storage devices. To date, all the encapsulation materials, including polymer layers and inorganic materials, are solid materials. These solid materials suffer from limited barrier lifetimes due to pinholes, cracks, and nanopores or from complicated fabrication processes and limited stretchability for interfacing with complex 3D surfaces. This paper reports a solution to this material challenge by demonstrating bioinspired oil-infused slippery surfaces with excellent waterproof property for the first time. A water vapor transmission test shows that locking a thin layer of oil on the silicone elastomer improves the water vapor barrier performance by three orders of magnitude. Accelerated lifetime tests suggest robust water barrier characteristics that approach 226 days at 37 °C even under severe mechanical damage. A combination of temperature- and thickness-dependent experimental measurements and reaction-diffusion modeling reveals the key waterproof property. In addition to serving as a barrier to water, the oil-infused surface demonstrates an attractive ion barrier property. All these exceptional properties suggest the potential applications of slippery surfaces as encapsulation materials for medical devices, underwater electronics, and many others.


Assuntos
Fluorocarbonos/química , Óleos/química , Elastômeros de Silicone/química , Interações Hidrofóbicas e Hidrofílicas , Teste de Materiais , Permeabilidade , Óleos de Silicone/química , Vapor , Propriedades de Superfície , Água/química
15.
Int J Biol Macromol ; 182: 1301-1309, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33989690

RESUMO

Agar/polyacrylamide/quaternary ammonium silane-based (A/P/QAS-based) composite films were developed for food and biomedical packaging applications. The structural, optical, and surface morphological properties of the A/P and A/P/QAS composites were characterized by various characterization techniques in terms of thermogravimetric analysis, differential scanning calorimetry analyses, mechanical and rheological properties. Results showed that the 5% gravimetric loss (57.8-139.1 °C), glass transition temperature (179-189.9 °C) and tensile strength (35.2-47.8 MPa) of the prepared composites increased with increasing polyacrylamide content. The contact angle and water barrier properties of the composites were considerably improved by the addition of QAS. To compare WVP values of the A/P/QAS composite with neat AP composite films it reduced nearly 46% (2.45 to 1.32 × 10-9 g/m2 Pas). The A/P/QAS composites showed excellent antimicrobial properties against five different organisms. The Staphylococcus aureus exhibited highest 25 mm for gel and 18.1 mm for film of A/P/QAS composites. All the composites exhibited shear-thinning behavior, and their viscosity increased with increasing polyacrylamide content. The storage moduli of the prepared hydrogel composites were in the range of 5000-10,600 Pa at 1 rad/s and increased continuously over the entire frequency range. The dynamic rheological properties of A/P and A/P/QAS composites indicated that the prepared composites had good mechanical strength. Biopolymer based A/P and A/P/QAS composite films are suitable for green composite packaging applications.


Assuntos
Resinas Acrílicas/química , Ágar/química , Embalagem de Alimentos , Compostos de Amônio Quaternário/química , Silanos/química , Anti-Infecciosos/farmacologia , Varredura Diferencial de Calorimetria , Módulo de Elasticidade , Testes de Sensibilidade Microbiana , Permeabilidade , Reologia , Resistência ao Cisalhamento , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Vapor , Estresse Mecânico , Temperatura , Termogravimetria , Viscosidade , Difração de Raios X
16.
Membranes (Basel) ; 12(1)2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35054544

RESUMO

This work evaluated the improvement effects of lipids incorporation on water resistance of composite biodegradable film prepared with wheat bran cellulose/wheat gluten (WBC/WG) using an alkaline-ethanol film forming system. Four types of lipids, paraffin wax (PW), beeswax (BW), paraffin oil (PO), and oleic acid (OA), were tested. We found that PW, BW, and PO incorporation at 5-20% improved water vapor permeability (WVP) and surface hydrophobicity of prepared films. Particularly, incorporation of 15% BW could best improve the water resistance properties of the film, with the lowest WVP of 0.76 × 10-12 g/cm·s·Pa and largest water contact angle (WCA) of 86.18°. Incorporation of OA led to the decline in moisture barrier properties. SEM images revealed that different lipids incorporation changed the morphology and of the composite film, and cross-sectional morphology indicated BW-incorporated film obtained more uniform and compact structures compared to other films. Moreover, Fourier transform infrared spectra indicated that the incorporation of PW or BW enhanced the molecular interactions between the film components, confirmed by the chemical shift of characteristic peaks at 3277 and 1026 cm-1. Differential scanning calorimetry results revealed that incorporation of PW, BW, and PO increased films' melting point, decomposition temperatures, and enthalpy values. Furthermore, the presence of most lipids decreased tensile strength and elongation at the break of the film. Overall, the composite film containing 15% BW obtained the most promising water resistance performance and acceptable mechanical properties, and it thus most suitable as a hydrophobic biodegradable material for food packaging.

17.
Food Chem ; 337: 127777, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32799163

RESUMO

Biodegradable films based on chitosan, glycerol, and defatted Chlorella biomass (DCB) were prepared and characterized in terms of thermal stability, mechanical, water barrier, and optical properties. Increasing DCB content from 5 to 25 wt% increased tensile strength of chitosan films by 235%. The incorporation of DCB decreased both moisture content and swelling degree of chitosan/defatted Chlorella biomass (Cs/DCB) films. Furthermore, increasing the content of defatted algal biomass decreased light transmission and reduced water vapor permeability of composite films by more than 60%. As confirmed by scanning electron microscopy and Fourier transform infrared analysis, such improvement in functional and physical properties is mainly due to the homogeneous and uniform distribution of DCB into the polymeric matrix along with the establishment of strong hydrogen bond interactions between chitosan and algal biomass constituents. Moreover, Cs/DCB composite films showed more than 50% of degradation in 60 days soil burial test.


Assuntos
Quitosana/química , Chlorella/química , Biomassa , Chlorella/metabolismo , Glicerol/química , Ligação de Hidrogênio , Permeabilidade , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
18.
Carbohydr Polym ; 230: 115626, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887859

RESUMO

Lignin containing cellulose nanofibrils (LCNF) were obtained by mechanically fibrillating unbleached tree bark after alkaline extraction and used as a reinforcement in thermoplastic starch (TPS) to develop novel biodegradable composite films. With the addition of 15 wt % LCNF, the tensile strength and modulus of the composites increased by 319 % and 800 % compared to neat TPS films, respectively. The crystalline property of cellulose and the high interaction between TPS and LCNF improved the mechanical property of the composite films. The composite film Tonset and Tmax were 263.1 °C and 316.5 °C, respectively, compared to 250.5 °C and 297.3 °C for neat TPS. The composite films also showed higher water barrier property. Experimental results showed that LCNF features a high lignin content. Lignin, a natural polymer, contains hydrophobic and aromatic groups and, thus, can increase the water barrier property and thermal stability of TPS/LCNF composite films.


Assuntos
Lignina/química , Nanocompostos/química , Nanofibras/química , Temperatura Alta , Interações Hidrofóbicas e Hidrofílicas , Estresse Mecânico , Resistência à Tração
19.
Int J Biol Macromol ; 141: 538-544, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494161

RESUMO

Agar (A), gellan gum (G) and montmorillonite (M) based ternary nanocomposite films were prepared via the solution-casting method for food packaging applications. The prepared nanocomposites were investigated for the effect of MMT clay on the structure-property relationships by studying the microstructural, rheological, mechanical, thermal, ultraviolet, and water-barrier properties of AG hydrogel composites. The results indicated that the thermal stability (T5%: 119.4-174.7) and tensile strength (29.9-44 MPa) were significantly enhanced in the reinforced MMT nanoclay. The water barrier (1.9-1.7) and contact angle (56.8°-49.4°) were reduced by the incorporation of MMT clay whereas the rheological properties improved. The AGM composite solution exhibited shear thinning behavior and viscosity reduction at a high rate. Additionally, the composites exhibited significantly higher storage and loss modulus at high frequencies. The complex viscosity differed from the shear viscosity and remained higher than the shear viscosity. The nanocomposite structure, molecular interaction, and interaction in the multicomponent were investigated by FT-IR, XRD and SEM analysis. The AG and AGM nanocomposites exhibited a synergistic reinforcement effect. The results of this study might introduce a new route for enhancing the nanocomposites for sustainable materials.


Assuntos
Ágar/química , Bentonita/química , Hidrogéis/química , Membranas Artificiais , Nanocompostos/química , Polissacarídeos Bacterianos/química , Embalagem de Alimentos , Reologia , Resistência à Tração
20.
Int J Biol Macromol ; 123: 1020-1027, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30452992

RESUMO

The hydrogel based composite film was prepared from k-Carrageenan (k-C), xanthan gum (X) and gellan gum (G) by solvent casting method. The transparent films made from these gellable materials with synergistic hydrogel composition have soft texture, good elasticity and excellent break strength. The k-C/X/G based nanocomposite films prepared from different weight ratio of TiO2 nanoparticles were characterized for new packaging materials. The morphology, structure and microstructure properties of the k-C/X/G and TiO2 nanocomposite films were characterized by FT-IR, XRD and SEM analysis. By the incorporation of TiO2 in the k-C/X/G nanocomposite films, the tensile strength, tensile modulus, Tg and thermal stability of the films were greatly enhanced. Due to the hydrophobic nature of the TiO2 nanoparticles there is an increase in contact angle whereas moisture content of the films decreased. The water vapor permeability (WVP) and ultra violet lights transmittance decrease upon increasing the TiO2 content. The k-C/X/G and TiO2 nanocomposites effectively shield the UV light, exhibited partial microbial activity against Staphylococcus aureus and have a high potential for the application in food and non-food industries as UV shielding packaging materials.


Assuntos
Carragenina/química , Elasticidade , Nanocompostos/química , Polissacarídeos Bacterianos/química , Titânio/farmacologia , Raios Ultravioleta , Antibacterianos/farmacologia , Varredura Diferencial de Calorimetria , Hidrogéis/química , Nanocompostos/ultraestrutura , Permeabilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Vapor , Temperatura , Termogravimetria , Difração de Raios X
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