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1.
Sci Rep ; 14(1): 12537, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38822031

RESUMO

This work presents a facile approach for controlling the optical and electrical parameters of a biopolymeric matrix for optoelectronics. Vanadium oxide (V2O5) and chromium oxide (Cr2O3) nanoparticles (NPs) were prepared and incorporated into the carboxymethylcellulose/polyethylene glycol (CMC/PEG) blend by simple chemical techniques. Transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD) data showed that V2O5 and Cr2O3 exhibited spherical shapes with sizes in the range of 40-50 nm and 10-20 nm, respectively. In addition, the blend's degree of crystallinity was sensitive to the V2O5 and Cr2O3 doping ratios. The scanning electron microscopy (FE-SEM) and the elemental chemical analysis (EDAX) used to study the filler distribution inside the blend, and confirmed the existence of both V and Cr in the matrix. Fourier transform infrared (FTIR) spectroscopy showed that the dopants significantly affected the blend reactive (C-O-C, OH, and C=O) groups. The stress-strain curves illustrated the reinforcing effect of the dopants up to 1.0 wt\% Cr2O3/V. The transmittance and absorption index spectra in the visible-IR wavelengths decreased with increasing filler content. Utilizing Tauc's relation and (optical) dielectric loss, the direct (indirect) band gap narrowed from 5.6 (4.5) eV to 4.7 (3.05) eV at 1.0   wt\% Cr2O3/V. All films have an index of refraction in the range of 1.93-2.17. AC conductivity was improved with increasing filler content and temperature. The energy density at 50 °C is in the range of 1-3 J/m3. The influence of V2O5 and Cr2O3 content on the optical conductivity, dielectric constant, loss, and dielectric modulus of CMC/PEG was reported. These enhancements in electrical and optical properties, along with the potential for band gap engineering, offer promising prospects for advanced applications in optoelectronics and energy-related fields.

2.
Int J Biol Macromol ; 253(Pt 8): 127410, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37844823

RESUMO

Biomaterials play a fundamental role in tissue engineering by providing biochemical and physical cues that influence cellular fate and matrix development. Decellularized extracellular matrix (dECM) as a biomaterial is distinguished by its abundant composition of matrix proteins, such as collagen, elastin, fibronectin, and laminin, as well as glycosaminoglycans and proteoglycans. However, the mechanical properties of only dECM-based constructs may not always meet tissue-specific requirements. Recent advancements address this challenge by utilizing hybrid biomaterials that harness the strengths of silk fibroin (SF), which contributes the necessary mechanical properties, while dECM provides essential cellular cues for in vitro studies and tissue regeneration. This review discusses emerging trends in developing such biopolymer blends, aiming to synergistically combine the advantages of SF and dECM through optimal concentrations and desired cross-linking density. We focus on different fabrication techniques and cross-linking methods that have been utilized to fabricate various tissue-engineered hybrid constructs. Furthermore, we survey recent applications of such biomaterials for the regeneration of various tissues, including bone, cartilage, trachea, bladder, vascular graft, heart, skin, liver, and other soft tissues. Finally, the trajectory and prospects of the constructs derived from this blend in the tissue engineering field have been summarized, highlighting their potential for clinical translation.


Assuntos
Fibroínas , Fibroínas/química , Matriz Extracelular Descelularizada , Materiais Biocompatíveis/química , Engenharia Tecidual/métodos , Colágeno/química , Matriz Extracelular/metabolismo , Alicerces Teciduais/química
3.
Polymers (Basel) ; 15(12)2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37376239

RESUMO

The use of biopolymeric materials is restricted for some applications due to their deficient properties in comparison to synthetic polymers. Blending different biopolymers is an alternative approach to overcome these limitations. In this study, we developed new biopolymeric blend materials based on the entire biomasses of water kefir grains and yeast. Film-forming dispersions with varying ratios of water kefir to yeast (100/0, 75/25, 50/50 25/75 and 0/100) underwent ultrasonic homogenisation and thermal treatment, resulting in homogeneous dispersions with pseudoplastic behaviour and interaction between both biomasses. Films obtained by casting had a continuous microstructure without cracks or phase separation. Infrared spectroscopy revealed the interaction between the blend components, leading to a homogeneous matrix. As the water kefir content in the film increased, transparency, thermal stability, glass transition temperature and elongation at break also increased. The thermogravimetric analyses and the mechanical tests showed that the combination of water kefir and yeast biomasses resulted in stronger interpolymeric interactions compared to single biomass films. The ratio of the components did not drastically alter hydration and water transport. Our results revealed that blending water kefir grains and yeast biomasses enhanced thermal and mechanical properties. These studies provided evidence that the developed materials are suitable candidates for food packaging applications.

4.
Int J Biol Macromol ; 236: 124006, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36907303

RESUMO

To better understand the correlation between structure and properties in thermoplastic starch biopolymer blend films, the effects of amylose content, chain length distribution of amylopectin and molecular orientation of thermoplastic sweet potato starch (TSPS) and thermoplastic pea starch (TPES) on microstructure and functional properties of thermoplastic starch biopolymer blend films were studied. After thermoplastic extrusion, the amylose contents of TSPS and TPES decreased by 16.10 % and 13.13 %, respectively. The proportion of the chains with the degree of polymerization between 9 and 24 of amylopectin in TSPS and TPES increased from 67.61 % to 69.50 %, and from 69.51 % to 71.06 %, respectively. As a result, the degree of crystallinity and molecular orientation of TSPS and TPES films increased as compared to sweet potato starch and pea starch films. The thermoplastic starch biopolymer blend films possessed a more homogeneous and compacter network. The tensile strength and water resistance of thermoplastic starch biopolymer blend films increased significantly, whereas thickness and elongation at break of thermoplastic starch biopolymer blend films decreased significantly.


Assuntos
Amilopectina , Amido , Amido/química , Amilopectina/química , Amilose/química , Água/química , Resistência à Tração
5.
Int J Mol Sci ; 23(16)2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-36012415

RESUMO

A facile methodology system for synthesizing solid polymer electrolytes (SPEs) based on methylcellulose, dextran, lithium perchlorate (as ionic sources), and glycerol (such as a plasticizer) (MC:Dex:LiClO4:Glycerol) has been implemented. Fourier transform infrared spectroscopy (FTIR) and two imperative electrochemical techniques, including linear sweep voltammetry (LSV) and electrical impedance spectroscopy (EIS), were performed on the films to analyze their structural and electrical properties. The FTIR spectra verify the interactions between the electrolyte components. Following this, a further calculation was performed to determine free ions (FI) and contact ion pairs (CIP) from the deconvolution of the peak associated with the anion. It is verified that the electrolyte containing the highest amount of glycerol plasticizer (MDLG3) has shown a maximum conductivity of 1.45 × 10-3 S cm-1. Moreover, for other transport parameters, the mobility (µ), number density (n), and diffusion coefficient (D) of ions were enhanced effectively. The transference number measurement (TNM) of electrons (tel) was 0.024 and 0.976 corresponding to ions (tion). One of the prepared samples (MDLG3) had 3.0 V as the voltage stability of the electrolyte.


Assuntos
Glicerol , Plastificantes , Biopolímeros/química , Eletrólitos/química , Transporte de Íons , Íons , Lítio
6.
J Food Sci Technol ; 59(7): 2562-2571, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35734131

RESUMO

Blend films from chicken protein isolate (CPI) and fish skin gelatin (FSG) at various CPI/FSG ratios (100:0, 80:20, 70:30, 60:40, 0:100), prepared at pH 3 or 11 were characterized. At the same pH, tensile strength (TS) of CPI/FSG films was higher than CPI and FSG films, and CPI/FSG film (60:40) had highest TS. Moreover, elongation at break (EAB) of blend films increased as FSG content augmented. EAB of CPI film and CPI/FSG (80:20) film was similar for both pHs. CPI films generally possessed higher water vapor permeability (WVP), light barrier property and b*-value than FSG counterpart. CPI films prepared at both pHs were not sealable. Nevertheless, addition of FSG improved sealing ability of blend films. At the same CPI/FSG ratio, seal strength and seal efficiency were lower for films prepared at pH 11. Moreover, higher TS and b*-value were gained, compared to those of films prepared at pH 3. Less cracks on surface and cross-section appeared for CPI/FSG films as revealed by scanning electron microscopy images, compared to CPI and FSG films. Therefore, incorporation of FSG up to 40% into blend film was able to improve mechanical properties, WVP, and sealing ability of blend films.

7.
Foods ; 12(1)2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36613300

RESUMO

A bacon-type meat analogue consists of different structural layers, such as textured protein and a fat mimetic. To obtain a coherent and appealing product, a suitable binder must glue those elements together. A mixture based on pea protein and sugar beet pectin (r = 2:1, 25% w/w solids, pH 6) with and without laccase addition and a methylcellulose hydrogel (6% w/w) serving as benchmark were applied as binder between textured protein and a fat mimetic. A tensile strength test, during which the layers were torn apart, was performed to measure the binding ability. The pea protein-sugar beet pectin mixture without laccase was viscoelastic and had medium and low binding strength at 25 °C (F ≤ 3.5 N) and 70 °C (F ≈ 1.0 N), respectively. The addition of laccase solidified the mixture and increased binding strength at 25 °C (F ≥ 4.0 N) and 70 °C (F ≈ 2.0 N), due to covalent bonds within the binder and between the binder and the textured protein or the fat mimetic layers. Generally, the binding strength was higher when two textured protein layers were glued together. The binding properties of methylcellulose hydrogel was low (F ≤ 2.0 N), except when two fat mimetic layers were bound due to hydrophobic interactions becoming dominant. The investigated mixed pectin-pea protein system is able serve as a clean-label binder in bacon-type meat analogues, and the application in other products seems promising.

8.
Appl Spectrosc ; 75(8): 980-987, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33825490

RESUMO

Inter- and intramolecular interactions in multicomponent polymer systems influence their physical and chemical properties significantly and thus have implications on their synthesis and processing. In the present study, chemical images were obtained by plotting the peak position of a spectral band from the data sets generated using in situ attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopic imaging. This approach was successfully used to visualize changes in intra- and intermolecular interactions in poly(3-hydroxybutyrate)/poly(L-lactic acid) (PHB/PLLA) blends during the isothermal melt crystallization. The peak position of ν(C=O) band, which reflects the nature of the intermolecular interaction, shows that the intermolecular interactions between PHB and PLLA in the miscible state (1733 cm-1) changes to the inter- and intramolecular interaction (CH3⋯O=C, 1720 cm-1) within PHB crystal during the isothermal melt crystallization. Compared with spectroscopic images obtained by plotting the distribution of absorbance of spectral bands, which reveals the spatial distribution of blend components, the approach of plotting the peak position of a spectral band reflects the spatial distribution of different intra- and intermolecular interactions. With the process of isothermal melt-crystallization, the disappearance of the intermolecular interaction between PHB and PLLA and the appearance of the inter- and intramolecular interactions within the PHB crystal were both visualized through the images based on the observation of the band position. This work shows the potential of using in-situ ATR FT-IR spectroscopic imaging to visualize different types of inter- or intramolecular interactions between polymer molecules or between polymer and other additives in various types of multicomponent polymer systems.

9.
Polymers (Basel) ; 12(12)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33353124

RESUMO

A ternary composite of poly(lactic acid) (PLA), poly(caprolactone) (PCL), and carbon black (CB) shows the PCL-induced CB self-aggregation and percolation formation when the amount of the PCL phase as the secondary phase is as small as the amount of CB. Furthermore, when the drop size of the PCL phase becomes smaller, the ternary composite forms a percolation of high order structure, resulting in a remarkable enhancement of the electrical conductivity (~4 × 10-2 S/m with 4 wt.% CB). To further control the percolation structure, the composite fabrication is controlled by splitting a typical single-step mixing process into two steps, focusing on the dispersion of the secondary PCL phase and the CB particles separately. Under the single-step mixing protocol, the ternary composite shows a structure with greater CB aggregation in the form of a high aspect ratio and large aggregates (aggregate perimeter~aggregate size 0.7). Meanwhile, the two-step mixing process causes the CB aggregates to expand and create a higher structure (aggregate perimeter~aggregate size 0.8). The reduced size of the secondary phase under a mixing condition with high shear force prior to the addition of CB provides a larger interfacial area for CB to diffuse into the PCL phase during the subsequent mixing step, resulting in a further expansion of CB aggregation throughout the composite. The particle percolation of such a high order structure is attributed to high storage modulus (G'), high Young's modulus, high dielectric loss (ε″), and negative-positive switching of dielectric constant at high frequency (of 103 Hz) of composite.

10.
Carbohydr Polym ; 250: 116867, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33049817

RESUMO

Poly(lactic acid) (PLA) was used in an effort to enhance the mechanical properties of poly(hydroxybutyrate) (PHB) and the blends were reinforced with cellulose nanofibrils (CNF). The conventional and dynamic mechanical, morphological, thermal and rheological properties of the obtained composite blends were determined. The results showed that the mechanical properties of neat PHB noticeably increased attributable to the good interaction between the biopolymers and CNF from the scanning electron microscopy (SEM) characterization. Thermal stability of the neat PHB was improved by adding PLA, however differential scanning calorimetry results showed that PLA created enhanced thermal properties while adding CNFs did not provide any change in the composite thermal properties. Dynamic mechanical and rheological properties of the neat PHB generally improved with both PLA and CNFs, however, it decreased at high loadings of CNFs attributed to fiber aggregations and fiber pull-out in comparison to the low loading level of CNF.

11.
J Biomater Sci Polym Ed ; 31(18): 2396-2417, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32838704

RESUMO

Biomimetic characteristics of hydrogel scaffold are tuned in this study utilizing the synergy of alginate, gelatin, and microfluidically embedded voids. Superposition of alginate and gelatin polymer networks results in additional rigidity, which can be tuned by introduction of voids, and thereby allowing faster release of pore pressure through movement of aqueous phase through the pore network. More importantly, voids enabled the cells to penetrate from the surface of seeding into the depth of the scaffold and proliferate there, as demonstrated for MDA MB 231 breast cancer cells. The uniform voids, generated by the microfluidic device, self-align creating uniform macroporosity within the gel structure, get readily filled by the media due to hydrophilicity, and extend the characteristics of composite uniformly across the entire scaffold.


Assuntos
Alginatos , Gelatina , Biomimética , Engenharia Tecidual , Alicerces Teciduais
12.
Polymers (Basel) ; 12(6)2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-32599794

RESUMO

This report presents the preparation and characterizations of solid biopolymer blend electrolyte films of chitosan as cationic polysaccharide and anionic dextran (CS: Dextran) doped with ammonium iodide (NH4I) to be utilized as electrolyte and electrode separator in electrical double-layer capacitor (EDLC) devices. FTIR and XRD techniques were used to study the structural behavior of the films. From the FTIR band analysis, shifting and broadening of the bands were observed with increasing salt concentration. The XRD analysis indicates amorphousness of the blended electrolyte samples whereby the peaks underwent broadening. The analysis of the impedance spectra emphasized that incorporation of 40 wt.% of NH4I salt into polymer electrolyte exhibited a relatively high conductivity (5.16 × 10-3 S/cm). The transference number measurement (TNM) confirmed that ion (tion = 0.928) is the main charge carriers in the conduction process. The linear sweep voltammetry (LSV) revealed the extent of durability of the relatively high conducting film which was 1.8 V. The mechanism of charge storage within the fabricated EDLC has been explained to be fully capacitive behavior with no redox peaks appearance in the cyclic voltammogram (CV). From this findings, four important parameters of the EDLC; specific capacitance, equivalent series resistance, energy density and power density were calculated as 67.5 F/g, 160 ohm, 7.59 Wh/kg and 520.8 W/kg, respectively.

13.
Molecules ; 24(13)2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31323966

RESUMO

In the present work, promising proton conducting solid polymer blend electrolytes (SPBEs) composed of chitosan (CS) and methylcellulose (MC) were prepared for electrochemical double-layer capacitor (EDLC) application with a high specific capacitance and energy density. The change in intensity and the broad nature of the XRD pattern of doped samples compared to pure CS:MC system evidencedthe amorphous character of the electrolyte samples. The morphology of the samples in FESEM images supported the amorphous behavior of the solid electrolyte films. The results of impedance and Bode plotindicate that the bulk resistance decreasedwith increasing salt concentration. The highest DC conductivity was found to be 2.81 × 10-3 S/cm. The electrical equivalent circuit (EEC) model was conducted for selected samples to explain the complete picture of the electrical properties.The performance of EDLC cells was examined at room temperature by electrochemical techniques, such as impedance spectroscopy, cyclic voltammetry (CV) and constant current charge-discharge techniques. It was found that the studied samples exhibit a very good performance as electrolyte for EDLC applications. Ions were found to be the dominant charge carriers in the polymer electrolyte. The ion transference number (tion) was found to be 0.84 while 0.16 for electron transference number (tel). Through investigation of linear sweep voltammetry (LSV), the CS:MC:NH4SCN system was found to be electrochemically stable up to 1.8 V. The CV plot revealed no redox peak, indicating the occurrence of charge double-layer at the surface of activated carbon electrodes. Specific capacitance (Cspe) for the fabricated EDLC was calculated using CV plot and charge-discharge analyses. It was found to be 66.3 F g-1 and 69.9 F g-1 (at thefirst cycle), respectively. Equivalent series resistance (Resr) of the EDLC was also identified, ranging from 50.0 to 150.0 Ω. Finally, energy density (Ed) was stabilized to anaverage of 8.63 Wh kg-1 from the 10th cycle to the 100th cycle. The first cycle obtained power density (Pd) of 1666.6 W kg-1 and then itdropped to 747.0 W kg-1 at the 50th cycle and continued to drop to 555.5 W kg-1 as the EDLC completed 100 cycles.


Assuntos
Quitosana/química , Eletrólitos/química , Polímeros/química , Algoritmos , Capacitância Elétrica , Técnicas Eletroquímicas , Metilcelulose/química , Modelos Teóricos , Análise Espectral
14.
Int J Biol Macromol ; 138: 693-703, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31306704

RESUMO

Biopolymers have received considerable attention in recent years given the environmental concern related to the incorrect disposal of materials based on synthetic plastics. Starch and chitosan are good examples of raw materials of interest, and its combination can exhibit some newsworthy barrier and mechanical properties. Therefore, this study aimed to determine the impact of the acid type, acetic and lactic solutions (1% v/v), used for chitosan solubilization and the starch:chitosan proportion on the properties of cornstarch/chitosan-based films. The films were prepared by casting and characterized by analyses of water vapor permeability, tensile strength, elongation, elastic modulus, antimicrobial activity, and biodegradability. Mechanical properties analyses showed that the films prepared by using acetic acid presented higher rigidity and lower deformation, giving higher values of Young's Modulus and a smaller percentage of elongation, in comparison to the films fabricated with lactic acid. Besides, starch/chitosan films containing acetic acid also exhibited better water vapor barrier properties, showing smaller water permeation values. Moreover, the antimicrobial activity of the cornstarch-based films containing chitosan was confirmed, obtaining better results for the blended films prepared with lactic acid, indicating a high potential for the development of active packaging. For the biodegradation tests, all samples started the degradation after 15 days.


Assuntos
Ácidos/química , Biodegradação Ambiental , Quitosana/química , Membranas Artificiais , Amido/química , Biopolímeros , Fenômenos Químicos , Fenômenos Mecânicos , Solubilidade , Análise Espectral , Termogravimetria
15.
Polymers (Basel) ; 11(5)2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-31108907

RESUMO

Poly (Lactic Acid), PLA, and Poly (ε-CaproLactone), PCL, compatibilized with Ethyl Ester l-Lysine Triisocyanate (LTI) can be employed as biomaterials. We mixed PLA with PCL and LTI in a twin extruder and by a melt spinning process obtained threads with an average diameter of about 0.3 mm. In order to study the possible application of these threads, mechanical tensile (with the calorimetric and morphological investigations) and biological tests were performed. The results highlighted these biopolymers as promising materials for sutures since they can be rigid and elastic (especially by increasing the PCL amount in the blend), and they are bioactive, able to inhibit bacterial growth. This paper represents a starting point to optimize the blend composition for biomedical suture application.

16.
Carbohydr Polym ; 174: 716-722, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28821123

RESUMO

The interfacial adhesion between polyhydroxyalkanoates (PHAs) and native starch is poor. To improve the interfacial adhesion, PHAs were in-situ grafted onto starch using dicumyl peroxide (DCP) as a free radical initiator. The grafting reaction was carefully characterized and confirmed by gel analysis and Fourier transform infrared spectroscopy (FT-IR). The gel yield of the PHAs/starch/DCP blend increased with the DCP concentration up to 2wt%. Meanwhile, obvious plastic deformation (stretched fibrils) was observed at the interface in the PHAs/starch/DCP blend in comparison with complete interfacial debonding in the PHAs/starch physical blend. The improved interfacial adhesion after grafting was further confirmed by a reduction in adhesion factor (Af) obtained from dynamic mechanical analysis (DMA). The mechanical strength and the crystallization rate of the PHAs were deteriorated after incorporation of starch, and were backed up by the interfacial improvement. A linear relationship between the mechanical properties and the gel yield was discovered. In addition, the PHAs/starch/DCP blend exhibited higher decomposition active energy (Ea) and thus better thermal stability in comparison with the PHAs and the PHAs/starch physical blend. Therefore, this study provides a simple route to utilize low-cost starch as a component in biopolymer blend.

17.
Mater Sci Eng C Mater Biol Appl ; 69: 609-15, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27612753

RESUMO

Bio-active bi-layer thin film having both bio-adhesive and non-adhesive end composed of polyvinyl alcohol (PVA) and gelatin/chitosan/polyethylene glycol (PEG) blend was developed for biomedical applications especially as an alternative of advanced tissue scaffold. The developed composite film was subjected to mechanical, thermal and physico-chemical characterization such as tensile strength (TS) and elongation at break (Eb), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), fluid drainage capacity and biocompatibility. Suitable packaging was also selected and stability study and aging test of the composite film were performed after packing. The incorporation of chitosan and PEG into gelatin showed improved mechanical properties of both TS and Eb, which suggested the occurrence of interaction among gelatin, chitosan and PEG molecules in the composite film. The presence of crosslinking as an interaction of above three polymers was also confirmed by FTIR study. Results from the DSC study suggested increased thermal stability after crosslinking. On the other hand, water uptake studies suggested excellent fluid drainage capability and hydro-stability of the composite film. The proposed dressing also showed excellent biocompatibility. Based on the studies related to the performance with confirmed identity, we concluded that our developed bi-layer film is very potential as an ideal wound dressing material.


Assuntos
Adesivos/farmacologia , Materiais Biocompatíveis/farmacologia , Coloides/farmacologia , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Soluções Tampão , Varredura Diferencial de Calorimetria , Quitosana/química , Reagentes de Ligações Cruzadas/química , Humanos , Teste de Materiais , Testes de Sensibilidade Microbiana , Polietilenoglicóis/química , Álcool de Polivinil/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração/efeitos dos fármacos
18.
Carbohydr Polym ; 138: 309-16, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26794767

RESUMO

The underlined microstructure of biopolymer blends reflects complexity of mass and heat transfer during processing. In the present work, such complexity is apprehended using simple and intuitive way to generate typical microstructures resulting from thermomoulding processing. The starting point is a simple generation scheme of the feed powder approximated as circular heat sources. Finite element computation of a transient thermal analysis is performed and the resulting nodal fields are again converted into 2D microstructures. The final microstructures prove to be similar in all geometrical characteristics starch-zein blends. Elasticity response of these blends is explored using finite element computation. Sensitivity analysis is performed to derive the effect of perfect and imperfect interface properties on the mechanical performance of the biopolymer blend. Predictions show a significant role of interfaces which trigger the elasticity properties of the biopolymer blends much larger than the contrast in phase properties. This study demonstrates that nonlinear interface effect on elasticity behaviour is related to geometrical percolation that occurs at specific phase content.


Assuntos
Biopolímeros/química , Algoritmos , Módulo de Elasticidade , Elasticidade , Microscopia Confocal
19.
Carbohydr Polym ; 131: 34-40, 2015 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-26256157

RESUMO

Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, <50%). This work proposes a novel method for the preparation of cellulose/chitin blend fibers using ionic liquids (ILs) as gentle, removable, recyclable and non-deacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers.


Assuntos
Biopolímeros/química , Celulose/química , Quitina/química , Líquidos Iônicos/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Celulose/ultraestrutura , Cristalização , Reologia , Temperatura , Têxteis , Viscosidade , Água/química
20.
Carbohydr Polym ; 103: 274-84, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24528730

RESUMO

Several blend membranes were prepared from different weight ratios of polyvinyl alcohol (PVA) and hydroxyethyl cellulose (HEC) and these unfilled membranes were crosslinked with maleic acid. In a similar way mixed matrix blend membranes were also prepared by varying weight ratio of PVA and HEC with micro and nano bentonite filler in each of these blends. These membranes were used for pervaporative dehydration of 89 wt% tetrahydrofuran (THF). Three membranes designated as UF (unfilled), MF2 (containing 2 wt% micro filler) and NF2 (containing 2 wt% nano filler) showing the best results for flux and selectivity were identified. These membranes were characterized by FTIR, UV, XRD and DTA-TG and used for separation of 80-99 wt% THF from water by pervaporation. The NF2 membrane was found to show the best results in terms of flux and separation factor.


Assuntos
Biopolímeros/química , Água/química , Celulose/análogos & derivados , Celulose/química , Furanos/química , Maleatos/química , Álcool de Polivinil/química
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