Biopolymer Blends Research Articles

Improvement of mechanical properties and in vitro bioactivity of freeze-dried gelatin/chitosan scaffolds by functionalized carbon nanotubes

ABSTRACTFunctionalized multiwall carbon nanotubes (f-MWCNTs) were used to reinforce the freeze-dried gelatin (G)/chitosan (Ch) scaffolds for bone graft substitution. Two types of G/Ch scaffolds at a ratio of 2:1 and 3:1 by weight incorporated with 0.025, 0.05, or 0.1 and 0.2 or 0.4 wt% f-MWCNT, respectively, were prepared by freeze drying, and their structure, morphology, and physicochemical and compressive mechanical properties were evaluated. The scaffolds exhibited porous structure with pore size of 80–300 and 120–140 µm for the reinforced scaffolds of G/Ch 2:1 and 3:1, respectively, and porosity 90–93% which slightly decreased with an increase in f-MWCNTs content for both types. Incorporation of f-MWCNTs led to 11- and 9.6-fold increase in modulus, with respect to their pure biopolymer blend scaffolds at a level of 0.05 wt% for G/Ch 2:1 and 0.2 wt% for G/Ch 3:1, respectively. The higher content of f-MWCNTs resulted in loss of mechanical properties due to agglomeration. The highest value of compressive strength and modulus was obtained for G/Ch 2:1 with 0.05 wt% f-MWCNT as 411 kPa and 18.7 MPa, respectively. Improvement of in vitro bioactivity as a result of f-MWCNTs incorporation was proved by formation of a bone-like apatite layer on the surface of scaffolds upon immersion in simulated body fluid. The findings indicate that the f-MWCNT-reinforced gelatin/chitosan scaffolds may be a suitable candidate for bone tissue engineering.

Interfacial modification on polyhydroxyalkanoates/starch blend by grafting ​in-situ

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.

On the representative elementary size concept to evaluate the compatibilisation of a plasticised biopolymer blend

This study combines experimental and numerical approaches to investigate the microstructure and mechanical behaviour of non-miscible plasticised starch/zein blends. The concept of Representative Elementary Size (RES) is used to rank the effect of five different plasticisers (cholinium acetate, glycerol, butyl methyl imidazolium chloride, glycerol-choline chloride, urea-choline chloride) inducing microstructural and mechanical changes in the blends. Microstructural and mechanical RESs are derived from microscopy image analysis and Finite Element Modelling of elasticity behaviour of studied blends. Compared to the usual consideration of ultimate mechanical properties (elongation and stress at break), the RES-based approach allows detecting the presence of perfect or imperfect interface between starch and zein particles depending on the nature of plasticiser.

Nanostructured cellulose-xyloglucan blends via ionic liquid/water processing

In this work, the properties of cellulose (CE)/xyloglucan (XG) biopolymer blends are investigated, taking inspiration from the outstanding mechanical properties of plant cell walls. CE and XG were first co-solubilized in an ionic liquid, 1-ethyl-3-methylimidazolium acetate, in order to blend these biopolymers with a varying CE:XG ratio. The biopolymers were then regenerated together using water to produce solid blends in the form of films. Water-soluble XG persisted in the films following regeneration in water, indicating an attractive interaction between the CE and XG. The final CE:XG ratio of the blends was close to the initial value in solutions, further suggesting that intimate mixing takes place between CE and XG. The resulting CE/XG films were found to be free of ionic liquid, transparent and with no evidence of phase separation at the micron scale. The mechanical properties of the blend with a CE:XG ratio close to one revealed a synergistic effect for which a maximum in the elongation and stress at break was observed in combination with a high elastic modulus. Atomic force microscopy indicates a co-continuous nanostructure for this composition. It is proposed that the non-monotonous variation of the mechanical performance of the films with XG content is due to this observed nanostructuration.

Selective localization of graphene oxide in electrospun polylactic acid/poly(ε-caprolactone) blended nanofibers

Despite their immiscibility, blending polylactic acid (PLA) with poly(ε-caprolactone) (PCL) provides an efficient strategy for obtaining a biopolymer blend with tailored properties due to their complementary physical properties. In this study, graphene oxide (GO) was employed as a 2-D nanofiller and nucleating agent to improve the properties of the immiscible PLA/PCL blends at 70/30, 50/50, and 30/70 wt ratios. Nanofibers of PLA/PCL blends and PLA/PCL/GO composites were investigated. It was interesting to find that the GO selectively localized in the minor phase resulting from the phase separation. The selective localization of the GO as the nucleating agent had an influence on the degree of crystallinity and crystalline morphology in the blended composites. This study also demonstrated that the molecular chains in the PLA phase oriented along the fiber axes, while in the PCL phase, the partial crystallites changed their orientation direction to be perpendicular to the fiber axes with the addition of GO.

Local mechanical behavior mapping of a biopolymer blend using nanoindentation, finite element computation, and simplex optimization strategy

ABSTRACTIn this study, we suggest a simple scheme to derive interfacial behavior using combination of nanoindentation and finite element computation. The starting point is the experimental generation of a rectangular grid composed of 32 indentations to measure the exact variation of stiffness across the interface of a bio‐based composite. A finite element simulation of nanoindentation is implemented based on elasto‐plastic material model. An optimization strategy is used to identify the behavior of all phases by matching predicted results to observed mechanical response. Results show that extent of interphase layer has a typical dimension of 8.0 ± 4.9 µm. The optimization strategy based on simplex proves to be efficient to derive the elasto‐plastic behavior of the blend across the interface with a residual value of less than 30 µN. The identification procedure demonstrates that the extent of the interfacial region depends on the measured physical quantity. The contrast across the interface for both Young's and the tangent moduli appear to be more effective than the contrast given by the yield stress. Identified Young's moduli for zein, starch, and interfacial zone are 4.78 ± 0.27, 4.13 ± 0.19, and 3.91 ± 0.17 GPa. Plasticity parameter represented by tangent modulus varies in the same order as 1238 ± 120, 847 ± 108, and 976 ± 94 MPa, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44891.

Silk scaffolds connected with different naturally occurring biomaterials for prostate cancer cell cultivation in 3D.

In the present work, different biopolymer blend scaffolds based on the silk protein fibroin from Bombyx mori (BM) were prepared via freeze-drying method. The chemical, structural, and mechanical properties of the three dimensional (3D) porous silk fibroin (SF) composite scaffolds of gelatin, collagen, and chitosan as well as SF from Antheraea pernyi (AP) and the recombinant spider silk protein spidroin (SSP1) have been systematically investigated, followed by cell culture experiments with epithelial prostate cancer cells (LNCaP) up to 14 days. Compared to the pure SF scaffold of BM, the blend scaffolds differ in porous morphology, elasticity, swelling behavior, and biochemical composition. The new composite scaffold with SSP1 showed an increased swelling degree and soft tissue like elastic properties. Whereas, in vitro cultivation of LNCaP cells demonstrated an increased growth behavior and spheroid formation within chitosan blended scaffolds based on its remarkable porosity, which supports nutrient supply matrix. Results of this study suggest that silk fibroin matrices are sufficient and certain SF composite scaffolds even improve 3D cell cultivation for prostate cancer research compared to matrices based on pure biomaterials or synthetic polymers.

Biosynthesis and physicochemical characterization of a bacterial polysaccharide/polyamide blend, applied for microfluidics study in porous media

Screening among some new isolated bacteria from oily samples, which were capable of producing extracellular polymeric substances (EPSs), one was selected and identified as Bacillus sonorensis. An efficient micro-total analysis approach was carried out to assay the produced EPSs by this bacterium. Sucrose and yeast concentrations as carbon and nitrogen sources, respectively, sodium salt concentration and initial pH were selected to be the variables in experimental design. Production of EPS in optimal condition was increased by 5.3 times. Further EPS purification was carried out to identify the biopolymers. The bacteria produced high molecular weight biopolymers with a number average molecular weight (M̅n) of 9.1×106g/mol determined by gel permeation chromatography (GPC). Biopolymer characterization demonstrated the biosynthesis of both polysaccharides and polyamides by the bacteria. For the biopolymer blend, thermal properties and morphological characteristics were studied using simultaneous differential scanning calorimetric and thermal gravimetric analyses (DSC/TGA) and field emission scanning electron microscope (FESEM) analyses. Finally, the biopolymer blend was injected into an oil saturated glass micro model to study the enhancement of oil recovery by biopolymer flooding in contrast with water flooding. It was found that oil recovery increased by 36%, from 23% using water flooding to 59% for biopolymer injection.

Characterization of starch-chitosan blend-based electrolyte doped with ammonium iodide for application in proton batteries

This paper reports on the characterization and application in proton batteries of corn starch-chitosan blend biopolymer electrolyte doped with NH4I as a proton provider. In this work, all electrolyte films are prepared by the solution cast method. Thermogravimetric analysis (TGA) reveals that the plasticized electrolyte is stable up to 180 °C. Differential scanning calorimetry (DSC) study shows that Tg values decrease with the addition of salt and plasticizer. The X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) analyses verify the conductivity results from a previous work. The cation transference number for the highest conducting electrolyte was 0.40. The highest conducting electrolyte has been used in fabrication of primary and secondary proton batteries.

Biomimetic Nanofibrillation in Two-Component Biopolymer Blends with Structural Analogs to Spider Silk.

Despite the enormous potential in bioinspired fabrication of high-strength structure by mimicking the spinning process of spider silk, currently accessible routes (e.g., microfluidic and electrospinning approaches) still have substantial function gaps in providing precision control over the nanofibrillar superstructure, crystalline morphology or molecular orientation. Here the concept of biomimetic nanofibrillation, by copying the spiders’ spinning principles, was conceived to build silk-mimicking hierarchies in two-phase biodegradable blends, strategically involving the stepwise integration of elongational shear and high-pressure shear. Phase separation confined on nanoscale, together with deformation of discrete phases and pre-alignment of polymer chains, was triggered in the elongational shear, conferring the readiness for direct nanofibrillation in the latter shearing stage. The orderly aligned nanofibrils, featuring an ultralow diameter of around 100 nm and the “rigid−soft” system crosslinked by nanocrystal domains like silk protein dopes, were secreted by fine nanochannels. The incorporation of multiscale silk-mimicking structures afforded exceptional combination of strength, ductility and toughness for the nanofibrillar polymer composites. The proposed spider spinning-mimicking strategy, offering the biomimetic function integration unattainable with current approaches, may prompt materials scientists to pursue biopolymer mimics of silk with high performance yet light weight.

Formation and functional attributes of electrostatic complexes involving casein and anionic polysaccharides: An approach to enhance oral absorption of lycopene in rats in vivo

The current work entails a novel strategy of formulating the microparticles of lycopene solely using rational blends of biopolymers without using equipment-intensive techniques. The study is intended to enhance oral bioavailability of lycopene by controlling its release from micro-formulation and facilitating its absorption though lymphatic pathways. Considering the minimum particle size, maximum entrapment efficiency and loading capacity, the amounts of casein (i.e., protein) and gum tragacanth (i.e., polysaccharide) were selected as the critical factors for formulation of microparticles. Complex formation and electrostatic interaction was confirmed by Fourier transform infra red (FTIR) spectra. Size and surface properties of microparticles were studied using scanning electron microscopy (SEM). The optimized formulation (mean particle size: ∼130μm; % entrapment efficiency: ∼67% and loading capacity: ∼71%) designated noticeable improvement in lycopene release profile (over 80% in 24h). Increment in the values of Cmax (2.22-fold) and AUC (1.97-fold) further indicated noteworthy augmentation in the rate and extent of bioavailability by the microparticles formulation compared to plain lycopene. The resulting formulation was found to be quite stable all through two months of study episode. The resultant microparticles formulation was evaluated for antioxidant activity and tested for their effectiveness in self life enhancement of vegetable oil by calculating peroxide value under temperature and storage condition. Encapsulation strongly increased the stability of micronutrients. The current investigations, therefore, report the successful development of biopolymeric microparticles with improved bioavailability potential of lycopene.

The Effect of Lithium Iodide to the Properties of Carboxymethyl κ-Carrageenan/Carboxymethyl Cellulose Polymer Electrolyte and Dye-Sensitized Solar Cell Performance

This study was undertaken to investigate the solid biopolymer electrolytes based on a carboxymethyl κ-carrageenan/carboxymethyl cellulose blend complexed with lithium iodide of various weight ratios. The complexation of the doping salt with the polymer blend was confirmed by Fourier transform infrared spectroscopy. Ionic conductivity of the film was determined by impedance spectroscopy in the frequency range of 10 Hz to 4 MHz and in the temperature range of 303–338 K. The ionic conductivity increased with the increase in lithium iodide concentration as well as temperature. The membrane comprising 30 wt % of lithium iodide was found to give the highest conductivity of 3.89 × 10−3 S·cm−1 at room temperature. The increase in conductivity was associated with the increase in the number as well as the mobility of the charge carries. The conductivity increase with temperature followed the Vogel–Tamman–Fulcher model. The fabricated dye-sensitive solar cell, FTO/TiO2-dye/CMKC/CMCE-LiI (30 wt %) +I2/Pt exhibited the highest conversion efficiency of 0.11% at a light intensity of 100 mW·cm−2. This indicated that the biopolymer blend electrolyte system has potential for use in dye-sensitized solar cells.

Improved miscibility of low‐density polyethylene/chitosan blends through variation in the compounding length

ABSTRACTSynthetic biopolymer blends are gaining interest in the packaging industry because the incorporation of natural materials imparts biodegradable properties to films. In this study, polyethylene/chitosan (chitosan) films with thicknesses of about 0.3 ± 0.01 mm were fabricated via compression molding. The effects of the variation in the length of compounding as a function of the length/diameter (l/d) ratio (15:1, 30:1, 45:1, 60:1, and 75:1) were investigated. The experimental results show that a higher degree of miscibility of the blends was achieved with increasing compounding length; this led to improved mechanical properties in the films, and this was verified by the statistical analysis of data with the analysis of variance procedure. The tensile strength (TS) increased by about 25%, whereas the elongation at break (Ebreak) increased by twofold. Films fabricated from blends compounded with an l/d ratio of 60:1 had the highest TS and Ebreak values, and the TS was comparable to that of low‐density polyethylene films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43796.

A combined rheology and time domain NMR approach for determining water distributions in protein blends

We present a combined time domain NMR and rheology approach to quantify the water distribution in a phase separated protein blend. The approach forms the basis for a new tool to assess the microstructural properties of phase separated biopolymer blends, making it highly relevant for many food and non-food related applications. First, we determine the relaxation rate of absorbed water, and the viscoelastic properties of the separated phases as function of the water content. Next, the same properties are measured for the protein blends. Finally, predictions for water distribution obtained from rheological experiments are made via the polymer blending law, and compared to a more direct assessment of the water distribution with time-domain NMR relaxometry (TD-NMR). In this study, the protein blend consists of soy protein isolate (SPI) and vital wheat gluten (WG). We demonstrate that predictions for water distribution are similar for both TD-NMR and rheological measurements. It turns out that water does not distribute homogenously over the phases. Independent of the SPI and WG ratio, more water is absorbed by the SPI phase relative to the WG phase, which largely determines the resulting rheological properties of the blends.

Characterization of Proton Conducting Carboxymethyl Cellulose/Chitosan Dual-Blend Based Biopolymer Electrolytes

This article presents the discovery on biopolymer electrolytes comprising of ammonium nitrate, NH4NO3 with dual-blend biopolymer materials, carboxymethyl cellulose/chitosan which were prepared via solution-casting technique. The biopolymer blend based electrolyte films were characterized by Fourier Transform Infrared spectroscopy to investigate the formation of the dual-blend biopolymer based complexes. X-Ray Diffraction result showed that all dual-blend samples were predominantly amorphous. Electrochemical impedance spectroscopy was conducted to obtain their ionic conductivities. The highest conductivity at ambient temperature of 1.03 × 10–5 S cm–1 was obtained for the electrolyte film containing 40 wt% of NH4NO3. These results indicated that the dual-blend biopolymer based electrolyte has potential for application of electrochemical devices.

State of the art and future prospectives of poly(lactic acid) based blends and composites

The finite availability of petroleum and environmental considerations has given emphasis on the development of raw materials for polymers from renewable resources. Polymers from renewable resources are expected to gain great momentum nowadays as petroleum resources become less secure. The use of biopolymer blends and composites can bring out a revolution in the field of automobile, pharmaceutical, packaging industry, etc. Poly(lactic acid) or polylactide (PLA) is the most extensively researched and utilized biodegradable and renewable thermoplastic polyester, with a potential to replace conventional petrochemical‐based polymers. Besides its relatively high tensile strength and modulus compared to other thermoplastics such as polyethylene terephthalate, polypropylene, the low impact strength and less heat tolerance of the material makes it inadequate for more demanding applications. It is the most promising material for the production of environment friendly high performance products. It is proven to be superior to conventional plastics in terms of energy consumption and carbon dioxide emission in life cycle analysis. The general purpose of this review is to introduce PLA, a compostable, biodegradable thermoplastic made from renewable sources and their blends. In the first part of this review, we briefly discuss the advantages, limitations, production methods of PLA. The second part, the major objective of this paper, focuses on the various toughening modification of PLA and also about PLA based green composites using natural fibers and agricultural residues. It also highlights the major research progress and strategies applied to improve the brittleness of polylactic acid. POLYM. COMPOS., 39:81–101, 2018. © 2016 Society of Plastics Engineers

Fabrication and Characterization of Electrospun Nanofiber Films of PHA/PBAT Biopolymer Blend Containing Chilli Herbal Extracts (Capsicum frutescens L.

Fabrication and Characterization of Electrospun Nanofiber Films of PHA/PBAT Biopolymer Blend Containing Chilli Herbal Extracts (Capsicum frutescens L.

Crosslinked biopolymer blend based tubular construct for vascular conduit application

Event Abstract Back to Event Crosslinked biopolymer blend based tubular construct for vascular conduit application Harpreet Pawar1, Nimmy K. Francis1, Arun P. Rameshbabu1 and Santanu Dhara1 1 Indian Institute of Technology, Kharagpur, School of Medical Science & Technology, India Introduction: The unmet need of autologous vascular grafts in Ischemic heart disease and peripheral vascular disease with underlying atherosclerosis necessitates the exploration of artificial vascular conduits. The principles of vascular tissue engineering outlined over the last decade, guides through the fabrication of biopolymer based vascular scaffolds in this study. Favorable hemocompatibility, biological interaction and degradation profile are the decisive factors for polymer selection and processing[1],[2]. Materials and Methods: 2,5-Dihydro-2,5-dimethoxyfuran (DMDF) cross-linked tubular scaffolds were fabricated from Silk fibroin and Chitosan blend by extrusion in Sodium hydroxide bath[3],[4]. The scaffolds were then subjected to structural, mechanical and chemical analysis followed by in vitro seeding of Human mesenchymal stem cells (hMSC) and immunolabeling for endothelial differentiation markers. In vivo studies were performed to elucidate the biocompatibility and temporal degradation. Results and Discussion: DMDF mediated temperature controlled gelation of chitosan could be the possible mechanism underlying the cross-linking of amine moieties in silk-chitosan blend in our experiment. Porous tubular scaffold demonstrated average pore size of 143 ±15.6 µm on SEM images which reduces on cross-linking to around 110 ± 8.3 µm, sufficient enough for in-growth of peri-scaffold tissue and transmural endothelization with angiogenesis[5],[6]. {AbstractFigure.1}} FTIR analysis showed characteristic peaks of newly formed C=N and C-N bond on crosslinking. Blending of chitosan and silk resulted in loss of the typical peak of chitosan at 10o and appearance of broad amorphous hump on XRD analysis, suggestive of molecular interaction between the two. A strong diffraction peak at ~20.4o substantiates the β-sheet formation on crosslinking of sample[7],[8]. On Nano-indentation studies, uncrosslinked sample showed greater non-reversible deformation (2270±19.3 nm) as well as permanent displacement (2160±27.4 nm) on application of equal load when compared to crosslinked sample with non-reversible and permanent displacement of 607±11.4 nm and 516±14.6 nm respectively[9]. The scaffold was found hemocompatible on clotting time, prothrombin time and SEM imaging for platelet adsorption. Histological studies revealed minimal inflammatory reaction and favorable tissue remodeling with the gradual replacement of the scaffold. In vitro cell seeding shows hMSC differentiation into endothelial cell like lineage with positive immunocytochemical profiling for PECAM-1 and von willebrand factor. Conclusion: Silk-Chitosan blend as a potential alternative to existing biopolymers for blood vessel engineering offers adequate mechanical properties along with its promising biocompatibility. Primary in vitro and in vivo studies warrant elaborative long term assessment for intended application. IIT Kharagpur has been acknowledged for providing infrastructural facility.

Polymer blend nanocomposites based on poly(l-lactic acid), polypropylene and WS2 inorganic nanotubes

The overall thermal and mechanical properties of PLLA/PPPP-g-MAH/INT-WS2 confirm the high-performance of these novel biopolymer blend nanocomposites, which opens new possibilities for use in biomedical applications.

Microencapsulation of stearidonic acid soybean oil in Maillard reaction-modified complex coacervates

The antioxidant capacity of Maillard reaction (MR)–modified gelatin (GE)–gum arabic (GA) coacervates was optimized to produce microcapsules with superior oxidative stability compared to the unmodified control. MR was used to crosslink GE and GA, with or without maltodextrin (MD), to produce anti-oxidative Maillard reaction products (MRP) which was used to encapsulate stearidonic acid soybean oil (SDASO) by complex coacervation. Biopolymer blends (GE–GA [1:1, w/w] or GE–GA–MD [2:2:1, w/w/w]) were crosslinked by dry-heating at 80°C for 4, 8, or 16h. Relationships between the extent of browning, Trolox equivalent antioxidant capacity (TEAC), and the total oxidation (TOTOX) of encapsulated SDASO were fitted to quadratic models. The [GE–GA–MD] blends exhibited higher browning rates and TEAC values than corresponding [GE–GA] blends. Depending on the type of biopolymer blend and dry-heating time, TOTOX values of SDASO in MRP-derived microcapsules were 29–87% lower than that of the non-crosslinked control after 30days of storage.