Mechanical Properties Of Biopolymers Research Articles

Effect of post-heat treatment on the UV transmittance, hydrophobicity, and tensile properties of PVA/Uncaria gambir extract blend films

The physical and mechanical properties of biopolymers can be improved by heating technologies. In this research, we improved the properties of Polyvinyl alcohol (PVA)/Uncaria gambir extract (UGE) blend films by post-heating method. After post-heating, the blend film exhibited higher resistance to UV light and improved contact angle performance, while water vapor permeability and moisture absorption decreased. The tensile strength and toughness of the PVA/UGE blend film with a post-heating duration of 40 min were 68.8 MPa and 57.7 MPa, respectively, an increase of 131 % and 127 %, compared to films without post-heating. This facile and cost-effective fabrication method, with environmentally friendly properties, can be applied to biodegradable PVA/UGE blend films to achieve desired properties for optical devices or food packaging materials.

Biopolymers as alternatives to synthetic polymers in flame‐retarded polymeric composites: A study of fire and mechanical behaviors

AbstractThe impact of polymeric materials on the environment is a growing concern and an incentive for their commercial appeal. In composites, the trend is to replace matrices of synthetic polymers (SPs) with biopolymers (BPs) to develop bio‐based composites. The increasing demand for such materials has driven their research and application in many industrial sectors, often accompanied by increasingly restrictive fire safety regulations. With the aim of decreasing the flammability of composites, various approaches have been pursued, in particular the use of flame‐retardant (FR) additives. However, at high FR loads, the mechanical properties can be compromised. This article briefly overviews some aspects of the fire behavior and mechanical properties of BPs and bio‐based composites. Using a chart‐based framework and quadrant‐based quantitative analysis, the fire and mechanical properties of flame‐retarded composite formulations are evaluated simultaneously, aimed at comparing the effects of BPs and SPs in flame‐retarded polymeric composites in relation with other variables.

A STUDY ON DIFFERENT TYPES OF EDIBLE PACKAGING MATERIALS (PLANTS BASED)

The food and pharmaceutical industries recognized edible packaging as a useful alternative or addition to conventional packaging to reduce waste and to create novel applications for improving product stability, quality, safety, variety and convenience for consumers. This study was done to compare the different types of edible packaging materials, their classifications and their applications. The aim of this study was to better understand the potential of fruits and vegetables to be used as components of edible packaging materials is discussed. Such application of fruits and vegetables is possible to the presence of matrix-forming polysaccharides and proteins in their composition. The development of edible fruit and vegetable packaging materials is a promising way of combining the barrier and mechanical properties of biopolymers with the nutritional and sensory properties. The application of fruits and vegetables as a component of edible packaging materials enables the utilization of raw materials with low commercial value. Edible packaging materials are a new method of their utilizing. There is also the possibility of just decreasing the amount of synthetic packaging waste by application of fruit and vegetable packaging materials simply as a passive or active layer partially replacing the non‐renewable materials. The dynamic forces behind the keen chase includes scientific innovation in the functionality of new materials, increased demand for novel foods and increased consciousness for environmental protection and conservation. In this study we’ll know about the different characteristics of edible packaging materials like light weight, low cost with significant strength, good oil and chemical resistance, moderation of elongation, good tensile strength, and act as good oxygen barriers, retard moisture loss, flexible and generally have no taste or flavor. Materials that have traditionally been used in food packaging include glass, metals (aluminum, foils and laminates, tinplate, and tin-free steel), paper and paperboards, and plastics. Moreover, a wider variety of plastics have been introduced in both rigid and flexible forms

Bioinspired interface design of multifunctional soy protein-based biomaterials with excellent mechanical strength and UV-blocking performance

Renewable and biodegradable plant-derived biomaterials are considered an ideal alternative to non-biodegradable petrochemical plastics. However, the inherent cohesion and mechanical properties of biopolymers are usually insufficient to meet the requirements of practical applications. Inspired by the supramolecular chemistry of mussels, we report a facile and sustainable strategy for fabricating a high-performance soy protein (SP)-based film by incorporating polyvinylpyrrolidone (PVP)-functionalized lignosulfonate (LS) hybrids. In this process, the polymerized LS molecules form rigid skeletal domains, and the PVP chains serve as soft components to ensure the flexibility of the composites. An interconnected cross-linking network was constructed in the SP/PVP@LS film via multiple non-covalent interactions including hydrogen bonding, hydrophobic interactions, and π–π interactions. As a result of the synergistic effect of supramolecular interactions, the tensile strength and toughness of the resulting film were significantly enhanced to 16.15 MPa and 23.50 MJ/m3, corresponding to increases of 111.39% and 386.54% relative to the pristine SP film. The SP/PVP@LS film also shows excellent ultraviolet-light resistance, improved flame retardancy, and favorable thermal stability owing to the unique aromatic ring structure and the ketones, phenol units, and chromophore functional groups in the PVP@LS hybrids. The bioinspired design strategy provides an innovative and facile route for producing multifunctional SP-based films for various prospective applications in fields such as biomass adhesives, active packaging, UV-protective coatings, and flame retardants.

Study of the structural and mechanical properties of biopolymers in order to obtain a capsule-type product

The article presents some theoretical and experimental data on promising technologies, namely, the processes of obtaining artificial food materials such as spheres or "caviar". They are derived from molecular processes: solubilization, spherification, etc. Possible applications are the food industry, the food service industry, biotechnology, and others. There are different features of obtaining artificial products based on alginates. The peculiarities of the alginate structuring are that it is possible to form a gel layer-encapsulation and gel formation over the entire thickness of the product due to the special chemical properties of the fixing salt. Based on the theory of the molecular structure of biopolymers, molecular technologies for the synthesis of artificial food products were developed, using the example of molecular "caviar". As a result of our own experiments, we obtained a satisfactory encapsulated product from a biopolymer crosslinked with Ca2+ salts in terms of organoleptic and physico-chemical properties. The colloidal biopolymer solution for forming "eggs" was characterized using the method of rotational viscometry, which showed the features of the sodium alginate solution as a structured thixotropic material, which is characterized by" difficulty " of shear at low speeds of rotation of the viscometer rotor. Further on the rheogram, such material exhibits a predicted relatively stable flow. As a result, it can be used to produce semi-finished products of a given shape and texture as a food semi-finished product or product. If the technology is refined, it is possible to use colloidal systems based on alginates and other biopolymers in biotechnology, including the cultivation of microorganisms of various taxonomic groups.

Development of mangiferin loaded chitosan-silica hybrid scaffolds: Physicochemical and bioactivity characterization

Development of hybrid materials with molecular structure of organic-inorganic co-network is a promising method to enhance the stability and mechanical properties of biopolymers. Chitosan-silica hybrid nanocomposite scaffolds loaded with mangiferin, a plant-derived active compound possessing several bioactivities, were fabricated using the sol-gel synthesis and the freeze-drying processes. Investigation on the physicochemical and mechanical properties of the fabricated scaffolds showed that their properties can be improved and tailored by the formation of 3-dimensional crosslinked network and the addition of ZnO nanoparticles. The scaffolds possessed porosity, fluid uptake, morphology, thermal properties and mechanical strength suitable for bone tissue engineering application. Investigation on the biomineralization and cell viability indicated that the inclusion of bioactive mangiferin further promote potential use of the hybrid nanocomposite scaffolds in guided bone regeneration application.

An overview of fruit and vegetable edible packaging materials

Various edible fruit and vegetable materials, including purees, residues, extracts, and juices, have been investigated in terms of their matrix‐forming properties to produce edible packaging materials to be applied to food products influencing their overall quality and improving the efficiency of synthetic packaging, thus leading to the reduction in amount of synthetic polymers used for each application.The potential of fruit and vegetables to be used as components of edible packaging materials is discussed. Such application of fruits and vegetables is possible thanks to the presence of matrix‐forming polysaccharides and proteins in their composition while the presence of bioactive compounds such as vitamins and polyphenols may confer, eg, antioxidant and antimicrobial properties of active packaging materials.The development of edible fruit and vegetable packaging materials is a promising way of combining the barrier and mechanical properties of biopolymers with the nutritional and sensory properties. The application of fruit and vegetables as a component of edible packaging materials enables the utilization of raw materials with low commercial value. Edible packaging materials are a new method of their utilizing. There is also the possibility of just decreasing the amount of synthetic packaging waste by application of fruit and vegetable packaging materials simply as a passive or active layer partially replacing the non‐renewable materials.

Effects of Compatibilizer on Thermal and Mechanical Properties of PLA/NR Blends

The aim of the research is to study the effects of compatibilizer on thermal and mechanical properties ofbiopolymer poly (lactic acid) (PLA) and natural rubber (NR) blends. PLA was blended with NR in the composition of 95/5 weight percentage with present of compatibilizer. The compatibilizers, PLA grafted maleic anhydride (MA) (PLA-g-MA) and NR grafted MA (NR-g-MA) were synthesized in a composition of 9 phr of MA by using internal mixer in presence of benzoyl peroxide (BPO). The formulations of PLA/NR blended with the compatibilizer were in the range of 1, 3, 5 and 10 wt.% of PLA-g-MA and NR-g-MA, respectively. Blending process was conducted using twin screw extruder then were pelletized and hot pressed before characterized. The mechanical (tensile, flexural, impact) and thermal properties of the blends was investigated and from the results, the addition of PLA-g-MA in PLA/NR blendimproved the impact strength and elongation at break of the blends as compared with neat PLA and PLA/NR blend without compatibilizer and for thermal stability, it only had a slight influence on the blends. Addition of NR-g-MA on contrary did not give improvement on mechanical properties but increasing in thermal stability.

Spectral Analysis Methods for the Robust Measurement of the Flexural Rigidity of Biopolymers

The mechanical properties of biopolymers can be determined from a statistical analysis of the ensemble of shapes they exhibit when subjected to thermal forces. In practice, extracting information from fluorescence microscopy images can be challenging due to low signal/noise ratios and other artifacts. To address these issues, we develop a suite of tools for image processing and spectral data analysis that is based on a biopolymer contour representation expressed in a spectral basis of orthogonal polynomials. We determine biopolymer shape and stiffness using global fitting routines that optimize a utility function measuring the amount of fluorescence intensity overlapped by such contours. This approach allows for filtering of high-frequency noise and interpolation over sporadic gaps in fluorescence. We use benchmarking to demonstrate the validity of our methods, by analyzing an ensemble of simulated images generated using a simulated biopolymer with known stiffness and subjected to various types of image noise. We then use these methods to determine the persistence lengths of taxol-stabilized microtubules. We find that single microtubules are well described by the wormlike chain polymer model, and that ensembles of chemically identical microtubules show significant heterogeneity in bending stiffness, which cannot be attributed to sampling or fitting errors. We expect these approaches to be useful in the study of biopolymer mechanics and the effects of associated regulatory molecules.

Influence of Electron Beam Irradiation on the Mechanical Properties of Vegetable-Oil-Based Biopolymers

The influence of electron beam (EB) irradiation on the mechanical properties of biopolymers from modified linseed oil is studied. The thermoset is prepared by copolymerizing norbornenyl-functionalized linseed oil and dicyclopentadiene (DCPD) by ring-opening metathesis polymerization (ROMP). EB irradiation of the bulk polymer results in a substantial increase in the crosslinking density. The residual carbon-carbon double bonds remaining after ROMP are expected to act as further crosslinking sites upon exposure to the high-energy electrons. The increase in the crosslinking density is studied by DMA and sol/gel fraction measurements from Soxhlet extraction. Tensile testing reveals that Young's modulus and tensile strength are enhanced after EB irradiation.

Influence of Processing Methods on Mechanical and Structural Characteristics of Vacuum Microwave Dried Biopolymer Foams

Control of physical and mechanical properties of biopolymer (derived from food hydrocolloid) porous solids in terms of stress strain relationship during compression, porosity and pore size would enable their use for a wider range of purposes. Different types of dried cellular biopolymer foams were produced using different food hydrocolloids such as locust bean and alginate gums, gelatin, low and high methoxy pectin, methyl cellulose and starches (corn and tapioca) at various proportions. First different types of wet hydrogels were prepared by varying gel processing methods. Then they dried using microwave energy under vacuum called vacuum microwave drying. Before performing the drying process the initial Young's modulus of the hydrogels was measured. Pore size analysis and distribution percentage were done using mercury pore size analyser after drying. Relationship between the pore size distribution after drying and the initial Young's modulus was developed. Compressive test was performed for dried porous solids and true stress strain relationship curves were developed to classify nature of dried foams obtained from various gel types. Scanning Electron Microscopic study of individual samples was performed to view the internal structure of dried porous biopolymers.

Water resistance and mechanical properties of biopolymer (alginate and soy protein) coated paperboards

The effect of biopolymer coating on the water barrier and mechanical properties of paperboards used as corrugated fiberboard box liners was studied under several conditions. Paperboards were coated with selected biopolymers, such as alginate and soy protein isolate (SPI) and studied with or without further treatment, such as cross-linking through CaCl 2 or formaldehyde treatment and compositing with organically modified montmorillonite (OMMT). Biopolymer coating increased the thickness of paperboards from 9% to 16%, depending on the coating materials and treatment methods, and resulted in a smoother and more homogeneous surface. Though the tensile strength (TS) of the coated paperboards decreased from 12.5% to 37.5% of the uncoated paperboards by coating, ring crush strength was not decreased. Wetting properties, such as contact angle of water drop, dynamic change in contact angle, water vapor permeability (WVP), and water absorptivity were also affected by biopolymer coating, but the degree of change was dependent on the coating materials as well as treatment methods. For example, the rate of change in contact angle of water on paperboards decreased dramatically from 1.4 to 3.8 times depending on the coating materials as well as treatment methods. Generally, SPI-coated paperboards were more water-resistant than alginate coated ones. However, water resistance of the alginate-coated paperboards post-treated with the CaCl 2 solution was comparable to the SPI coated ones.

Hydrogen Bonding in Lignin: A Fourier Transform Infrared Model Compound Study

Hydrogen bonding plays an important role in the thermal and mechanical properties of biopolymers. To investigate hydrogen bond formation in lignin, an abundant natural polymer found in plants, Fourier transform infrared (FTIR) analysis of various lignin model compounds was performed. Four monomeric model compounds and one dimeric model compound were studied under various conditions. FTIR analysis revealed aliphatic hydroxyl groups form stronger hydrogen bonds than phenolic hydroxyl groups. Further, the dimeric biphenyl-type structure formed significantly stronger intermolecular hydrogen bonds as compared to the other monomeric model compounds. Results from the model compound studies were used to explain the observed complex hydrogen-bonding system present in both softwood and hardwood technical lignins. Together with chemical analysis, we discuss the difference in hydrogen bonding between hardwood and softwood lignin and the observed differences in the glass transition temperature.

Nonlinear assembly kinetics and mechanical properties of biopolymers

This paper discusses the role of nonlinearities in the physical description of key biomolecules that participate in crucial subcellular processes, namely actin, microtubules and ions crowding around these filaments. The assembly kinetics of actin is that of a nonlinear process that is governed by coupled nonlinear equations involving monomer concentration and filament number as the dynamical variables. The dendritic growth of actin networks in cell motility phenomena is described by the coupling of actin filaments to the protein Arp2/3. We then discuss how coupled differential equations describing the interactions between ions in solution and the filament they surround can lead to solitonic signal transmission. We also investigate the role of nonlinear dynamics in the formation of microtubules. Space-flight laboratory experiments have shown that the self-organization of microtubules is sensitive to gravitational conditions. We propose a model of self-organization of microtubules in a gravitational field based on the dominant chemical kinetics. The pattern formation of microtubule concentration is obtained in terms of a moving kink. Finally, we present a model of elastic properties of microtubules describing a microtubule as an elastic rod. We found that when the microtubule is subjected to bending forces, the tangent angle satisfies a Sine-Gordon equation whose solutions describe kink and anti-kink bending modes that may propagate at a range of velocities along the length of the microtubule.

Molecular composition and mechanical properties of biopolymer interfaces studied by sum frequency generation vibrational spectroscopy and atomic force microscopy

Sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM) have been used to study the surface structure and surface mechanical behavior of biologically-relevant polymer systems. These techniques have emerged as powerful surface analytical tools to deduce structure/property relationships in situ, at both air/solid and air/liquid interfaces. SFG and AFM studies have been performed to understand how the surface properties of polymers are linked to polymer bulk compositions, changes in the ambient environment, or the degree of mechanical strain. Specifically, this review discusses (1) the macroscopic- and molecular-level tracking of small end groups attached to polyurethane blends, engineered to reduce blood clotting; (2) the role of ambient humidity on the surface mechanics of soft contact lenses possessing different water content in the bulk; (3) the affect of cyclic stretch on the molecular surface structure of polyurethane films, designed to mimic the mechanical deformation caused by heartbeat; and (4) the molecular ordering of functional groups at the polystyrene-protein interface. The correlation of spectroscopic and mechanical data by SFG and AFM is a powerful methodology to study and design materials with tailored surface properties.