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18 pages, 6122 KiB

Open AccessArticle

Fabrication and Characterization of Lignin/Dendrimer Electrospun Blended Fiber Mats

by Somaye Akbari, Addie Bahi, Ali Farahani, Abbas S. Milani and Frank Ko

Molecules 2021, 26(3), 518; https://doi.org/10.3390/molecules26030518 - 20 Jan 2021

Cited by 13 | Viewed by 2570

Abstract

Blending lignin as the second most abundant polymer in Nature with nanostructured compounds such as dendritic polymers can not only add value to lignin, but also increase its application in various fields. In this study, softwood Kraft lignin/polyamidoamine dendritic polymer (PAMAM) blends were [...] Read more.

Blending lignin as the second most abundant polymer in Nature with nanostructured compounds such as dendritic polymers can not only add value to lignin, but also increase its application in various fields. In this study, softwood Kraft lignin/polyamidoamine dendritic polymer (PAMAM) blends were fabricated by the solution electrospinning to produce bead-free nanofiber mats for the first time. The mats were characterized through scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, zeta potential, and thermogravimetry analyses. The chemical intermolecular interactions between the lignin functional groups and abundant amino groups in the PAMAM were verified by FTIR and viscosity measurements. These interactions proved to enhance the mechanical and thermal characteristics of the lignin/PAMAM mats, suggesting their potential applications e.g. in membranes, filtration, controlled release drug delivery, among others. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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12 pages, 2948 KiB

Open AccessArticle

A Preliminary Environmental Assessment of Epoxidized Sucrose Soyate (ESS)-Based Biocomposite

by Shokoofeh Ghasemi, Mukund P. Sibi, Chad A. Ulven, Dean C. Webster and Ghasideh Pourhashem

Molecules 2020, 25(12), 2797; https://doi.org/10.3390/molecules25122797 - 17 Jun 2020

Cited by 11 | Viewed by 4589

Abstract

Biocomposites can be both environmentally and economically beneficial: during their life cycle they generally use and generate less petroleum-based carbon, and when produced from the byproduct of another industry or recycled back to the manufacturing process, they will bring additional economic benefits through [...] Read more.

Biocomposites can be both environmentally and economically beneficial: during their life cycle they generally use and generate less petroleum-based carbon, and when produced from the byproduct of another industry or recycled back to the manufacturing process, they will bring additional economic benefits through contributing to a circular economy. Here we investigate and compare the environmental performance of a biocomposite composed of a soybean oil-based resin (epoxidized sucrose soyate) and flax-based reinforcement using life cycle assessment (LCA) methodology. We evaluate the main environmental impacts that are generated during the production of the bio-based resin used in the biocomposite, as well as the biocomposite itself. We compare the life cycle impacts of the proposed biocomposite to a functionally similar petroleum-based resin and flax fiber reinforced composite, to identify tradeoffs between the environmental performance of the two products. We demonstrate that the bio-based resin (epoxidized sucrose soyate) compared to a conventional (bisphenol A-based) resin shows lower negative environmental impacts in most studied categories. When comparing the biocomposite to the fossil fuel derived composite, it is demonstrated that using epoxidized sucrose soyate versus a bisphenol A (BPA)-based epoxy resin can improve the environmental performance of the composite in most categories except eutrophication and ozone layer depletion. For future designs, considering an alternative cross-linker to facilitate the bond between the bio-based resin and the flax fiber, may help improve the overall environmental performance of the biocomposite. An uncertainty analysis was also performed to evaluate the effect of variation in LCA model inputs on the environmental results for both the biocomposite and composite. The findings show a better overall carbon footprint for the biocomposite compared to the BPA-based composite at almost all times, demonstrating a good potential for marketability especially in the presence of incentives or regulations that address reducing the carbon intensity of products. This analysis allowed us to pinpoint hotspots in the biocomposite’s supply chain and recommend future modifications to improve the product’s sustainability. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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14 pages, 3850 KiB

Open AccessArticle

Environmental Durability Enhancement of Natural Fibres Using Plastination: A Feasibility Investigation on Bamboo

by Daanvir K. Dhir, Armin Rashidi, Grant Bogyo, Ron Ryde, Sepideh Pakpour and Abbas S. Milani

Molecules 2020, 25(3), 474; https://doi.org/10.3390/molecules25030474 - 22 Jan 2020

Cited by 11 | Viewed by 3536

Abstract

Natural fibers are gaining wide attention due to their much lower carbon footprint and economic factors compared to synthetic fibers. The moisture affinity of these lignocellulosic fibres, however, is still one of the main challenges when using them, e.g., for outdoor applications, leading [...] Read more.

Natural fibers are gaining wide attention due to their much lower carbon footprint and economic factors compared to synthetic fibers. The moisture affinity of these lignocellulosic fibres, however, is still one of the main challenges when using them, e.g., for outdoor applications, leading to fast degradation rates. Plastination is a technique originally used for the preservation of human and animal body organs for many years, by replacing the water and fat present in the tissues with a polymer. This article investigates the feasibility of adapting such plastination to bamboo natural fibres using the S-10 room-temperature technique in order to hinder their moisture absorption ability. The effect of plastination on the mechanical properties and residual moisture content of the bamboo natural fibre samples was evaluated. Energy dispersive x-ray spectroscopy (EDS) and X-ray micro-computed tomography (Micro-CT) were employed to characterize the chemical composition and 3-dimensional morphology of the plastinated specimens. The results clearly show that, as plastination lessens the hydrophilic tendency of the bamboo fibres, it also decreases the residual moisture content and increases the tensile strength and stiffness of the fibers. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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16 pages, 4608 KiB

Open AccessFeature PaperArticle

Influence of Water Absorption on the Low Velocity Falling Weight Impact Damage Behaviour of Flax/Glass Reinforced Vinyl Ester Hybrid Composites

by Angeline Paturel and Hom Nath Dhakal

Molecules 2020, 25(2), 278; https://doi.org/10.3390/molecules25020278 - 9 Jan 2020

Cited by 30 | Viewed by 3730

Abstract

Due to rigorous new environmental legislations, automotive, marine, aerospace, and construction sectors have redirected their focus into using more recyclable, sustainable, and environmentally friendly lightweight materials driven by strengthening resource efficiency drive. In this study, the influence of moisture absorption on flax and [...] Read more.

Due to rigorous new environmental legislations, automotive, marine, aerospace, and construction sectors have redirected their focus into using more recyclable, sustainable, and environmentally friendly lightweight materials driven by strengthening resource efficiency drive. In this study, the influence of moisture absorption on flax and flax/glass hybrid laminates is presented with the aim to investigating their low velocity impact behaviour. Three different types of composite laminates namely, flax fibre reinforced vinyl ester, flax fibre hybridised glass fibre and glass fibre reinforced vinyl ester composites were fabricated using resin infusion technique. The moisture immersion tests were undertaken by immersing the different specimens in sea water bath at room temperature and 70 °C at different time durations. The low velocity falling weight impact testing was performed at 25 Joules of incident energy level and impact damage behaviour was evaluated at both ageing conditions using scanning electron microscopy (SEM) and X-ray microcomputed tomography (micro CT). The percentage of moisture uptake was decreased for flax vinyl ester specimens with glass fibre hybridisation. The maximum percentage of weight gain for flax fibre, flax/glass hybrid and glass fibre reinforced composites immersed at room temperature for 696 h is recorded at 3.97%, 1.93%, and 0.431%, respectively. The hybrid composite exhibited higher load and energy when compared flax/vinyl ester composite without hybridisation, indicating the hybrid system as a valid strategy towards achieving improved structural performance of natural fibre composites. The moisture absorption behaviour of these composites at room was observed to follow Fickian behaviour. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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13 pages, 3041 KiB

Open AccessArticle

Chitosan-Based Bio-Composite Modified with Thiocarbamate Moiety for Decontamination of Cations from the Aqueous Media

by Nisar Ali, Adnan Khan, Muhammad Bilal, Sumeet Malik, Syed Badshah and Hafiz M. N. Iqbal

Molecules 2020, 25(1), 226; https://doi.org/10.3390/molecules25010226 - 6 Jan 2020

Cited by 72 | Viewed by 3685

Abstract

Herein, we report the development of chitosan (CH)-based bio-composite modified with acrylonitrile (AN) in the presence of carbon disulfide. The current work aimed to increase the Lewis basic centers on the polymeric backbone using single-step three-components (chitosan, carbon disulfide, and acrylonitrile) reaction. For [...] Read more.

Herein, we report the development of chitosan (CH)-based bio-composite modified with acrylonitrile (AN) in the presence of carbon disulfide. The current work aimed to increase the Lewis basic centers on the polymeric backbone using single-step three-components (chitosan, carbon disulfide, and acrylonitrile) reaction. For a said purpose, the thiocarbamate moiety was attached to the pendant functional amine (NH₂) of chitosan. Both the pristine CH and modified CH-AN bio-composites were first characterized using numerous analytical and imaging techniques, including ¹³C-NMR (solid-form), Fourier-transform infrared spectroscopy (FTIR), elemental investigation, thermogravimetric analysis, and scanning electron microscopy (SEM). Finally, the modified bio-composite (CH-AN) was deployed for the decontamination of cations from the aqueous media. The sorption ability of the CH-AN bio-composite was evaluated by applying it to lead and copper-containing aqueous solution. The chitosan-based CH-AN bio-composite exhibited greater sorption capacity for lead (2.54 mmol g⁻¹) and copper (2.02 mmol g⁻¹) than precursor chitosan from aqueous solution based on Langmuir sorption isotherm. The experimental findings fitted better to Langmuir model than Temkin and Freundlich isotherms using linear regression method. Different linearization of Langmuir model showed different error functions and isothermal parameters. The nonlinear regression analysis showed lower values of error functions as compared with linear regression analysis. The chitosan with thiocarbamate group is an outstanding material for the decontamination of toxic elements from the aqueous environment. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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18 pages, 5019 KiB

Open AccessArticle

Injection Molded Novel Biocomposites from Polypropylene and Sustainable Biocarbon

by Mohamed A. Abdelwahab, Arturo Rodriguez-Uribe, Manjusri Misra and Amar K. Mohanty

Molecules 2019, 24(22), 4026; https://doi.org/10.3390/molecules24224026 - 7 Nov 2019

Cited by 28 | Viewed by 4393

Abstract

Achieving sustainability in composite materials for high-performance applications is a key issue in modern processing technologies. In this work, the structure-property relationships of injection molded polypropylene (PP)/biocarbon composites were investigated with a focus on the thermal properties and specific emphasis on the coefficient [...] Read more.

Achieving sustainability in composite materials for high-performance applications is a key issue in modern processing technologies. In this work, the structure-property relationships of injection molded polypropylene (PP)/biocarbon composites were investigated with a focus on the thermal properties and specific emphasis on the coefficient of linear thermal expansion (CLTE). Biocomposites were produced using 30 wt.% biocarbon in a PP matrix, and two different sources of biocarbon produced at ~650 and 900 °C were used. The overall results were compared with 30 wt.% glass- and talc-filled PP composites. Due to the lamellar morphology of the talc developed during the extrusion-injection molding processing, talc-filled composites showed an increase in the CLTE in the normal direction (ND), and a reduction in the flow direction (FD) with respect to the neat polymer. Glass fiber composites also showed an improvement in the CLTE with respect to the neat polymer. However, the biocarbon-based composites showed the best properties in the ND, with improved values in biocarbon produced at higher temperature. The FD values for both biocarbon composites were improved with respect to the matrix, while biocarbon created at lower temperature showed slightly lower expansion values. A comprehensive explanation of these overall phenomena is supported by a series of morphological, thermal, mechanical and rheological tests. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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14 pages, 4957 KiB

Open AccessArticle

Preparation and Characterization of Bletilla striata Polysaccharide/Polylactic Acid Composite

by Renyu Yang, Dongyue Wang, Hongli Li, Yi He, Xiangyu Zheng, Mingwei Yuan and Minglong Yuan

Molecules 2019, 24(11), 2104; https://doi.org/10.3390/molecules24112104 - 3 Jun 2019

Cited by 14 | Viewed by 3381

Abstract

Polylactic acid (PLA) is limited in its application due to its high price, high brittleness and low glass-transition temperature. Modification methods are currently used to overcome these shortcomings. In this study, Bletilla striata polysaccharide (BSP) was blended with PLA by a solvent method. [...] Read more.

Polylactic acid (PLA) is limited in its application due to its high price, high brittleness and low glass-transition temperature. Modification methods are currently used to overcome these shortcomings. In this study, Bletilla striata polysaccharide (BSP) was blended with PLA by a solvent method. DMA data showed that the BSP/PLA film had a higher glass-transition temperature, and the glass-transition temperature of the film showed an extreme value of 68 °C when the proportion of the chalk polysaccharide was 0.8%. TG data indicates that the composite film material has good thermal stability. Tensile tests show that the composite film is improved in rigidity and elasticity compared to the pure PLA film. The blending modification of PLA with white peony polysaccharide not only reduces the cost of PLA, but also improves the thermal and mechanical properties of PLA. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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20 pages, 4137 KiB

Open AccessReview

From Dermal Patch to Implants—Applications of Biocomposites in Living Tissues

by Karolina Papera Valente, Alexandre Brolo and Afzal Suleman

Molecules 2020, 25(3), 507; https://doi.org/10.3390/molecules25030507 - 24 Jan 2020

Cited by 6 | Viewed by 4311

Abstract

Composites are composed of two or more materials, displaying enhanced performance and superior mechanical properties when compared to their individual components. The use of biocompatible materials has created a new category of biocomposites. Biocomposites can be applied to living tissues due to low [...] Read more.

Composites are composed of two or more materials, displaying enhanced performance and superior mechanical properties when compared to their individual components. The use of biocompatible materials has created a new category of biocomposites. Biocomposites can be applied to living tissues due to low toxicity, biodegradability and high biocompatibility. This review summarizes recent applications of biocomposite materials in the field of biomedical engineering, focusing on four areas—bone regeneration, orthopedic/dental implants, wound healing and tissue engineering. Full article

(This article belongs to the Special Issue Biocomposites – A Path Towards Circular Economy)

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