Development of hydrophobic thermoplastic starch composites

This work deals with provision and characterization of the biopolymer-based composites achieved by incorporation of cellulose fibers as the reinforcement within the glycerol plasticized matrix formed by thermoplastic cornstarch biopolymer. The function of starch-based polymers is limited due to poor mechanical properties. However, it is improved with forming a biocomposite of thermoplastic starch (TPS) as matrix and the cellulose fibers (CF) as reinforcement. The surface of cellulose fibers is successfully modified using the air plasma treatment with the aim of improving the matrix/fiber adhesion. The modified fibers are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The TPS/CF composites are prepared using high friction and hot compression procedure. Tensile test results and SEM images of the fracture surfaces show significant improvement of adhesion between treated cellulose fibers and TPS matrix. In another hand, starch nanoparticles (SNP) were prepared by delivering ethanol as the precipitant into starch-paste solution dropwise. According to the characterization of starch nanoparticles with FTIR, XRD and SEM, amorphous SNP could not be gelatinized in hot water because of the cross-linking. The TPS/SNP films were also prepared using casting process. SEM and atomic force microscopy (AFM) revealed that SNP was dispersed evenly in the starch matrix. As shown in the dynamic mechanical thermal analysis (DMA) and TGA, the introduction of SNP could improve the storage modulus and the glass transition temperature of the prepared films.Este trabalho trata do fornecimento e caracterização de compósitos à base de biopolímero obtidos pela incorporação de fibras de celulose como reforço dentro da matriz plastificada de glicerol formada por biopolímero de amido de milho termoplástico. A função dos polímeros à base de amido é limitada devido a propriedades mecânicas ruins. No entanto, melhora-se com a formação de um biocompósito de amido termoplástico (TPS) como matriz e as fibras de celulose (CF) como reforço. A superfície das fibras de celulose é modificada com sucesso usando o tratamento com plasma de ar com o objetivo de melhorar a adesão matriz / fibra. As fibras modificadas são estudadas por meio de difração de raios X (DRX), microscopia eletrônica de varredura (MEV) e espectroscopia de infravermelho por transformada de Fourier (FTIR). Os compósitos TPS/CF são preparados usando procedimentos de alta fricção e compressão a quente. Resultados de testes de tração e imagens de MEV das superfícies de fratura mostram uma melhora significativa na adesão entre as fibras de celulose tratadas e a matriz de TPS. Por outro lado, as nanopartículas de amido (SNP) foram preparadas pela entrega de etanol como precipitante na solução de pasta de amido, gota a gota. De acordo com a caracterização de nanopartículas de amido com FTIR, DRX e MEV, o SNP amorfo não pode ser gelatinizado em água quente por causa do cross-linking. Os filmes TPS/SNP também foram preparados usando o processo de fundição. MEV e microscopia de força atômica (AFM) revelaram que o SNP foi disperso uniformemente na matriz de amido. Como mostrado na análise térmica mecânica dinâmica (DMA) e TGA, a introdução do SNP poderia melhorar o módulo de armazenamento e a temperatura de transição vítrea dos filmes preparados

Obesity Phytotherapy: Review of Native Herbs Used in Traditional Medicine for Obesity.

Obesity is an important disorders due to which 25 million deaths occur annually worldwide. Synthetic drugs for weight loss have low efficacy and high side effects. Apart from synthetic drugs in modern medicine, various other methods including the use of herbal medications are used to induce weight loss. Cambodia hoodia, green tea, Citrus aurantium, white beans, fenugreek, caffeine, ephedrine, capsaicin, yohimbine, chitosan, fitostreols, and guar gum have been studied in clinical trials and their effects have been confirmed. It seems necessary to study more to determine the effectiveness and safety of medicinal plants and herbal extracts as well as pharmaceutically active ingredients that may have the property of weight loss. In this article, we aimed to review recent knowledge about medicinal plants that are recommended for weight loss

Lignocellulosic biomass from agricultural waste to the circular economy: A review with focus on biofuels, biocomposites and bioplastics

Funding Information: All authors are grateful to FinELib and VTT Technical Research Centre of Finland for the support to make this article open access. L. F., S. M. S., G. A. M., A. E. S. P., and S. D. M., are grateful to the São Paulo Research Foundation (FAPESP - #2017/21004–5 ), Coordination for the Improvement of Higher Education Personnel (Capes), and the National Council for Scientific and Technological Development (CNPq). Publisher Copyright: © 2023 The AuthorsIndustries are working to minimize their reliance on petrochemicals and petroleum-based industrial components and replace them with biobased, sustainable, and environmentally friendly alternatives due to the global warming emergency caused by the uncontrolled production of greenhouse gases. The agricultural waste provides large volumes of lignocellulosic biomass, a sustainable resource material to develop a wide portfolio of bioproducts. Recent developments in integrated biorefineries have enhanced the utilization of waste lignocellulose components to generate biofuels, platform chemicals, resins, bioplastics, additives, and other biobased materials for a variety of applications. Here in this review, we have summarized recent advancements in the processing of lignocellulosic biomass from agricultural waste. Additionally, this review thoroughly discussed the recent technological advancements in the utilization of various lignocellulose biomass constituents for biofuels, biocomposites, and bioplastics. Finally, an assessment of the currently existing literature gaps and prospective future perspectives for the development of lignocellulosic biomass from agricultural waste has been conducted.Peer reviewe

Developing Self-Assembled Starch Nanoparticles in Starch Nanocomposite Films

Starch nanoparticles (SNPs) are synthesized by different precipitation techniques using corn starch, and SNP films are prepared by the evaporation casting method. The morphological study is investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The distribution and sizes of precipitated SNPs after synthesizing are discovered by these methods as well. The crystallinity of the SNPs is studied by the X-ray diffractometry (XRD) method that demonstrates reduction compared to neat starch granules, and it is changed from A-style to VH-style after precipitation. The chemical bonding of different SNPs after the nanoprecipitation is analyzed by Fourier transform infrared spectroscopy (FT-IR). Thermogravimetric analysis (TGA) demonstrates the decomposition of starch nanoparticles and the starch matrix that is related to the depolymerization of carbon chains in the range of 260 to 350 °C. The mechanical properties of the SNP films versus the temperature changing are discovered by dynamic mechanical analysis (DMA). The water contact angles of SNP films are measured using a goniometer, and the results showed the hydrophobic surfaces of the prepared films. Our study indicates that SNPs have a promising impact on the properties of corn starch films, which would be useful in biodegradable packaging material.Peer reviewe

The effect of waterborne polyurethane coating on the mechanical properties of epoxy-based composite containing recycled carbon fibres

The current study focuses on the influence of waterborne polyurethane surface-modified recycled carbon fibre (rCF) on tensile, flexural, and low-velocity impact properties of the epoxy-based composite. The recycled carbon fibres were coated by five different concentrations of waterborne polyurethane (WBPU) bonded with 3-aminopropyltriethoxysilane. The chemical bonding between the fibres and the coating and their morphological structures are demonstrated by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. Furthermore, the single fibre tensile tests showed the enhancement of tensile strength and Young's modulus results after the coating. The thermal stability of the coated fibres was changed significantly compared to the uncoated fibres and the contact angle of their surface was reduced dramatically. The measured contact angles between the single fibres and the resin decreased from 70° to 40°. The epoxy-based composites were manufactured by the vacuum infusion method at room temperature. Significant improvements were attained in the tensile and flexural properties of the composites reinforced by coated fibres. The tensile and flexural strength of the mentioned composites were enhanced by up to 107% and 68%, respectively. Fractography confirmed the strong adhesion between the coated fibres and the matrix. Eventually, the impact resistivity of the fabricated composites was improved by approximately 49%

Recycled carbon fiber reinforced composites: Enhancing mechanical properties through co-functionalization of carbon nanotube-bonded microfibrillated cellulose

The imperative challenge of repurposing recycled carbon fiber (rCF) in composite structures, due to its cost-effectiveness and eco-friendly attributes, has spurred innovative research. This study introduces a scalable processing technique, integrating carbon nanotube (CNT)-bonded microfibrillated cellulose (MFC) onto randomly oriented rCF mats, focusing on enhancing mechanical properties. Employing electrophoretic deposition (EPD), rCF surfaces are effectively functionalized with CNT/MFC, probed through X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Modified fiber surfaces exhibit reduced contact angles, indicating improved wettability. Epoxy-based composites, fabricated via vacuum infusion, show up to 32% and 27% improvements in tensile and flexural strength. Dynamic mechanical analysis (DMA) confirms elevated storage modulus and energy dissipation capability. SEM analysis of fracture surfaces illustrates robust adhesion between coated fibers and the matrix, supporting the proposed approach's efficacy. This study unveils an innovative pathway to enhance recycled carbon fiber composite properties, extending their application potential in diverse engineering domains.Peer reviewe

Lignin beyond the status quo:recent and emerging composite applications

The demand for biodegradable materials across various industries has recently surged due to environmental concerns and the need for the adoption of renewable materials. In this context, lignin has emerged as a promising alternative, garnering significant attention as a biogenic resource that endows functional properties. This is primarily ascribed to its remarkable origin and structure that explains lignin's capacity to bind other molecules, reinforce composites, act as an antioxidant, and endow antimicrobial effects. This review summarizes recent advances in lignin-based composites, with particular emphasis on innovative methods for modifying lignin into micro and nanostructures and evaluating their functional contribution. Indeed, lignin-based composites can be tailored to have superior physicomechanical characteristics, biodegradability, and surface properties, thereby making them suitable for applications beyond the typical, for instance, in ecofriendly adhesives and advanced barrier technologies. Herein, we provide a comprehensive overview of the latest progress in the field of lignin utilization in emerging composite materials.</p

Autophagy, a critical element in the aging male reproductive disorders and prostate cancer: a therapeutic point of view

Abstract Autophagy is a highly conserved, lysosome-dependent biological mechanism involved in the degradation and recycling of cellular components. There is growing evidence that autophagy is related to male reproductive biology, particularly spermatogenic and endocrinologic processes closely associated with male sexual and reproductive health. In recent decades, problems such as decreasing sperm count, erectile dysfunction, and infertility have worsened. In addition, reproductive health is closely related to overall health and comorbidity in aging men. In this review, we will outline the role of autophagy as a new player in aging male reproductive dysfunction and prostate cancer. We first provide an overview of the mechanisms of autophagy and its role in regulating male reproductive cells. We then focus on the link between autophagy and aging-related diseases. This is followed by a discussion of therapeutic strategies targeting autophagy before we end with limitations of current studies and suggestions for future developments in the field