Natural fiber-reinforced hybrid polymer nanocomposites: effect of fiber mixing and nanoclay on physical, mechanical, and biodegradable properties

Combining two kinds of fibers is a potential way to improve the essential properties of natural fiber-reinforced hybrid polymer composites. Biocomposites produced from natural resources are experiencing an increase in interest due to their high demand in the market for manufacturing, in addition to environmental and sustainability issues. In this study, natural fiber-reinforced hybrid polymer nanocomposites were prepared from coir fiber, wood fiber, polypropylene, and montmorillonite nanoclay using a hot press technique. The effects of fiber mixing and montmorillonite on their physico-mechanical and biodegradable properties were subsequently investigated. Before being used, both the wood and the coir fibers were alkali-treated to reduce their hydrophilicity. The mechanical properties of the fabricated composites were measured using a universal tensile testing machine and found to be enhanced after fiber mixing and nanoclay incorporation. Fourier transform infrared spectra indicated that the characteristic peaks of the composites shifted after fiber mixing. A new peak around 470 cm-1 was observed in the case of the nanocomposites, which confirmed the interaction between the fiber, polymer, and montmorillonite (MMT). Scanning electron microscopic analysis revealed that MMT strongly improved the adhesion and compatibility between the fiber and polymer matrix. The combining of fibers improved the biodegradability and water absorption properties, while MMT addition had the reverse effect on the same properties of the composites

Utilization of agrowaste-derived nanoparticles as reinforcement in microfilled epoxy composites

The substantial release of oil palm ash into ground water has been a serious concern to the environmentalist due to the enormous generation of oil palm ash waste from oil palm incineration. The effective utilization of this agrowaste is yet to be fully exploited. In this context, herein we, investigated the potential of oil palm ash nanofiller as an effective reinforcement in epoxy-based composites. Transmission electron microscopy (TEM) revealed that the prepared oil palm ash nanoparticles had circular morphology with particle size in the range of 20to 25 nm. X-ray diffraction patterns of the prepared oil palm ash nanoparticles revealed the crystalline nature of the oil palm ash nanoparticles. Tensile strength and tensile modulus of the epoxy composites were substantially improved to 64, 67, 70,and 75 MPa and 1.01,1.05,1.16,and 1.18 MP a at oil palm ash nanofiller loading of 1%,2%,3%,and %,respectively.The impact strength of nanocomposite was enhanced from 2.7015 ± 0.13 kJ/m2to 3.98 ± 0.17kJ/m2 at 3% of oil palm ash nanofiller loading. The optimum values of mechanical properties were attained at 4% filler loading,after which further loading resulted in the decrement of mechanical properties of epoxy nanocomposite. Thermal stability of the epoxy nanocomposite was enhanced substantially to 435 °C by the incorporation of oil palm ash nanofillers. This study proved that nano-sized oil palm ash could be an efficient reinforcement in polymer composite

Utilization of Renewable Biomass and Waste Materials for Production of Environmentally-Friendly, Bio-based Composites

The introduction of renewable biomass into a polymer matrix is an option competing with other possibilities, such as energy recovery and/or re-use in the carbonized state, or production of chemicals, such as, in the case of ligno-cellulosic waste, concentrates on the production of simple sugars, then possibly leading to the development of biopolymers. These competitive applications have also some interest and market, however with a considerable energy, water and materials consumption, due also to the not always high yielding. Other possibilities for renewable biomass are therefore being used as fillers to increase mechanical performance of polymers or to allow e.g., the absorption of toxic chemicals. This review concentrates on the use of biomass as close as possible to the “as received” state, therefore avoiding whenever suitable any thermal treatment. More specifically, it focuses on its introduction into the three categories of oil-based (or bio-based replacement) of engineered polymers, into industrial biopolymers, such as poly(lactic acid) (PLA) and self-developed biopolymers, such as thermoplastic starch (TPS)

A review on nanocellulosic fibres as new material for sustainable packaging: process and applications

The demand for exploring advanced and eco-friendly sustainable packaging materials with superior physical, mechanical and barrier properties is increasing. The materials that are currently used in packaging for food, beverage, medical and pharmaceutical products, as well as in industrial applications, are non-degradable, and thus, these materials are raising environmental pollution concerns. Numerous studies have been conducted on the utilization of bio-based materials in the pursuit of developing sustainable packaging materials. Although significant improvements have been achieved, a balance among environmental concerns, economic considerations and product packaging performance is still lacking. This is likely due to bio-based materials being used in product packaging applications without a proper design. The present review article intends to summarize the information regarding the potential applications of cellulosic nanofiber for the packaging. The importance of the design process, its principles and the challenges of design process for sustainable packaging are also summarized in this review. Overall it can be concluded that scientists, designers and engineers all are necessarily required to contribute towards research in order to commercially exploit cellulose nanofiber for sustainable packaging

Thermal and mechanical properties of chitosan nanocomposites with cellulose modified in ionic liquids

In this paper, ionic liquid treatment was applied to produce nanometric cellulose particles of two polymorphic forms. A complex characterization of nanofillers including wide-angle X-ray scattering, Fourier transform infrared spectroscopy, and particle size determination was performed. The evaluated ionic liquid treatment was effective in terms of nanocrystalline cellulose production, leaving chemical and supermolecular structure of the materials intact. However, nanocrystalline cellulose II was found to be more prone to ionic liquid hydrolysis leading to formation larger amount of small particles. Each nanocrystalline cellulose was subsequently mixed with a solution of chitosan, so that composite films containing 1, 3, and 5% mass/mass of nanometric filler were obtained. Reference samples of chitosan and chitosan with micrometric celluloses were also solvent casted. Thermal, mechanical, and morphological properties of films were tested and correlated with properties of filler used. The results of both, tensile tests and thermogravimetric analysis showed a significant discrepancy between composites filled with nanocrystalline cellulose I and nanocrystalline cellulose II

Caracterização morfológica de nanocristais de celulose por microscopia de força atômica

RESUMO O isolamento de nanocristais de celulose (CNCs) de fibras vegetais é uma alternativa promissora para sua aplicação como reforço em matrizes poliméricas. A caracterização dos CNCs é fundamental para a confiabilidade da técnica, além de determinar as aplicações possíveis a partir de cada tipo de fibra. A partir da técnica de microscopia de força atômica, um estudo da morfologia e distribuição dos CNCs de semente de manga, vagem de algaroba, pseudocaule da bananeira e fibra do mesocarpo de dendê foi realizado neste trabalho. Os CNCs foram obtidos via reação hidrolítica com ácido sulfúrico em concentrações que variaram de acordo com a fonte da fibra. Os resultados obtidos revelaram dimensões variando de 300 a 500 nm em comprimento e 4 a 16 nm em diâmetro. A apresentação morfológica em forma de agulha demonstrou que o isolamento das fibras de celulose em CNCs foi efetiva. A razão de aspecto associada à formação cilíndrica em agulha dos CNCs isolados evidenciou o alto potencial das fontes de dendê e de vagem de algaroba para o reforço de bionanocompósitos

A newborn liver mass that never existed: a somber reminder of embryonic ties between umbilical vein and portal venous system

Allah Haafiz1, Jonathan L Williams2, Joel M Andres1, Don A Novak11Pediatric Gastroenterology, Hepatology; 2Department of Pediatric Radiology, University of Florida College of Medicine, Gainesville, FL, USAAbstract: A 6-day-old, known to have transposition of the great vessels, received care in the neonatal intensive care unit at a tertiary care center. A computed tomography scan was performed for abdominal distention and upper gastrointestinal bleeding, which revealed a “mass lesion” in the left liver lobe. Analysis of antecedent events and the clinical and laboratory course uncovered an iatrogenic etiology and pathogenesis of the lesion. As the nature of the lesion was clarified, no specific therapy was required. This case is presented to show a serious yet preventable complication of a commonly performed procedure.Keywords: portal vein thrombosis, liver mass, umbilical venous cathete

Relationship between hepatic CTGF expression and routine blood tests at the time of liver transplantation for biliary atresia: hope or hype for a biomarker of hepatic fibrosis

Allah Haafiz1, Christian Farrington1, Joel Andres1, Saleem Islam21Hepatology and Liver Transplantation, Division of Pediatric Gastroenterology, Hepatology and Nutrition, 2Division of Pediatric Surgery, University of Florida College of Medicine, Gainesville, FL, USABackground: Progressive hepatic fibrosis (HF) is a prominent feature of biliary atresia (BA), the most common indication for liver transplantation (LT) in children. Despite its importance in BA, HF is not evaluated in routine patient care because the invasiveness of liver biopsy makes histologic monitoring of fibrosis unfeasible. Therefore, the identification of noninvasive markers to assess HF is desirable especially in children.Purpose: The main goal of this pilot project was to establish an investigational framework correlating hepatic expression of fibrogenic markers with routine blood tests in BA.Methods: Using liver explants from patients with BA (n = 26), immune-expression of connective tissue growth factor (CTGF), a key fibrogenic cytokine was determined using horseradish-labeled antibodies. Expression intensities of lobular (L-CTGF) and portal (P-CTGF) CTGF were determined by using ImageJ software. These CTGF intensities were correlated with blood tests performed at the time of LT. Correlation coefficients were determined for each blood test variable versus mean L-CTGF and P-CTGF expression intensities. A P-value of less than 0.05 was considered statistically significant.Results: All patients had end-stage liver disease and persistent cholestasis at the time of LT. Kendall tau (t) rank correlation coefficient for L-CTGF and white blood cell (WBC) was inversed (—0.52; P ≤ 0.02). Similar but statistically nonsignificant inverse relationships were noted between L-CTGF and prothrombin time (PT) (—0.15; P ≤ 0.4), international normalized ratio (INR) (—0.14; P ≤ 0.5), and platelet count (—0.36; P ≤ 0.09). Inversed (t) rank correlation coefficients were also evident between P-CTGF expression and gamma-glutamyl transpeptidase (GGT), PT, INR, and platelet count. Pearson correlation coefficients for combinational analysis of standardized total bilirubin (TB), alkaline phosphatase, GGT, and platelet count with L-CTGF (0.33; P = 0.3) and P-CTGF (0.06; P = 0.8), were not significant. Similar analysis for alanine aminotransferase, TB, and GGT combination (L-CTGF, 0.16; P = 0.5; P-CTGF —0.3; P = 0.2) as well as WBC, platelet count, and TB (L-CTGF: —0.36; P = 0.09; P-CTGF —0.33; P = 0.13) also revealed nonsignificant results.Conclusion: Hepatic expression of fibrogenic markers can be correlated with routinely performed blood tests in patients with BA. We document that although a trend of inverse relationship is noted, hepatic CTGF expression does not correlate well with routinely performed blood tests in advanced BA. Further work is required to determine more reliable ways of noninvasive diagnosis of HF.Keyword: connective tissue growth factor, liver fibrosis, blood tests, fibrogenesi

Hybrid montmorillonite/cellulose nanowhiskers reinforced polylactic acid nanocomposites: a comparative study based on formulation design

The effects of formulation design on the tensile, morphological, and biodegradability properties of hybrid cellulose nanowhiskers/montmorillonite (CNW/MMT) reinforced polylactic acid (PLA) nanocomposites were investigated in this chapter. The CNWs were obtained from microcrystalline cellulose (MCC) using chemical swelling with N,. N-dimethylacetamide containing 0.5% lithium chloride. Based on the tensile properties of PLA/MMT nanocomposites, 5 phr (parts per hundred parts of resin) MMT was selected as optimum content (P/MT5/CW0). The PLA/MMT/CNW hybrid nanocomposites were prepared using two different sets of formulations by solution casting method. The hybrid nanocomposites were produced by incorporation of different content of CNW (1, 3, 5, 7, and 9 phr) into P/MT5/CW0 nanocomposite and partial replacement of MMT with CNW at total filler content of 5 phr. The highest tensile strength for the PLA/MMT/CNW hybrid nanocomposites was obtained at 1 phr CNW for both sets of formulations. Interestingly, the ductility of the hybrid nanocomposites increased remarkably from approximately 10 to 90 and 79% by incorporation of 1 phr CNW into P/MT5/CW0 nanocomposite and partial replacement of 1 phr MMT with CNW, respectively. Furthermore, the biodegradability of PLA/MMT/CNW hybrid nanocomposites improved compared to neat PLA and optimum formulation of PLA/MMT nanocomposites

Interface modification of compatibilized polyethylene terephthalate/polypropylene blends: effect of compatibilization on thermomechanical properties and thermal stability

Polyethylene terephthalate (PET) and polypropylene (PP) are incompatible thermoplastics because of differences in chemical structure and polarity, hence their blends possess inferior mechanical and thermal properties. Compatibilization with a suitable block/graft copolymer is one way to improve the mechanical and thermal properties of the PET/PP blend. In this study, the toughness, dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA) of PET/PP blends were investigated as a function of different content of styrene-ethylene-butylene-styrene-g-maleic anhydride (SEBS-g-MAH) compatibilizer. PET, PP, and SEBS-g-MAH were melt-blended in a single step using the counter rotating twin screw extruder with compatibilizer concentrations of 0, 5, 10, and 15 phr, respectively. The impact strength of compatibilized blend with 10 phr SEBS-g-MAH increased by 300% compared to the uncompatibilized blend. Scanning electron microscope (SEM) micrographs show that the addition of 10 phr SEBS-g-MAH compatibilizer into the PET/PP blends decreased the particle size of the dispersed PP phase to the minimum level. The improvement of the storage modulus and the decrease in the glass transition temperature of the PET phase indicated an interaction among the blend components. Thermal stability of the PET/PP blends was significantly improved because of the addition of SEBS-g-MAH. J. VINYL ADDIT. TECHNOL., 23:45–54, 2017