Physicochemical properties of new cellulosic fiber extracted from Carica papaya bark

This article presents the characteristics of Carica papaya fibers (CPFs) extracted from the bark of the perennial papaya plant. Detailed chemical compositions of CPFs such as cellulose, lignin, ash, moisture, and wax contents were established and determined by using standard methods. Further, chemical groups, crystalline structure, surface roughness, and thermal stability of CPFs were examined using Fourier transform infrared analysis, X-ray diffraction, atomic force microscope, and thermogravimetric analysis, respectively. The physico-chemical properties of CPFs, crystallinity index (56.34%), cellulose content (38.71 wt. %), hemicellulose (11.8%), and density (943 kg/m³) were compared to those properties of other natural fibers. The results suggest that the biodegradable CPFs can be used as a potential reinforcemnet in the polymer matrix composite structure.     

Physicochemical,tensile, and thermal characterization of new natural cellulosic fibers from the stems of Sida cordifolia

Natural fibers are the one worthy substitute for replacing synthetic fibers and used as a polymer reinforcement due to their eco-friendly nature. This investigation deals with the newly identified Sida cordifolia fibers (SCFs) characterized by chemical analysis, single fiber tensile test, thermogravimetric analysis (TGA/DTG), Fourier transform-infrared spectroscopy (FT-IR) analysis, X-ray diffraction (XRD), and atomic force microscopy (AFM). The chemical constituents of SCFs contains cellulose (69.52%), hemicellulose (17.63%), and lignin (18.02. %). The SCFs are thermally stable up to a temperature of 338.2°C evidenced by TGA analysis. The X-ray diffraction confirmed that SCFs were rich in cellulose fraction with a crystallinity index of 56.92%.     

Physicochemical Properties of New Cellulosic Fibers from Azadirachta indica Plant

This research study was aimed at examining newly identified natural fiber from the bark of Azadirachta indica (AI). The various properties were analyzed and compared with other available bark fibers. The chemical composition of Azadirachta indica fibers (AIFs), high cellulose (68.42 wt.%) content, and low lignin (13.58 wt.%) were discovered. The lower density of 740 kg/m³, and crystallinity index of 65.04% properties were identified. The maximum peak temperature obtained was 321.2 °C in Differential thermogravimetry (DTG) curve. Taken together, all the properties of AIFs indicated that they could be suitable to make green composites for various types of applications.     

Characterization of New Natural Cellulosic Fiber from the Bark of Dichrostachys Cinerea

The increasing environmental awareness has directed attention of the researchers towards the field of natural fiber composites. The aim of this investigation is to understand the physico-chemical properties of fibers extracted from the bark of the Dichrostachys Cinerea (DC) plant. Dichrostachys Cinerea fibers (DCFs) has cellulose (72.4 wt. %), hemicellulose (13.08 wt. %), lignin (16.89 wt. %), density (1240 kg/m³), crystallinity index (57.82%), and tensile strength (873 ± 14 MPa). Besides the cellulose degradation of DCFs at 359.3° vide by the thermo-gravimetric analysis and chemical groups are identified by Fourier transform analysis. Eventually the characterization results of DCFs strongly show the possibility of reinforcement in polymer matrices.     

Characterization of natural cellulosic fiber from Epipremnum aureum stem

The natural fiber Epipremnum aureum was extracted from its plant. E. aureum fibers (EAFs) were investigated by chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and single fiber tensile test. Chemical analysis, FTIR, and X-ray analysis evidenced that these fibers has 66.34% cellulose content with crystallinity index of 49.33%. The thermogravimetric analysis reveals that EAFs can thermally withstand temperatures until 328.9°C. The morphology of the EAFs was observed by scanning electron microscope. It was established that the fiber can be utilized as reinforcement in polymer composites.     

Extraction and Characterization of New Natural Cellulosic Chloris barbata Fiber

Natural swollen finger grass fibers being novel are botanically known as “Chloris barbata fibers (CBFs)” and are selected for this study in order to understand their morphological properties. The CBF has higher cellulose (65.37 wt%) content and lower density (634 kg/m³). Crystallinity Index (CI) of CBF was calculated from X-ray diffraction studies and is valued as 50.29%. The surface of CBF was examined using a Scanning Electron Microscope (SEM) for observing the surface morphology. Structural characterization and Chemical functional group were confirmed by Fourier transform infrared spectroscopy (FT-IR). The thermal behavior of CBFs was determined using TG and DTG curves from Thermo gravimetric (TG) analysis. Findings show that the fiber has a semi-elongated nearly circular cross-sectional shape, the fiber diameter is between 180 and 200 μm. TG analysis revealed that these fibers are thermally stable until 210°C. Thus the characterization results confirm the possibility of using CBF for the manufacture of sustainable fiber reinforced polymer composite.     

Characterization of New Natural Cellulosic Fiber from Heteropogon Contortus Plant

Natural fibers are one of effective substitute for switching artificial fiber and concentrating to reinforce polymer matrixes due to their decomposable character. This study was implied to realize physico-chemical properties of bio fiber obtained from Heteropogon contortus (HC) plant. Heteropogon contortus fibers (HCFs) had cellulose (64.87 wt. %), hemicellulose (19.34 wt. %), lignin (13.56 wt. %), and low density (602 kg/m³). The chemical functional group of HCFs was established by Fourier transform infrared spectroscopy, thermal stability of the fiber up to 220°C discovered by thermogravimetric analysis. Further the assets of HCFs proved that it can act as an excellent reinforcement material as a bio composite. Finally, the tensile properties were carried out through single fiber tensile tests, such as tensile strength, tensile modulus and microfibrillar angle.     

Silver migration from nanosilver and a commercially available zeolite filler polyethylene composites to food simulants

Polyethylene composites containing Agion^TM commercial silver ion filler at three different percentage fill rates (0.5, 1.0 and 2% w/w) and polyethylene composites containing laboratory produced silver nanoparticles (Agnps) at two different percentage fill rates (0.1 and 0.5% w/w) underwent migration tests according to Commission Regulation (EU) No. 10/2011. Migrated silver in the two simulants (acidified water with 3% acetic acid and distilled water) was quantified using two techniques: inductively coupled atomic emission spectroscopy (ICPAES) and Hach Lange spectroscopy. The former had higher sensitivity with mean silver migration from Agion composites (n = 12) ranging from < 0.001 to 1.50 × 10^?2 mg l^–1. Mean silver migration from Agnps composites ranged from 4.65 × 10^?2 to 0.38 mg l^–1 and 8.92 × 10^?2 and 5.15 × 10^?2 mg l^–1 for Hach Lange spectrophotometry and ICPAES, respectively. Both percentage fill rate in the composite and the simulant type, as factors, were found to be significant in both silver migration from Agion (p < 0.0001 and < 0.01, respectively) and Agnps (p < 0.05 and < 0.01, respectively). Transmission electron microscopy (TEM) imagery showed differences in size distributions and morphology of particles (shape and degree of agglomeration) before and after migration. PE composites containing 0.5% Agion, simulating contact with non-acidic foods, was the only scenario that did not exceed the permitted migration level of non-authorised substances given in EU 10/2011. This study illustrates the need for careful engineering of the composite filler system to conform to limits with cognisance of food pH and percentage fill rate.     

Extraction and Characterization of Novel Natural Cellulosic Fibers from Pigeon Pea Plant

ABSTRACT

This study is mainly focused on the extraction and characterization of the lingo-cellulosic fibers from the Pigeon Pea plant. The chemical components of the fibers such as cellulose content (55.03%), lignin (18.32%), wax content (2.38%), moisture content (8.13%), and density (1.7389 g cc^?1) were identified. Functional groups present in the fibers were obtained by infrared spectroscopy. By using X-ray diffraction analysis, Crystallinity Index is found to be 68% and thermogravimetric analysis showed that thermal degradation of the fiber begins at 225°C.The results suggest that the Pigeon pea fibers can be used as reinforcement in polymer-matrix composites.     

Natural Fibers from Plantain Pseudostem (Musa Paradisiaca) for Use in Fiber-Reinforced Composites

Agricultural crops from plantain produce a significant amount of wastes and they are currently considered worthless. Accordingly, in this study, non-wood fibers from pseudostem of plantain plants were extracted through mechanical processing to be used as reinforcing material in polyester composites. Bio-based composites were obtained using a 4% wt. of lignocellulosic reinforcement and were prepared after the fibers underwent alkaline and acetylation treatments in order to enhance the compatibility of organic loads with the polyester matrix. The higher cellulose content of plantain fibers indicates that they can be used to reinforce composites with a polymeric matrix. The plantain fibers have bast fiber bundle of around 120 µm; single fibers of around 5 µm; and mesofibers with a diameter between 0.5 and 1 µm. The results showed that plantain fibers can be used as a filler material to obtain an alternative polymer composite. The flexural strength of composites (polyester with acetylated plantain fibers) was improved 28% when the properties are compared to control composite.     

Characterization of cellulosic fibers from Morus alba L. stem

The chemical microstructural, physical, and thermal properties of the Morus alba L. stem fibers (MAFs) are described for the first time in this work. By analyzing the results of chemical composition, it was observed that the cellulose content of the stem of MAFs is an acceptable value when compared with other fibers and showed better results. Due to their lightweight (1316 kg/m³) and the presence of high cellulose content (58.65%) with very little amount of wax (0.56%), they provide good bonding properties. In addition, analyzing the results of X-ray diffraction and Fourier transform infrared spectroscopy, we observe a degree of crystallinity of 62.06%, which is closely associated with the presence of crystalline cellulose, while the other components are amorphous. The diameter of the extracted cellulosic fibers was in the range 6–20 µm. Moreover, it was possible to identify the degradation step of each primary component of lignocellulosic fiber and to observe that it is thermally stable up to 216°C. The characterization results show that the MAF is a better replacement material for synthetic fibers because of its significant physical, chemical, and thermal properties.     

Preparation and Properties of Cellulose/Tamarind Nut Powder Green Composites

Using biopolymer cellulose as the matrix and tamarind nut powder (TNP) obtained from agricultural waste of tamarind nuts as the filler, the green composites were made. Cellulose was dissolved in environmental friendly solvent of aq. 8 wt. % Lithium hydroxide and 15 wt. % urea which was precooled to ?12 ° C. To the cellulose solutions, TNP was added in 5 wt. % to 25 wt. % of cellulose separately. Each solution was evenly spread on glass plates and the wet composites were prepared by regeneration method using ethyl alcohol coagulation bath. The wet films were dried in air at room temperature. The dried composite films were characterized by FTIR spectroscopy, X-ray diffraction, thermogravimetric analysis and also tested for their tensile properties. The tensile strength and the % elongation at break of the composites were higher than those of the matrix and increased with TNP content. While the matrix had a tensile strength of 111.8 MPa, the cellulose/TNP composite loaded with 25 wt.% TNP possessed a tensile strength of 125.4 MPa (12% increase). Though the thermal stability of the composites was lower than cellulose matrix, all the composites were stable up to a temperature of 350 °C.     

A new study on characterization of Pithecellobium dulce fiber as composite reinforcement for light-weight applications

ABSTRACT

A bio-fiber, Pithecellobium dulce is abundantly available in all over the world. It has a higher cellulose content (75.15 ± 0.26 wt.%) and low density (865 ± 26 kg/m³). To acquire fundamental knowledge about Pithecellobium dulce Fibers (PDFs), its physicochemical, crystalline, tensile, and morphological properties were examined and compared with other plant fibers. The chemical functional groups and crystallinity index (49.2 ± 2.45%) of the PDFs were obtained via Fourier transform-infrared analysis and X-ray diffraction, respectively. The Thermogravimetric analysis results of PDFs exhibit thermal stability up to 170°C. The surface morphology of PDF was analyzed by scanning electron microscopy. The attained results conclude that PDFs are appropriate fibers for acting as reinforcement in manufacturing of green composite product.     

GR CALUX assay detects synthetic glucocorticoids in calf urine: a validation study

Member States of the EU are required to monitor the use of pharmacologically active substances in food-producing animals. There is evidence, however, that the target-based approach currently applied in official monitoring plans might under-estimate the real incidence of growth promoter abuse in livestock. As demonstrated for sex hormones, the association of effect-oriented biological screening with chemical confirmatory techniques could be the best strategy in revealing the abuse of veterinary drugs. Here we demonstrate the reliability of a cell-based assay to screen calf urine samples for synthetic glucocorticoids. The validation included the most widely used synthetic drugs (flumethasone, dexamethasone, betamethasone, methylprednisolone and prednisolone) and was developed according to the Commission Decision 2002/657/EC, thus including the verification of cut-off level, the β error, the specificity, ruggedness and stability. The study was carried out using prednisolone as representative substance at 5 ng mL^?1 concentration. All blank and spiked urine fulfilled the EU criteria, moreover the method resulted in being specific and sound, and the analytes in urine were stable for at least 30 days. The assay results indicated its suitability for a qualitative analysis of calf urine samples. This method enabled the detection of low doses of synthetic glucocorticoids (GCs) in matrix (<2 ng mL^?1 for flumethasone, dexamethasone, betamethasone; < 4 ng mL^?1 for methylprednisolone; 5 ng mL^?1 for prednisolone), with the possibility of detecting new or unknown molecules and cumulative effects of low-level mixtures with glucocorticoid bioactivity.     

Characterization of Thermal Properties of Pig Hair Fiber

Hair fiber is a key by-product of humane slaughter of pigs with considerable economic value. In the present study, we investigated the thermal properties of pig hair fiber using Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC curve showed a broad endotherm (around 50–80°C) initially, followed by denaturation doublet peaks (229°C and 239°C) and finally a pyrolysis endotherm. The melting enthalpy of pig hair fiber was 9.93 J/g on dry basis. During TGA, distinct phases of initial weight loss due to loss of moisture and later through thermal degradation of protein around 238–240°C were observed. Mean thermal insulation and conductivity values of pig hair fiber were 0.068 ± 0.004 m²K/W and 0.029 ± 0.003 W/m/K, respectively. The thermal characteristics of pig hair fiber were similar to other keratin fibers of animal origin.     

Polyvinyl Chloride Reinforced with Areca Sheath Fiber Composites—An Experimental Study

ABSTRACT

This research work deals with fibrous composites obtained by using treated and untreated areca sheath (AS) fibers reinforced in polyvinyl chloride (PVC) by injection molding process. Surface treatments of fibers have been carried out to have a better compatibility with PVC matrix. The tensile and flexural strength have been found to increase at the early stage with the increase in treated areca fiber content till optimum (18 wt% of fiber) fiber loading thereafter declines. At optimum fiber loading, the tensile strength, flexural strength and young’s modulus values are 42.38 MPa, 18.22 MPa and 2.38 GPa, respectively, which give maximum values in comparison to other fiber loadings. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), biodegradability tests and scanning electron microscopy (SEM) have been used for analysis. The TGA inferred that the thermal stability of the composites increased as compared to neat PVC matrix. Further, the composites exhibit excellent biodegradability property and their biodegradability increases with the increase of areca fiber content. From the properties obtained at optimum fiber loading (18 wt% of fiber), the composite can be suitable for automotive dashboard and door panel applications.     

Upconversion Nanoparticles Capped with Molecularly Imprinted Polymer as Fluorescence Probe for the Determination of Ractopamine in Water and Pork

A novel fluorescence probe was designed and synthesized to quantify ractopamine in foods using molecularly imprinted polymer (MIP) as a specific recognition element and YF₃:Yb³⁺, Er³⁺ upconversion nanoparticles (UCNPs) as a fluorescence signaling component. The developed UCNP@MIP probe was characterized using X-ray powder diffraction, scanning electron microscopy, and thermogravimetric analysis. The fluorescence of UCNP@MIP probe was quenched specifically by ractopamine, and good linear regression ranging from 1.66 × 10^?8 to 3.3 × 10^?7 mol/L was obtained with the limit of detection of 8.6 × 10^?10 mol/L. This method was further applied to determine ractopamine in water and pork samples. Recoveries between 76.61 and 88.97% were obtained with relative standard deviation ranging from 1.15 to 2.67% (n = 3). This UCNP@MIP probe combined high selectivity of MIP and high sensitivity of upconversion fluorophore and showed potential to determine various food chemical hazards.     

Effect of Treatments on the Physical and Morphological Properties of SPF/Phenolic Composites

This study aims at evaluating the physical properties and effects of fiber treatments of natural fiber reinforced polymer composite’s friction applications. Sugar palm fibers (SPFs) were used as fillers (≤ 150 µm) with phenolic resin to fabricate the composites by the hot press technique. The loading of SPFs varied from 0 to 40 vol.% with an interval of 10 vol.% in phenolic composites. The fibers were treated with sea water for 30 days, and with 0.5 M of alkaline solution for 4 hrs. Rockwell hardness, density, voids content, water/oil absorption, and moisture content were studied. Scanning electron microscopy (SEM) was used to investigate the morphology and interfacial bonding of the fiber-matrix in composites. With an increase in the SPF loading in the composites, the results indicated a decline in Rockwell hardness, an increase in water/oil absorption, and density. It was also observed that higher the density of the composites, lower was the voids content. In terms of physical properties, sea water treatment showed better improvement than alkaline treatment. The outcome of this research indicated that SPFs can be effectively used in reinforcing polymer composites, such as friction composites.     

African Teff Straw as a Potential Reinforcement in Polymer Composites for Light-Weight Applications: Mechanical,Thermal, Physical,and Chemical Characterization before and after Alkali Treatment

ABSTRACT

The present study concerns the morphological, mechanical, thermal characterization and activation energy of African teff straw, a natural and almost inexpensive fiber as a potential reinforcement in polymer composites. The fiber is treated with different concentrations of alkali NaOH (5% and 10%) to improve the properties, and the effect has been observed by Fourier transform infrared spectroscopy, scanning electron microscope (SEM) analysis, X-ray diffraction, atomic force microscopy(AFM), mechanical property tester, and thermogravimetric analysis. Flynn–Wall–Ozawa method, Kissinger–Akahira–Sunose method, and Friedman method have been used for calculation of activation energy of untreated and treated teff straw. There is an increase of approximately 31% (280–368 MPa) in tensile strength and 21% (136–164 kJ/mol) in average activation energy in case of 5% alkali-treated fiber compared to untreated one. This treated fiber can be recommended as a reinforcement in polymer composites for light-weight applications.     

Preparation and characterization of electrically semi-conductive polyfuran-coated poly(ethylene terephthalate) fibers

One of the most important textile materials, poly(ethylene terephthalate) (PET) fiber, was coated with a semi-conductive polyfuran (PFu) by in situ oxidative polymerization using FeCl₃ oxidant in solvent mixture of acetonitrile–chloroform. The effects of polymerization conditions such as volume ratios of acetonitrile/chloroform, monomer concentration, and oxidant/monomer mol ratio were investigated on PFu content (%) of the composites. It was observed that pretreatment of PET in dichloromethane increased PFu content and its coating continuity before polymerization. The highest PFu content (12.0%) was obtained using FeCl₃/furan mol ratios of 3.5 in acetonitrile/chloroform mixture (5/1). The density values of the composites with different PFu contents were measured. Composite fibers were also subjected to doping processes with HCl and I₂ vapors, separately, and it was observed that the surface resistivity of PFu/PET (10¹² Ω/cm²) reached to 53 Ω/cm² after doping with I₂. The structural, thermal, and morphological characterization was performed with FTIR, XRD, TGA, and SEM, respectively.