Properties of cellulose/Thespesia Lampas short fibers bio-composite films

Abstract: Cellulose was dissolved in pre cooled environment friendly solvent (aq.7% sodium hydroxide+12% urea) and regenerated with 5%H2SO4 as coagulation bath. Using cellulose as matrix and alkali treated short natural fibers extracted from the newly identified Thespesia Lampas plant as reinforcement, the green composite films were prepared. The effect of fiber loading on the tensile properties and thermal stability was studied. The fractographs indicated better interfacial bonding between the fibers and cellulose. The crystallinity of the composite films was found to be lower than the matrix and decreased with increasing fiber content. In spite of better interfacial bonding, the tensile properties of the composites were found to be lower than those of the matrix and decreased with increasing fiber content and this behavior was attributed to the random orientation of the fibers in the composites. The thermal stability of the composite films was higher than the matrix and increased with fiber content

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

Effect of chemicals treatment and fiber loading on mechanical properties of borassus (Toddy palm) fiber/epoxy composites

Abstract: The aim of the present study was to investigate and compare the mechanical properties of untreated and chemically modified Borassus fiber reinforced epoxy composites. Composites were prepared by hand lay-up process by reinforcing Borassus fibers with epoxy matrix. To improve the fiber-matrix adhesion properties, alkali (NaOH), and alkali combined with silane (3- aminopropyltriethoxysilane) treatments on the fibers surface were carried out. Examinations through Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were conducted to investigate the structural and physical properties of the Borassus fibers. Tensile properties such as modulus and strength of the composites made by chemically modified and untreated Borassus fibers were studied using a Universal Testing Machine (UTM). Based on the experimental results, it was found that the tensile properties of the Borassus reinforced epoxy composites were significantly improved, as compared with the neat epoxy. It was also found that the fiber treated with combination of alkali and silane exhibited superior mechanical properties as compared with alkali and untreated fiber composites. The nature of fiber/matrix interface was examined through SEM of cryo-fractured samples. Chemical resistance of composites was also found to be improved with chemically modified fiber composites

Tensile and thermal properties of poly(lactic acid)/eggshell powder composite films

Biodegradable composite films of poly(lactic acid) (PLA)=eggshell powder (ESP) were prepared by the composite film casting method using chloroform as the solvent. ESP was loaded in PLA in 1 to 5 wt.%. The films were subjected to tensile, FT-IR spectral, thermogravimetric, X-ray, and microscopic analyses. The tensile strength and modulus of the composite films were found to be higher than those of PLA and increased with ESP content up to 4 wt.% and then decreased. A reverse trend was observed in the case of percentage elongation at break. The X-ray diffractograms of the composite films indicated an increase in crystallinity with ESP content. The optical micrographs indicated uniform distribution of ESP particles in the composite films. However, the fractographs indicated agglomeration of ESP particles at 5 wt.% loading. The FT-IR spectra revealed no specific interactions between PLA and ESP. The thermal stability of the composite films increased with ESP content

Formulation and characterization of in situ generated copper nanoparticles reinforced cellulose composite films for potential antimicrobial applications

Cellulose was dissolved in aq.(LiOH C urea) solution pre-cooled to –12.5 C and the wet films were prepared using ethyl alcohol coagulation bath. The gel cellulose films were dipped in 10 wt.% Cassia alata leaf extract solution and allowed the extract to diffuse into them. The leaf extract infused wet cellulose films were dipped in different concentrated aq. copper sulphate solutions and allowed for in situ generation of copper nanoparticles (CuNPs) inside the matrix. The morphological, structural, antibacterial, thermal, and tensile properties of dried cellulose/CuNP composite films were carried out. The presence of CuNPs was established by EDX spectra and X-ray diffraction. The composite films displayed higher thermal stability than the matrix due to the presence of CuNPs. Cellulose/CuNP composite films possessed better tensile strength than the matrix. The composite films showed good antibacterial activity against E.coli bacteria. We conclude that good antibacterial activity and better tensile properties of the cellulose/CuNP composite films make them suitable for antibacterial wrapping and medical purposes

Extraction and characterization of novel lignocellulosic fibers from Thespesia lampas plant

In this work, the lignocellulosic fibers from the plant Thespesia lampas were extracted and investigated in detail. The prime objective of this work was to study the effect of alkali treatment on the chemical composition, tensile properties, morphological and structural changes, and thermal degradation of Thespesia lampas fibers. Chemical analysis, FT-IR, and 13C CP-MAS NMR spectroscopic studies indicated lowering of amorphous hemicellulose content on alkali treatment. Wide-angle X-ray diffraction studies indicated increase in crystallinity of the fibers on alkali treatment. The tensile strength and modulus of the fibers and thermal stability increased on alkali treatment. Scanning electron micrographs revealed roughening of the surface of the fibers due to the removal of the hemicellulose layer on alkali treatment. Tensile properties of Thespesia fibers were compared to those of other important natural fibers, and it was indicated as an alternative suitable source for composite construction

Preparation and properties of biodegradable spent tea leaf powder/poly(propylene carbonate) composite films

Abstract: The aim of the present work is to develop novel biobased lightweight material with improved tensile and thermal properties. Spent tea leaf powder (STLP) is used as a filler to improve the tensile and thermal properties of polypropylene carbonate (PPC). Tea is an important material of hotels and household and spent tea leaf forms a conjugal solid waste. Composite films are obtained by solution casting method. These films are characterized by Optical microscopy, scanning electron microscopy, Fourier transforms infrared spectroscopy, thermogravimetric analysis and tensile testing to examine the effect of filler content on the properties of the composites. The results have shown that composite films are having increased tensile strength due to enhanced interfacial adhesion between the filler and the matrix. In addition, the composite films have also exhibited higher thermal degradation temperatures compared to pure polypropylene carbonate. The morphology results indicate that there is a good interface interaction between STLP and PPC. Results of the study reveal STLP to be a promising green filler for polymer plastics

Nanocomposite cotton fabrics with in situ formed copper nanoparticles using citrus lemon leaf extract as reducing agent

Nanocomposite cotton fabrics (NCCFs) with in situ formed copper nanoparticles (CuNPs) using aqueous extraction of citrus lemon leaves as reducing agent have been made. The NCCFs have been analyzed by SEM, FTIR, XRD and TGA techniques and antibacterial test. The CuNPS have been roughly spherical in shape with a mean size in the range of 82-114 nm. The OH and C-OH groups of leaf extract has played an important role in the generation of the CuNPs in the NCCFs as established by the FTIR spectral analysis. The XRD analysis has indicated that the formation of CuNPs in NCCFs lowered the crystallinity of NCCFs. The thermal stability of NCCFs has been lowered by the CuNPs. However, the NCCFs with in situ generated CuNPs exhibited higher antibacterial activity against both gram-negative and gram-positive bacteria and hence can be effectively used as antibacterial wound dressing and hospital bed materials