M. A. Gafur

Thermal, Mechanical and Morphological Characterization of Jute/Gelatin Composites

Jute fabrics/gelatin biocomposites were fabricated using compression molding. The fiber content in the composite varied from 20–60 wt%. Composites were subjected to mechanical, thermal, water uptake and scanning electron microscopic (SEM) analysis. Composite contained 50 wt% jute showed the best mechanical properties. Tensile strength, tensile modulus, bending strength, bending modulus and impact strength of the 50% jute content composites were found to be 85 MPa, 1.25 GPa, 140 MPa and 9 GPa and 9.5 kJ/m2, respectively. Water uptake properties at room temperature were evaluated and found that the composites had lower water uptake compared to virgin matrix.

Mechanical Properties of Natural Fiber Containing Polymer Composites

We have studied the mechanical properties of ethylene vinyl acetate (EVA) and cellulose acetate (CA) composite containing cellulosic natural fibers (Sterculia villosa) and tried to explain with the help of mixing of fiber in the composite. It is observed that the tensile strength (TS) of EVA composite decreases with the addition of fiber. Whereas in a CA composite, TS increases or reinforcement happens with the fiber content. This anomalous trend could be explained with the adhesion of fiber with the polymer matrix in the composite. The composite shows the same increasing trend for flexural strength (FS) up to a certain composition of fiber. With the further addition of fiber, we have found decreasing FS for the EVA composite, but a gradual increase in the CA composite with the fiber content. It is thought that fiber is well distributed in the CA composite and that the fiber-matrix could bear the load resulting in an increase of FS. This consideration can be well explained from the SEM picture that shows fiber forms a domain in the EVA composite or coagulation of fiber, as a result the FS decrease, but there is no such type of coagulation in the CA composite, resulting in increasing TS and FS with the fiber content. Toughness of the composites are also compared. It is believed that the cellulose-containing EVA and CA composites will be environment-friendly. We also suggest that this composite could be used in a low weight application such as gasket materials, toothbrushes, spoon handles, mirror frames, partition panels, etc.

Modification of pineapple leaf fibers and graft copolymerization of acrylonitrile onto modified fibers

Raw pineapple leaf fibers (PALFs) were chemically modified by scouring, NaOH treatment, and bleaching (NaClO2). The graft copolymerization of synthetic acrylonitrile monomer onto bleached PALFs was carried out in aqueous medium using potassium persulfate (K2S2O8/FeSO4) as a redox initiator. The maximum grafting level at optimum conditions, namely, monomer concentration, initiator concentration, catalyst concentration, reaction time, and temperature have been determined. The main objective of this study is to decrease the amorphous region of lignocellulose in PALFs and improve its hydrophobic nature by incorporation of synthetic polymer of polyacrylonitrile and mechanical properties. The modified and grafted fibers were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetric analysis, and X-ray diffraction study techniques. The moisture content and tensile strength properties were also evaluated for their environmental and mechanical performances.

Mechanical and degradation characteristics of natural silk and synthetic phosphate glass fiber reinforced polypropylene composites

Degradable phosphate glass fiber is a synthetic fiber and silk is one of the strongest natural fibers. In this study, composites are fabricated from PP reinforced with phosphate glass fiber and silk fiber using compression molding. Tensile testing, flexural testing and impact testing are carried out to evaluate the composites mechanical properties. It has been found that silk fiber composites provided higher tensile strength (46 MPa), bending strength (50 MPa), and impact strength (17 kJ/m2) compared to glass fiber composites which are respectively 39 MPa, 46 MPa, and 8 kJ/m2. Degradation studies are carried out by accelerated weathering as well as by natural weathering. After weathering, the mechanical properties are evaluated and it has been found that phosphate glass fiber/PP composites degrade more rapidly compared to silk/PP composites.

Effect of the Incorporation of PVC on the Mechanical Properties of the Jute-Reinforced LLDPE Composite

Jute fabrics-reinforced linear low density polyethylene (LLDPE) matrix composites (50 wt% fiber) were prepared by compression molding and mechanical properties were studied. Polyvinyl chloride (PVC) matrix was incorporated instead of LLDPE in the jute based composites and their mechanical properties were investigated and compared with the control composites. It was found that with the increase of PVC in the LLDPE based composites, the mechanical properties were found to improve significantly. Degradation tests of the composites for upto 24 weeks were performed in soil medium. Water uptake and Thermo-mechanical properties of the composites were also studied.

Study on the Mechanical and Thermal Properties of Jute-Reinforced Methyl Acrylate Grafted PET Composites

Polyethylene terephthalate (PET) granules were grafted with methyl acrylate (MA) from the solution containing 10% MA in methanol (86%) solvent and photo initiator (4%) for 10 min and then cured under UV radiation. MA-grafted PET films were prepared at 260°C and 5 ton pressure using heat press. Jute fabric-reinforced, MA-grafted, PET-based composites (25% fiber by weight) were fabricated by compression molding. Mechanical, thermal and soil degradation tests of the composites were performed. It was found that the MA grafted PET composites showed higher mechanical properties over the ungrafted PET/jute composite.

Structural transition and its effect in La, Zr co-substituted mono-domain BiFeO3

A new approach was employed in explaining the weak ferromagnetic behavior of conventionally synthesized Zr4+ modified Bi0.8La0.2FeO3. Rietveld refinement of XRD patterns revealed a polar-to-non-polar R3c → Pnma structural transition in Zr4+substituted samples. Magnetic properties were discovered to be remarkably enhanced, with extracted coercivity and remanence as high as 14 kOe and 0.2 emu/g, respectively. More importantly, an answer to the essential question of the magnetic domain state of the samples has been put forward. Our analysis established, nearly without doubt, the presence of grains consisting of a single magnetic domain. Separated ferromagnetic and anti-ferromagnetic components of the total M-H curves helped to reveal an immense effect of the structural transition on the shape of the hysteresis loops. The orthorhombic magnetocrystalline anisotropy of the Pnma phase has been primarily deemed responsible for the high coercivity and remanence of the Zr4+ modified samples. The effect of the grain...

Comparative Studies on the Mechanical, Degradation and Interfacial Properties between Jute and E-Glass Fiber-Reinforced PET Composites

Jute fiber mat (hessian cloth) reinforced PET-based composites (50% fiber by weight) and E-glass fiber matreinforced PET based composites (50% fiber by weight) were fabricated by compression molding and the mechanical properties tensile strength (TS), tensile modulus (TM), elongation at break (%), bending strength (BS), bending modulus (BM), impact strength (IS) and hardness (Shore-A) of the composites were evaluated and compared. The interfacial properties of the both composites were also compared. Water uptake test and soil degradation test were also investigated.

Effect of Chemical Modifications on Surface Morphological, Structural, Mechanical, and Thermal Properties of Sponge-gourd Natural Fiber

Sponge-gourd (SG) natural fibers obtained from Luffa cylindrica plant were chemically treated separately using alkali (5, 10, and 15 wt%), acetic anhydride (5, 10, and 15 wt%), and benzoyl chloride (5, 10, and 15 wt%). Both untreated and chemically treated SG fibers (SGFs) were subsequently characterized using a field emission scanning electron microscope, a Fourier transform infrared spectrometer, an X-ray diffractometer, a universal testing machine, and a thermogravimetric analyzer. Surface analysis by scanning electron microscopy shows that the alkali treatments promote better outer surface layer than other treatments of the SGF with the exposition of inner fibrillar structure, thereby increasing roughness of the fiber surface. Alkali treatment also improves the crystallinity and exhibits new chemical bond formation in the SGF. The tensile strength and Young’s modulus have been analyzed through a two-parameter Weibull distribution model, where a significant increase in mechanical property of benzoylated fibers has been observed. The thermal stability of the modified fibers is also found to increase by acetic anhydride treatment.

Renewable Okra Bast Fiber Reinforced Phenol Formaldehyde Resin Composites: Mechanical and Thermal Studies

Okra bast fiber (OBF) reinforced thermoset phenol formaldehyde (PF) resin composites were prepared by compression molding methods. In order to found better wetting of filler and matrix, OBF was treated with NaOH. The properties of composites were studied by mechanical tests, thermal methods and water uptake. The mechanical properties such as tensile strength (TS), Young’s modulus (YM), tensile elongation, flexural strength (FS) and flexural modulus of composites were varied with NaOH concentration, treatment time and fiber loading. TS and FS were found to increase for fiber loading upto 30% and then decreased whereas YM, FM and tensile elongation were increased with increase of weight fraction. About 21% more TS and 85% more FS was found for 10% alkali treated fiber composite than untreated fiber composite. Treated fiber composites also showed greater thermal stability and lower water absorption property