Physical and mechanical characterization of jute fabric composites

As‐received and washed jute fabrics were used as reinforcement for a thermoset resin. The mild treatments performed on the jute fabrics did not significantly affect their physical and thermal behaviors. The washed fibers absorbed less water than the unmodified (as received) ones, indicating that the coating used to form the fabrics was hygroscopic. Measurements of the fiber mechanical properties showed a high dispersion due to fiber irregularities, although the values obtained were in agreement with data reported in the literature. These results were also analyzed with the Weibull method. To investigate the effect of the jute treatments on the interface properties, impact, compression, and tensile tests were carried out. The composites made from as‐received jute had the highest impact energy, which was probably associated with weak interfacial adhesion. Composite samples behaved more ductilely in compression than in tensile situations due to the brittle characteristics of the resin used as matrix. The effect of the orientation of the fibers with respect to the direction of the applied force in the different mechanical tests was also studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 639–650, 2005     

Effect of acetylation on dimensional stability,mechanical, and dynamic properties of jute board

Jute slivers were acetylated in pilot scale following a no catalyst‐no solvent method at 120°C for 2 h. The weight % gain was found to be 11.37. Different jute boards were pressed under heat and pressure using acetylated jute sliver and urea formaldehyde resin. Neutral salt (NaCl), acid salt (NH₄Cl), and melamine powder were used separately for curing urea formaldehyde. For comparison purposes, control boards were also prepared using nonacetylated slivers. The boards were tested for water soaking, cyclic water soaking, and cyclic humidity to see the effect of acetylation on dimensional stabilization. This chemical modification was found to improve the dimensional stability to a great extent for NaCl and NH₄Cl cured boards and to a less extent for a melamine‐cured one. Tensile and flexural strengths were tested by Instron before and after the cyclic tests. Retention values were found to be as high as 60% after cyclic water tests for acetylated boards and the same was as low as 24% for control boards. Dynamic parameters, such as storage flexural modulus (E′), loss flexural modulus (E"), and loss factor or damping efficiency (tan δ) were determined in a fixed‐frequency mode. Dynamic mechanical study revealed that tan δ peaks were lowered due to increased bulkiness of the fiber after acetylation and thus restricted mobility. A tiny additional peak was also visible at ∼90°C beside the main peak at ∼125°C for boards with modified slivers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 935–944, 1999     

Effect of coupling agents on the thermal and mechanical properties of polypropylene–jute fabric composites

Composites with different jute fabric contents and polypropylene (PP) were prepared by compression molding. The composite tensile modulus increased as the fiber content increased, although the strain at break decreased due to the restriction imposed on the deformation of the matrix by the rigid fibers. Moreover, and despite the chemical incompatibility between the polar fiber and the PP matrix, the tensile strength increased with jute content because of the use of long woven fibers. The interfacial adhesion between jute and PP was improved by the addition of different commercial maleated polypropylenes to the neat PP matrix. The effect of these coupling agents on the interface properties was inferred from the resulting composite mechanical properties. Out‐of‐plane instrumented falling weight impact tests showed that compatibilized composites had lower propagation energy than uncompatibilized ones, which was a clear indication that the adhesion between matrix and fibers was better in the former case since fewer mechanisms of energy propagation were activated. These results are in agreement with those found in tensile tests, inasmuch as the compatibilized composites exhibit the highest tensile strength. Scanning electron microscopy also revealed that the compatibilized composites exhibited less fiber pullout and smoother fiber surface than uncompatibilized ones. The thermal behavior of PP–compatibilizer blends was also analyzed using differential scanning calorimetry, to confirm that the improvements in the mechanical properties were the result of the improved adhesion between both faces and not due to changes in the crystallinity of the matrix. Copyright © 2006 Society of Chemical Industry     

Mechanical properties of glass fabric/polyester composites: Effect of silicone coatings on the fabrics

An experimental investigation was carried out to study the effect of a silicone coating on the mechanical properties of polyester/woven glass fabric composites, fabricated by resin transfer molding. E‐glass woven fabrics were coated with a silicone elastomer by solution dip coating. The effect of variation of silicone amounts on the impact resistance, toughness, and mechanical properties of the composite was determined. Short beam shear tests were performed to assess the effect of coating on the adhesion of the fiber to the matrix. The coated specimens exhibited worse interlaminar shear strength over that of uncoated fabrics. Three‐point bending tests were also performed to investigate the effect of the coating on flexural properties. Whereas flexural strength and Young's modulus decreased with increasing amount of coating, the toughness, represented by the area under the stress–strain curve, presented a maximum. Finally, notched Izod impact tests were carried out and the curve for the energy absorbed during impact versus the amount of coating also appeared to have a maximum, indicating an interesting slot for optimum impact performance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1300–1308, 2004     

Effect of silane monomer on the improvement of mechanical and degradable properties of photografted jute yarn with acrylamide

UV radiation was used to graft acrylamide (AA) to jute yarn in order to improve the mechanical properties. The physicomechanical properties of the grafted jute yarn were investigated. A series of solutions of different AA concentrations in methanol along with photoinitiator (Irgacure‐907, 2%) were prepared. The jute yarns were soaked in the solution for 30 min before radiation. The effect of irradiation time, concentration of monomer on polymer loading, and tensile properties of the jute yarn were studied. The highest polymer loading (22%) and tensile strength (95%) of the yarn were observed when the yarn was treated in 30% AA in methanol with 60 min of UV radiation. The surfaces of both treated and untreated jute were characterized by X‐ray photospectrometry, infrared spectroscopy, and environmental scanning electron microscopy, and it was observed that the AA reacted or deposited on the jute surface. A minute amount (1%) of silane monomer [3‐(trimethoxysilyl)‐propyl methacrylate] was used as an additive in the AA solution to further improve the mechanical properties of jute yarn. Better improvement was achieved by using 1% silane monomer. Water uptake, simulating weathering, and soil degradation tests of untreated and treated yarns were also performed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3530–3538, 2003     

Influence of electron beam treatment of jute on the thermal properties of random and two-directional jute/poly(lactic acid) green composites

In the present study, randomly aligned jute fiber/poly(lactic acid) (PLA) and two-directionally aligned jute fabric/PLA green composites with jute (50% by weight) treated with electron beam at different dosages (0, 5, 10, 30, 50, and 100?kGy) were fabricated by compression molding technique and the effect of electron beam treatment on their thermal properties was investigated in terms of thermal expansion, thermal stability, dynamic mechanical thermal property, and heat deflection temperature (HDT). The dynamic storage modulus and HDT of neat PLA were significantly increased by incorporating jute fibers or fabrics into PLA, whereas the coefficient of thermal expansion (CTE) and the damping property were decreased, reflecting the enhancement in the interfacial adhesion between the jute and the PLA by electron beam treatment with an optimal dosage of 10?kGy and the reinforcing effect by jute. The result exhibited that the thermal stability, storage modulus, and HDT of jute/PLA green composites were highest with the electron beam irradiation of jute at 10?kGy and lowest at 100?kGy, whereas the CTE and tan δ were lowest at 10?kGy and highest at 100?kGy. The thermal behavior of random jute/PLA green composites shows a similar tendency to that of 2D jute/PLA counterparts and the influence of electron beam irradiation on the thermal properties studied was consistent with each other. The thermomechanical analysis, dynamic mechanical thermal analysis, thermogravimetric analysis, and HDT results were in agreement with each other, showing a comparable effect of electron beam irradiation on composites thermal characteristics.     

Effects of plasma treatment on mechanical properties of rubber/cellulose fibre composites

Natural rubber materials reinforced with cellulose fibres have been studied with respect to crosslink density, tensile strength and stress relaxation. The fibres have been grafted with butadiene or divinylbenzene by plasma treatment. Chemiluminescence analysis was used to indicate the grafting on the surface of the cellulose fibres and also to estimate the effect of the plasma on the cellulose fibres. The results indicate the possibility of obtaining a surface layer on the fibres, which is a conceivable way of improving the mechanical properties of rubber composites.     

Short jute fiber‐reinforced polypropylene composites: Dynamic mechanical study

Short jute fiber‐reinforced polypropylene (PP) composites were prepared using a high‐speed thermokinetic mixer. A compatibilizer was used to improve the molecular interaction between jute and PP. Both the percent weight fraction of the jute fiber and compatibilizer were varied to study the dynamic mechanical thermal (DMT) properties. Dynamic parameters such as storage flexural modulus (E′), loss flexural modulus (E″), storage shear modulus (G′), loss shear modulus (G″), and loss factor or damping efficiency (tan δ) were determined in a resonant frequency mode. The transition peak nature, amplitude, and temperature of E′, E″, G′, G″, and tan δ of different compositions were shown to indicate possible improvements of molecular interaction in the presence of a compatibilizer. The modulus retention term, a plot of the reduced modulus with the weight fraction of the jute fiber, also indicate its improvement. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 531–539, 1999     

Effect of graft copolymerization of mixtures of acrylamide and methyl methacrylate on mechanical properties of jute fibers of different compositions

The role of persulfate-induced graft copolymerization of mixtures of acrylamide and methyl methacrylate at 50°C in modifying mechanical properties of jute fibers of different compositions was studied in a limited aqueous system following a pretreatment technique. Results obtained indicate that such a process admits a good scope for modification of mechanical properties of jute fiber depending on degree of grafting achieved and compositional variations of (1) the feed monomer mixture and (2) the multiconstituent jute itself, consequent to selective removal of lignin and hemicellulose to different extents from the fiber. Low to moderate removal of hemicellulose is more effective than a similar degree of removal of lignin from jute in rendering the fiber more amenable to vinyl grafting using the mixed monomer system without being adversely affected with respect to tensile properties. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1139–1147, 1998     

Effect of fiber treatments on mechanical properties of coir or oil palm fiber reinforced polyester composites

The use of plant fibers as a reinforcement in polyester matrices requires the issue of compatibility between the two phases to be addressed. Because plant fibers present hydrophilic surfaces and polyesters are generally hydrophobic, poor fiber–matrix dispersion and wetting of the fibers by the matrix may result. As a consequence, the mechanical properties of the composite are severely reduced. This study considers the effect of fiber treatment by chemical modification of the fibers (acetylation) or the use of silane or titanate coupling agents on the mechanical properties of coir or oil palm reinforced polyester composites. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1685–1697, 2000     

Effect of coupling agents on the mechanical properties of fly ash/polyester particulate composites

Fly ash (FA)/general purpose unsaturated polyester resin (GPR) particulate composites were made. The effect of the surface treatment of FA with two different silane coupling agents (CAs) on the mechanical properties, such as the tensile, flexural, compressive, and impact strengths and hardness, of FA–GPR composites were studied. The properties of FA–CA–GPR were also compared with that of GPR and CaCO₃–GPR. An enhancement in the tensile, flexural, compressive, and impact strengths and a decrease in the tensile and flexural moduli were observed when FA was surface treated with CA. Hardness also increases with CA‐treated FA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1755–1760, 2001     

Short jute fiber-reinforced polypropylene composites: Effect of compatibilizer

Jute fibers were chopped to approximately 100 mm in length and then processed through a granulator having an 8-mm screen. Final fiber lengths were up to 10 mm maximum. These fibers along with polypropylene granules and a compatibilizer were mixed in a K-mixer at a fixed rpm, 5500, and dumped at a fixed temperature, 390°F, following single-stage procedure. The fiber loadings were 30, 40, 50, and 60 wt %, and at each fiber loading, compatibilizer doses were 0, 1, 2, 3 and 4 wt %. The K-mix samples were pressed and granulated. Finally, ASTM test specimens were molded using a Cincinnati injection molding machine. At 60% by weight of fiber loading, the use of the compatibilizer improved the flexural strength as high as 100%, tensile strength to 120%, and impact strength (unnotched) by 175%. Remarkable improvements were attained even with 1% compatibilizer only. Interface studies were carried out by SEM to investigate the fiber surface morphology, fiber pull-out, and fiber–polymer interface. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 329–338, 1998     

The effect of atmospheric plasma treatment of recycled carbon fiber at different plasma powers on recycled carbon fiber and its polypropylene composites

To increase the mechanical properties of recycled carbon fiber-reinforced polypropylene (PP) composites, recycled carbon fibers (RCF) were subjected to atmospheric plasma treatment at different plasma powers (100, 200, and 300 W). The changes on surface topography and roughness of RCF were examined by atomic force microscopy. Plasma treatment of RCF increased the roughness value of RCF. The variation of surface elemental compositions and tensile strength of RCF were determined by using X-ray photoelectron spectroscopy and tensile test, respectively. Plasma-treated RCF-reinforced PP composites were fabricated using high speed thermo-kinetic mixer. Plasma treatment of RCF at 100 W increased the tensile and flexural strength values of RCF-reinforced PP composites considerably by 17 and 11%, respectively. However, plasma treatment of RCF at higher plasma powers (200 W and 300 W) decreased tensile and flexural strength values of composites because of the etching of RCF. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47131.     

Effect of alkaline treatment on physical,mechanical, and thermal characteristics of jute filler reinforced epoxy composites

With burgeoning environmental concerns worldwide, using natural fibers/fillers to produce composites rather than conventional fibers is on the rise. The current work focuses on the physical and thermomechanical characteristics of alkaline-treated jute filler-based epoxy composites. The composites have been prepared with different weight fraction of jute fillers (0%, 2.5%, 5%, 7.5%, 10%, and 12.5%) using hand layup process. The X-ray diffraction and Fourier transform infrared spectroscopy analysis observed that the alkali treatment of jute fillers improved the crystallinity and molecular structure, enhancing the interfacial and molecular bond between fillers and matrix. The mechanical characterizations of developed composites analyzed that the inclusion of treated jute fillers strengthened the tensile and flexural properties. The 5% filler-based composites have demonstrated maximum tensile strength (54.06 MPa) and modulus (3.12 GPa) with maximum flexural strength (67.55 MPa) and modulus (3.90 GPa). The viscoelastic characteristics of composites revealed that the 7.5% filler-based composite has the highest storage modulus (3.75 GPa), loss modulus (0.496 GPa), and glass transition temperature (91°C) due to greater interfacial interactions of molecules. The weight loss and degradation of composites analyzed with thermogravimetric analysis, and observed better thermal stability with treated jute fillers. The morphological analysis at fracture surfaces analyzed the brittle catastrophic failure of composites. Therefore, the finding produced better specific strength and stiffness with greater thermal stability for electronics equipment, packaging, and transportation.     

Horseradish peroxidase-mediated functional hydrophobization of jute fabrics to enhance mechanical properties of jute/thermoplastic composites

In this study, nonpolar octyl gallate (OG), dodecyl gallate (DG), and octadecyl gallate (OCG) were grafted onto the surface of hydrophilic jute fabrics, which were mediated by horseradish peroxidase to improve the hydrophobicity of jute materials. The gallate-grafted jutes were characterized by infrared spectroscopy and grafting percentage (Gp), and the hydrophobic properties were evaluated by water contact angle and wetting time measurements. The Gps determined by saponification was 3.91%, 5.12%, and 4.58% for OG, DG, and OCG, respectively. The nonpolar chain length and the grafting rate of the monomers had a considerable effect on the hydrophobicity of the modified jute fabrics. The as-prepared hydrophobized jute fabrics had superior interfacial compatibility with nonpolar resins, such as polypropylene (PP) and polylactic acid (PLA) making them most suitable to be utilized in the development of jute fiber-reinforced thermoplastic composites. The tensile and dynamic mechanical properties of the grafted jute/PP or jute/PLA composites were improved compared with pure PP, PLA, and non-modified jute composites.     

Effect of short carbon fiber content on the mechanical properties of TiB2-based composites prepared by spark plasma sintering

In this study, TiB₂-30 vol% SiC composites containing 0, 5, 10, and 15 vol% short carbon fibers (C_f) were produced by spark plasma sintering (SPS). The effect of carbon fiber content on microstructure, density, and mechanical properties (micro-hardness and flexural strength) of the fabricated composites was studied. Scanning electron microscopy (SEM) results indicated that the fibers were uniformly dispersed in the TiB₂–SiC matrix using wet ball milling before SPS process. Fully dense TiB₂–SiC–C_f composites were achieved by SPS process at 1900°C for 10 min under 30 MPa. With the addition of fibers, the relative density of the composites did not change considerably. Mechanical tests revealed that microhardness was reduced about 19% by the incorporation of carbon fibers, whereas the flexural strength improved significantly. However, the flexural strength diminished by adding carbon fibers above to critical value (5 vol%) due to residual thermal stresses, nonhomogeneous structure and graphitization of carbon fibers. It was found that the composite with 5 vol% C_f had the highest flexural strength (482 MPa), which was enhanced by 20% compared with the TiB₂–SiC composite.     

The flame retardancy and mechanical properties of jute/polypropylene composites enhanced by ammonium polyphosphate/polypropylene powder

Surface flame retarded jute/polypropylene composites (J/P/A) were prepared via a modified strategy: the mixture of PP and APP powder was spread over the surface of jute/PP nonwoven felts, and then transformed into the flame retarded layer by the hot pressing process. The flame retardancy and thermal properties of composites were analyzed by limit oxygen index (LOI), horizontal burning rate (HBR), thermogravimetric analyses (TGA), and differential scanning calorimetry (DSC). We demonstrated that the flame retardancy and mechanical properties of composites was significantly improved compared with those obtained by presoaking the nonwoven fiber felts in flame retardant (FR) solvent before hot pressing. The mechanism of thermal degradation of jute fiber and flame‐retardant mechanism of composites were analyzed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscope (SEM). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43889.     

Characterization of alkali‐treated jute fibers for physical and mechanical properties

Changes occurring in jute fibers when treated with a 5% concentration of a NaOH solution for 0, 2, 4, 6, and 8 h were characterized by weight loss, linear density, tenacity, modulus, FTIR, and X‐ray measurements. A 9.63% weight loss was measured during 2 h of treatment with a drop of hemicellulose content from 22 to 12.90%. The linear density value showed no change until 2 h of treatment followed by a decrease from 33.0 to 14.5 denier by 56% after 6 h of treatment. The tenacity and modulus of the fibers improved by 45 and 79%, respectively, and the percent breaking strain was reduced by 23% after 8 h of treatment. X‐ray diffractograms showed increase in crystallinity of the fibers only after 6 h of treatment, while FTIR measurements showed much of the changes occurring by 2 h of treatment with an increased amount of OH groups. By measuring the rate of change of the modulus, tenacity, and percent breaking strain with the time of treatment, a clear transition was apparent at 4 h of treatment with the dissolution of hemicellulose, causing a weight loss and drop in the linear density before and development of crystallinity with an improvement in the properties after the transition time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1013–1020, 2001     

Jute sliver–LDPE composites: Effect of aqueous consolidation on mechanical and dynamic properties

The aqueous consolidation of jute slivers and its comparison with the control in the LDPE matrix were studied in this article. The increase in strength of the consolidated jute sliver–LDPE composite was noticed. Jute slivers were immersed in water, squeezed, air dried, and finally consolidated at 160°C for 5 min. These treated jute slivers with or without CSM (chopped strand mat) and LDPE films were compression molded to different boards and compared among themselves. The studies undertaken for characterization and analysis of the system were (a) flexural behavior, (b) tensile behavior, (c) impact behavior, (d) DMA study, and (e) SEM study. Among mechanical properties maximum gain was found in the impact strength. In the SEM study splitting of fibers were observed after consolidation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 684–689, 2000     

Influence of silicon carbide filler on mechanical and dielectric properties of glass fabric reinforced epoxy composites

Fiber‐reinforced polymeric composites (FRPCs) have emerged as an important material for automotive, aerospace, and other engineering applications because of their light weight, design flexibility, ease of manufacturing, and improved mechanical performance. In this study, glass‐epoxy (G‐E) and silicon carbide filled glass‐epoxy (SiC‐G‐E) composite systems have been fabricated using hand lay‐up technique. The mechanical properties such as tensile strength, tensile modulus, elongation at break, flexural strength, and hardness have been investigated in accordance with ASTM standards. From the experimental investigations, it has been found that the tensile strength, flexural strength, and hardness of the glass reinforced epoxy composite increased with the inclusion of SiC filler. The results of the SiC (5 wt %)‐G‐E composite showed higher mechanical properties compared to G‐E system. The dielectric properties such as dielectric constant (permittivity), tan delta, dielectric loss, and AC conductivity of these composites have been evaluated. A drastic reduction in dielectric constant after incorporation of conducting SiC filler into epoxy composite has been observed. Scanning electron microscopy (SEM) photomicrographs of the fractured samples revealed various aspects of the fractured surfaces. The failure modes of the tensile fractured surfaces have also been reported. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009