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.     

Preparation and properties of successive alkali treated completely biodegradable short jute fiber reinforced PLA composites

The natural fiber reinforced biodegradable polymer composites were prepared with short jute fiber as reinforcement in PLA (Poly lactic acid) matrix. The short jute fiber is successively treated with NaOH at various concentrations (5%, 10%, and 15%) and H₂O₂. The composites were prepared with untreated and treated short jute fibers at different weight proportions (up to 25%) in PLA and investigated for mechanical properties. The results showed that the composite with successive alkali treated jute fiber at 10% NaOH and H₂O₂ with 20% fiber loading has shown 18% higher flexural strength than neat PLA and untreated jute/PLA composite. The flexural modulus of the composite at 25% fiber loading was 125% and 110% higher than that of composites with untreated fibers and neat PLA, respectively. The impact strength of composite with untreated fibers at higher fiber weight fraction was 23% high as compared to neat PLA and 26% high compared to composite with treated fibers. The water absorption was more for untreated jute/PLA composite at 25% fiber loading than all other composites. The composite with untreated fibers has high thermal degradation compared with treated fibers but lower than that of pure PLA matrix. The enzymatic environment has increased the rate of degradation of composites as compared to soil burial. Surface morphology of biodegraded surfaces of the composites were studied using SEM method. POLYM. COMPOS., 37:2160–2170, 2016. © 2015 Society of Plastics Engineers     

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.     

Mechanical properties of surface modified jute fiber/polypropylene nonwoven composites

In this study, the jute/polypropylene nonwoven reinforced composites were prepared using film stacking method. The surface of jute fibers was modified using alkali treatment. These alkali treated jute fiber nonwoven composites were analyzed for their tensile and flexural properties. Increasing the amount of jute fibers in the nonwovens has improved the mechanical properties of their composites. The effect of stacking sequence of preferentially and nonpreferentially aligned nonwovens within the composites was also investigated. The flexural and tensile moduli of composites were found to be significantly enhanced when nonwovens consisting of preferentially and nonpreferentially aligned jute fibers were stacked in an alternate manner. The existing theoretical models of tensile modulus of fiber reinforced composites have been analyzed for predicting the tensile modulus of nonwoven composites. In general, a good agreement was obtained between the experimental and theoretical results of tensile modulus of nonwoven composites. POLYM. COMPOS., 35:1044–1050, 2014. © 2013 Society of Plastics Engineers     

Recycling of jute textile in phenol formaldehyde–jute composites

Jute textile was recycled into composites using different percents of phenol formaldehyde (PF) resin. The effect of the resin percent, from 12 to 30%, on the flexural strength, tensile strength, water absorption, and thickness swelling of the produced composites was studied. To improve the dimensional stability of the produced composites, jute textile was acetylated or steamed. The effect of steaming and acetylation on the structure and thermal stability of jute fibers was studied using Fourier Transform Infrared (FTIR) spectroscopy and Thermogravimetric analysis (TGA), respectively. The effect of these treatments on the flexural strength, tensile strength, water absorption, and thickness swelling of the produced composites was studied. Steaming of jute textile was superior to acetylation in improving the dimensional stability. Cyclic wetting and drying test of the composites showed that steaming of the jute textile resulted in much less irreversible and reversible thickness swelling than in case of using acetylated or untreated jute textile. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3588–3593, 2003     

Recycled milk pouch and virgin LDPE‐LLDPE‐based jute fiber composites

The present investigation deals with the thermo‐mechanical recycling of post consumer milk pouches (LDPE‐LLDPE blend) and its use as jute fiber composite materials for engineering applications. The mechanical, thermal, morphological, and dynamic‐mechanical properties of recycled milk pouch‐based jute fiber composites with different fiber contents were evaluated and compared with those of the virgin LDPE‐LLDPE/jute fiber composites. Effect of artificial weathering on mechanical properties of different formulated composites was determined. The recycled polymer‐based jute fiber composites showed inferior mechanical properties as well as poor thermal stability compared to those observed for virgin polymer/jute fiber composites. However, the jute‐composites made with (50:50) recycled milk pouch‐virgin LDPE‐LLDPE blend as polymer matrix indicated significantly superior properties in comparison to the recycled milk pouch/jute composites. Overall mechanical performances of the recycled and virgin polymeric composites were correlated by scanning electron microscopy (SEM). The dynamic mechanical analysis showed that storage modulus values were lower for recycled LDPE‐LLDPE/jute composites compared to virgin LDPE‐LLDPE/jute composites throughout the entire temperature range, but an increase in the storage modulus was observed for recycled‐virgin LDPE‐LLDPE/jute composites. POLYM. COMPOS. 28:78–88, 2007. © 2007 Society of Plastics Engineers     

Study of jute fiber reinforced polyester composites by dynamic mechanical analysis

Cyanoethylation of jute fibers in the form of nonwoven fabric was studied, and these chemically modified fibers were used to make jute–polyester composites. The dynamic mechanical thermal properties of unsaturated polyester resin (cured) and composites of unmodified and chemically modified jute–polyester were studied by using a dynamic mechanical analyzer over a wide temperature range. The data suggest that the storage modulus and thermal transition temperature of the composites increased enormously due to cyanoethylation of fiber. An increase of the storage modulus of composites, prepared from chemically modified fiber, indicates its higher stiffness as compared to a composite prepared from unmodified fiber. It is also observed that incorporation of jute fiber (both unmodified and modified) with the unsaturated resin reduced the tan δ peak height remarkably. Composites prepared from cyanoethylated jute show better creep resistance at comparatively lower temperatures. On the contrary, a reversed phenomenon is observed at higher temperatures (120°C and above). Scanning electron micrographs of tensile fracture surfaces of unmodified and modified jute–polyester composites clearly demonstrate better fiber–matrix bonding in the case of the latter. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1505–1513, 1999     

Effect of the atmospheric plasma treatment parameters on jute fabric: The effect on mechanical properties of jute fabric/polyester composites

The effect of atmospheric air plasma treatment of jute fabrics on the mechanical properties of jute fabric reinforced polyester composites was investigated. The jute fabrics were subjected to different plasma powers (60, 90, and 120 W) for the exposure times of 1, 3, and 6 min. The effects of plasma powers and exposure times on interlaminar shear strength, tensile strength, and flexural strength of polyester based composites were evaluated. The greatest ILSS increase was about 171% at plasma power of 120 W and exposure time of 6 min. It is inferred that atmospheric air plasma treatment improves the interfacial adhesion between the jute fiber and polyester. This result was also confirmed by scanning electron microscopy observations of the fractured surfaces of the composites. The greatest tensile strength and flexural strength values were determined at 120 W for 1 min and at 60 W for 3 min, respectively. Moreover, it can be said that atmospheric air plasma treatment of jute fibers at longer exposure times (6 min) made a detrimental effect on tensile and flexural properties of jute‐reinforced polyester composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

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     

挤出-注塑制备黄麻增强PLA复合材料及其性能

通过挤出共混、造粒、注射成型的方式制备了黄麻纤维填充聚乳酸(PLA)复合材料,研究了复合材料的力学性能以及黄麻与PLA之间的微观界面形貌。结果表明:黄麻的加入,并没有很好地改善黄麻/PLA复合材料的拉伸强度和弯曲强度;碱处理后的黄麻与PLA之间的界面性能有所改善;碱处理黄麻的加入,改善了黄麻/PLA复合材料的断裂伸长率与冲击韧性。     

Short polyethylene terephthalate fiber (PET) reinforced NBR rubber composites

Acrylonitrile-butadiene rubber (NBR) has been reinforced with different content of PET up to 25 phr. Vulcanization of prepared composites as will as the unreinforced ones have been induced by ionizing radiation of accelerated electron beam of varying dose up to 150 kGy. Evaluations of the vulcanized composites have been followed up through the measurement of mechanical, physical and thermal properties. Also, scanning electron microscope (SEM) was performed. Mechanical properties, namely tensile strength (TS) and hardness were found to increase with the increase of irradiation dose as well as the increase in the content of PET up to 25 phr. Also, elongation at break (ε _b) was found to decrease with the increase of irradiation dose; however, the decrease in ε_b is not consistence with the increase in fibers loading. Young’s modulus (E) and tensile modulus at 25% elongation (E25) were found to increase with the increase of irradiation dose and fiber loading up to 20 phr. Also, the volume fraction of swollen rubber increases as irradiation dose and/or fiber content increased; it was more influenced by irradiation rather than fiber loading. Anisotropic swelling increased with irradiation and fiber loading up to 20 phr. SEM photomicrograph showed that irradiation causes adhesion between PET fiber and NBR where less pulling out and less pitting on the surface were observed. The thermal properties of the composite irradiated at 100 kGy reveal that the activation energy (E _a) increases up to 10 phr fiber content. When the composite that contains 10 phr fiber irradiated at doses higher than100 kGy, Ea decreased.     

Rheological characterization of PP/jute composite melts

The present article summarizes an experimental study on the molten viscoelastic behavior of PP/jute composites under steady and dynamic mode. Variations in melt viscosity and die swell of the composites with an increase in shear rate, fiber loading, and coupling agent concentration have been investigated using capillary rheometer. It was observed that with the addition of fibers and MAPP, the melt viscosity of the composites increased due to improved fiber‐matrix interfacial adhesion. Further, the dynamic viscoelastic behavior, measured using parallel plate rheometer, revealed an increase in the storage modulus (G′), indicating higher stiffness in case of fiber‐filled composites as compared with the virgin matrix. Time–temperature superposition was applied to generate various viscoelastic master curves. The fiber‐matrix morphology of the extrudates was also examined using scanning electron microscopy, which corroborated the findings of rheological properties. The treated composites displayed uniform distribution of fibers within the PP matrix with lesser surface irregularities. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1476–1484, 2006     

Effect of layering pattern on the physical,mechanical, and thermal properties of jute/bagasse hybrid fiber‐reinforced epoxy novolac composites

In this study, randomly oriented short jute/bagasse hybrid fiber‐reinforced epoxy novolac composites were prepared by keeping the relative volume ratio of jute and bagasse of 1:3 and the total fiber loading 0.40 volume fractions. The effect of jute fiber hybridization and different layering pattern on the physical, mechanical, and thermal properties of jute/bagasse hybrid fiber‐reinforced epoxy novolac composites was investigated. The hybrid fiber‐reinforced composites exhibited fair water absorption and thickness swelling properties. To investigate the effect of layering pattern on thermomechanical behavior of hybrid composites, the storage modulus and loss factor were determined using dynamic mechanical analyzer from 30 to 200°C at a frequency of 1 Hz. The fracture surface morphology of the tensile samples of the hybrid composites was performed by using scanning electron microscopy. The morphological features of the composites were well corroborated with the mechanical properties. Thermogravimetric analysis indicated an increase in thermal stability of pure bagasse composites with the incorporation of jute fibers. The incorporation of hybrid fibers results better improvement in both thermal and dimensional stable compared with the pure bagasse fiber composites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Processing and characterization of jute fiber reinforced hybrid biocomposites based on polylactide/polycaprolactone blends

The main focus of this work is to develop biocomposites with improved stiffness and toughness. For this purpose, hybrid biocomposites composed of surface modified jute fiber and varying weight fractions of polylactide (PLA) and polycaprolactone (PCL) are fabricated by hot pressing of solvent impregnated prepregs. Mechanical, thermal (DSC), viscoelastic properties and biodegradation of the developed biocomposites were evaluated. Surface modification of the jute fiber resulted in improvement of tensile strength and modulus and reduction in impact toughness along with vibration damping capacity. The addition of biodegradable resin PCL to PLA matrix leads to recovery of the impact toughness and damping capacity of the biocomposites, without much sacrifice in stiffness and strength. Hybrid biocomposite with 10 wt% PCL attained an optimum balance between stiffness and toughness. In addition, PCL also accelerated the biodegradation rate of the composites. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Mechanical properties of poly lactic acid composite films reinforced with wet milled jute nanofibers

In the present study, waste jute fibers generated in textile industries, were wet pulverized to the scale of nanofibers of 50 nm diameter using high energy planetary ball milling for 3 h. The presence of water during wet pulverization found to reduce the rising temperature of mill, which prevented sticking of nanofibers on the mill wall and resulted in unimodal size distribution. In the subsequent stage, 1, 5, and 10 wt% of jute nanofibers were incorporated in poly(lactic acid) (PLA) matrix to prepare nanocomposite films by solvent casting. The reinforcement of nanofibers was investigated from the improvements in mechanical properties based on tensile tests, dynamic mechanical analysis, and differential scanning calorimetry. The maximum improvement was observed in case of 5 wt% nanocomposite film where initial modulus and tensile strength increased by 217.30% and 170.59%, respectively as compared to neat PLA film. These improvements are attributed to the increased interaction between nanofibers and matrix as well as to the increased crystallinity of PLA in composites. The improvements in load bearing capacity of nanocomposite films were significant at 60°C than 35°C, which showed ability of jute nanofibers to improve the softening temperature of PLA matrix. In the end, experimental results of Young's modulus were compared with predicted modulus of mechanical models. A good level of agreement was observed up to 5 wt% loading of jute nanofibers. POLYM. COMPOS., 34:2133–2141, 2013. © 2013 Society of Plastics Engineers     

A Comparative Study on the Mechanical,Degradation and Interfacial Properties of Jute/LLDPE and Jute/Natural Rubber Composites

Jute fabric (hessian cloth) reinforced low-density polyethylene (LLDPE) composites (40 wt%) and solid natural rubber-(NR) based composites (40 wt%) were fabricated by compression molding. Tensile strength (TS), tensile modulus (TM) and percentage elongation at break (Eb) of jute/LLDPE composites were found to be 29, 680 MPa and 20%, and for jute/NR-based composites were also found to be 15, 122 MPa and 94%, respectively. Interfacial shear strength (IFSS) of the jute/LLDPE and jute/NR systems was investigated by using the single fiber fragmentation test (SFFT). Scanning electron microscopy (SEM) and aqueous degradation tests were also performed.     

Effects of gamma irradiation on properties of PLA/flax composites

Polylactic acid (PLA) is a well-known renewable and biodegradable polymer but is still limited by its low heat distortion temperature and brittleness. In this study, a PLA/flax composite containing flax fiber strands (5 wt%) was prepared through melt-compounding process followed by gamma irradiation at doses ranging from 0 to 20 kGy in the presence of a small amount of triallyl isocyanurate (TAIC) as cross-linking agent. The gel fraction of the composite was tested, and the datum showed that the gel fraction sharply increased first, and then slightly decreased with increasing irradiation dose. Gamma irradiation induced cross-linking of the polymer to form a three-dimensional network in the PLA/flax composite system. Irradiated composite could only swell instead of dissolving completely in chloroform, and the swollen morphology correlated with irradiation dose. The thermal stability of the PLA/flax composite was characterized using thermogravimetric analysis (TGA) temperature, and dimensional stability. Overall, irradiation modification improved the thermal resistance and dimensional stability of PLA composites. The mechanical property tests of the irradiated composites revealed increased tensile and impact strengths, reduced elongation-at-break, and unchanged tensile modulus. The analysis of water absorption of the composite demonstrated that the irradiation cross-linking induced no obvious effect on water absorption. Irradiation cross-linking modification cannot change the hydrophilicity or hydrophobicity of PLA composites. Overall, these findings look promising for future use in reinforcement and improvement of the thermal resistance of PLA/flax composites.     

Preparation,morphology and properties of natural rubber composites filled with untreated short jute fibres

Green composites were obtained by incorporation of short jute fibres in natural rubber matrix using a laboratory two-roll mill. The influence of untreated fibre content (1, 2.5, 5, 7.5 and 10 phr) on the mechanical properties, dynamic mechanical properties, swelling properties was examined. The behaviour of prepared green composites under cyclic compression was also investigated. Fibre dispersion in rubber matrix was studied by scanning electron microscopy. The highest tensile strength (21.1 MPa) and highest tear strength (39.9 N/mm) were found for composites containing 2.5 and 5 phr of short jute fibres, respectively. The results also suggested that increasing fibrous filler content resulted in increasing of tensile moduli 100, 200 and 300 % of elongation and hardness, and decreasing of rebound resilience and abrasion resistance of prepared jute/natural rubber composites. The cyclic compression test showed that increasing the amount of short jute fibres in the rubber matrix is related to increase of the energy dissipated in the composite. The incorporation of short jute fibres into the rubber matrix improves the stiffness of the composites, and it is related to the interaction between fibre surface and rubber matrix. The application of short fibres in higher amounts leads to formation of fibre agglomerates reducing the mobility of the rubber polymer chains. The mentioned agglomerates act as defects in rubber matrix, which caused decreasing of some properties, e.g. relative elongation at break.     

Crystallization and thermomechanical properties of PLA composites: Effects of additive types and heat treatment

This research work has concerned a study on thermomechanical and crystallization properties of poly(lactic acid) (PLA) composites containing three different types of additives; namely: kenaf fiber (20 pph), Cloisite30B nanoclay (5 pph), and hexagonal boron nitrile (h‐BN; 5 pph). The composites were prepared using a twin screw extruder before molding. Crystallization behaviors of the various composites were also examined using a differential scanning calorimetry. By adding the additives, tensile modulus of the polymer composites increased, whereas their tensile strength and elongation values decreased as compared to those of the neat PLA. Heat distortion temperature (HDT) values of the materials slightly increased, for about 3–5°C. However, after annealing at 100°C, HDT values of the fabricated PLA composites rapidly increased with annealing time before reaching a plateau after 10 min. The HDT values of above 120°C were achieved when 20 pph kenaf fiber was used as an additive. The above results were in a good agreement with DSC thermograms of the composites, indicating that percentage crystallinity of the materials increased on annealing and crystallization rate of the PLA/kenaf system was the highest. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013