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     

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     

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     

Studies of acetylation of jute using simplified procedure and its characterization

Dried and defatted jute fibers were acetylated for different time and temperature in the absence of catalyst and solvent. Extent of acetylation were measured by weight percent gain (WPG). These values were compared with the standard method of acetylation using a cosolvent (pyridine) system. The characterization of acetylated fibers was performed by FTIR, DSC, TGA, and SEM studies. The maximum WPG was 18.0 for an acetic anhydride-pyridine system at 120°C for 4 h whereas using only acetic anhydride WPG was 12.3 at the same reaction condition. Thermal stability of acetylated jute was found to be higher than the untreated jute. SEM studies were carried out to investigate the fiber surface morphology. FTIR studies also produced evidence for acetylation. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1517–1523, 1997     

Fabrication and evaluation of some mechanical and electrical properties of jute‐biomass based hybrid composites

Hybrid composites based on bisphenol‐C‐formaldehyde resin and jute mat with rice, wheat, sugar cane, and jamun husks have been fabricated at 150°C under 30.4 MPa pressure for 2 h. The resin content in composites was 50% of fibers. Tensile strength, flexural strength, electric strength, and volume resistivity of hybrid composites have been evaluated and compared with those of jute‐bisphenol‐C‐formaldehyde composites. It is observed that the tensile strength of composites is found to decrease by 53–72%, which is mainly due to random orientation of sandwiched fibers. Flexural strength has increased by 53–153% except jute–rice husk composite for which it is decreased by 26%. A little change in dielectric breakdown strength (1.89–2.11 kV/mm) is found but volume resistivity of Jute–wheat husk and Jute–jamun husk composites has improved by 437–197% and it is slightly decreased(2.3–25.2%) for the remaining two composites. Thus, hybrid composites possess good mechanical and electrical properties signifying their importance in low strength and light weight engineering applications as well as low cost housing units such as partition and hard boards. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1754–1758, 2006     

Jute fabric reinforced engineering thermoplastic sandwich composites. I. The effect of molding time

Jute fabric‐reinforced sandwich composites were fabricated using engineering thermoplastics. The jute fabrics were precoated with thermosetting resin to improve their thermal resistance before molding of the composites. Thermal gravimetric analysis (TGA) studies revealed that the resin coated fabrics decomposed at higher temperature than the uncoated jute. The onset of degradation of the coated fibers also falls between that of jute fibers and the thermoset resins. This indicates the presence of good interfacial bonding between jute fibers and both resins. Isothermal TGA studies revealed that jute could withstand brief exposure to higher temperature at 270 and 290°C. The sandwich composites were fabricated at 270°C by compression molding for 1.5 and 3 min in each case, and then characterized by flexural, tensile and morphological studies, i.e., SEM and optical microscopy. The uncoated jute fabric yielded composites of superior mechanical properties even with 3 mins molding at 270°C which is close to the degradation temperature of uncoated jute fibers. This is an indication that it is feasible to prepare jute fiber filled engineering polymer composites provided the exposure time at high temperature during processing does not exceed 3 mins as determined by TGA isothermal studies. SEM studies revealed strong fiber/matrix interfacial bonding between jute and the thermoset resins while the inferior mechanical properties of the resin coated sandwich composites could be attributed to the poor interfacial bonding between the already cured thermoset coating and the matrix based on optical microscopy of the polished cross‐sections. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Jute composite with MMA by gamma and UV radiations in the presence of additives

Jute yarns treated with MMA + MeOH solutions were irradiated either with Co‐60 gamma source or with UV radiation. In gamma radiation, polymer loading of MMA (methyl methacrylate) onto jute increased quite substantially, but the strength of the composite decreases sharply after 15% polymer loading. The gamma‐treated jute samples were very brittle. On the other hand, jute yarns irradiated in situ under UV radiation was found to be grafted with MMA. The tensile strength of the UV‐cured jute yarn composite increases with an increase of grafting level, in contrast to the behavior observed with the gamma‐irradiated jute composite samples. The tensile properties of the composites can be further enhanced by the incorporation of certain additives and coadditives into MMA + MeOH solutions. This opens diverse applications for jute materials. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 900–906, 1999     

Studies on jute-reinforced composites,its limitations,and some solutions through chemical modifications of fibers

Jute, unlike other natural fibers, absorbs moisture and its moisture regain property is quite high. Water migration and subsequent degradation of jute-based composites can be a problem. Because jute is hydrophilic and the matrix resins are mostly hydrophobic, wetting of the fibers with resins is poor, for which high resin consumption may occur that would increase the cost of composites. To reduce the moisture regain property of jute fiber, it is essential to pretreat the jute fiber so that the moisture absorption is reduced and the wettability of the resin is improved. Jute fiber in the form of nonwoven jute has been pretreated with precondensate like phenol formaldehyde, melamine formaldehyde, cashew nut shell liquid-formaldehyde, and polymerized cashew nut shell liquid. The moisture content of the pretreated nonwoven jute has been determined by conventional methods and by a differential scanning calorimetric technique. Treatment of jute with precondensate causes the reduction of water regain property in jute. Pretreated nonwoven jute has been impregnated with phenol formaldehyde resin, and the composite board has been prepared therefrom. The jute composite board has been tested for bending strength, tensile strength, thickness swelling, and water absorption. Thermal analyses, such as differential scanning calorimetry and thermogravimetry, have also been conducted on jute and pretreated jute fibers. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1093–1100, 1998     

Novel,low-cost jute-polyester composites. Part 1: Processing,mechanical properties,and SEM analysis

The development of high performance composites from a cheap natural fiber, jute, as reinforcement is particularly significant from an economic point of view. In this work, jute fiber-unsaturated polyester(GP) composites having appreciable mechanical properties were prepared by using solution impregnation and hot curing methods. Both unbleached (control) and bleached jute slivers with various percentages of fiber loadings were used to prepare the composites and were named JPH (C) i.e., Jute Polyester Hot Curing (control), and JPH (B) i.e., Jute Polyester Hot Curing (bleached), respectively. Mechanical properties such as tensile and flexural strain, toughness, and moduli of both the grades have been compared. Composites having 60 wt% of jute fiber yielded the best results. JPH (B) showed much better flexural properties than JPH (C), although the tensile properties of the latter were better. The inter-laminar shear strength (ILSS) of the JPH (B) was found to be higher than JPH (C). The nature of fiber-resin bonding was studied from scanning electron micrographs of the specimens subjected to tensile and flexural fracture. Dynamic mechanical properties were found to be very high, superior even to those of glass fiber reinforced composites. The flexural storage modulus was found to be 12.3 GPa at 30°C and to decrease slowly with temperature. The major finding in this work is the attainment of high mechanical properties of composite specimens with 60 wt %fiber loading. On a weight and cost basis, bleached jute fibres were found to be better reinforcements than other fibers with usual surface modification by coating or grafting processes.     

Vapor Phase Acetylation of Southern Pine,Douglas-Fir,and Aspen Wood Flakes

Abstract

Southern pine, Douglas-fir, and aspen wood flakes were acetylated with acetic anhydride vapor and compared with flakes acetylated with liquid acetic anhydride diluted with xylene. The rate of acetylation was much lower for the vapor than for the liquid phase reaction. Acetylation weight percent gains above 20 were achieved by both methods. Flakeboards made from both types of flakes absorbed much less water, both in water soaking tests and when subjected to humid air, and swelled at a lower rate and to a lower extent than did control boards. At low weight gains of vapor phase acetylation, the rate and extent of swelling were higher than those found for the controls.

Hygroscopicity of the resulting flakeboards decreased with increased level of wood acetylation. The equilibrium moisture content for flakeboards made from liquid phase acetylated flakes was the lowest at each relative humidity tested as compared to control boards, and boards made from vapor acetylated flakes at the same weight gain.     

Mechanical properties of jute fibers and interface strength with an epoxy resin

Four different forms of jute fibers, namely untreated jute filament (UJF), sliver jute filament (SJF), bleached jute filament (BJF), and mercerized jute filament (MJF), have been subjected to tensile strength analysis following Weibull's theory. The MJF and BJF were obtained by the chemical modification of the UJF. A minimum of 50 fibers of each type, at three different gauge lengths, i.e., 15, 30, and 50 mm, were used to study the strength distribution and the effect of gauge length. The mean fiber strength was found to be the maximum for UJF followed, in the order, by BJF, MJF, and SJF (∼ 700, ∼ 660, ∼ 580, and ∼ 540 MPa, respectively, at 50‐mm gauge length). The strength was also found to decrease with an increase in gauge length. In all cases, good agreement was found with Weibull's statistical model. Single fiber composite tests, with an epoxy resin as the matrix, were carried out determine the critical fragment lengths and interfacial strength, following the Kelly–Tyson approach. The BJF was found to have the maximum interfacial adhesion (τ ≈ 140 MPa) followed by UJF, SJF, and MJF having τ values of ∼ 83, ∼ 57, and ∼ 47 MPa, respectively. Scanning electron microscope pictures showed the fiber surface was physically modified by the various treatments. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1585–1596, 2000     

Study on the mechanical and dielectric properties of photocured jute fabrics with 2‐hydroxyethyl methacrylate

Jute fabric (Hessian cloth) was treated with 2‐hydroxyethyl methacrylate (HEMA) under ultraviolet radiation in order to improve the mechanical and electrical properties. Concentration of the monomer 2‐hydroxyethyl methacrylate (HEMA), radiation dose, and soaking time were optimized with respect to mechanical properties such as tensile strength and elongation at break of the treated and untreated Hessian cloth. The 10% HEMA, 15 min soaking time, and 15th pass of radiation rendered the best tensile properties. The variations of dielectric properties with temperature were measured at 10 kHz frequency. It was observed that dielectric constant and loss tangent (tan Ω) increased with increasing temperature up to the transition temperature and then decreased, and at the end become almost constant. The surfaces of treated and untreated jute were characterized by scanning electron microscope. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 655–661, 2003     

FTIR spectra and physico-chemical behavior of vinyl ester participated transesterification and curing of jute

In this article we report the transesterification of jute with n-Butylacrylate (BA) under appropriate condition using NaOH, Pyridine (Py), and a Pyridine–acetone mixture as a catalyst. The modified vinylog jute was subsequently cured with benzoylperoxide (BPO) in acetone at 50–60°C. The parent and chemically modified jute were characterized by FTIR spectra. The percent moisture regain, mechanical strength, and behavior to common chemical reagents of the parent and modified fibers have also been tested. Transesterification and curing of jute lowered the percentage of moisture regain, imparted mechanical strength, and resistance to common chemical reagents. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 575–581, 2001     

Modification of jute by acrylic acid in the presence of Na3PO4 and K2S2O8 as catalysts under thermal treatment

Jute fabric was modified using acrylic acid (AA) as the finishing agent in the presence of K₂S₂O₈ and Na₃PO₄ catalysts separately or in selected combinations, employing a pad–dry–cure technique. Treatment with 10% acrylic acid at 30°C and at pH 7 produced optimum effects: a batching time of 45–60 min at 30°C, followed by drying of the batched fabric at 95°C for 5 min and curing of the dried fabric at 140°C for 5 min produced most balanced improvements in the textile related properties. Na₃PO₄ catalyst allowed esterification of AA with cellulosic, hemicellulosic, and lignin constituents of jute, and K₂S₂O₈ catalyst allowed radical polymerization of free acrylic acid or jute-bound acrylic acid moieties; the said processes ultimately lead to some degree of crosslinking of the chain polymers of jute. Examination of the surface morphology of untreated and treated jute fabrics by scanning electron microscopy revealed a good degree of masking effect on the unit cells of jute and intercellular regions by a cohesive film of polyacrylic acid or its salts, particularly when K₂S₂O₈ was used either alone or in combination with Na₃PO₄ as catalyst. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:63–74, 1998     

Flame retardant cotton

The water‐soluble organophosphorus compound, namely, hexahydroxymethylamidocyclotriphosphatriazatriene (HHMAPT) was synthesized by reacting phosphonitrile chloride with liquid ammonia followed by reaction with formaldehyde. It is rich in phosphorus and nitrogen and as a polyfunctional compound it can undergo several reactions with itself forming an in situ polymer or with cotton cellulose similar to conventional N‐methylol finishing agents. It was successfully used as a flame retarding agent in the absence and presence of etherified methylolated melamine (EMM). Investigations into the different factors that affect these reactions and the effect of these on the properties of the finished fabrics give rise to the following points; (1) P%, N% and crease recovery increase by increasing the curing time and temperature; (2) the most effective catalyst is NH₄Cl; P% and N% increase by increasing the concentration of NH₄Cl from 5 to 12.5 g/l (3) an increase in EMM and HHMAPT concentrations is accompanied by enhancement in P%, N% and crease recovery; (4) the fabric samples exhibit durable flame retardancy at temperatures higher than 120°C in the absence of EMM while in the presence of EMM, all samples exhibit durable flame retardancy properties, regardless of the temperature of curing; (5) the durable flame retardancy is achieved at concentrations higher than 60 g/l HHMAPT and 7.5 g/NH₄Cl. All samples exhibit loss in tensile properties but within an acceptable range (20%), crease recovery is improved in all samples. Copyright © 1999 John Wiley & Sons, Ltd.     

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     

Evaluation of melamine‐modified urea‐formaldehyde resins as particleboard binders

Particleboards bonded with 6 and 12% melamine‐modified urea‐formaldehyde (UMF) resins were manufactured using two different press temperatures and press times and the mechanical properties, water resistance, and formaldehyde emission (FE) values of boards were measured in comparison to a typical urea‐formaldehyde (UF) resin as control. The formaldehyde/(urea + melamine) (F/(U + M)) mole ratio of UMF resins and F/U mole ratio of UF resins were 1.05, 1.15, and 1.25 that encompass the current industrial values near 1.15. UMF resins exhibited better physical properties, higher water resistance, and lower FE values of boards than UF resin control for all F/(U + M) mole ratios tested. Therefore, addition of melamine at these levels can provide lower FE and maintain the physical properties of boards. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Physico-Mechanical,Interfacial, Degradation,and Dielectric Properties of Jute/PP Composites: Effect of Dye and Gamma Radiation

Jute fabrics/polypropylene composites were prepared by compression molding. Jute fabrics were treated with red dye solutions (0.1–1%, w/w) for different soaking times and we found that 0.5% red-dye-treated jute/PP composite for 5 min soaking time showed better results. Gamma radiation (250-1000 krad dose) was applied on both jute and matrices. Composites were fabricated with non-irradiated jute/non-irradiated PP (C-0), non-irradiated jute/irradiated PP (C-1), irradiated jute/non-irradiated PP (C-2), and irradiated jute/irradiated PP (C-3). It was found that a C-3 composite made using 500 krad dose showed the best results. Simulating weathering and dielectric properties of the composites were also performed.     

Effect of crosslink structures on dynamic mechanical properties of natural rubber vulcanizates under different aging conditions

The effects of crosslink structures on the dynamic mechanical properties (DMPs) of unfilled and carbon black N330‐filled natural rubber (NR) vulcanizates cured with conventional (CV), semiefficient (SEV), and efficient (EV) cure systems and having about the same total crosslink densities were investigated before and after aerobic and anaerobic aging at 100°C. The three unfilled NR vulcanizates cured with the CV, SEV, and EV systems had about the same mechanical loss factor (tan δ) values at about 0°C but showed some apparent differences in the tan δ values in the order EV > SEV > CV at relatively high temperatures of 40–80°C before aging. However, N330‐filled NR vulcanizates gave higher tan δ values than the unfilled vulcanizates and showed little effect of the crosslink types on the tan δ at different temperatures over the glass‐transition temperature (T_g) before aging. Aerobic heat aging increased the T_g and tan δ values of the vulcanizates over a wide range of temperatures from ?80 to 90°C that was mainly due to the changes in the total density and types of crosslinks. The unfilled vulcanizates cured with the CV system showed the greatest change in DMP because of their poor resistance to heat aging. Aerobic heat aging of NR vulcanizates caused a more significant change in the DMP than anaerobic heat aging because of the dominant effect of the oxidative degradation during aerobic heat aging on the main‐chain structure, crosslink structures, and DMPs of the vulcanizates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 710–718, 2001     

Effect of hydrogen peroxide bleaching onto sulfonated jute fiber

Bleaching of raw and sulfonated jute fiber with hydrogen peroxide were carried out in an aqueous medium. To obtain the optimum condition for bleaching, the effects of hydrogen peroxide concentration, temperature, time, pH, and fiber–liquor ration were studied. Bleaching affected the whiteness and tenacity, and the optimum whiteness index (76) and tenacity (13.7 g/tex) for the bleached sulfonated jute fiber were obtained with 2.1% hydrogen peroxide at pH 11, temperature 95°C, treatment time 110 min, and fiber–liquor ratio 1 : 7. The photo‐oxidative degradation of bleached sulfonated jute fiber was characterized by UV light exposure and compared with that of bleached raw jute fiber. It has been observed that the photo‐oxidative degradation as well as loss in tenacity and yellowness of the bleached sulfonated jute fiber was 63 and 40% lower than that of bleached raw jute fiber. Bleached sulfonated jute fiber had excellent impact on color fastness with reactive dyes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3603–3607, 2006