Experimental characterization of woven jute‐fabric‐reinforced isothalic polyester composites

In this article, mechanical performance of isothalic polyester‐based untreated woven jute‐fabric composites subjected to various types of loading has been experimentally investigated. The laminates were prepared by hand lay‐up technique in a mold. Specimens for tests were fabricated as per ASTM standards. All the tests (except impact) were conducted on closed loop servo hydraulic MTS 810 material test system using data acquisition software Test Works‐II. From the results obtained, it was found that the tensile strength and tensile modulus of jute‐fabric composite are 83.96% and 118.97% greater than the tensile strength and modulus of unreinforced resin, respectively. The results of other properties, such as flexural, in‐plane shear, interlaminar shear, impact, etc., also revealed that the isothalic‐polyester‐based jute‐fabric composite have good mechanical properties and can be a potential material for use in medium load‐bearing applications. The failure mechanism and fiber‐matrix adhesion were analyzed by scanning electron microscope. Effects of long‐term immersion in water on mechanical properties are also presented. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2650–2662, 2007     

Enzyme‐mediated surface modification of jute and its influence on the properties of jute/epoxy composites

Surface modification of jute fibers is necessary to improve the adhesion and interfacial compatibility between fibers and resin matrix before using fibers in polymer composites. In this study, dodecyl gallate (DG) was enzymatically grafted onto the jute fiber by laccase to endow the fiber with hydrophobicity. A hand lay‐up technique was then adopted to prepare jute/epoxy composites. Contact angle and wetting time measurements showed that the surface hydrophobicity of the jute fabric was increased after the enzymatic graft modification. The water absorption and thickness swelling of the DG‐grafted jute fabric/epoxy composite were lower than those of the other composites. The tensile and dynamic mechanical properties of the jute/epoxy composites were enhanced by the surface modification. Scanning electron microscopy images revealed stronger fiber–matrix adhesion in composites with modified fibers. Therefore, the enzymatic graft modification increased the fiber–matrix interface area. The fiber–matrix adhesion was enhanced, and the mechanical properties of the composites were improved. POLYM. COMPOS., 38:1327–1334, 2017. © 2015 Society of Plastics Engineers     

Effect of epoxidized soybean oil on mechanical properties of woven jute fabric reinforced aromatic and aliphatic epoxy resin composites

A systematic study was performed to describe the effect of epoxidized soybean oil (ESO) on storage modulus, glass transition temperature (T _g) and mechanical properties in epoxy resin composites reinforced by jute fabric. In addition to aromatic diglycidylether of bisphenol‐A (DGEBA) resin, a glycerol (GER)‐and a pentaerythritol (PER)‐based aliphatic resin was applied as base resin, which can be also synthesized from renewable feedstock. Based on strip tensile test results, the usual alkali treatment of jute fabric was avoided. By increasing the ESO‐content in aliphatic composites the T _g increases, whereas in case of DGEBA, it decreases. The results indicate that although ESO has a significant softening effect, the jute fiber‐reinforced DGEBA composite can be replaced without significant compromise in mechanical properties by a potentially fully bio‐based composite consisting of 25 mass% ESO‐containing aliphatic PER‐reinforced by jute fibers. POLYM. COMPOS., 38:884–892, 2017. © 2015 Society of Plastics Engineers     

Characterization of the draping behavior of jute woven fabrics for applications of natural‐fiber/epoxy composites

In this study, we investigated the draping behavior of jute woven fabric to study the feasibility of using natural fabrics in place of synthetic glass‐fiber fabrics. Draping behavior describes the in‐mold deformation of fabrics, which is vital for the end appearance and performance of polymer composites. The draping coefficient was determined with a common drapemeter for fabrics with densities of 228–765 g/m² and thread counts under different humidity and static dynamic conditions. The results were compared to glass‐fiber fabrics with close areal densities. Characterization of the jute fabrics was carried out to fill the knowledge gap about natural‐fiber fabrics and to ease their modeling. The tensile and bending stiffnesses and the shear coupling were also characterized for a plain woven jute fabric with a tensile machine, Shirley bending tester, and picture frame, respectively. As a case study, the draping and resin‐transfer molding of the jute fabric over a complex asymmetric form was performed to measure the geometrical conformance. The adoption of natural fibers as a substitute for synthetic fibers, where the strength requirements are satisfied, would thus require no special considerations for tool design or common practices. However, the use of natural fibers would lead to weight and cost reductions. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1453–1465, 2013     

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     

Mechanical properties of phenolic composites reinforced with jute/cotton hybrid fabrics

Mechanical properties (tensile, flexural, impact, and dynamic mechanical thermal analysis) of novolac type phenolic composites reinforced with jute/cotton hybrid woven fabrics were investigated as a function of fiber orientation and roving/fabric characteristics. Scanning electron microscopy (SEM) was carried out to investigate the fiber‐matrix adhesion. Results showed that the composite properties are strongly influenced by test direction and rovings/fabric characteristics. The anisotropy degree was shown to increase with test angle and to strongly depend on the type/architecture of fabric used, i.e., jute rovings diameter, relative fiber content, etc. It was possible to obtain composites with higher mechanical properties and lower anisotropy degree by producing cross‐ply laminates. Best overall mechanical properties were obtained for the composites tested along the jute rovings direction. Composites tested at 45° and 90° with respect to the jute roving direction exhibited a controlled brittle failure combined with a successive fiber pullout, while those tested in the longitudinal direction (0°) exhibited a catastrophic failure mode. Our results indicate that jute promotes a higher reinforcing effect and cotton avoids catastrophic failure. Therefore, this combination of natural fibers is suitable to product composites for lightweight structural applications. POLYM. COMPOS., 26:1–11, 2005. © 2004 Society of Plastics Engineers.     

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     

Coating of jute with natural rubber

Jute fabric was coated with natural rubber to develop double‐texture rubberized waterproof fabric and fabric‐reinforced rubber sheeting for hospitals. The vulcanization of such natural‐rubber‐coated flexible composites at 120°C for 3 h produced optimum effects. The jute/natural‐rubber composite was much superior to a conventional polyester/natural‐rubber composite for producing such double‐texture rubberized fabric with respect to the fabric‐to‐natural‐rubber adhesion, breaking strength, tear strength, abrasion resistance, puncture resistance, and biodegradability. For fabric‐reinforced rubberized sheeting, the jute/natural‐rubber composite was superior to a conventionally used cotton/natural‐rubber composite with respect to the fabric‐to‐natural‐rubber adhesion, breaking strength, tear strength, and abrasion resistance. However, for both applications, the jute‐based products were commonly found to be less extensible, heavier, and thicker. Unsaturation in the lignin fraction of jute established a chemical linkage with the unsaturation of natural rubber via sulfur at the jute/natural‐rubber interface. An examination of the surface morphology of uncoated and coated jute fabrics by scanning electron microscopy revealed a good degree of deposition and filling even in the intercellular regions of jute by a cohesive mass of natural rubber, which remained unseparated from the fiber, when mechanical force was applied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 484–489, 2005     

Synthesis and physicochemical study of bisphenol‐C‐formaldehyde‐toluene diisocyanate polyurethane–jute and jute–rice husk/wheat husk composites

Bisphenol‐C‐formaldehyde‐toluene‐2,4‐di isocyanate polyurethane (PU) has been synthesized at room temperature and used for the fabrication of jute and jute–rice husk/wheat husk hybrid composites. PU–jute and PU–jute–RH/WH composites were prepared under pressure of 30.4 MPa at room temperature for 8 h, while PU–jute–RH/WH composites were prepared under same pressure at 110°C for 5 h. PU–jute composite has good tensile strength and flexural strength (50–53 MPa), while PU–jute–RH/WH hybrid composites have moderate tensile strength (9–11 MPa) and a fairly good flexural strength (15–31 MPa). Composites possess 1.1–2.2 kV electric strength and 0.94–1.26 × 10¹² ohm cm volume resistivity. Water absorption in PU–jute composite is different in water (9.75%), 10% HCl (12.14%), and 10% NaCl (6.05%). Equilibrium water uptake time in salt environment is observed 96 h, while in pure water and acidic environments it is 192 h. In boiling water equilibrium water content and equilibrium time are found to be 21.7% and 3 h, respectively. Water absorption increased 2.2 times in boiling water, whereas equilibrium time reduced 64 times. Thus, PU–jute composite has excellent hydrolytic stability against boiling water, 10% HCl, and 10% NaCl solutions. Fairly good mechanical and electrical properties and excellent hydrolytic stability of composites signify their usefulness for low cost housing units and in electrical and marine industries. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2363–2370, 2006     

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     

Analysis of the Effects of Atmospheric Helium Plasma Treatment on the Surface Structure of Jute Fibres and Resulting Composite Properties

This work investigates the mechanisms involved in the improvement of flexural properties of a jute/polyester composite when the reinforcement material has been atmospherically plasma treated using helium gas. All composites were laid-up by hand and cured using a Quickstep? cure cycle. Surface characterization techniques including scanning probe microscopy (SPM), and surface wettability combined with fabric tensile strength, composite flexural strength and composite Mode-I properties have been used to quantify the effects of plasma modification. Flexural strength and modulus increased with plasma treatment time, reaching a maximum at 25 passes before decreasing. SPM topographical analysis showed that roughness of the fibre decreased as the plasma treatment time increased until 25 passes after which the roughness was found to increase again. The coefficient of friction increased rapidly after only a short plasma treatment time (5 passes) whilst wettability continued to increase until 25 passes after which it remained constant. The fabric tensile strength followed the same trend as the flexural properties of the composites. Decreasing fibre surface roughness is postulated as a reason for decreasing Mode-I interlaminar fracture toughness properties of the composites.     

腰果酚接枝黄麻纤维不饱和聚酯复合材料的力学性能及界面调控

用甲苯二异氰酸酯与腰果酚(CNSL)合成大分子偶联剂接枝黄麻纤维。以接枝的黄麻纤维为增强体,通用的不饱和聚酯树脂为基体,采用热压方式制备复合材料。比较了纯饱和聚酯树脂、5 %CNSL增韧的不饱和聚酯树脂、25 %碱处理的黄麻纤维不饱和聚酯树脂复合材料和25 %的CNSL接枝黄麻纤维不饱和聚酯树脂复合材料的拉伸强度和冲击强度。结果表明,CNSL接枝于黄麻纤维上;CNSL的加入能提高材料的韧性,黄麻纤维能提高材料的拉伸强度而不能提高材料韧性;25 %CNSL接枝的黄麻纤维不饱和聚酯树脂能提高材料的拉伸强度和韧性,25 %CNSL接枝的黄麻纤维增强含5 %CNSL的不饱和聚酯复合材料,其冲击强度为12.10 kJ/m^2。     

Development of Silicon Carbide Reinforced Jute Epoxy Composites: Physical,Mechanical and Thermo-mechanical Characterizations

The aim of the present study was to investigate the physical and thermo-mechanical characterization of silicon carbide filled needle punch nonwoven jute fiber reinforced epoxy composites. The composite materials were prepared by mixing different weight percentages (0–15 wt.%) of silicon carbide in needle punch nonwoven jute fiber reinforced epoxy composites by hand-lay-up techniques. The physical and mechanical tests have been performed to find the void content, water absorption, hardness, tensile strength, impact strength, fracture toughness and thermo-mechanical properties of the silicon carbide filled jute epoxy composites. The results indicated that increase in silicon carbide filler from 0 to 15 wt.% in the jute epoxy composites increased the void content by 1.49 %, water absorption by 1.83 %, hardness by 39.47 %, tensile strength by 52.5 %, flexural strength by 48.5 %, and impact strength by 14.5 % but on the other hand, decreased the thermal conductivity by 11.62 %. The result also indicated that jute epoxy composites reinforced with 15 wt.% silicon carbide particulate filler presented the highest storage modulus and loss modulus as compared with the unfilled jute epoxy composite.     

Composites based on jute fibers and phenolic matrices: Properties of fibers and composites

Composites based on phenolic matrices and both untreated and alkali and ionized air–treated jute fibers were prepared. Different fiber lengths and fiber content were used to reinforce the phenolic matrices. The jute fibers were characterized with respect to lignin, holocellulose, ash, and humidity contents and also to the crystallinity index. The mechanical properties of fibers were investigated by means of tensile analysis and the morphology by SEM. The untreated and treated jute fiber–reinforced composites were characterized as to water absorption. The mechanical property and morphological aspects of the composites were evaluated by impact strength and photomicrographs obtained from SEM. Among the jute fiber treatments considered in the present work, the treatment with a solution of 5% NaOH presented the best results because: (1) the fiber presented a higher tensile strength, and a larger percentage of elongation at break; (2) the composite reinforced with this fiber presented the highest impact strength results when this was the unique treatment (20% of fiber), as well as when it was combined with ionized air (30% of fiber); and (3) the composite that presented the lowest water uptake was that reinforced with this fiber. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1077–1085, 2004     

Optimization of biodegradation of natural fiber (Chorchorus capsularis): HDPE composite using response surface methodology

Deterioration in mechano-chemical properties due to biodegradation of prepared high-density polyethylene and jute eco-friendly polymer composites in soil and pure microbial culture was investigated through a programmed experimental design. The composite was prepared by compression molding process and then subjected to biodegradation. The biodegradation process was studied using face-centered central composite experimental design protocol and the model equations were formulated to assess the effects of jute fiber loading and treatment time on biodegradation (expressed as percentage loss in composite weight and tensile strength) of the composite. The optimal process conditions corresponding to maximum biodegradation were evaluated for both the media using response surface methodology. The maximum weight losses were 25.8924 % for soil medium and 12.4167 % for pure culture medium at 30 wt% jute fiber loading and 6 months of treatment time. At the derived optimal conditions, the effects of biodegradation were also manifested as 84.2621 and 70.9842 % losses in the tensile strength in soil and pure culture media, respectively. The present study, thus, demonstrates that HDPE/jute composite polymer can be appreciably biodegradable and the extent of biodegradation is more pronounced in soil medium compared to pure microbial culture. The analyses of the evolution of chemical composition and microstructure of the composite before and after biodegradation were performed through Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. FTIR spectra indicated significant changes in chemical composition due to biodegradation, while the ruptured structure of the treated composite revealed notable changes in the morphology due to biodegradation.     

NOVEL LOW-COST JUTE–POLYESTER COMPOSITE. II. SEM OBSERVATION OF THE FRACTURED SURFACES

The scanning electron micrographs (SEM) were taken at different magnifications with respect of the fractured surfaces of the polymer composites prepared from unsaturated polyester resin and jute sliver with 60% fiber loading by weight. The composite specimens were prepared using both untreated (control) and chemically modified (bleached) jute fibers by solution impregnation and hot curing methods and are designated as JPH-60(C) and JPH-60(B), respectively. The method of preparation of the composite specimens have been discussed. The specimens were subjected to tensile and flexural tests and the fractured surfaces were observed under SEM as stated. The fiber surface morphology was also studied from the SEM photographs in the case of the control and bleached jute filaments. The SEM photographs of the fractured surfaces of the composites showed varied extents of fiber pull-outs under both tensile and flexural failure modes. The nature of interfacial adhesion has been discussed on the basis of the SEM study. A good correlation between the SEM study and the mechanical strength properties of the composites could be established. Exceptionally high flexural strength of the composites JPH-60(B) compared to JPH-60(C) could be explained from the SEM study.     

Three‐body abrasive wear behavior of E‐glass fabric reinforced/graphite‐filled epoxy composites

The present article summarizes an experimental study on three‐body abrasive wear behavior of glass fabric reinforced/graphite particulate‐filled epoxy composites. The wear behavior was assessed by rubber wheel abrasion tests (RWAT). The angular silica sand particle sizes in the range 200–250 μm were used as dry and loose abrasives. The tests were carried out for 270, 540, 810, and 1,080 m abrading distances at 22 and 32 N loads. The worn surfaces were examined using scanning electron microscopy (SEM). The results showed varied responses under different abrading distance due to the addition of glass fabric/graphite filler into neat epoxy. It was observed that the glass fabric reinforcement to epoxy matrix (G‐E) is not beneficial to abrasive wear resistance. Further, inclusion of graphite filler to glass fabric reinforced epoxy composite performed poorly resulting in significant deterioration in wear performance while the neat epoxy showed better wear performance. Selected mechanical properties such as hardness, ultimate tensile strength, and elongation at fracture were analyzed for investigating wear property correlations. The worn surface features were studied using SEM to give insight into the wear mechanisms. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Lignin in jute fabric–polypropylene composites

In this work, the feasibility of using lignin as a compatibilizer for composites made from jute fiber fabric and polypropylene (PP) was studied. Since lignin contains polar (hydroxyl) groups and nonpolar hydrocarbon, it was expected to be able to improve the compatibility between the two components of the composite. It was found that lignin acted as β nucleation, fire retardant, and toughening agent for PP matrix. Jute composites exhibit higher stiffness, tensile strength, and impact behavior in respect to those of neat PP. Although scanning electron micrographic observations indicate that PP‐jute adhesion was slightly improved by lignin addition, additional benefits were only obtained from impact behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Jute Reinforced Polymer Composite by Gamma Radiation: Effect of Surface Treatment with UV Radiation

Jute (Hessian cloth) reinforced polymer composites were prepared with a mixture of 2-hydroxy ethyl methacrylate (HEMA) and aliphatic urethane diacrylate oligomer (EB-204), and then cured under gamma radiation. Thick pure polymer films (2 mm thickness) were prepared by using the same monomer and oligomer at different weight ratios, and 500 krad of total gamma radiation dose at 600 krad/hr was selected for the curing of all composites. Total radiation dose, jute content, and monomer concentration were optimized with the extent of mechanical properties. Among all resulting composites, the composite of 38% jute content at monomer:oligomer = 50:50 (w/w) ratios showed the better mechanical properties, such as 108% increase in tensile strength (TS), 58% increase in bending strength (BS), 138% increase in tensile modulus (TM), and 211% increase in bending modulus (BM) relative to pure polymer film. The gel content values were also found to increase with the increase of jute content in the composite. But the elongation at break (Eb) for both tensile and bending was found to decrease with increasing jute content. The best mechanical properties were obtained when jute fibers were pre-irradiated with UV radiation, such as 150% increase in TS, 90% increase in BS relative to polymer film, 19% increase in TS, and 15% increase in BS relative to untreated jute-based composites. A water uptake behavior investigation of the resulting composites was also performed and composites based on UV-treated jute showed the minimum water uptake value.     

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