WSN 158 (2021) 227-246 EISSN 2392-2192
Potential comparison of montmorillonite filled and
unfilled epoxy methacrylate of bisphenol-C-glass/
jute/treated jute and hybrid composites
Ritesh D. Bhatt, Jignesh P. Patel, Parsotam H. Parsania*
Department of Chemistry, Saurashtra University, Rajkot-360 005, Gujarat, India
*E-mail address: phparsania22@gmail.com and phparsania@aol.com
ABSTRACT
Montmorillonite filled and unfilled controls, jute/treated jute/glass/hybrid composites were prepared at room temperature for three h and under 5 MPa pressure. The composites were post cured at 150°C for 30 min. A 40% styrene was used as a reactive diluent, and 1% methylethylketone peroxide, 1.5 % cobalt octoate, and 1.5% dimethylaniline were used as initiator and accelerator, and a promoter.
Filled and unfilled composites showed good to excellent mechanical and electrical properties, excellent hydrolytic stability and chemical resistance against water acids, alkali, salt solutions; high water absorption tendency (7.9-20.5%), and longer equilibrium times (288-432h). In different environments at 30°C observed water absorption trend is H2SO4 > HCl > NaOH > H2O > NaCl. Hybrid composites showed intermediate properties of their parent composites. MMT filled treated jute (46), and unfilled glass (48), and MMT filled glass (48) composites revealed Barcol hardness between the suggested range of 45-65 for scratch and wear resistance proof materials. The nature of the reinforcements, matrix, and filler; fiber treatment, environmental conditions, etc., had affected studied properties and water absorption behavior.
Keywords: Epoxy methacrylate, montmorillonite, composites, mechanical and electrical properties, chemical resistance, hydrolytic stability, diffusivity
1. INTRODUCTION
Natural fibers' unquestionable advantages are their easy availability, renewability, and economically cheaper, reducing overall production costs of the end products [1]. Natural fibers are more inexpensive than glass fibers by two times, aramid fibers by four times, and carbon fibers by five times [2].
The manufacturing cost of the composites based on powder-like natural fillers is significantly lower [3]. Compared to synthetic fibers-based composites, natural fibers-based composites possess low density, high vibration damping ability, good thermal and satisfactory mechanical properties [4], and alternative materials to traditional materials like wood and polymer composites modified by inorganic fillers. Strength, stiffness, and thermal resistance or conductivity of the composites [5-15] may be improved by reinforcing natural fibers into different materials.
Vinyl ester resins (VERs) are found alternative materials of epoxy and unsaturated polyester resins. VERs can be cross-linked at room temperature with control rate and suitable reaction conditions such as catalyst concentration, temperature, etc [4, 16, 17]. VERs help molding compounds, structural laminates, coatings, adhesives materials, and electrical and marine components [18-24].
Their higher design flexibility, suitable mechanical properties, low water absorption, excellent chemical, corrosion, fire, and heat resistance are most commonly used in making tanks, reinforced pipes, scrubbers, hulls, and deck structures [25].
Most of the work reported in the literature is based on the vinyl esters of epoxy resins of bisphenol-A. Solid epoxy acrylate of 1,1’-bis(3-methyl-4-hydroxy phenyl)cyclohexane (EMCA) was synthesized and characterized by Adroja et al. [26] EMCA was found to be thermally stable up to 308°C and followed first order (0.88) degradation kinetics. Patel et al.
[27] had synthesized and characterized semisolid epoxy methacrylate of 1,1’-bis(4- hydroxyphenyl)cyclohexane (EMABCS).
EMABCS-Jute/Glass composites showed fairly good mechanical and electrical properties and excellent chemical resistance against harsh environmental conditions. Parsania et al. [28]had synthesized liquid epoxy methacrylate of bisphenol-C (EMABCS) and compared its physical properties with Aeropol-7105. EMABCS and Aeropol-7105 showed comparable studied physical properties. Neat and montmorillonite (MMT) filled EMABCS showed better mechanical and electrical properties and equivalent water absorption.
To our knowledge, no work is reported on MMT filled and unfilled EMABCS- Jute/treated jute/Glass/hybrid composites, which encouraged us to investigate their mechanical and electrical properties; and chemical resistance against water, acids, alkali, and salt solutions.
2. EXPERIMENTAL 2. 1. Materials
Laboratory grade solvents and chemicals used in this work were purified before their use [29]or used as received. The synthesis of epoxy methacrylate of bisphenol-C (EMABC) and its complete characterization is described in our recent publication [27, 28].
The reaction Scheme 1 is shown below:
Scheme 1. Reaction scheme for the synthesis of epoxy methacrylate of bisphenol-C
The styrene solution (40% of EMABC) was prepared at room temperature, and 0.2%
hydroquinone was added as an inhibitor. Hereafter this solution was designated as EMABCS.
EMABCS used in this work had 1.12 g cm-3 density, 300 cP viscosity, 20 min gel time, and 135
°C peak exotherm temperature28.
Methylethylketone peroxide (MEKP), 6% cobalt octoate, silane treated E-glass fabric (G) (450 GSM), montmorillonite (MMT), and mylar were supplied by EPP Composites, Rajkot as free samples and were used as received. Jute fabric (J) (350 GSM) was purchased from a local market (Rajkot). Jute was alkali (4%) treated at room temperature for 12 h [30]. Alkali treated jute was designated TJ.
2. 2. Preparation of controls and the composites
Unfilled (EMABCS) and MMT-filled (EMABCS-MMT-5) control samples were prepared according to our recent publication28. The required quantities (Table 1) of EMABCS, initiator, accelerator, and promoter were transferred into a 500 mL beaker at room temperature and mixed well with a glass rod to prevent air bubble formation. Jute/ treated jute/glass fabric of 20 cm × 20 cm sizes (5 plies) was impregnated by a smooth brush and kept at room temperature for 15-20 min.
The impregnated plies were arranged one over the other and held between two mold releasing films (mylar film), placed between two mold platen, cured at room temperature for three h under 5 MPa pressure. The composites were post-cured in an oven at 150°C for 30 min.
After cooling the sheets, mylar films were peeled off, and edges were machined.
Table 1. The experimental details for the preparation of filled and unfilled controls and jute/
treated jute/glass and hybrid composites.
Control/Composite EMABCS, g Fabric, g Total wt, g
EMABCS 200 - 200
EMABCS-MMT-5 190 - 200
EMABCS-J 43 70 113
EMABCS-J- MMT-5 48 70 118
EMABCS-TJ 43 70 113
EMABCS-TJ- MMT-5 48 70 118
EMABCS-G 62 90 172
EMABCS-G- MMT-5 63 90 157
EMABCS-TJ-J-TJ 50 70 128
EMABCS-J-G-J 46 78 124
EMABCS-TJ-G-TJ 48 78 126
Similarly, MMT filled, and hybrid composites were prepared. For tensile and flexural testing, the widths and thicknesses of the composites are shown in Table 2. For the water absorption study, 2 cm × 2 cm samples were cut from the respective sheets, and their edges were sealed by using corresponding resin solutions and cured at room temperature, and post- cured in an oven.
Table 2. Width and thickness of composite samples.
2. 3. Testing methods of composites
For tensile and flexural testing, the samples were prepared as per standard test methods.
Tensile strength (ASTM-D-638-01) and flexural strength (ASTM-D-790-03) measurements were carried out at a speed of 10 mm min-1 on a W & T Avery Ltd. Type 1010 Model No E- 46234 (Birmingham, England). Izod impact strength (ASTM-D-256-06) tests were carried out on an Izod Impact Tester Model No.E-46204 Type A-1300 (Birmingham, England). Electric strength (IEC-60243-Pt-1-1998) quantifications were carried out in the air using 25/75 mm brass electrodes on a high voltage tester (Automatic Electric-Mumbai).
Volume resistivity (ASTM-D-257-2007) measurements were carried out in the air at 25
°C after 60 s charging at 500 V DC applied voltage on a Hewlett Packard high resistance meter.
Replicate tests were carried out 3-5 times, and average values were considered. Water absorption (ASTM-D-570-98) measurements were carried out at 30±2°C by the change in mass method. The samples were weighed and dipped in water, 10% aq. NaCl, 10% aq. NaOH, 10%
aq. HCl and 10% aq. H2SO4 solutions at 30±2°C. The samples were withdrawn at the interval of 24 h; the samples' surfaces were cleaned with tissue papers, reweighed, and immediately dipped in the respective solutions. The testing was carried out till the saturation equilibrium was established.
3. RESULTS AND DISCUSSION 3. 1. Mechanical properties
Composite
Tensile Flexural
Width, mm
Thickness, mm
Width, mm
Thickness, mm
EMABCS-J 9.27 4.65 12.37 4.57
EMABCS-J-MMT 10.25 5.27 12.16 5.29
EMABCS-TJ 9.2 4.25 12.37 4.25
EMABCS-TJ-MMT 10.85 5.61 12.18 5.58
EMABCS-G 10.82 3.0 12.11 3.05
EMABCS-G-MMT 10.18 5.27 12.05 5.28
EMABCS-TJ-J-TJ 10.15 4.41 12.26 4.47
EMABCS-J-G-J 10.26 3.59 12.16 3.67
EMABCS-TJ-G-TJ 9.98 3.75 12.15 3.78
Figures 1-5 show respectively tensile strength (TS), flexural strength (FS), and flexural modulus (FM), Izod impact strength (IS), and Barcol hardness (BH) of the control samples, MMT filled/unfilled jute/treated jute/glass/hybrid composites. In comparison with EMABCS, EMABCS-MMT-5 showed decrease of TS (-7.3%), FS (-10.4%), FM (-4.7%) and IS (-21.7%), and an increase of BH (5.4%). MMT has influenced the interfaces and lowered the interfacial strength and stiffness.
Let us compare the mechanical properties of treated and untreated jute composites with EMABCS and EMABCS-MMT-5. As compared to EMABCS, jute reinforcement showed improved FS (34%), IS (14.8%), and FM (42.6 times), and a decrease of TS (-52.7%) and BH (-2.7%). The interactions among hydroxyl groups of jute (δ+) and ether and ester groups (δ-) of EMABCS improved interfacial bond strength and interactions of hydroxyl groups of jute and EMABCS decreased interfacial bond strength and improved stiffness [31-33]. In comparison with EMABCS-J, EMABCS-J-MMT-5 showed improved TS (50%), FS (9%), and BH (13.9%); and reduction in FM (-40.4%) and IS (-22.2%) due to overall improved interfacial bond strength and stiffness [31-34].
Comparison of mechanical properties of EMABCS-TJ with EMABCS-J revealed good to excellent improved TS (123%), FS (95.5%), FM (39.2%), IS (22.2%), and BH (11.1%). The improved mechanical properties are due to removing natural and artificial impurities present in untreated jute, chemical composition change, and % crystallinity in the jute fibers. Alkali treatment produced rough surface topography, broken down of fiber bundles into smaller fibers, and improved effective surface area and wetting property. Alkali treatment led to improved interfacial bond strength and stiffness of the composite [31-33].
Figure 1. Comparative tensile strength of filled and unfilled controls, jute/treated/glass, and hybrid composites.
Figure 2. Comparative flexural strength of filled and unfilled controls, jute/treated/glass, and hybrid composites.
Figure 3. Comparative flexural modulus of filled and unfilled controls, jute/treated/glass, and hybrid composites.
Figure 4. Comparative Izod impact strength of filled and unfilled controls, jute/treated/glass, and hybrid composites.
Figure 5. Comparative Barcol hardness of filled and unfilled controls, jute/treated/glass, and hybrid composites.
In comparison to EMABCS-TJ, EMABCS-TJ-MMT-5 showed somewhat improved TS (20.7%), FS (1.5%), FM (8.5%), and BH (15%); and a considerable decrease of IS (-36.6%).
MMT caused a decrease in interfacial bond strength and stiffness of the composite [34].
EMABCS-G showed excellent improved TS (212.7%), FS (588.2%), FM (14550.6%), IS (100%), and BH (29.7%) due to increased interfacial bond strength and stiffness. As compared to EMABCS-G, EMABCS-G-MMT-5 exhibited a little improved TS (5.2%) and FS (3.4%), and reduction of FM (-4.9%), and IS (-8.7%); and Barcol hardness remained unchanged due to an overall decrease in interfacial bond strength and stiffness of the composite [34].
Semisolid EMABC based EMABCS-J (34.5MPa) [27] showed better TS than liquid EMABC based EMABCS-J (26 MPa). Liquid EMABC based EMABCS-J (67 MPa) revealed much better FS than semisolid EMABC based EMABCS-J (32.3 MPa). Similarly, semisolid EMABC based EMABCS-G (220.9 MPa) exhibited much better TS than liquid EMABC based EMABCS-G (172 MPa). Liquid EMABC based EMABCS-G (351 MPa) showed much better FS than semisolid EMABCS-G (101.6 MPa). Thus, the matrix, fibers, fiber treatment, and filler nature influenced the composites' overall mechanical properties.
Hybrid composites: EMABCS-TJ-J-TJ, EMABCS-J-G-J, and EMABCS-TJ-G-TJ showed intermediate mechanical properties of their parent composites: EMABCS-J, EMABCS- TJ, and EMABCS-G. They are found cost-effective for specific applications.
EMABCS-TJ-MMT-5 (46), EMABCS-G (48), and EMABCS-G-MMT-5 (48) showed Barcol hardness (45-65) [35] values for scratch and wear resistance composite materials for specific engineering applications. EMABCS-TJ-G-TJ (43) showed Barcol hardness close to the lower boundary range of suggested values [35]. In the present investigation, the nature of the matrix, reinforcement and filler, fiber treatment, interfacial bond strength, and degree of cross- linking affected the mechanical properties of the composites [12-15, 36].
3. 2. Electrical properties
Figures 6 and 7 show electric strength (ES) and volume resistivity (VR) of the unfilled and filled controls and the composites, respectively. Both control samples showed good ES and excellent VR, i.e., insulating property. In comparison to EMABCS, EMABCS-MMT-5 showed a lower ES (-5.6%) and improved VR (34.6%), i.e., a decrease in electrical conductivity.
Molecular interactions changed the overall polarity of EBCMAS-MMT-5 [31-34], thereby changing ES and VR.
EMABCS-J exhibited a lowering in ES (46.7 %) and VR (106 times) due to electrostatic interactions of hydroxyl groups of jute fibers; and hydroxyl, ether, and ester groups of EMABCS resulted in improved overall polarity caused the lowering of interfacial bond strength and a drastic reduction in volume resistivity [31-34]. EMABCS-J-MMT-5 revealed no change in ES, but it showed a drastic decrease in VR (7.7×105 times) due to overall improved polarity.
Semisolid EMABC based EMABCS-J [27] showed 3.6 times lower ES and 1.1 times better VR than liquid EMABC based EMABCS-J. Similarly, semisolid EMABC based EMABCS-G27 exhibited 7.2 times lower ES and nine times better VR than liquid EMABC based EMABCS- G. Thus, the electrical properties of EMABCS-J and EMABCS-G are affected by the state of EMABC. As compared to EMABCS, EMABCS-TJ showed somewhat lower ES (-6.5%) and a drastic decrease in VR (1.92×106 times) due to overall improved polarity and alkali treatment of jute fibers. In comparison to EMABCS-J, EMABCS-TJ showed 1.75 times ES and 1.92 times VR.
Figure 6. Comparative dielectric strength of filled and unfilled controls, jute/treated/glass, and hybrid composites.
Figure 7. Comparative volume resistivity of filled and unfilled controls, jute/treated/glass, and hybrid composites.
The combined effect of alkali treatment and MMT filler showed improved ES (11.9%) and a drastic reduction in VR (6.43×104 times) confirmed improved overall polarity.
EMABCS-G manifested improved ES (41.1%) and a drastic reduction of VR (9231 times) than EMABCS. Similarly, EMABCS-G-MMT-5 showed improved ES (17.8%) and a drastic decrease of VR (6857 times) in comparison to EMABCS-MMT-5. EMABCS-G-MMT- 5 revealed a lowering in ES (-21.2%); and found no change in VR. Glass and MMT are polar materials, which caused the composites' overall improved polarity to show a considerable improved ES and a drastic reduction in VR [31-34].
EMABCS-TJ-J-TJ manifested considerably better ES and VR compared to EMABCS-J and substantially lower compared to EMABCS-TJ. Similarly, EMABCS-J-G-J showed better ES and VR compared to EMABCS-J and lowered compared to EMABCS-G. EMABCS-TJ-G- TJ displayed lower ES and VR compared to EMABCS-TJ and EMABCS-G. Thus, hybrid composites showed intermediate ES and VR of their parent composites. The nature of reinforcement, matrix, filler, and fiber treatment affected the composites' overall electrical properties.
3. 3. Chemical resistance
Assuming, uni-dimensional Fickian [37] type diffusion in composites, water absorption study was carried out at the interval of 24 h. The % water absorbed in the composites was calculated according to Eqn.1:
M = Wm − Wd
Wd × 100 (1) where:
M is the % water absorbed, Wm and Wd are weights of the moist and dry samples, respectively.
The water absorption in the composites followed the capillary mechanism. Absorbed moisture can swell and plasticize the polymers and thereby affect the mechanical properties.
The % weight gain against time curves for different composites are shown in Figures 8-12.
The % weight gain in different environments was increased with time, reached the maximum, and remained practically constant. Equilibrium water content and equilibrium time for all the composites in other environments were determined from Figures 8-12 and are reported in Table 3. All the composites showed high equilibrium water content due to hydrophilic hydroxyl groups present in jute fibers and EMABCS [26-28, 30, 31]. The high equilibrium water content of jute composites is due to cellulose, hemicellulose, lignin, and noncrystalline cellulose present in jute [38-43].
Equilibrium water content and equilibrium time of EMABCS (1.3% and 168h) and EMABCS-MMT-5 (1.3% and 168h) were determined after 15 days of soaking [27]. Both EMABCS and EMABCS-MMT-5 showed low water absorption tendency and low equilibrium times. Observed water absorption trend in different environments is H2SO4 > HCl > NaOH >
H2O > NaCl. Equilibrium water content in different environments varied between 17.7-20.5%
for EMABCS-J and EMABCS-J-MMT-5; 13.6-16.9% for EMABCS-TJ and EMABCS-TJ- MMT-5; 7.9-11.4% for EMABCS-G and EMABCS-G-MMT-5; and 9.2-20.3% for hybrid composites. Hybrid composites showed the intermediate water absorption tendency of their parent composites.
Figure 8. Comparative plots of % weight gain against time for EMABCS-J and EMABCS-J-MMT-5 in various environments at 30°C.
Figure 9. Comparative plots of % weight gain against time for EMABCS-TJ and EMABCS- TJ-MMT-5 in various environments at 30°C.
Figure 10. Comparative plots of % weight gain against time for EMABCS-G and EMABCS- G-MMT-5 in various environments at 30°C.
Figure 11. The plots of % weight gain against time for EMABCS-TJ-J-TJ in various environments at 30°C.
Figure 12. Comparative plots of % weight gain against time for EMABCS-J-G-J and EMABCS-TJ-G-TJ in various environments at 30°C.
Table 3. Equilibrium time and equilibrium water content data of MMT filled and unfilled EMABCS-J, EMABCS-TJ, EMABCS-G, and hybrid composites.
Composite
Equilibrium water content,% Equilibrium time, h
H2O 10 % NaCl
10 % NaOH
10 % HCl
10 %
H2SO4 H2O 10 % NaCl
10 % NaOH
10 % HCl
10 % H2SO4
EMABCS-J 18.8 17.8 19.6 20.1 20.5 408 384 408 384 408
EMABCS-J-MMT-5 18.5 17.7 19.5 19.9 20.2 408 432 408 432 408 EMABCS-TJ 15.2 14.4 15.6 16.5 16.9 360 360 360 360 360 EMABCS-TJ-MMT-
5 14.4 13.6 15.2 15.9 16.6 432 408 432 408 432
EMABCS-G 8.9 7.9 9.3 9.6 10.2 360 360 360 336 384
EMABCS-G-MMT-5 9.2 8.1 9.8 10.7 11.4 312 288 312 336 336 EMABCS-TJ-J-TJ 18.1 17.1 19.6 20.2 20.3 408 408 408 384 408
EMABCS-J-G-J 10.5 9.6 11.2 11.8 12.6 336 360 360 336 360 EMABCS-TJ-G-TJ 10.3 9.2 10.5 10.9 11.5 360 408 360 360 360
Equilibrium time in different environments varied between 384-408h for EMABCS- J;408-432h for EMABCS-J-MMT-5; 308h for EMABCS-TJ; 408-432h for EMABCS-TJ- MMT-5; 288-336h; 336-384h for EMABCS-G; and 228-336h for EMABCS-G-MMT-5.
Hybrid composites displayed the intermediate equilibrium time of their parent composites.
Thus, the composites manifested excellent hydrolytic stability, and chemical resistance, and longer equilibrium times in different conditions.
In different environments, EBCMAS-J-MMT-5 showed 0.5-1.6% lower equilibrium water absorption than EBCMAS-J. MMT crystals are soft and not bound tightly, and therefore, water can intervene into them and swell the clay. The swollen clay can increase the free volume [34]. A slight decrease in equilibrium water content is due to H-bonds' formation between matrix and jute fibers [34]. Comparing EMABCS-TJ with EMABCS-J revealed an 18-20%
lower equilibrium water content in different environments due to already mentioned reasons in mechanical properties section [31-33]. The combined effect of alkali treatment and MMT filler ensured an 18-23% lowering of equilibrium water content due to overall improved interfacial bond strength. Similarly, compared with EMABCS-G, EMABCS-G-MMT-5 showed 2.5- 11.8% more water absorption tendency in different environments. Thus, MMT filler caused a negligible effect on water absorption in jute composites and an appreciable glass composites effect.
3. 4. Diffusivity
Using Eqns. 2 and 3, diffusivities in3 different environments were determined from the initial slopes of the plots of the % weight gain against √𝑡:
M =
4Mmh
√
tπ
√D
x (2)D
x= π (
h4Mm
2
) (Slope
2)
(3)where: Dx = diffusivity, t = time (second), h = sample thickness (m) and Mm = equilibrium water content.
The diffusivities in different environments for different composites are reported in Table 4. Different diffusivities are found in different environments because of the different nature of electrolytic solutions. Different strong electrolytes show different water breaking and structure- making tendencies. Normal water exists in a polymeric form because of intermolecular H- bonds. The addition of strong electrolytes in water breaks the water structure and forms a new water structure, i.e., solvated ions. Solvated ions exhibited different diffusivities in different composites due to their different sizes [26-28, 30, 31].
Compared to EMABCS-J, EMABCS-J (Figure 8) exhibited a lower water absorption tendency, increased diffusivity in water, saline, and alkaline environments, and decreased diffusivity in acidic conditions. In comparison with EMABCS-TJ, EMABCS-TJ-MMT-5 (Figure 9) showed increased water absorption tendency, and decreased diffusivity in water, alkaline, and acidic environments, and increased propensity in a saline environment. Similarly, compared to EMABCS-G, EMABCS-G-MMT-5 (Figure 10) showed increased water absorption tendency, and decreased diffusivity in water, alkaline, and acidic environments, and increased diffusivity in a saline environment.
Table 4. Diffusivity data of MMT filled and unfilled EMABCS-J, EMABCS-TJ, EMABCS-G, and hybrid composites.
Composite
Diffusivity (Dx), 10-13 m2s-1
H2O 10 % NaCl
10 % NaOH
10 % HCl
10 % H2SO4
EMABCS-J 1.85 2.03 1.84 1.71 2.12
EMABCS-J-MMT-5 2.33 3.12 2.37 1.56 1.31
EMABCS-TJ 1.8 2.3 2.4 1.9 2.1
EMABCS-TJ-MMT-5 1.4 2.6 1.8 1.1 1.7
EMABCS-G 6 5.8 5.7 4 6.3
EMABCS-G-MMT-5 1.5 9.9 1.1 1.1 1.2
EMABCS-TJ-J-TJ 1.6 2.3 1.7 4.9 4.8
EMABCS-J-G-J 2.65 1.81 2.16 3.29 3.14
EMABCS-TJ-G-TJ 4.55 4.53 3.79 3.81 3.23
Compared to EMABCS-J and EMABCS-TJ, EMABCS-TJ-J-TJ (Figure 11) showed increased diffusivity in acidic environments and is more than EMABCS-J and the same as EMABCS-TJ in a saline environment, and decreased somewhat in an alkaline environment.
EMABCS-TJ-G-TJ (Figure 12) manifested lower water absorption propensity in different environmental conditions than EMABCS-J-G-J. EMABCS-J-G-J and EMABCS-TJ-G-TJ showed lower diffusivity in different backgrounds compared to EMABCS-G. In contrast, EMABCS-J-G-J showed increased diffusivity in water, alkaline, and acidic environments and is decreased diffusivity in a saline environment as compared to EMABCS-J.
In comparison with EMABCS-TJ, EMABCS-TJ-G-TJ exhibited increased diffusivity in different backgrounds.
Water absorption in the composites continued until equilibrium attained and then after free water occupied voids. Free water may interact with the composite's constituent components and leads to delamination, degradation, and void formation [44-49]. Absorbed water can weaken the interface and increases the delamination rate, and thereby deteriorate the mechanical properties of the composite [15-18, 43, 44]. Excellent hydrolytic stability and chemical resistance of the composites confirmed applications in marine industries.
4. CONCLUSIONS
MMT filled and unfilled control samples, jute/treated jute /glass/hybrid composites showed good to excellent mechanical and electrical properties, excellent hydrolytic stability, and chemical resistance against water, acids, alkali, and saline environments. The composites exhibited a high water absorption tendency and longer equilibrium times. Good to excellent physicochemical properties suggested their industrial applications in engineering, low load- bearing housing and building construction, electrical and electronics, and marine industries.
Acknowledgments
The authors are thankful to the Department of Chemistry for research facilities and Director TIPCO industries Ltd., Valsad-Gujarat, India, for composite testing.
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