Communications in Science and Technology 8.
100Ae107
COMMUNICATIONS IN
SCIENCE AND TECHNOLOGY
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Effect of multi-walled CNTs polyurethane mats lamination with basalt fabrics reinforced-epoxy composites reviewed on tension and bending Sugiarti,a,b K.
Adi Atmika, a,b I.
G Ary Subagiaa,b,c,* Mechanical Engineering.
Engineering Faculty.
Udayana University.
Bukit Jimbaran-Badung Bali 80361.
Indonesia Engineering Materials Laboratories.
Udayana University.
Bukit Jimbaran-Badung Bali 80361.
Indonesia Technology and Materials Center.
Technology and Social Communities Unit.
Udayana University.
Bukit Jimbaran-Badung Bali 80361.
Indonesia Article history:
Received: 30 May 2023 / Received in revised form: 27 June 2023 / Accepted: 28 June 2023 Abstract Material technology continues to develop with various innovations and engineering to improve weaknesses in both mechanical an d physical In this study, electrospun fibres containing a multi-wall blend of CNT and Polyurethane (PU) with or without surfactant that laminated into a basalt fibre-reinforced composite were uniquely demonstrated.
Multi-wall CNT 3wt% was added to the PU/MEK/DMF solution and produced using an electrospinning process.
PU fibre mat containing 3wt% CNT was made without and with surfactants.
Also.
Basalt fibre reinforced epoxy composite as a control sample was produced.
In addition, vacuum-assisted resin transfer printing has been used in the manufacture of composite panels containing both fibres.
The aim of combining basalt fibre and PU CNT spun mats was to investigate their effect on the tensile and flexural mechanical properties.
Tensile and flexural tests were carried out on a universal testing machine (UTM) in accordance to ASTM D 638 and ASTM D790 standards.
FESEM and TEM on composite morphology test were done after testing.
The results indicated that the basal matting fibre-reinforced epoxy composites stacked by PU mats with or without surfactants were affected by CNT inclusions.
Nanofiber spun mats laminated in a basalt fibre composite lead to a considerable increase in both loads .
tensile and flexural propertie.
The highest tensile and flexural load values occurred in the BF PU-mat-2 sample with triton-x 100 surfactants compared to BFRP.
The increase in tensile and flexural modulus values was at 13% and 17.
3%, respectively.
On the other hand, there was a decrease in shear failure due to tensile and bending loads due to the brittleness of the composite reinforcement.
In conclusion, this CNF-mat lamination is highly suitable to be used to improve the strength properties of BFRP composites.
It is highly recommended for automotive parts, marine compartments and storage Keywords: Electrospinning.
basalt fabric.
Introduction Engineering materials continue to be developed to achieve characteristics such as high stress, long deflection, lightweight, corrosion resistance, and environmentally friendly for future needs .
Fibre Reinforced Polymer (FRP) composite is nonmetal material .
that has received much attention and is designated as modern material.
It is unique as it could be made from two different phases of material.
Several advantages such as the behaviour of mechanical, chemical, physical, and economist, as well as environmental have been explored by FRP composites compared to metal .
Ae.
However, it depends on the adhesion and cohesion force between them .
Thus, it becomes interesting to do more studies based upon the physical force against the FRP structures.
During the last two decades, the application of organic reinforcement has been powerful attention by the government in composite material products.
This pressure is a part of the * Corresponding author.
Email: arsubmt@unud.
https://doi.
org/10.
21924/cst.
green products programme.
To realize the target, a new class of reinforcement, i.
basalt fibre (BF) was introduced .
Ae.
BF is a unique reinforcement sourced from the volcano rock.
As a fibre, it is produced by the melting process of the volcano rock .
at a high temperature of around 1700oC as shown in Figure 1 .
The important compound of BF is 64% of SiO2, and 40% is shared with other compounds such as Fe2O.
Mg, and Al.
Advantageously.
BF is non-toxic, non-flammable and explosion-proof .
When being in contact with other chemicals, it does not produce ions, and chemical reactions that can damage health or the environment .
In addition, basalt has good hardness and thermal properties .
Several studies for behaviour of BF in composite structures have been conducted by .
Ae.
The presence of cellulose, hemicellulose, pectates, pigments and waxes in natural fibres affects the binding capacity of the matrix.
thereby, it reduces strength and increases delamination under tension and bending.
Furthermore, the efforts that have been made so far are to increase the binding capacity of natural fibres, in this case, by combining BF .
with other fibres .
Currently, the combination of Nano-sized materials has been widely used in A 2023 KIPMI Sugiarti et al.
/ Communications in Science and Technology 8.
100Ae107 an effort to increase the bond matrix and natural reinforcement .
This is done because the Nano-sized material is easily absorbed by the fibres.
In addition, the carbon nanotubes .
have an extraordinary influence on both the reinforcing and/or matrix, which is the potential to improve the mechanical, physics, electrical, and thermal properties of the composite materials .
Ae.
Many scientists have done this method by mixing nanoparticles into the matrix.
Ae.
Generally, the application of CNTs is added into the polymer to improve the matrix ability in transfer load together with the fibres .
,21,25,28Ae.
Based on the previous results of studies, the Nano-Carbon-Fibre (CNF) lamination method has not been commonly used to improve composite properties.
This research has focused on the role of CNF-mat made through the electrospinning process.
We studied the effect of CNF-mat laminated with basalt fibres as the reinforcement of composites.
Their mechanical properties would be observed under tensile and flexural loads.
The CNF-mat was produced through an electrospinning process and by the mixtures of Polyurethane DMF/MEK 3wt% CNT with and without surfactant Triton-X-100 and epoxy resin as substrate.
This research aims to observe the performance of CNF-mat against the mechanical properties of composites epoxy with basalt fibre reinforced under the tensile and flexural load.
The CNT-mat in all variations was characterized in accordance to FESEM and TEM analysis.
set-up.
Electrospinning is a widely developed approach to producing polymer fibers with Nano-sized diameters .
Ae.
into ultra-thin layers.
The morphology and diameter of the electrospinning fiber were significantly affected by temperature .
, and concentration .
,39,.
In this work, a high voltage of 15 kV was employed to inject electrospinning solutions in a plastic syringe at a feed rate of 1 mL/h.
The distance of the collector .
lat Aluminu.
was covered with basalt fabrics .
mm x 250 m.
and the needle tip was kept constant at 150 mm.
In addition, the humidity chamber was kept at 30% using the seal.
In the last electrospinning process, the nanofiber laminates on basalt fiber were dried at 60oC for two days inside an oven to remove any residual solvent.
Fig.
Schematic representation electrospinning processes a.
materials, and b.
electrospinning setup Table 1.
Laminate variation and concentrations CNT
BFRE
PU mat-1 PU mat-2 Laminate configurations BF/Epoxy BF Spun .
wt% CNT)/Epoxy BF Spun .
wt% CNT Triton-X) Epoxy Fig.
Process manufacturing BF Materials and Methods Materials CNF has prepared through electrospinning method as shown in Figure 2.
Prior to electrospinning, we prepared the CNF solutions with a CNT concentration of 3 wt.
% according to the weight of PU added to the mats PU solutions.
Before mixing in the PU solutions, the CNTs in DMF/MEK were bath-sonicated .
Hz.
Mujigae.
Kore.
for an hour.
Then, mat PU .
solutions were mixed in the DMF/MEK in the ratio of 50:50 % by overnight stirring.
Next solution containing 3 wt.
CNT/DMF/MEK solution with a surfactant Triton-X in the ratio of 100:20 (CNT: Triton-X, wt.
/wt.
%) was also produced to investigate the effect of surfactant on the CNT spread and its subsequent effect on the mechanical property enhancement of the composite.
2 Manufacture process Figure 2 shows the electrospinning process carried out in the Fig.
Schematic of vacuum resin transfer injections moulding process The BFRP laminated with CNF spun mats were fabricated through the VRTM as exhibited in Figure 3 .
Meanwhile.
Table 1 shows the stacking sequence mode between BF and CNF PU mats.
The mass ratio of the epoxy resin versus the hardener was conducted at 100:20 wt%.
During the process, six layers of basalt fibers and four layers of CNF mats .
ith the size 250 x 250 cm, respectivel.
were employed and the vacuum of -0.
8 kPa was maintained.
Then, it was cured inside an oven with the temperature at 65oC for 2 hours .
The BFRP containing six BF was also fabricated and evaluated as a Measurement The tensile test was used widely for testing the strength and strain of samples in a unidirectional manner.
The ASTM D-638 standard was reflected for each sample's geometry.
In this work, the testing of the samples was conducted on the Universal Testing machine (UTM) (Unitect-M brand R&B) Sugiarti et al.
/ Communications in Science and Technology 8.
100Ae107 with a crosshead speed of 3 mm/min and load cells of 2 tons.
In addition, an extensometer (Epsilon Tech.
Corp.
Model 3.
was installed on the sample to measure the elongation values occurred during the tensile testing.
In this test, to find consistency values, each variation of the samples was repeated 5 times.
A three-point bending is one flexural test manner of This testing was conducted by placing the material on two supports on each end of the beam.
The beam deflection was analysed statically on a central loaded.
The BFRE-CNF sample geometry refers to standard ASTM D-790.
This test used a similar machine and treatment the tensile testing where each sample was tested with five repetitions.
In the advanced study of material Nano size can usually be detected using the Nano Field Emission Scanning Electron Microscope (FESEM).
Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM).
This is a nondestructive method for providing detailed information on the morphology, composition, and structure of materials .
It is utilized to find the good characteristics of materials regarding the influence of nanofiber laminated with microfiber on mechanical and physical properties.
It has been conducted on a laminate cross-section of composite broken after tensile and flexural loads.
The results FESEM and SEM analysis of each sample are shown in Figure 4 and 5, respectively.
Results and Discussion Fiber characterization Figure 4 illustrates Raman Spectroscopy (RS) of CNTs in PU nanofibres.
There are two prominent peaks as a feature of CNT with a Raman shift of 1320 cm-1 and 1577 cm-1.
The Dband and the G-band are two peaks related to the defect and the plane vibration of the CNTs, respectively.
As seen, the peaks of CNP-NF have neater than those of neat PU nanofibres.
However, due to the interaction between PU and CNTs, new hydrogen has been generated, which causes a shift in peak.
previous characteristic because CNTs could distribute the loads to the polymer well and evenly.
The results showed that the addition of triton-X surfactant (CNTs Triton-X) could help to distribute CNTs more evenly, compared to those without surfactant, which could form agglomeration .
Due to the agglomeration phenomenon in the dispersions of CNTs, it is possible to degrade the mechanical properties of polymeric composites without surfactant .
Thereby, nanoparticle dispersion in the polymer matrix is functionally very important to carry out.
Fig.
Characteristics of MWCNT images analysed through.
FE-SEM, .
TEM Figure 5.
show the CNF morphology containing 3wt% CNT with and without surfactant.
The CNF fibre weave has a white colour with a smooth surface.
As observed, the CNF weave was white with a smooth surface.
However, the pores appeared .
ed arrow.
in the structure with solid cylindrical fibre shapes.
Also.
Figure 6 .
show agglomeration occurred with increasing CNT concentration .
ellow arro.
, if without surfactant, and they formed nanofibre knots bonded together .
lue arro.
Previous studies .
,23,45,.
explained that the fewer beads formed would affect the mechanical properties of CNF.
However, the thermal conductivity of CNF as well as the electrical properties of nanofibre increased .
Fig.
FESEM and TEM of electrospun mat nanofiber containing .
3wt % CNT, .
3wt % CNT Triton-X Fig.
Raman spectroscopy of neat PU nanofibre.
CNTs, and CNP Furthermore, in the microscopic studies by FESEM and TEM observations, it can be seen that the CNTs of 11 Nm diameter was smaller than the diameter of the electrospinning CNP fibre.
Thus.
CNTs fibre was very well used as a filler in the structure of composites as it could bind well fibres.
This increased the characteristics of the composite more than the Mechanical properties The mechanical properties of CNF-mats were carried out according to variations planned in the present study.
Figure 7 .
show the tensile and flexural test of the sample containing 3wt% CNF mats with/without surfactant.
Figure 7.
shows the load-displacement curves of tensile load and loadAe displacement curve of flexural shown in Figure 7.
Then.
Figure 7.
illustrates the strength average value comparison Sugiarti et al.
/ Communications in Science and Technology 8.
100Ae107 between the tensile and flexural loads.
For the modulus of elasticity, average values between tensile and flexural loads are shown in Figure 7.
As seen in Figure 7.
, a linear increase occurred in tensile load for each sample.
In this case.
PU contained CNT 0.
3 wt.
with surfactant Trinitron Ae X that had the highest value in However, they had the lower displacement rates.
showed that the material became more brittle.
This result was also declared in experiments by several material scientists .
Hereinafter, a similar characteristic is also shown for flexural loads .
ee Figure 7.
This phenomenon further described that the proper mixing of CNTs and the presence of surfactants could help to spread the CNTs evenly, thereby improving the characteristics of the composite material .
These results were are also determined by the characteristics of the CNF-PU nanofiber mats as shown in Figure 4, 5, and 6.
Figure 7.
shows the characteristics in which, due to tensile and flexural loading, there was a linear increase.
As we observed, the addition of nanofiber with the characteristics shown in Figure .
, had a positive effect on the tensile and flexural loads.
It can be seen that the tensile stress had a higher value than the flexural strength for each of sample types.
The highest tensile strength value was shown by PU-Mat-2 (BF 3wt% CNF surfactan.
compared to PU-Mat-1 and BFRP.
The average values of tensile at the break of the samples were 30 MPa.
PU-mat-1.
74 MPa, and PU-mat-2.
MPa, respectively.
The difference number of tensile strengths PU Mat-2 to other configurations was 11.
35% approximately.
The overall variation of CNF-PU laminates increased for tensile strength was 4% and 12%, respectively to BFRE.
On the other hand, triton-X surfactant was effectively caused by improving tensile strength.
It had some arguments similar to the previous studies by .
Furthermore, similar phenomena for the flexural testing result of each sample type shown in Figure 7.
are PU-mat-1 .
1 MP.
, and PU mat2 .
09 MP.
compared to BFRP .
7 MP.
Also, the average values the flexural of samples were 15.
87 GPa.
PUMat-1 17.
94, and PU Mat-2.
20GPa, respectively.
According to the testing results, the flexural strength linearly increased for every concentration of CNT-PU mat laminated with BF of 10.
6 % and 17.
3 % to the BFRE composites.
Also, the flexural strength linearly increased for every concentration of CNT-PU mat laminated with BF of 10.
% and 17.
3 % to the BFRE composites, respectively.
Figure 7.
shows the modulus of elasticity comparison of BFRP.
PU-Mat-1 and PU-Mat-2 under tensile and flexural The modulus of elasticity average value of tensile loads for BFRP.
PU-Mat-1 and PU-Mat-2 were 17.
11 GPa, 20.
GPa, and 19.
35 GPa, respectively.
Furthermore, the modulus of elasticity average values of flexural loads for the BFRP.
PUMat-1 and PU-Mat-2 were 15.
87 GPa, 17.
94 GPa, and 9.
GPa, respectively.
Based on the modulus of elasticity of tensile and bending loads, it can be explained that the increase occurred was linear for each sample variation in terms of BFRP, namely an average of 12% and 15%.
The increase in stress due to tensile and bending loading in the composite with basalt fibre reinforcement was strongly determined by the layer of CNF-PU mat.
The best result was shown by the lamination of basalt fibre with CNF-PU mat with triton -X surfactant.
this case, triton-X surfactant helped in dispersing CNT so that the resulting solution between PU and CNT was more uniform .
In addition, due to the uniformity of the solution, it avoided agglomeration .
ee also performances in Figures 4, 5 and .
As a result, it can improve the interfacial tension and load transfer in accepting the tensile and flexural load.
These results were also widely reported in several previous .
,48,53,.
Fig.
Load-displacement curve of tensile, .
load-displacement of flexural, .
stress-strain Tensile and Flexural, .
modulus elasticity tensile and flexural Failure properties A failure is a characteristic of each of the materials as the Sugiarti et al.
/ Communications in Science and Technology 8.
100Ae107 behaviour of its inability to receive or absorb energy either statically or dynamically.
In this study, the reported fracture behaviour was only focused on the incorporation of filler with nanoparticles with properties as shown in Figure 4 to improve load transfer on the matrix.
few studies have reported on strengthening Nano fillers for epoxy matrices in FRP lamination .
,34,55Ae.
composites with variation number of CNT, as indicated by the cross-sectional shape of the fracture obtained through SEM In addition.
Figure 8 .
shows a cross-section of spun mat containing 3wt % CNF with and without surfactant .
triton-X) after loading, respectively.
As seen in Fig.
8 it can be observed that the relatively solid fracture manner In other words, they had fewer voids number on the However, there were some observed slight delamination and cracks only on the matrix occurred.
previously reported .
, nanofibers have a surface area with several orders of magnitude wider than basalt fibres.
In these cases, the increase in the surface area of the nanofiber is caused by the emergence of CNTs on the nanofiber.
Despite it can improve the interfacial bond of the epoxy.
Then, the uneven repair of CNT spread can be carried out by added surfactants .
Wherein, the surfactants have a function to dissolve the CNTs and provide CNTs more dispersebility into the PU Furthermore, it can be argued that CNTs spread has a significant influence on the properties of nanofibers, which means CNT-PU nanofibers can improve a matrix capability in transfer load as shown in Figure 8.
Discussions Fig.