Experimental Investigation of Hybrid Glass-Sisal Fiber Reinforced Polyester Composites

doi:10.21203/rs.3.rs-3897166/v1

In this study, the experimental testing of hybrid fiber composite material was conducted to characterize the mechanical properties such as tensile, compressive, and flexural strength. To improve the mechanical properties, natural fibers such as sisal fiber was hybridized with synthetic glass fiber. The hybrid fiber was prepared by hand lay-up method with consideration of process parameters such as fiber weight ratio (30%, 35%, and 40%), fiber orientation (mat-mat-mat, unidirectional-mat-unidirectional, mat-unidirectional-mat, mat-random-mat, and random-mat-random), and ply arrangement (sisal-glass-sisal, glass-sisal-glass, and sisal-sisal-sisal) respectively to form composites. The sisal fiber surfaces were chemically treated with 10% NaOH. The treated sisal fibers and glass fibers were combined by using matrix material unsaturated polyester and the hardener (methyl ethyl ketone peroxide). The tests are carried out as per the ASTM standards. From the mechanical property tests, the result showed that 35% fiber weight ratio composite material with mat-mat-mat fiber orientation and glass-sisal-glass ply arrangement revealed the highest tensile, flexural and compressive strength when compared to other composite materials.

Glass fiber

Hand lay-up

Mechanical properties

Sisal fiber

Unsaturated polyester

Nowadays, the enhanced environmental awareness all over the world has increased a growing interest in natural fibers and their applications. Natural fiber composites are environment-friendly composites that have useable in different applications at a relatively low cost. It offers good thermal and insulating properties, are easily recyclable and biodegradable material. Some of the natural fibers have gained substantial importance as reinforcements in polymer matrix composites like sisal, hemp, jute, coir, banana, etc. Due to growing interest in natural fibers, these fibers are extensively used in the development of composite materials for industrial applications and have gained interest in the automotive industry where materials of lightweight, high strength to weight ratio, and minimum environmental impact are required. Moreover, natural fibers have low specific gravity as compared to synthetic fibres. The usage of natural fibers also considered as healthier working condition than the synthetic fibres for polymer composite manufacture [1-6].

However, synthetic fiber-reinforced composites have very good specific properties, but they have main limitations such as degradability at the end of their operational life [3]. Synthetic fibers such as carbon, glass, and aramid have dominated the composite manufacturing sector because of their low cost of production and fairly good mechanical properties [2]. The demand for the fiber-reinforced polymeric composite specifically for the synthetic fiber as it is utilized in making pipes, in tanks, sports goods, and construction of bridges, boat hulls, automotive industry, and aircraft secondary structure while thermoset matrices and thermoplastic require natural fiber [7-8]. However, with increasing environmental concerns, studies on the possibility of replacing synthetic fibers with natural fibers for polymer composite manufacture are on the rise [3].

In the present study the characterization of mechanical properties such as tensile, flexural, and compressive strength of sisal-glass fiber reinforced composite material are carried out, also investigate the effect of process parameter like fiber orientation, fiber weight ratio, and ply arrangement. The study is to focus on preparing composite material from sisal-glass fiber by considering different process parameters such as fiber/ matrix ratio, fiber orientation and ply arrangement.

Hand layup method was used to prepare these composite materials. It includes the design of fiber orientation, ply arrangement, and casting of prepared composite materials. In the hand lay-up technique, the fibers were arranged in the mold by hand and the hardener mixture (10:1) was poured for every layer. After that, it was compacted with a lightweight press. For the second layer of the reinforcement, the fibers were placed on the resin surface then rolled to remove the entrapped air and to uniformly spread the mixture.

The processes are repeated for all plies of the reinforcement and resin until getting the desired thick composite. The compression process was done by using the hydraulic pressing machine by applying compression pressure of 5 MPa. Then taken out the composite material and placed outside to dry at room temperature for 72 hours. The required sisal-glass-fiber-reinforced hybrid composite materials were developed with a different type of fiber orientation, ply arrangement, and fiber weight ratio.

2.1 Materials

For the present study, the sisal plant leaves and glass fibers are obtained from local sources. Matrix material used for this investigation was unsaturated polyester, which was purchased from local market. It was mixed with the hardener methyl ethyl ketone peroxide (MEKP) in a proportion of 10:1 and used to cure the resin.

2.2 Methods

Mold preparation

The mold used in this work was prepared from wood with a dimension of 300mm × 200mm × 10mm. The top, bottom surfaces of the mold and the wall side are coated with a mold releasing wax to prevent the sticking of composite to the surface of the mold. The function of top and bottom plates is to cover, compress the fiber after the unsaturated polyester is applied, and to avoid the debris from entering into the composite parts during the curing time. A thin plastic sheet is also used between the top and bottom plates of the mold. It is to avoid the sticking of composite to the plate surface and to get a good surface finish.

Composite material preparation

The composite materials were prepared by using the hand layup method. The required sisal-glass-fiber-reinforced hybrid composite materials are developed with a different type of fiber orientation, ply arrangement, and fiber weight ratio. Twenty-seven sample laminates are fabricated by using sisal and glass fibers along with unsaturated polyester matrix materials, these laminates are differentiated based on fiber weight percentages (30%, 35%, 40%) of glass and sisal fiber, fiber orientation (mat, unidirectional and continuous random), and stacking sequences such as (sisal-glass-sisal, glass-sisal-glass, and sisal-sisal-sisal).

2.3 Testing

Tensile, Compressive, and Flexural Strength Test

After preparing the specimen in the desired dimension based on the respective standards, the mechanical properties tests were conducted. The specimens for a tensile test cut by using a band saw cutting machine and their dimensions are according to the ASTM standard D3039 for each designed composite material. During the test, the specimens were placed in the grips of the Universal testing machine and an axial load was applied through both ends of the specimen. The test was conducted at a crosshead speed of 5 mm/min and carried out at room temperature. A typical specimen under the tensile strength test is shown in Figure 1.

The compressive strength test was carried out based on the ASTM D3410 standard by using Universal testing machine. The test was conducted to investigate the compressive strength of the developed composite material. Figure 2 indicates the specimen under the compressive strength test and flexural strength test; the samples were placed between the compression anvils to start compression testing. The flexural test was performed on the same tensile testing machine in accordance with ASTM D790 standards. The specimen hooked on the grip, then applies the load with a central grip that is fixed at the center of the specimen. When the specimen starts bending, the onboard computer generates the required data and graphs.

2.4 Results and Discussions

Tensile Strength Test Result

The tensile property result of developed composite materials for different fiber weight ratios, fiber orientation, and ply arrangement were presented. The tensile, compressive and flexural strength of each composite laminates were presented in Table 1. The fiber orientations, which were used in this investigation, are Mat, Unidirectional and Random fiber orientations. The orientations are Mat-Mat-Mat (MMM), Unidirectional-Mat-Unidirectional (UMU), Mat-Unidirectional-Mat (MUM), Random-Mat-Random (RMR), and Mat-Random-Mat (MRM). The ply arrangement forms Sisal-Glass-Sisal (SGS), Glass-Sisal-Glass (GSG), and Sisal-Sisal-Sisal (SSS). The fiber matrix weight ratios for this study were 30%, 35%, and 40% of the fiber in the prepared composite and the remaining were a matrix. The tensile characteristics of each composite laminates the tensile strength graphs were plotted in Figure 3.

It is observed that the mat or woven fiber orientation with glass-sisal-glass (GSG) ply arrangement and 35% fiber weight ratio composite material has the highest tensile strength as compared to other composite laminates. It is revealed from the experiment that an enhancement in the tensile strength due to better adhesion, and uniform dispersion of the fibers in the matrix.

Figure 3 implies that the tensile properties of prepared composite materials are affected by both ply arrangement and fiber orientation. Hybrid fiber composite material with Glass-Sisal-Glass (GSG) ply arrangement shows preferable tensile strength than Sisal-Glass-Sisal (SGS) and Sisal-Sisal-Sisal (SSS) ply arrangements. Since in the case of GSG ply arrangement, more glass fiber lamina was used than SGS and SSS ply arrangement. Additionally, it reveals concentrating glass fiber in the composite gives better tensile strength than concentrating sisal fiber.

The experiment data shows fiber weight ratio also affects the tensile strength of the composite material. When the fiber ratio is increased from 30% to 35%, it shows increases in tensile strength up to a certain limit. It shows that further addition of more fiber in composite causes a decrease in tensile strength; it is due to poor interfacial adhesion between fiber and matrix.

The glass-sisal fiber reinforced composite with 35% fiber weight concentration has higher tensile strength than the other fiber weight concentrations. In this case, the fiber-matrix interaction is excellent to withstand the applied load because the matrix may impregnate the fiber appropriately.

The tensile property of this study is compared with some of the other studies. As shown in Table 2, the tensile strength obtained from the current work is higher when compared to [4], and clearly shows that hybrid synthetic fibers with natural fibers and fiber orientation have a significant effect on the tensile strength of materials.

Compressive Strength Test Result

For different weight ratio, fiber orientations, and ply arrangements the compressive strength of composite materials were presented. The test was carried out in a Universal testing machine

The variation in compressive strength for various stacking sequences is shown in Figure 4. It is noticed that the MMM fiber orientation with glass-sisal-glass (GSG) ply arrangement and 35% fiber weight ratio composite material shows the highest compressive strength as compared to other composite materials.

The Figure 4 implies that the compression properties of prepared composite materials are affected by varying stacking sequences. It is observed that the lowest values of compressive strength are recorded on RMR fiber orientation of sisal composite with sisal-sisal-sisal (SSS) ply arrangement and 40% fiber weight fraction composite material than other composite materials.

The prepared composite with a glass- sisal- glass (GSG) ply arrangement shows preferable compressive strength than sisal-glass- sisal (SGS) and sisal-sisal-sisal (SSS) ply arrangements. This is because more glass fiber was found in GSG ply arrangement than SGS and SSS ply arrangement. This implies that the stiffness of glass fiber is higher than that of sisal fiber.

Table 1 Tensile, compressive, and flexural properties of the prepared composite materials.

Laminates	Fiber weight ratio, %	Orientation	Ply arrangement	Tensile strength (MPa)	Compressive strength (MPa)	Flexural strength (MPa)
L₁	30	MMM	SGS	46.82	28.4	72
L₂	30	MMM	GSG	92.53	49.2	102
L₃	30	MMM	SSS	30.87	16	54
L₄	35	MMM	SGS	50.76	31.34	87.6
L₅	35	MMM	GSG	98.26	55.32	156
L₆	35	MMM	SSS	32.32	17.2	56.4
L₇	40	MMM	SGS	48.04	33.91	84.6
L₈	40	MMM	GSG	94.68	45.06	120
L₉	40	MMM	SSS	27.28	15.03	42
L₁₀	30	UMU	SGS	41.61	22	62.4
L₁₁	30	MUM	GSG	79.2	44.14	99
L₁₂	30	UMU	SSS	20.52	14.66	52.32
L₁₃	35	UMU	SGS	44.36	30.56	70.8
L₁₄	35	MUM	GSG	85.76	46.26	109.2
L₁₅	35	UMU	SSS	28.96	12.94	60
L₁₆	40	UMU	SGS	43.23	26.14	67.2
L₁₇	40	MUM	GSG	81.04	40.6	96
L₁₈	40	UMU	SSS	22.64	13.64	53.4
L₁₉	30	RMR	SGS	37.11	25	67.8
L₂₀	30	MRM	GSG	70.68	36.64	79.2
L₂₁	30	RMR	SSS	18.16	12.54	39
L₂₂	35	RMR	SGS	40.34	31.2	64.9
L₂₃	35	MRM	GSG	75.41	42.1	87
L₂₄	35	RMR	SSS	24.21	11.68	41.4
L₂₅	40	RMR	SGS	39.07	24.8	57.6
L₂₆	40	MRM	GSG	72.56	35.26	72.6
L₂₇	40	RMR	SSS	15.64	10.42	40.5

Table 2 Comparison of tensile properties reported.

Fiber	Matrix	Fiber orientation	Fiber/ matrix ratio	Fabrication method	Tensile strength (MPa)	References
Glass/ Sisal	UPR	Mat form	35/65	Hand layup	98.26	Current work
Sisal/Coir	Epoxy	Unidirectional for sisal random coir	40/60	Hand layup	57	[5]
Jute	Epoxy	Random	30/70	Hand layup	69.5	[6]
Sisal	Polyester	Random	35/65	Hand layup	44.78	[7]
Sisal	Polyester	Random	30/70	Hand layup	65.93	[8]
Sisal/Glass	Epoxy	Unidirectional	20/80	Hand layup	26	[9]
Hemp	Polypropylene	Random	50/50	Hand layup	50	[10]
Sisal	Epoxy	Random	30/70	Hand layup	83.96	[4]

Therefore, the higher glass fiber percentage in the composite can improve the compressive strength of the material.

Table 3 Comparison of compressive properties reported in this work with previous work

Fiber	Matrix	Fiber orientation	Fiber/ matrix ratio	Fabrication method	Compressive strength (MPa)	References
Glass/ Sisal	UPR	Mat form for both fibers	35/65	Hand layup	55.32	Current work
Sisal	Epoxy	Random	30/70	Hand layup	44.66	[11]
Glass/ Sisal	UPR	Mat for glass and unidirectional for sisal	-	Hand layup	60.5	[12]

Compressive properties of the current work compared with some of the other researcher’s work. From Table 3 the compressive strength obtained from current work is lower when compared to [12]. It is clearly shown that the length of fiber has a significant effect on the compression property of the composite material.

Flexural Strength Test Result

The flexural strength of all prepared composite materials for different fiber weight ratio, fiber orientation, and ply arrangements were presented in Figure 5. It is observed that the mat- mat-mat (MMM) fiber orientation with glass-sisal-glass (GSG) ply arrangement and 35% fiber weight fraction composite material reveals the highest flexural strength. This is due to better adhesion between fiber and matrix interfaces to a uniform load transfer.

It is observed that the lowest value of flexural strength is found on random-mat-random (RMR) fiber orientation with Sisal-Sisal-Sisal (SSS) ply arrangement composite material than other composite materials. The reason may be that the laminates are exposed to poor adhesion between the fiber and matrix interface.

Figure 5 implies that the flexural properties of prepared composite materials are affected by varying stacking sequences. Sisal glass fiber hybrid composite with Glass-Sisal-Glass (GSG) ply arrangement shows preferable flexural strength than Sisal-Glass-Sisal (SGS) and Sisal-Sisal-Sisal (SSS) ply arrangements. Since in the GSG ply arrangement more glass fiber lamina was used than SGS and SSS ply arrangement. The data obtained from the experiment investigation shows that concentrating glass fiber in the composite gives better flexural strength than concentrating sisal fiber in hybrid fiber composite material.

The result shows, when the fiber weight ratio increases, the flexural strength of the composite also increases up to a certain limit. However, further addition of sisal fibers in the composite causes decreases the flexural strength. The possible reason is that the fibers are not fully impregnated in the matrix or poor interaction of the lamina in the sandwich model.

In this study, sisal-glass fiber reinforced hybrid composites were fabricated successfully by using hand layup fabrication techniques with different fiber weight ratios, fiber orientation, and different ply arrangements. In addition, their mechanical properties like tensile strength, flexural strength and compressive strength, were investigated.

From tensile strength test results, the mat or woven fiber orientation with glass- sisal-glass (GSG) ply arrangement and 35% fiber weight fraction composite offer better tensile strength. Enhancement in the tensile strength was due to better bonding, adhesion, and uniform dispersion of the fibers in the matrix. It is obtained that the mat or woven fiber orientation with glass-sisal-glass (GSG) ply arrangement and 35% fiber weight fraction composite material shows the highest flexural strength as compared to other composite laminates. For compressive strength test results, the mat or woven fiber orientation with glass-sisal-glass (GSG) ply arrangement and 35% fiber weight fraction composite material reveals the highest compressive strength as compared to other composite materials. Finally, this study concluded that the effective method to enhance the properties of natural fiber-reinforced composites is to combine distinct fibers to produce hybrid composites.

Acknowledgment

This work supported by EFDRE Ministry of Science and Higher Education, Ethiopia.

Authors’ Contribution: Conceptualization, Belachew A. and Degefe L.; methodology, Belachew A. and Guta E.; investigation, Belachew A.; writing-review and editing, Tesfaye T.; Visualization, Tesfaye T. and Belachew A.; Supervision, Degefe L., Tesfaye T. and Zablon Z. All authors have read and agreed to the published version of the manuscript.

Competing interests: The authors have no competing interests to declare that are relevant to the content of this article.

Bongomin, O., Gilibrays Ocen, G., Oyondi Nganyi, E., Musinguzi, A., Omara, T.: Exponential Disruptive Technologies and the Required Skills of Industry 4.0, J. Eng. (United Kingdom), vol. p. 4, 2020, (2020). 10.1155/2020/4280156
Asim, M., Jawaid, M., Saba, N., Ramengmawii, M., Nasir, Sultan, M.T.H.: Processing of hybrid polymer composites-a review. Elsevier Ltd (2017)
Prasad, V.J.J., Suresh Kumar, P.: A Review of Recent Developments in Natural Fiber Composites and their Mechanical, Thermal & Machinabilty Properties. Adv. Mater. Res. 1148, 61–71 (2018). 10.4028/www.scientific.net/amr.1148.61
Gupta, S.R.: MK, Properties of sisal fibre reinforced epoxy composite. (2016)
Girisha, S.G., Sanjeevamurthy, C.: Sisal/coconut coir natural fibers-epoxy composites: Water absorption and mechanical properties. Int. J. Eng. Innov. Technol. 2, 166–170 (2012)
Seki, Y.: Innovative multifunctional siloxane treatment of jute fiber surface and its effect on the mechanical properties of jute/thermoset composites. Mater. Sci. Eng. 508, 247–252 (2009)
N. Kotresh sardar1, Veeresh, D.K., Rangaswamy, D.T.: Characterization and Investigation of Tensile Test on Sisal Fiber Reinforced Polyester Composite Material. Int. J. Recent. Dev. Eng. Technol. 3(4), 85–89 (2014)
Khanam, P.N., Khalil, H.P.S.A., Reddy, G.R., Naidu, S.V.: Tensile, Flexural and Chemical Resistance Properties of Sisal Fibre Reinforced Polymer Composites : Effect of Fibre Surface Treatment. J. Polym. Env. 19, 115–119 (2011). 10.1007/s10924-010-0219-7
Madhuri, R.D.: KS, An Investigation of Mechanical and Thermal properties of Reinforced Sisal-Glass fibers epoxy hybrid composites. Int. J. Eng. Res., (2014)
Hargitai, A.R., Rácz, H.: Development of hemp fiber reinforced polypropylene composites. J. Thermoplast Compos. Mater. 21(2), 165–174 (2008)
Dr, D.N.H., Dinesh, K.R., Jagadish, S.P., Thimmanagouda, D.A.: Characterization and Investigation of Tensile and Compression Test on Sisal Fibre Reinforcement Epoxy Composite Materials Used as Orthopaedic Implant. Int. J. Appl. or. Innov. Eng., vol. 2, no. 12, (2013)
Natarajan, S.P., Bharathidhasan, N., Thanigaivelan, S.: R, Sisal fiber glass fiber hybrid nano composite: the tensile and compressive properties, in Int International & 26th All India Manufacturing Technology, Design and Research Conference, pp. 1–6. (2014)

No competing interests reported.

Experimental Investigation of Hybrid Glass-Sisal Fiber Reinforced Polyester Composites

Status:

Version 1

Abstract

Figures

1. Introduction

2. Material and Methods

3. Conclusions

Declarations

References

Additional Declarations

Status:

Version 1