Treated Fiber Composites Research Articles

Experimental investigation on tensile strength and impact strength of palmyra palm leaf stalk – Sisal fiber reinforced polymer hybrid composite

Natural fiber-reinforced polymer composites are the most widely used materials and preferable in terms of biodegradability, cost production, recyclability, and low density. The main aim of this study is to conduct an experimental investigation on tensile strength and impact strength of palmyra palm leaf stalk fiber (PLSF) and sisal fiber reinforced polymer hybrid composite. The composite material was fabricated using hand lay-up techniques. The working parameters are mass fraction ratio of PLSF/sisal fiber and volume fiber fraction with the matrix. Tensile strength and impact energy resistance tests were experimentally conducted according to the ASTM standard dimensions. The results revealed that the addition of sisal fiber to PLSF enhanced the tensile strength by 12.850 %, 26.540 %, and 30.630 % respectively compared to pure Palmyra palm leaf stalk fiber reinforced composite (PPFRC). Whereas, the addition of PLSF to sisal fiber improved the impact of energy by 20.980 %, 13.610 %, and 11.880 % compared to pure sisal fiber reinforced composite (PSFRC). The tensile strength with 20 % fiber volume fraction is improved by 53.996 % and 12.188 % compared to 10 % and 15 % of fiber respectively. The impact strength was also enhanced by 24.931 % and 10.030 % compared to 10 % and 15 % of volume fiber fraction respectively. The tensile strength and impact energy of the treated fiber composite increased by 62.243 % and 22.478 % respectively compared to the untreated hybrid Palmyra palm leaf stalk and sisal hybrid fiber reinforced composite (UHPSFRC). Generally, the HPSFRC-2 (Palmyra palm leaf stalk/sisal fiber) (P/S ratio 50/50 % ratio with 20/80 % ratio of fiber/matric percentage reinforced polymer hybrid composite) has good tensile strength and impact energy. Therefore, the mechanical property of the (Palm/Sisal) hybrid composite can be used for the manufacturing of the automotive interior parts like door panel, dash board, seat back, and automotive roof.

Response of short jute fibre preform based epoxy composites subjected to low-velocity impact loadings

This work aimed to investigate the low velocity impact behaviour of short jute fibre non-woven preform epoxy matrix composites experimentally. Dry fibre preforms were developed using an optimised process and a laboratory made preforming device. The effects of alkali and poly vinyl alcohol (PVA binder) treatments on impact performances of jute composites were investigated and compared at 3 J and 6 J impact energy levels. To identify the failure modes of tested composites, the X-ray µCT tomography was employed. The results demonstrated that the developed untreated short jute fibre preform reinforced composites absorbed a higher impact energy, when they were compared to treated (alkali or PVA binder) composites. For untreated composites, maximum impact forces at 3 J and 6 J energies, were found as ⁓2478 N and ⁓2319 N, respectively; for the PVA treatment these values were measured as ⁓2457 N and ⁓2216 N, while, at same energy levels, alkali treated composites showed the lowest values as ⁓1683 N and ⁓1440 N, respectively. Untreated jute fibre contains natural matrices such as hemicellulose, lignin and waxes, which ensured a positive response to absorb more energy upon impact loading. In contrast, the alkali treatment facilitates a highly fibre packed composite structure, which accelerated the impact crack propagation in tested composites, resulting in lower resistance to impact energy. Although, PVA treated composites showed reduced impact properties compared to untreated composites due to the PVA polymer brittleness on the treated fibre surface during the impact incidents, this treatment demonstrated better impact responses over the alkali treatment. The application of PVA binder on alkali-treated fibres provided an extra support to fibres and a better fibre/matrix interface and hence, this combined treatment demonstrated a slightly better impact resistance (⁓2027 N and ⁓1874 N impact forces at 3 J and 6 J respectively) compared to only alkali treated fibre composites. The SEM fracture images and the X-ray µCT damage analysis revealed different impact damage modes, which supported the observed impact results. The obtained results from this investigation could be helpful for using short jute fibre composites in various load demanding applications where impact incidents are likely to be happened.

Influence of Alkali Treatment on Bamboo/Coconut Husk Hybrid Fibre Polyester Composite

This research addresses the importance of hybrid composites in material science, specifically, demonstrating the effective reinforcement of unsaturated polyester with bamboo and coconut husk fibre through alkali treatment. The primary problem this work aims to solve is the improvement of the mechanical properties of unsaturated polyester by combining it with bamboo and coconut husk fibres which contain both lignocellulosic and cellulose fibres. Alkali treatment, particularly, sodium hydroxide (NaOH) solution, was used in this study due to its cost-effective nature and its ability to enhance the strength of both individual fibres and resulting composite. The effect of NaOH treatment with concentrations ranging from 2 – 10 wt.% on dried hybrid fibres was investigated. Chemically treated fibre composites were discovered to have improved mechanical characteristics as both tensile tests and thermogravimetric analysis (TGA) showed higher strength and thermal stability after being treated. Notably, findings identified an optimal content of 8 wt.% NaOH solution for surface modification, showcasing the potential for using NaOH-treated waste fibres to reinforce polyester resin. The implications of this study extend to a promising avenue for enhancing the performance and application of natural fibre-reinforced composites. The insights provided here offer a foundation for advancing the utilization of hybrid composites.

An inquisition on alkaline treated Banana/Sisal/Pineapple fiber epoxy composites for light to moderate load applications

To address the sustainable development goals, an attempt was made to investigate the alkaline treated and untreated Banana, Sisal, and Pineapple fiber epoxy hybrid composite for their mechanical and thermal properties. Tensile, Flexural, Impact, modulus, and Heat Deflection temperature (HDT) were evaluated and analyzed for low-load structural applications. The performance of Alkaline Treated Fiber composites was better than the untreated fiber composites. The treated Banana, Sisal, and Pineapple hybrid fiber epoxy composite has a high HDT value of about 78 °C, a maximum tensile strength of 104 MPa, a tensile modulus of 25 MPa, a flexural strength of 78 MPa, a flexural modulus of 5286 MPa,and an impact strength of 286 J m−1 when compared to other composites. Interfacial failure analysis was also carried out with the help of a Scanning Electron Microscope (SEM) to study the microstructural behavior of the tested specimens. It was observed that the alkaline treatment increases fiber-matrix interaction.

The Behavior of Banyan (B)/Banana (Ba) Fibers Reinforced Hybrid Composites Influenced by Chemical Treatment on Tensile, Bending and Water Absorption Behavior: An Experimental and FEA Investigation

Natural fiber-based composites are highly prioritized in present industries due to their properties and benefits over synthetic fibers. Due to their biodegradable nature, banyan and banana fibers were used for the present work. This paper deals with an experimental and FEA investigation of the tensile and bending behavior of banyan (B) and banana (Ba)-reinforced composites with different volume fractions, such as 25B/25Ba, 30B/20Ba, and 35B/15Ba, with a 50% weight fraction of epoxy resin and different fiber orientations. The hybrid composites treated with a 5% NaOH solution have better results as compared to untreated hybrid composites, with a volume fraction of 30% banyan fibers and 20% banana fiber (30B/20Ba), giving greater tensile and flexural properties for both treated and untreated fiber composites when compared to other volume fraction composites at 0/0/0/0 orientation. The maximum tensile and bending strength was found in the 30B/20Ba volume fractions to be 63.37 MPa and 67.07 MPa, respectively. For treated fiber composites, water absorption increases with an increase in the duration of immersion in composites up to 144 h.

IMPROVEMENT OF SAWDUST FIBER IN PROPERTIES OF POLYLACTIC ACID COMPOSITES: EFFECT OF FIBER SURFACE TREATMENTS

In this study, we investigated the impact of surface treatment on polylactic acid (PLA)/sawdust fiber (SF) composites. Utilizing a 20% weight-to-weight ratio of agricultural waste, three distinct chemical modification approaches were employed to treat the sawdust, with the aim of enhancing the compatibility between the PLA matrix and the wood fibers. The treatments included alkali-, benzoyl chloride-, and permanganate-treated SFs. The results demonstrated an increase in rigidity with alkali treatment, while composites treated with benzoyl chloride and permanganate exhibited improved ductility. However, the thermal stability of the treated fiber composites was reduced. Comparative analysis revealed that wood fibers treated with sodium hydroxide and permanganates exhibited superior dispersion in the PLA matrix compared to fibers treated with benzoyl chloride. Beyond these findings, this assessment carries significant implications for sustainable material development, since the utilization of agricultural waste provides an alternative composite material for construction or industrial applications. The study's outcomes contribute to the ongoing quest for eco-friendly solutions in material science and offer practical insights for selecting the most suitable composite material based on specific applications and industry needs.

Chopped Areca Nut Fibers as Filler in Epoxy Matrix: Mechanical and Tribological Studies

In the current investigation, fibers extracted from the areca nut tree husk were either used unprocessed or processed with an alkaline treatment by being submerged in a 5 % sodium hydroxide solution. The average length of the areca fibers used in this work is 30 mm. Compression molding is used to create the composite out of an epoxy matrix with fibers added at 10, 15, 20 and 25 weight percent. The composites were tested for tensile strength, flexural modulus, Charpy impact, and shore D hardness, all of which showed the significant advantage acquired with quantity of fibers and fiber treatment. Pin on disc tribometer was used to conduct tribological tests on the treated fiber composites to analyse how the fiber-matrix bonding improved with an increase in fiber content. The primary shortcoming of the fibers is their relatively low elongation, which, even after treatment, hardly approaches 4 %. This indicates that the fibers are not uniform in length and prevents direct comparison to comparable composites containing a similar volume and length of natural fibers. The mechanical qualities of materials made with alkali treated chopped areca fibers where found to be enhanced when it was at 20 % volume fraction. A linear increment in values where observed in samples till 20 % volume fraction and a decrement with further increase in volume fraction. In the case of tribological evaluations, lesser values or wears were obtained at combination III for all the 3 loads, 10N, 15N and 20N. HIGHLIGHTS Three different amounts of fibers, namely 10, 15, 20 and 25 wt%, have been introduced in an epoxy matrix, fabricating the composite by compression molding. The composites were subjected to tensile, flexural, Charpy impact and Shore D hardness testing, which all demonstrated the considerable advantage obtained with quantity of fibers and fiber treatment, except in the case of hardness, where limited advantages were encountered. Also wear tests were carried out on treated fiber composites and surface morphology of the worn-out samples was studies, which demonstrated the improvement in fiber-matrix bonding obtained with the growing amounts of fibers. From the results on composites testing, it is evident that the areca nut husk fiber/epoxy polymer composites with an amount of short (30 mm length) random reinforcement introduced of 20 wt%, exhibits the highest peak mechanical properties among all the calculated properties. GRAPHICAL ABSTRACT

Water aging effects on the flexural properties of fully biobased coir fiber composites

AbstractThis work describes the flexural behavior of biocomposites composed of a polyurethane matrix derived from castor oil plants and coir fibers. A statistical design is performed to identify the effects of fiber alkaline treatment and aging on the flexural modulus and strength of the composites. Physical tests and failure analyses are carried out to better assess their mechanical performance. A second experiment at 100% relative humidity is performed on treated fiber composites to compare with those obtained by immersion in water. The flexural modulus of the composites is not significantly affected by the fiber alkali treatment, while the strength is reduced by 35.17% when treated fibers are considered. Increasing the exposure time of composites under both aging conditions progressively reduces their flexural properties. The aging process of biocomposites in an environment with 100% relative humidity takes twice as long to reduce to the same flexural properties as those aged in water.Highlights Composites made with treated fibers showed higher apparent density and lower porosity. Water aging reduces flexural modulus and strength of biobased coir composites. The bending properties are strongly dominated by the properties of biobased polymer. 100% relative humidity takes twice as long to reduce to the flexural properties as those aged in water. Untreated coir fibers achieve superior bending properties under moisture aging.

Characterization of an eco-friendly rubber composite material based on Sansevieria cylindrica fibers

The weak bonding of the natural fiber in its raw state, with easy breakage and extreme moisture absorption, has many flaws, disadvantages, such as low load-bearing capacity. In addition, these factors are at the root of a mixture of fibers that control the performance or properties. In this paper, the surface is alkali-modified on Sansevieria Cylindrica fibers to overcome the above limitations and the treated fibers are introduced in the maximum viable agglomeration-free amount of 30% (assuming natural rubber quantity as equal to 100) to act as the reinforcement for new composites. Tensile, tear properties and Shore A hardness of the obtained composites, indicated as Sansevieria Cylindrica rubber composites (SCRC), with respect to neat rubber and untreated fibers composites are analyzed and the fracture morphology of treated fiber composites is also elucidated.

X-ray diffraction and thermo gravimetric analysis of surface modified areca sheath fibre epoxy composites

Focus of the current study is to shed more light on thermal behaviour of composites made up of areca sheath fibres. The XRD analysis revealed that crystallinity index and crystallinity percentage increased with different treatments, as it leads to better interaction of fibre and resin. The crystallinity percentage of alkali treated fibre and benzoyl peroxide treated fibre increased by 5.87 and 8.44% respectively compared to untreated fibre. This was further evident in thermo studies which proved better thermal stability in benzoyl peroxide treated fibre composite.

Identification of micro‐failure processes of HDPE‐henequen fiber composite material by using acoustic emission monitoring: Effect of fiber surface modification

AbstractIt is well known that fiber‐matrix interface region is crucial to ensure an efficient stress transfer between matrix and reinforcement and that it controls the composite behavior when subjected to external loads. In this experimental study, micro‐damage mechanisms of HDPE/surface modified henequen fiber reinforced composites are investigated in tensile quasi‐static mode. Two essential parameters of the materials composition were taken as main indicators: fiber length and quality of the fiber matrix adhesion. Essential Work of Fracture theory (EWF) was applied on double edge notch tensile (DENT) specimen geometry. Acoustic Emission (AE) technique was coupled to composite samples to obtain the characteristics of stress waves signals to monitor in real time damage evolution and failure mechanisms detection. Results demonstrated the substantial effect of chemical bonds interaction in the interface area on the composite mechanical properties. The total fracture work (Wf) exhibited an increasing value in both components, We and Wp, in chemically treated fiber composites. Likewise, mechanical properties are reported to be higher by 37% in maximum load in such materials. Elastic waves detected by AE were identified and correlated to micromechanical events during composite damage sequence. Most of the signals corresponded to microcracks (signals of low amplitude, short duration), propagation of microcracks (signals of medium amplitude), fracture of fibers and matrix (signals of long duration and high amplitude). AE signals detected exhibiting higher energy were associated to an enhanced fiber/matrix interface.

Fabrication and characterization of woven and comingled nonwoven sheet polypropylene hybrid composite by recycling and alkali-treated jute waste fibers

Natural fiber reinforced hybrid composite materials, with their enhanced characteristics, represent the future of our advanced material search. Natural fibers are the substitute for synthetics because their less manufacturing cost, bio-degradable, easy availability, durability, resistance to environmental degradation, etc., makes them popular nowadays. This paper presents how jute fibers are recycled from various jute waste sources. After recycling, jute fibers are used to fabricate the hybrid composites. Two forms of recycled jute sheets are used to fabricate the composites that is, woven sheets and nonwoven comingled (jute and polypropylene) sheets. The NaOH treatment was performed on recycled jute sheets with different concentrations (0%, 2%, 4%, 6%, and 8%). The hybrid composites are made using three distinct fiber-polypropylene weight fraction ratios (50/50, 40/60, and 30/70), as well as five different stacking sequences. Mechanical parameters such as tensile strength, elongation (%), flexural strength, impact strength, and water absorption were evaluated. Among the five fabricated combinations, it is found that the combination of (40/60), (JJJ), with 2% NaOH treated fibers composite gives the maximum tensile and flexural strength, and the combination of (30/70) (CCC) with 2% NaOH treated fiber composites exhibits the maximum Impact strength. The combination of (50/50), and (CCC) with 2% NaOH treated fiber composite gives the maximum Elongation %, and the combination of (50/50), (JJJ), and 0% NaOH treatment yields the maximum water absorption. A relationship between fabric loading, tensile modulus, and flexural modulus and other relationship between chemical treatment and water absorption% has been established for JJJ laminated sheet which shows almost best properties among them. These assessments make them most valuable for a variety of sectors, including car, aircraft, marine, and building construction.

Thermomechanical Analyses of Alkali-Treated Coconut Husk-Bagasse Fiber-Calcium Carbonate Hybrid Composites

Natural fiber-reinforced composites can contribute to reducing carbon footprint goals due to their ability to reduce overall product weight, bio-diverse feedstocks, and recyclability potential. In this work, natural fiber-based composites containing the reinforcement of coconut husk and bagasse fiber with calcium carbonate (CaCO3) ingredients were prepared and analyzed. The composites were analyzed for mechanical, thermomechanical, and morphological properties. The reinforcements were chemically functionalized using 5% w/v NaOH to enhance their interactions with the epoxy resins. The chemical functionalization created perforation on the fiber surface, improving the interlocking of fibres with the resin material and strengthening the mechanical performance of the composite. The composites developed using modified reinforcement treatment resulted in increased tensile strength (64.8%) and flexural strength (70%). The reinforcement treatment influenced the hydrophilicity, and the water absorption of treated composites was reduced more than five times compared to the unmodified composites. Scanning electron microscopy revealed morphological changes due to fiber modification, the underlaying mechanism of fiber contraction, and enhanced fiber matrix interface interlocking and adhesion strengthening. Thermal analysis confirmed that alkali treatment improves the crystallinity of the fiber and thereto the degradation temperature of treated fiber composites (both bagasse and coconut husk), which is 375.27 °C, the highest amongst the developed hybrid composites.

Evaluation of mechanical properties of biocomposites treated with date palm fiber

The utilization of environmentally friendly composite materials for building insulation offers a practical solution to reducing energy consumption. This study explores the application of novel biocomposites, comprising cement, sand, treated (DPFT) and raw (DPF) date palm fibers and their influence on the thermal and mechanical properties of mortars. The samples were prepared with varying weight percentages of date palm fibers (0%− 20%), treated with NaOH, and possessing a fiber length of 7 mm. Water absorption, density, resistance to bending and compression, thermal conductivity and diffusivity were encompassed. The results indicate that incorporating treated fibers has a beneficial effect on the thermal and mechanical properties of the composite when compared to using raw fibers. Additionally, higher proportions of DPF lead to decreased thermal conductivity, diffusivity, and resistance to bending and compression, highlighting the positive impact of DPFT on the composite’s thermal and mechanical attributes. Notably, the treated fiber composite significantly enhances the insulation capacity of the mortar.

Effect of alkali and silane treatment on water absorption and mechanical properties of sisal fiber reinforced polyester composites

The present work deals with the effect of water absorption on the mechanical properties of untreated, 10% alkali-treated, and 10% alkali plus 1% silane treated sisal fibers (5%, 10%, and 15%) reinforced polyester composites. Hand lay-up was used to create the composite. The samples were prepared in accordance with ASTM standards, and tests for tensile strength, flexural strength, impact strength, and water absorption were performed. An increase in the tensile, flexural and impact strength was observed with an increase in fibre loading for untreated, alkali-treated and alkali plus silane treated sisal fibre reinforced polyester composites without water absorption, the increase being maximum for 10% alkali plus 1% silane treated fibre composite. Water absorption reduces tensile strength while increasing flexural and impact strength in untreated sisal fiber reinforced composites. There is an increase in tensile, flexural, and impact strength with higher fiber loading for 10% alkali-treated and 10% alkali-treated plus 1% silane treated sisal fiber reinforced polyester composites with and without water absorption. The tensile, flexural, and impact strength of alkali plus silane treated fiber is maximum at any given fiber loading, indicating that the alkali plus silane treatment is effective in improving the fiber matrix interface. Water absorption increases with fiber loading in untreated, 10% alkali-treated, and 10% alkali plus 1% silane treated sisal fiber reinforced polyester composites, with the rate being lowest in alkali plus silane treated fiber reinforced composites.

Effect of chemical treatments on properties of injection molded Nypa fruticans fiber reinforced polypropylene composite

The rise in environmental awareness prompted consideration of environment friendly materials. Natural fiber, on the contrary, has a structure that allows it to absorb moisture attributable to its hydrophilicity, which hinders its wide application and leads to poor interfacial bonding with the polymer matrix. Therefore, fiber surface modification is inevitable, which is usually based on using the functional group of some chemicals to replace the hydrophilic hydroxyl group to make it more moisture resistant and ameliorate the boding between fiber and polymer matrix. In this study, injection molded nypa fiber reinforced polypropylene composites were fabricated. Three different chemical modification i.e., mercerization, H2O2 treatment, maleic anhydride polypropylene (MAPP) compatibilizer, were employed. Other parameters on which the properties of the composite depend, i.e., fiber volume (30%), manufacturing process, etc. were kept the same. Field emission scanning electron microscopic (FE-SEM) images were also investigated to verify the result of experiments. Moisture resistance of the composite was also evaluated. The tensile and flexural properties of treated composite were significantly enhanced than the untreated one. The maximum strength was obtained for MAPP treated composite. The chemical treatment has a less impact on the impact strength of the composite. Better moisture resistance was observed for treated fiber composites. This study provides the insight of using chemical treatment for better adhesion between the fiber and the polymer.

Modification of short sugarcane bagasse fibres for application in cementitious composites: A statistical approach to mechanical and physical properties

This work describes the physical and compressive properties of cement composites reinforced with short bagasse fibres to promote the recycling of sugarcane residues. Stearic acid and castor oil reagents are used as fibre modifiers leading to a hydrophobic character. A 32 factorial Design of Experiment (DoE) is used to evaluate the fibre amount and treatment factors statistically. A reference mortar is made to compare the results. Treated fibre composites achieve higher mechanical properties and lower physical properties. The low amount of fibres leads to superior responses, except for apparent density. A DoE optimisation shows that cementitious composites with 2 wt% of stearic acid-treated fibres achieve optimal mechanical and physical properties. Mechanical responses increase by up to 22.25%, while physical responses reduce by up to 20.46% in relation to the reference mortar. Short fibres treated with stearic acid can improve the physical and mechanical properties of mortars for secondary applications in civil construction.

RETRACTED: Effect of Silane Coupling Agent on the Mechanical Properties of Oil Palm Frond Fiber Composite

Retracted article: In this study, the influence of silane coupling agent on the matrix/ fiber interface bonding and its effect to the mechanical properties of oil palm frond fiber reinforced polyester composites were investigated. Tensile and flexural properties of the composites were studied at 0 - 10.2 volume fraction (% fiber content). Results showed an increasing trend in tensile modulus while tensile strength and flexural strength reduced as the fiber content increased. Higher tensile modulus values were observed in silane treated fiber composites due to additional fiber/ matrix interaction and increment in polyester molecular chain mobility constraint. Reduction in tensile strength is caused by decrease in the matrix crystallinity and formation of stress concentration spots emerging from interface discontinuity. These obstructions, however, were reduced by fiber surface modification, which improved the tensile strength. Enhanced fiber dispersion upon surface modification was unveiled through scanning electron micrograph images.

Synergistic effect of alkali and silane treatment on mechanical, flammability, and thermal degradation of hemp fiber/epoxy composite

AbstractCurrently, natural fiber composites are used in many applications (industrial, automotive, and construction) where fire resistance is a critical factor. The main objective of this research work is to investigate the thermal degradation and fire performance of raw and treated fiber composites developed using hand layup with different fiber loadings of 5, 10, 15, and 20 wt%. Alkali treatment (5%, wt/vol) and silane treatment (5%, wt/vol) were used to improve the thermal stability and compatibility of hemp fiber with polymer matrix. The developed composites were characterized for thermal (thermogravimetric analysis), chemical (Fourier transform spectroscopy), morphological (scanning electron microscopy and X‐ray diffraction), and mechanical behavior. Further, the flammability behavior of the developed composites was investigated using vertical cum horizontal flammability test apparatus and limiting oxygen index (LOI) tester. The results of mechanical characterization reveal that alkali treated fiber composites (20% loading) have the highest tensile strength (24.4 MPa) and flexural strength (46.1 MPa). Composite reinforced with silane‐treated fibers have shown excellent flame retardancy with the lowest horizontal burning rate (16.11 mm/min) and higher LOI (23.5%). Scanning electron microscopy confirms the better fiber‐matrix compatibility of silane‐treated fiber with epoxy.

Investigation and prediction of mechanical properties of hot water treated jute/poly(lactic acid) composite laminates using response surface methodology and genetic algorithm

AbstractThe main objective of this work was to estimate the usefulness of response surface methodology (RSM) and genetic algorithm (GA) in modeling and predicting the strength of jute/poly(lactic acid) (PLA) composite laminates. Firstly, the impact of the hot water treatment on the thermal, molecular structure, and morphological characterizations as well as kinetic analysis of jute fibers were performed by Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM). The FTIR results showed that the hot water treatments reduced the content of lignin, hemicellulose, and impurities of the fibers. Hot water treated fibers exhibited higher thermal stabilities compared with untreated fibers as shown with TGA results. The SEM results showed effect contact surface area improved after the hot water treatment, leading to better mechanical properties of bio‐composites. Secondly, the influences of the ply orientation, plies and fiber content on the tensile strength and flexural strength of the hot water treated fibers composites were evaluated by RSM. RSM with the Box Behnken Design was utilized to establish the quadratic models of two objectives in response to input parameters. Analysis of variance (ANOVA) was used to determine percentage contribution of various parameters on two quality objectives. According to the ANOVA results, ply orientation had the most important impact on tensile strength while the ply orientation‐fiber content interaction had the most important impact on flexural strength. Finally, multi‐objective optimization was carried out to maximize tensile strength and flexural strength using the desirability function and GA. The optimized results both showed an acceptable relative error between experimental and optimized values.