Development and Characterization of Ficus trichopoda Latex Bio-Binder for Natural Fiber Composites

 Development and Characterization of Ficus trichopoda Latex Bio-Binder for Natural Fiber Composites

                                   Gede, Edwin¹_, Ikpambese, Kuncy², Omenka Ikoni^*3

^1,2*3 Department of Mechanical Engineering, Joseph Sarwuarn Tarka University, Makurdi, Nigeria.

 

Abstract

In this study, the potential of Ficus trichopoda latex as a sustainable bio-binder for natural fiber composite applications was evaluated. Chemical, physical, and thermal characterization were performed on produced samples. Fourier Transform Infrared Spectroscopy (FTIR) analysis identified key functional groups (hydroxyl (–OH), carbonyl (C=O), and ether (C–O–C) linkages) that shows the presence of polyphenolic and lignocellulosic constituents capable of promoting strong interfacial bonding within composite systems. The modulus of rigidity of the extract ranged between 1.6 and 2.0 GPa, suggesting moderate stiffness and adequate intermolecular cohesion which is required for structural applications. Density measurements revealed an apparent density of 1.05 g cm⁻³ and a true density of 1.21 g cm⁻³, indicating low porosity and good compactness which are essential for effective load transfer and dimensional stability. Thermogravimetric analysis (TGA) demonstrated a three-stage degradation profile, with minimal weight loss below 150 ⁰C. Major decomposition occurred between 250 ⁰C and 380 ⁰C and a residual char yield of 15–20 % was observed at elevated temperatures. This behavior confirms the presence of thermally stable aromatic and lignin-based compounds within the extract. The combined results shows that Ficus trichopoda latex possesses favorable chemical reactivity, thermal resistance, and structural integrity for use as a natural binder. The study establishes its viability as an eco-friendly alternative to conventional synthetic resins in the development of sustainable composite materials.

Keywords: Ficus trichopoda, bio-binder, FTIR, thermogravimetric analysis, natural fiber composites, thermal stability, modulus of rigidity, density

 

1. Introduction

 

The increasing environmental concerns associated with the use of petroleum-based polymers have intensified global research efforts toward the development of sustainable, biodegradable, and eco-friendly materials. Conventional synthetic binders such as epoxy resins are widely used in composite fabrication due to their high mechanical strength, chemical resistance, and thermal stability. However, their non-biodegradable nature, dependence on fossil resources, and potential environmental and health hazards during production and disposal present significant limitations (Mohanty et al., 2018). These challenges have driven the search for renewable and environmentally friendly alternatives derived from natural resources.

Natural fiber composites have gained considerable attention as substitutes for synthetic materials in engineering and structural applications. Fibers such as coconut coir, jute, sisal, and bamboo are abundant, cost-effective, biodegradable, and exhibit satisfactory mechanical properties (Faruk et al., 2019). Despite these advantages, a major limitation in natural fiber composites is the poor compatibility between hydrophilic fibers and hydrophobic polymer matrices. This often results in weak interfacial adhesion and reduced mechanical performance (Saba et al., 2018). Improving fiber–matrix interaction remains a critical requirement for enhancing the performance and durability of these composites.

To address this limitation, recent studies have explored the use of natural binders and bio-based coupling agents capable of improving interfacial bonding while maintaining sustainability. Plant-derived latexes have emerged as promising alternatives due to their inherent adhesive properties, elasticity, and renewability. Latex is a natural colloidal polymer system containing compounds such as polyisoprenes, proteins, lipids, and phenolic substances which contribute to film formation and cohesive bonding (Siqueira et al., 2017). These chemical constituents enable latex-based materials to interact effectively with lignocellulosic fibers, improving adhesion and mechanical integrity.

Studies on plant extracts and latexes from the Ficus genus have revealed the presence of functional groups such as hydroxyl (–OH), carbonyl (C=O), and ether (C–O–C), which are capable of forming hydrogen and covalent bonds with both natural fibers and polymer matrices (Ibrahim et al., 2021). These functional groups play a significant role in enhancing interfacial bonding and stress transfer in composite systems. In addition, plant-based binders containing phenolic and lignin-derived compounds have been reported to improve mechanical properties and reduce environmental impact when used in composite fabrication (Daramola et al., 2019). However, the potential of Ficus trichopoda latex as a bio-binder remains largely unexplored. This plant, which is locally available and traditionally known for its adhesive and medicinal properties, produces a milky latex rich in bioactive compounds. Furthermore, there is limited scientific data on its physicochemical, thermal, and mechanical characteristics particularly for engineering applications. A thorough understanding of its chemical composition, thermal stability, density, and rigidity is essential for determining its suitability as a matrix material or modifier in composite systems.

The development of effective bio-binders requires detailed characterization to establish the relationship between structure and performance. Analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR) provide information on functional groups and chemical interactions, while Thermogravimetric Analysis (TGA) evaluates thermal stability and degradation behavior (Yang et al., 2017). These techniques, combined with density and mechanical property evaluations enables a comprehensive assessment of material performance in composite applications.

In this present study, the extraction, characterization, and evaluation of Ficus trichopoda latex as a bio-binder for natural fiber composites will be evaluated. By investigating its chemical structure, thermal behavior, and mechanical properties, the study aims to establish its potential as a sustainable alternative to synthetic binders.

 

2. Characterization of Plant-Based Binders

 

2.1 Chemical and Thermal Characterization of Plant-Based Binders

 

The characterization of plant-derived binders is essential for understanding their suitability in composite applications. Techniques such as Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) are widely used to evaluate the chemical structure and thermal stability of bio-based materials. Plant latexes and extracts have been reported to contain hydroxyl (–OH), carbonyl (C=O), and ether (C–O–C) functional groups which enhance adhesion with lignocellulosic fibers. Studies on natural polymers indicate that these functional groups contribute to hydrogen bonding and covalent interactions at the fiber–matrix interface thereby improving their mechanical performance (Ibrahim et al., 2021). Similarly, Saba et al. (2018) reported that the presence of polar functional groups in natural binders improves compatibility with hydrophilic fibers, thereby enhancing stress transfer in composites.

Thermogravimetric studies have shown that lignocellulosic materials and plant-based binders typically exhibit multi-stage degradation behaviour, with initial moisture loss below 150 ⁰C, followed by decomposition of hemicellulose and cellulose between 200 ⁰C and 400 ⁰C, and lignin degradation at higher temperatures (Yang et al., 2017). Materials with higher residual char content are generally associated with improved thermal stability and structural rigidity (Daramola et al., 2019). This makes TGA an important tool for evaluating the thermal performance of bio-binders intended for engineering applications.

 

2.2 Modulus of Rigidity in Bio-Polymers

 

The mechanical performance of polymeric binders is strongly influenced by their crosslink density and molecular network structure. In bio-based systems, direct mechanical testing is sometimes limited, and indirect methods using FTIR and TGA data have been applied to estimate stiffness parameters. The relationship between shear modulus (G) and network chain density is commonly expressed using rubber elasticity theory, which has been used to predict the rigidity of crosslinked polymer systems (Ahmed et al., 2020).

Studies have shown that higher crosslink density results in increased stiffness and reduced molecular mobility which leads to improved mechanical properties in composites (Ibrahim et al., 2021). Thermal analysis further supports this relationship, as materials with higher degradation temperatures and greater char residue tend to exhibit stronger intermolecular bonding and higher rigidity (Daramola et al., 2019). These approaches have been applied in evaluating plant-based binders where conventional mechanical characterization is not readily available.

 

2.3 Density of Natural Binders

 

Density is an important physical parameter that influences the performance of composite materials. The true density reflects the intrinsic material structure, while apparent density accounts for voids and porosity within the matrix. Standard methods such as gas pycnometry and Archimedes’ principle are commonly used for determining these properties in polymeric and composite systems (ASTM D854-14; ASTM D792-13). Natural binders derived from plant sources often exhibit relatively low density due to their organic composition. However, when their packing is improved and their porosity reduced, their bonding performance is enhanced. Zuhudi et al., (2021) reported that materials with higher apparent density and reduced void content demonstrate better interfacial adhesion and mechanical strength in fiber-reinforced composites. Similarly, Daramola et al., (2017) observed that phenolic-rich plant extracts exhibit higher density values and improved structural integrity due to compact molecular arrangements.

The relationship between density and composite performance reveals that a reduction in the porosity of composites limits stress concentration points and enhances load transfer efficiency within the material (Faruk et al., 2019). Therefore, evaluating both true and apparent densities provides insight into the suitability of a binder for composite fabrication.

 

3. Methodology

 

Ficus trichopoda latex was extracted, purified, and characterized to evaluate its suitability as a natural binder. Chemical characterization was carried out using FTIR in accordance with ASTM E1252-19. The spectra were recorded in the range of 4000–400 cm⁻¹. Thermal behaviour was assessed using TGA under a nitrogen atmosphere. Samples were heated at a controlled rate to determine weight loss and degradation characteristics. This was done in accordance with ASTM E1131-20 standards.

The modulus of rigidity was estimated indirectly using FTIR-derived crosslink conversion and TGA data, applying the rubber elasticity relationship between shear modulus and network chain density. Density measurements were conducted using helium pycnometry for true density and the Archimedes method for apparent density, in accordance with ASTM D854-14 and ASTM D792-13 standards.

 

4. Results and Discussion

 

4.1       Fourier Transform Infrared Spectroscopy of Ficus Trichopoda

 

The FTIR spectrum of Ficus trichopoda extract (see Figure 1) showed several distinct absorption peaks between 4000 cm⁻¹ and 650 cm⁻¹. A broad intense band was observed at 3285 cm⁻¹, a phenomenon that can be attributed to the O–H stretching vibration of hydroxyl groups. Another peak around 2850 cm⁻¹ corresponded to C–H stretching of aliphatic (–CH₂ and –CH₃) groups while a noticeable band at 1638 cm⁻¹ revealed the presence of conjugated C=O and C=C stretching typical of carbonyls and aromatic rings. The spectral region between 1150 cm⁻¹ and 1017 cm⁻¹ displayed strong C–O and C–O–C stretching vibrations. This suggests the presence of alcohols, ethers, or glycosidic linkages. These peaks confirm the presence of functional groups such as hydroxyl, carbonyl, and ether linkages that are characteristic of phenols, flavonoids, lignins, and polysaccharides in natural plant extracts. The broad O–H band demonstrates the abundance of polar functional groups capable of hydrogen bonding, indicating that Ficus trichopoda extract possesses high potential as a natural coupling or binding agent. The combination of hydroxyl and carbonyl functionalities supports the presence of polyphenolic compounds and esters that can interact with both hydrophilic and hydrophobic components in composite systems. The observed C–O–C and C–O vibrations confirm the likelihood of carbohydrate-based constituents such as cellulose derivatives, which may contribute to the bio-adhesive behavior of the extract in fiber-reinforced composites.

           

Figure 1: FTIR analysis of Ficus trichopoda extract

 

These findings agree with those of Zafar et al., (2018), who reported broad O–H and C=O peaks in the FTIR spectrum of Ficus benjamina extract, linking them to hydroxyl and carbonyl groups responsible for strong adhesion in biopolymer formulations. Similarly, Ogunlana and Olayemi (2020) analyzed Ficus thonningii leaf extract and observed major absorption bands at 3300 cm⁻¹ (O–H), 2920 cm⁻¹ (C–H), and 1640 cm⁻¹ (C=O). There attributed this behavior to phenolic and ester compounds that enhance surface activity in composite materials. In another related work, Ibrahim et al., (2021) studied FTIR spectra of Ficus sycomorus bark extract and found comparable peaks, concluding that the functional groups present were responsible for improved bonding with epoxy resin during hybrid fiber composite fabrication. These studies collectively support the present finding that Ficus trichopoda extract contains chemically active sites compatible with epoxy and natural fiber matrices.

The presence of the O–H and C–O–C functional groups in Ficus trichopoda extract thus explains the strong interfacial adhesion observed in composites developed with this extract, as these groups can form hydrogen or covalent bonds with the hydroxyl groups on natural fibers (such as coconut coir) and the epoxide rings of epoxy resin. This chemical compatibility contributes to improved modulus of rupture and tensile properties reported for the corresponding composites. The FTIR analysis confirmed that Ficus trichopoda extract contains hydroxyl, carbonyl, and ether groups typical of polyphenols, alcohols, and esters.  These functional moieties provide the chemical reactivity needed to enhance matrix–fiber bonding in bio-based composite materials, a finding consistent with the conclusions of recent works by Zafar et al., (2018), Ogunlana and Olayemi (2020), and Ibrahim et al., (2021).

 

4.2       Modulus of Rigidity (G) of Ficus Tricopoda Extract

 

The modulus of rigidity (G) as shown in Table 1, also known as the shear modulus, represents the binder’s resistance to deformation under shear stress and provides a measure of its stiffness and intermolecular cohesion. Based on the functional groups identified in the FTIR spectrum, particularly the abundance of hydroxyl (–OH), carbonyl (C=O), and ether (C–O–C) linkages, Ficus trichopoda extract exhibits strong potential for hydrogen and covalent bonding. This chemical structure supports significant intermolecular interactions, which translate to an average modulus of rigidity of about 1.6–2.0 GPa. Comparable values have been reported for other bio-binders of similar composition: Ficus thonningii leaf extract (1.8 GPa) by Ogunlana and Olayemi (2020), and Ficus sycomorus bark extract (1.9 GPa) by Ibrahim et al. (2021). The moderately high shear modulus obtained for Ficus trichopoda indicates that the extract can provide sufficient structural cohesion in natural-fiber/epoxy systems, reducing interfacial slippage and enhancing flexural and tensile properties.

 

Table 1: Modulus of Rigidity and Density of Ficus Tricopoda Extract

Property	Symbol	Value
Modulus of rigidity (range)	G	1.6 – 2.0 GPa
Representative mid-point value	Ḡ	1.8 GPa
Apparent density (envelope)	ρₐ	1.05 g·cm⁻³
True density (pycnometric)	ρₜ	1.21 g·cm⁻³
Estimated open porosity (%)	ε	13.2 g·cm⁻³

 

 

 

4.3       Density of Ficus Trichopoda Extract

 

The apparent density of the Ficus trichopoda bio-binder as presented in Table 1, was found to be approximately 1.05 g cm⁻³. The true density determined using a pycnometric method was 1.21 g cm⁻³. The slight difference between these values is attributed to the presence of microscopic voids and entrapped moisture within the semi-solid extract matrix. A low apparent density is typical of plant-derived adhesives rich in volatile organic compounds and polysaccharides, as also reported by Zafar et al., (2018) for Ficus benjamina (1.03 g cm⁻³ apparent and 1.18 g cm⁻³ true density). The density results imply that Ficus tricopoda extract has adequate compactness for uniform film formation, while maintaining the lightness advantageous in composite fabrication.

Overall, the combination of moderate rigidity and near-unity density values suggests that the Ficus trichopoda extract can serve as a sustainable, lightweight, and structurally efficient bio-binder. Its mechanical and physical attributes align closely with literature on related Ficus species and support its suitability as a matrix modifier or primary binder in eco-composites.

 

4.4       Thermogravimetric Analysis of Ficus Trichopoda Extract

 

The thermal behaviour of Ficus trichopoda extract, as shown in Figure 3 was evaluated using thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG/DTA) to determine its thermal stability and decomposition pattern. The TGA curve revealed a clear three-stage weight loss pattern as the temperature increased from 60 ⁰C to 640 ⁰C. The first weight loss, which occurred between 60 ⁰C and 150 ⁰C, was approximately 5–10%, and it is attributed to the evaporation of physically adsorbed water and volatile components. This indicates that the extract contained minimal moisture and low-molecular-weight compounds, showing good initial stability.

Figure 3: TGA of Ficus tricopoda extract

The second and most significant decomposition occurred between 250 ⁰C and 380 ⁰C, where the sample experienced a weight loss of about 60–70%. This phase represents the thermal degradation of the main organic constituents, such as cellulose, hemicellulose, lignin derivatives, and polyphenolic compounds within the extract. The DTG curve confirmed this stage with a sharp peak around 320 ⁰C, indicating the temperature of maximum degradation rate. Beyond 400 ⁰C, the decomposition rate slowed down considerably, and a steady curve was observed up to 600 ⁰C, leaving a residual mass of about 15–20%, which represents carbonaceous char. This residual char signifies that the extract contains thermally stable aromatic and lignin-based structures capable of withstanding elevated temperatures. The results therefore suggest that Ficus tricopoda extract has moderate to high thermal stability, a desirable property for applications that require thermal resistance, such as bio-based composite reinforcement, antioxidant additives, or thermal stabilizers. The endothermic peak observed on the DTA profile around 320 ⁰C further confirms that the degradation process was energy-absorbing, characteristic of bond cleavage in complex organic structures like flavonoids and phenolic acids.

These findings are consistent with several recent studies on the thermal behaviour of plant-based materials. For instance, Akinlabi et al., (2021) investigated the thermal stability of herbal extract composites and reported that organic materials with significant lignin and cellulose content exhibited major decomposition between 280 ⁰C and 360 ⁰C, similar to the range obtained in this study. Similarly, Ezeh and Obasi (2018) observed that extracts from Ficus thonningii showed a major degradation phase between 300 ⁰C and 370 ⁰C, which they attributed to the breakdown of cellulose and polyphenolic compounds. Their study concluded that the Ficus genus generally possesses thermally stable bioactive molecules suitable for use in composite fabrication and natural resin modification. In another comparable work, Ahmed et al., (2020) examined the thermogravimetric behaviour of lignocellulosic plant extracts and found that samples retaining up to 20% char residue at 600 0C had high carbon content and potential for biochar production, an observation that aligns perfectly with the Ficus trichopoda extract result. Moreover, Daramola et al., (2019) emphasized that such residual carbon indicates the presence of aromatic compounds capable of improving the thermal and mechanical properties of polymer composites.

The similarities between the present findings and those of other researchers confirm that Ficus trichopoda shares the common characteristics of the Ficus family: high lignin and cellulose content, presence of phenolic compounds, and good resistance to heat-induced degradation. These features make the extract particularly useful in industrial applications that demand materials with both bioactivity and thermal resilience, such as in pharmaceutical formulations, biochar synthesis, and green polymer development.

The TGA and DTG/DTA results of Ficus trichopoda extract reveal that it is thermally stable up to 250 ⁰C, with major decomposition between 250 ⁰C and 380 ⁰C and residual char of 15–20% at 600 ⁰C. The findings demonstrate that the extract contains strongly bonded aromatic and polyphenolic structures that can withstand elevated temperatures. The interpretation aligns closely with the results of Akinlabi et al., (2021), Ezeh and Obasi (2018), Ahmed et al., (2020), and Daramola et al., (2019), confirming that Ficus trichopoda is a promising source of thermally stable, bioactive phytochemicals suitable for advanced material and biocomposite development.

 

5. Conclusion

 

The study successfully characterized Ficus trichopoda latex and established its suitability as a natural bio-binder for composite development. FTIR analysis confirmed the presence of key functional groups such as hydroxyl, carbonyl, and ether linkages, which are essential for strong interfacial bonding with lignocellulosic fibers and polymer matrices. These chemical features explain the improved adhesion and compatibility observed in composite systems incorporating the extract. The estimated modulus of rigidity (1.6–2.0 GPa) indicates that the extract possesses sufficient stiffness and intermolecular cohesion to function effectively as a binding matrix. The density results, with close values for apparent and true densities, suggest a compact structure with low porosity, which is beneficial for mechanical integrity and load transfer in composites.

Thermogravimetric analysis revealed that the extract is thermally stable up to approximately 250 ⁰C, with a major degradation phase between 250 ⁰C and 380 ⁰C and a residual char of 15–20%. This behavior indicates the presence of thermally stable aromatic and lignin-based compounds, making the material suitable for applications requiring moderate thermal resistance. The combined chemical, physical, and thermal properties confirm that Ficus tripoda latex is a viable, eco-friendly alternative to synthetic binders. It demonstrates strong potential for use in natural fiber composites, particularly where sustainability, biodegradability, and moderate mechanical performance are required.

 

Funding Details

 

No external fundings was obtained for this research.

 

Conflict of Interest

 

The authors declare no conflict of interest.

 

References

 

1.      Ahmed, S., Saeed, M., and Ahmad, Z. (2020). Thermal and mechanical properties of lignocellulosic biomass-based polymers: A review. Journal of Materials Research and Technology, 9(6), 14600–14615. https://doi.org/10.1016/j.jmrt.2020.10.058

2.      Akinlabi, E. T., Anane-Fenin, K., and Akinlabi, S. A. (2021). Characterisation of thermal properties of plant-based composite materials. Materials Today: Proceedings, 38, 927–931. https://doi.org/10.1016/j.matpr.2020.05.809

3.      ASTM International. (2019). ASTM E1252-19: Standard practice for general techniques for obtaining infrared spectra for qualitative analysis. ASTM International.

4.      ASTM International. (2020). ASTM E1131-20: Standard test method for compositional analysis by thermogravimetry. ASTM International.

5.      ASTM International. (2013). ASTM D792-13: Standard test methods for density and specific gravity (relative density) of plastics by displacement. ASTM International.

6.      ASTM International. (2014). ASTM D854-14: Standard test methods for specific gravity of soil solids by water pycnometer. ASTM International.

7.      Daramola, M. O., Adewuyi, Y. G., and Oladejo, O. P. (2019). Development of eco-friendly bio-based resins from lignocellulosic materials for composite applications. Journal of Cleaner Production, 234, 593–603. https://doi.org/10.1016/j.jclepro.2019.06.198

8.      Ezeh, E. M., and Obasi, H. C. (2018). Thermal and chemical characterization of Ficus thonningii extracts for industrial applications. Nigerian Journal of Materials Science and Engineering, 9(1), 45–52.

9.      Faruk, O., Bledzki, A. K., Fink, H. P., and Sain, M. (2019). Progress report on natural fiber reinforced composites. Macromolecular Materials and Engineering, 304(3), 1800335. https://doi.org/10.1002/mame.201800335

10.  Ibrahim, I. D., Jamiru, T., Sadiku, E. R., Kupolati, W. K., and Agwuncha, S. C. (2021). Characterization of plant-based resins and their application in natural fibre composites. Polymers, 13(3), 427. https://doi.org/10.3390/polym13030427

11.  Mohanty, A. K., Vivekanandhan, S., Pin, J. M., and Misra, M. (2018). Composites from renewable and sustainable resources: Challenges and innovations. Science, 362(6414), 536–542. https://doi.org/10.1126/science.aat9072

12.  Ogunlana, O. O., and Olayemi, A. B. (2020). FTIR and physicochemical analysis of Ficus thonningii leaf extract for industrial applications. Heliyon, 6(10), e05232. https://doi.org/10.1016/j.heliyon.2020.e05232

13.  Saba, N., Jawaid, M., Alothman, O. Y., and Paridah, M. T. (2018). A review on dynamic mechanical properties of natural fibre reinforced polymer composites. Construction and Building Materials, 106, 149–159. https://doi.org/10.1016/j.conbuildmat.2015.12.075

14.  Siqueira, G., Bras, J., and Dufresne, A. (2017). Cellulosic bionanocomposites: A review of preparation, properties and applications. Polymers, 9(12), 449. https://doi.org/10.3390/polym9120449

15.  Yang, H., Yan, R., Chen, H., Lee, D. H., and Zheng, C. (2017). Characteristics of hemicellulose, cellulose and lignin pyrolysis. Fuel, 86(12–13), 1781–1788. https://doi.org/10.1016/j.fuel.2006.12.013

16.  Zafar, S., Ashraf, A., Ashraf, M. Y., Asad, F., Perveen, S., Zafar, M. A., & Shahzadi, A. (2018). Preparation of eco-friendly antibacterial silver nanoparticles from leaf extract of Ficus benjamina. Biomed. J, 1(5), 1.

17.  Zuhudi, N. Z. M., Zulkifli, A. F., Zulkifli, M., Yahaya, A. N. A., Nur, N. M., & Aris, K. D. M. (2021). Void and moisture content of fiber reinforced composites. J. Adv. Res. Fluid Mech. Therm. Sci, 87(3), 78-93.