**3.2** *Opuntia* **(Cactaceae) fibrous network (F-N)-reinforced polymer composites: PVOH/F-N and SBR/F-N**

The reinforcing potential of F-N obtained from *Opuntia* (Cactaceae) trunk was also investigated by Mannai et al. [57], and the flowchart in **Figure 1** shows the main manufacture steps. Composites filled with F-N from *Opuntia* (Cactaceae) seem to be promising materials for green applications. Natural plant fiber polymer composites are a composite material consisting of a polymer matrix embedded with natural fibers [58]. It is representing a promising domain of value-added products derived from low-cost and naturally occurring raw materials. The processing methods performed to synthesize bio-composites are mainly based on fiber type, form, and position. *Opuntia* F-N was used as a bidirectional filler with intricate structure; it is considered as a heterogeneous sheet filler. Two thermoplastic polymers, which were polyvinyl alcohol (PVOH) and styrene-butadiene rubber (SBR), were used as the matrix polymers. The hand lay-up molding processing of PVOH and SBR-based composites was chosen according to the networks form of fibrous layer of *Opuntia*. The reinforcing potential of fibrous networks in composites was investigated by evaluating their properties, and interfacial adhesions between polymer/fibers were studied. The major factor that affects the reinforcement composite properties is the bonding strength between fiber and polymer matrix in the composite.

The previous sections have provided some characters of *Opuntia* (F-N) reinforced polymer composites obtained from dynamic mechanical analysis (DMA), thermogravimetric analyses (TGA), and biodegradation potential (BP). DMA was carried out by testing strips in axial (VF) and horizontal (HF) directions of incorporated fibers in order to understand the effect of additives and fillers on composites or filled materials [59]. As given in the previous work reported by Mannai et al. [57], the incorporation of fibers vertically for each matrix enhanced the storage modulus, especially for SBR-based composite. Otherwise, the relaxation process for composites reinforced with fibers oriented vertically is significantly higher than the one obtained for the filler oriented horizontally [57]; this can be explained by the elastic behavior of thicker axial fibers than other fibers interconnected with bifurcation ones [9] (see **Figure 3**). Mechanical interlocking and interfacial bonding adhesion are sensitive and can be improved by the natural fibers'surface roughness (**Figure 3**). The thermal behavior of *Opuntia* (F-N) reinforced polymer composites was carried out using TGA in the conditions described in detail by Mannai et al. [57]. The main thermal data are summarized in

**3. Potential applications of cellulose fibers from** *Opuntia* **(Cactaceae)**

*Invasive Species - Introduction Pathways, Economic Impact, and Possible Management Options*

For papermaking, two main steps are followed in which the raw material is firstly cooked to obtain fibrous mass (pulp), and then the pulp is converted into paper. Mannai et al. [25, 26] were the first to find the preparation of pulp and papers from *Opuntia* trunk using semi-chemical and chemical pulping procedures, with yields of 80.8 and 41.1%, respectively [54]. Multistep pulping processes were followed to produce pulps and papers from *Opuntia* as shown in **Figure 1**. The manufacturing of pulp starts with raw material preparation [55], in which the dried

have already been applied to the delignification of *Opuntia* chips. The semichemical procedure based on the chemical treatment of raw material using soda– hydrogen peroxide (soda–HP) mixture (with the control of pH11) and the delignification reaction steps are done under reflux [25, 54]; these steps are

followed by mechanical deliberation operation of cooked chips to more individualize and deliberate the fibrous suspensions. The obtained soda–HP pulp was purified by the classification of fibers by applying the standard T275 sp-12 method. Likewise, it has already been applied to the delignification of *Opuntia* trunk chips in a procedure described by Mannai et al. [26, 54], which utilized a total soda alkali charge of 20% (w/w o.d.) and an anthraquinone concentration of 0.1% (w/w o.d.). The liquor to solid ratio was kept at 10, and the mixture was cooked for 120 min at 170°C with a temperature ramping rate equal to 2.4°C/min. All of their experiments were conducted in a 1 L reactor that took 1 h to reach a constant temperature.

The morphological fiber's dimensions of the obtained fibrous suspensions in terms of their average length (mm) and width (μm) and the percentage of fine elements were examined using a MORFI (LB-01) analyzer developed by Techpap. The obtained results are summarized in **Table 4**. The fiber length (and width) of the *Opuntia* semi-chemical and chemical pulps were 764 μm (38 μm) and 737 μm (54.6 μm), respectively, which are in the same range of hardwood fibers [56]. The

**Semi-chemical [25] Chemical [26]**

**Pulp and paper properties Pulping process**

Bases weight (g/m<sup>2</sup>

Burst index (kPa m<sup>2</sup> g<sup>1</sup>

Tear index (mNm<sup>2</sup> g<sup>1</sup>

Bulk (cm<sup>3</sup>

**Table 4.**

**150**

*pulping procedures.*

Yield (%) 80.8 41.4 Fiber length (μm) 764 737 Fiber width (μm) 38 45.6 Fine elements (%) 16.3 29.3

Thickness (μm) 149 135

Young's modulus (GPa) 1.7 1.83 Breaking length (km) 1.9 1.57

/g) 2.26 2.07

*Fiber and handmade paper produced from* Opuntia *(Cactaceae) pulps after semi-chemical and chemical*

) 38.4 65.2

) 0.67 5.8

) 19.2 12

) [25, 26]. Two processes

**3.1 Pulping and paper manufacturing**

*Opuntia* trunk was cut into chips (2–<sup>3</sup> <sup>1</sup>–<sup>2</sup> 1.5–2 cm<sup>3</sup>


valuable advice and assistance, as well as to the Tunisian Ministry of Higher

, Ramzi Khiari4,5,6 and Younes Moussaoui2,3\*

2 Organic Chemistry Laboratory (LR17ES08), Faculty of Sciences of Sfax,

4 Faculty of Sciences, UR13 ES 63, Research Unity of Applied Chemistry and

5 Department of Textile, Higher Institute of Technological Studies of Ksar Hellal,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

3 Faculty of Sciences of Gafsa, University of Gafsa, Tunisia

Environment, University of Monastir, Monastir, Tunisia

6 University of Grenoble Alpes CNRS, Grenoble, France

\*Address all correspondence to: y.moussaoui2@gmx.fr

provided the original work is properly cited.

1 Material Environment and Energy Laboratory (UR14ES26), Faculty of Sciences of

Education and Scientific Research for the financial support.

*Novel Trend in the Use of* Opuntia *(Cactaceae) Fibers as Potential Feedstock…*

The authors declare no conflict of interest.

*DOI: http://dx.doi.org/10.5772/intechopen.92112*

**Conflict of interest**

**Author details**

Gafsa, University of Gafsa, Tunisia

University of Sfax, Tunisia

Faten Mannai<sup>1</sup>

Tunisia

**153**

**Table 5.**

*Thermal characteristics of PVOH and SBR-based composites reinforced with F-N layers of* Opuntia *(Cactaceae) trunk obtained from TGA measurements.*

**Table 5**. From the discussion in **Table 5**, we can notice that F-N enhances the thermal properties of the used thermoplastic polymers.

The biodegradability potential (BP) (soil-burial test) of the matrix and produced composites were obtained by the mass retention technique, following the procedure outlined in literature [60, 61], and the results are given in the previous work [57]. The evolution of BP vs. time for the different materials after soil burial decreases gradually and tends to 93 and 86.6%, respectively, for PVOH/F-N and SBR/F-N [57]. These values are higher than those reported for PVOH/palm kernel shell powder bio-composites (20%) [62] and PVOH/corn starch films (40%) [63]. It should be mentioned that cellulosic fibers from *Opuntia* (Cactaceae) plant, PVOH, and SBR are biodegradable in nature, in which they may serve as a source of energy and carbon for specific microorganisms [64, 65]. From this study, eco-friendly *Opuntia*-derived fiber-reinforced polymer (thermoplastic) composites would be the materials for near future not only as a solution to the growing environmental threat but also as a solution to alleviating the uncertainty of the petroleum supply.
