**3.1 Pulping and paper manufacturing**

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 *Opuntia* trunk was cut into chips (2–<sup>3</sup> <sup>1</sup>–<sup>2</sup> 1.5–2 cm<sup>3</sup> ) [25, 26]. Two processes 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


#### **Table 4.**

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

*Novel Trend in the Use of* Opuntia *(Cactaceae) Fibers as Potential Feedstock… DOI: http://dx.doi.org/10.5772/intechopen.92112*

processing with semi-chemical procedure gives a thick individualized fiber. It was considered as short fiber species [54]. It is also necessary to note that the pulp obtained from chemical procedures (at high temperature 170°C) was characterized by a high content (29.3% of the length) of fine elements.

The semi-chemical and chemicals pulps obtained from *Opuntia* trunk after delignification were exploited to make hand sheets. Paper sheets have been successfully manufactured as shown in **Figure 1**. Papers from semi-chemical pulps are the whitish than the ones obtained from chemical pulp. This is explained by the treatment with hydrogen peroxide which oxidizes the color of chemical groups.

The given data of physical properties of hand sheet papers, as seen in **Table 4**, confirms that the studied raw material has potential for use in paper manufacturing using the soft delignification by applying the semi-chemical procedure which can affect the paper properties by increasing the fiber flexibility and strength [22, 25, 54]. Thus, these data suggest that *Opuntia* (Cactaceae) fibers can be used for producing paper from non-woody plants with various qualities (strength) and for future green product applications.
