2.2.2. Crystallinity Index (CI)

The calculation of the crystallinity index (CI) by XRD was applied using the method described by Segal et al. [34]. The maximum intensity of the peaks (1 0 1) and (0 0 2) was used. These peaks are associated with the amorphous and crystalline phases of the fibers. The CI value was determined using Equation (6) where, *I*<sup>1</sup> is the intensity of the

diffraction minimum (amorphous region) and *I*<sup>2</sup> is the intensity of the diffraction maximum (crystalline region). *2.3. SEM Analysis* 

CI = 1 −

The calculation of the crystallinity index (CI) by XRD was applied using the method described by Segal et al. [34]. The maximum intensity of the peaks (1 0 1) and (0 0 2) was used. These peaks are associated with the amorphous and crystalline phases of the fibers. The CI value was determined using Equation (6) where, *I*1 is the intensity of the diffraction minimum (amorphous region) and 2 is the intensity of the diffraction maximum (crystal-

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*Sustainability* **2022**, *14*, x FOR PEER REVIEW 5 of 12

$$\text{CI} = 1 - \frac{I\_1}{I\_2} \ast 100\tag{6}$$

∗ 100 (6)

#### *2.3. SEM Analysis* (SEM) in a model Quanta FEG 250 Fei microscope (Hillsboro, OR, USA) operating with

The ubim fiber surface morphology was analyzed by scanning electron microscopy (SEM) in a model Quanta FEG 250 Fei microscope (Hillsboro, OR, USA) operating with secondary electrons at 5 kV. secondary electrons at 5 kV. **3. Results** 

#### **3. Results** *3.1. Density Measurements*

line region).

*3.1. Density Measurements* 3.1.1. Geometric Method

2.2.2. Crystallinity Index (CI)
