721 2.3 Characterizations The raw materials and biomaterials, processed via casting and extrusion, were characterized for their chemical, structural, thermal, morphological, and mechanical properties. XRD patterns were obtained using a Bruker D4 Endeavor diffractometer with Co Kα radiation (40 kV/40 mA). Scans were performed over a 2θ range of 5-80°, with a 0.02° step and a LynxEye detector. To evaluate basal spacing modifications, clay samples were subjected to ethylene glycol solvation (12 h) and calcination (550°C, 1 h). FTIR spectra were recorded using a PerkinElmer Spectrum 100 spectrometer equipped with an attenuated total reflection (ATR) accessory. Spectra were acquired over a wavenumber range of 4000-600 cm⁻¹, with 32 scans per sample and a spectral resolution of 4 cm⁻¹. TGA was performed on a Mettler Toledo TGA/DSC 1 STARe System, operating from 25 to 1000 °C at a heating rate of 10 °C/min, using a platinum sample holder under a nitrogen atmosphere. DSC analyses were performed on a TA Instruments Q200 calorimeter. Samples (∼10 mg) were heated from 40 to 200 °C (10 °C/min). Thermal transitions, including glass transition (Tg), crystallization (Tc), and melting (Tm) temperatures, were determined from the second heating cycle. Crystallinity (Xc) was calculated as: Xc = 100 (ΔHc –ΔHm /ΔHm100%) (%) where ΔHc is PLA’s enthalpy of cold crystallization, ΔHm is the enthalpy of melting of PLA, and ΔHm100% is the theoretical melting enthalpy of 100% crystalline PLA, 93 J/g [Puchalski ET AL., 2017]. Scanning electron microscopy (SEM) analysis was performed on samples sputter-coated with gold and examined using a Hitachi TM3030Plus SEM (15 kV, high vacuum). Backscattered electron imaging provided elemental contrast. Tensile properties, including maximum strength, elastic modulus, and elongation at break, were evaluated following ASTM D638 using an Emic DL-3000 universal tester (30 kN load cell, 5 mm/min crosshead speed, 100 mm clamp distance, 23 °C, 50 ± 5% RH). Five replicates were tested after 48 h conditioning 3. RESULTS AND DISCUSSION 3.1 XRD Studies 3.1.1 Evaluation of basal spacing of bentonites XRD analysis revealed characteristic montmorillonite and kaolinite peaks, indicating smectite-rich clays. Thermal treatment (550 °C) induced structural collapse (Figures 4.1, 4.3), while ethylene glycol treatment expanded interlayers (Figures 4.2, 4.4), confirming smectitic nature. Temperature-induced lattice distortions altered Bragg reflections, affirming smectite clay mineralogy [Bertagnolli ET AL., 2011]. CTAB intercalation increased basal spacing (Figure 4.5), rendering bentonites hydrophobic and enhancing organic adsorption capacity. Figure 4 - XRD patterns: (1 and 3) K-saturated clays (Bofe and Chocolate) - montmorillonite and kaolinite 001 reflections: (a) natural, (b) room temperature, (c) 110°C, (d) 350°C, (e) 550°C. (2 and 4) Mg-
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