Effect of temperature on the esterification process for surface modification of coal bottom ash (CBA) in the development of green polymer composite

• Main Authors: Zainal, Mohamad Fetri, Yapandi, Md Fauzan Kamal Mohd, Zaman, Nur Zaqira Izzati Sukhairul, Latif, Famiza, Zamri, Sharil Fadli Mohamad, Zailani, Nabilah Akemal Muhd
• Format: Conference Proceeding
• Language: English
• Subjects: Aluminum; Bottom ash; Distilled water; Esterification; Hydrophilicity; Interlayers; Moisture effects; Palmitic acid; Polymer matrix composites; Polymers; Silicon dioxide; Sulfuric acid; Sustainable development; Temperature; Temperature effects
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0148051

The hygroscopic nature and porosity of Coal Bottom Ash (CBA) was successfully rectified with the surface modification via esterification process, prior to mixing with polypropylene (PP) in the development of green polymer composite. The optimum temperature for acid esterification was studied to enhance the compatibility and surface adhesion between modified CBA (mCBA) and PP. Esterification reactions were carried out for 4 hours at varying temperatures of 40°C, 50°C, 60°C, 70°C and 80°C. 50 g of Palmitic acid (PA) and 3.6 g of sulphuric acid (H2SO4) were used as the organic modifier and reaction catalyst. The mCBA samples were filtered and washed with distilled water before the samples were oven-dried at 60°C. The esterification reaction treated the polarity and converted the hydrophilic CBA into an organic hydrophobic material. CHNS analysis displayed high proportions of carbon and hydrogen in mCBA due to the embedment of PA’s organic segment on the surface of CBA. The attachment of alkyl group of PA into the mCBA chains altered the intensity peaks of Si-OH, Al-OH and ethylene (-CH2) groups at ∼3700cm-1, ∼900cm-1 and ∼2980cm-1. The intense peak depicted at ∼26o in XRD diffractogram signified the presence of large interlayer spacing (d) of SiO2 in mCBA and the formation of more amorphous phase of the composite at low esterification temperature. Subsequently, denser PP-mCBA composite with fewer voids were observed which indicate the reaction occurred between free hydrophilic sites at oxide groups and its surrounding moisture. Overall, the relatively amorphous PP-mCBA composite treated at 40°C exhibited superior drop impact energy (2.66J) than the unmodified composite.