Effect of Chemical Treatment Sequence on Pineapple Peel Fiber: Chemical Composition, Thermal Stability and Thermal Degradation Kinetics

Millions of tons of fruit wastes are generated globally every year from residual agriculture, which makes essential to find alternative uses to increase their aggregate value and reduce the impact of environmental damage. The present study aimed to explore pineapple peel as an alternative source of cellulose by evaluating its composition and physical properties, which are essential to provide a clue to its application function diverse. Cellulose was extracted by a sequence of chlorine-free treatments to delignify the fresh pineapple peels, followed by characterization using chemical composition, XRD, FTIR, SEM and TGA to determine its crystallinity, structural properties, morphology thermal characteristics, and thermal degradation kinetic study. The result revealed that the pineapple peel amorphous segments containing hemicelluloses and lignin were extensively removed with increasing chemical treatments, leading to increased purity, crystallinity index and thermal stability of the extracted materials. The maximum degradation, and crystallinity index of the 2B isolated from the PPF are 150 °C and 80.91% respectively. The cellulose content increased from 24.05% (pineapple peel) to 80.91% (bleached cellulose). These results indicated that pretreatment via bleaching has suitable potential applications in nanocrystal production and suggests possible uses in the development of cellulose nanocrystal and application for packaging films.

Exploration of Thermal Degradation Kinetics of Epoxy Resin Composites

The thermal degradation process of epoxy resin/intumescent flame retardant/flake graphite/hexagonal boron nitride (EP/IFR/FGP/h-BN) was analyzed by thermogravimetry. The effects of binary nano flake graphite/hexagonal boron nitride as synergistic flame retardant on the thermal stability. Flynn wall Ozawa method was used to calculate the activation energy of thermal degradation kinetics of EP/IFR/FGP/h-BN. The mechanism functions of the EP/IFR/FGP/h-BN in different reaction stages were determined according to Malek method, and the thermal degradation mechanism of EP/IFR/FGP/h-BN was obtained. The binary nanoFGP/h-BN is helpful to improve the thermal stability of EP.

Synthesis and characterization of novel methacrylate copolymers having pendant piperonyl group: monomer reactivity ratio, thermal degradation kinetics, and biological activity

In this study, 2-{[(2H-1,3-benzodioxol-5-yl)methyl]amino}-2-oxoethyl 2-methylprop-2-enoate (BMAOME) monomer was synthesized, and copolymers were prepared with glycidyl methacrylate (GMA). Structural characterizations of the compounds were performed using FTIR, 1H-, and 13C-NMR techniques. Monomer reactivity ratio values were calculated by Finemann–Ross (FR) and Kelen–Tudos (KT) methods. The Tg value of the polymers was determined by differential scanning calorimetry (DSC) and their thermal stability was determined by thermogravimetric analysis (TGA). The molecular weights (w and n) and polydispersity index of the polymers were determined by gel permeation chromatography. The Ea value of thermal decomposition was determined by using the Ozawa and Kissinger methods. The photo-stability of the copolymers was investigated. Furthermore, the photo-stability of the copolymers and the biological activity of polymers against different types of bacteria and fungi were investigated.