Abstract In this paper, the crystallization, fusion, and activation energy (Ea) of PBT/TiO2 were thoroughly evaluated using DSC. Increasing the rates shifted the peaks of melt crystallization to lower temperatures while the fusions were almost unaffected. TiO2 hindered the melt crystallization of PBT and lower crystallization rates, i.e., CMAX and K’ were acquired, in general, the crystallinity degree (Xc) was 4% higher in PBT/TiO2 which is in the marginal error. Pseudo-Avrami and Mo models were applied to evaluate the melt crystallization kinetics; both fitted the melt crystallization quite well; deviations were observed at the beginning and the crystallization end most due to the nucleation and spherulites impingement during the secondary crystallization. Ea was evaluated using the Friedman model, considering the values of Ea less energy has to be removed from PBT/TiO2 when compared to PBT, specifically at 1% of TiO2.

Abstract In this work eggshell membrane was added as biobased curing catalyst to epoxy (DGEBA), for comparison purposes the synthetic catalyst DEH 35 data was reported, the curing of compounds was followed through differential scanning calorimetry (DSC) under dynamic conditions and their kinetics were modeled using Kissinger, Friedman, Friedman model based and Málek approaches. From evaluated Ea and l n A two steps of curing were verified, for the synthetic catalyst compound (S5) Ea abruptly increased for the degree of conversion α > 0.7 the opposite trend was observed for the eggshell membrane compound (M10). It is supposed for S5 Ea increases due to the competitive reactions leading to viscosity increase until reach the solid phase with decrease of the reactive groups availability, hampering the cross-linking, whereas for M10 Ea decreases at α > 0.7, hence invalidating the Kissinger model which assumes constant Ea.

The effect of alcaline and hot water surface treatments of piassava Attalea funifera fibers was investigated. The efficiency of each treatment was evaluated by Fourier transform infrared spectroscopy, X-ray diffractometry, optical microscopy, scanning electron microscopy and atomic force microscopy. The alkaline treatments were effective in removing the superficial lignin layer from the fiber, while the hot water treatment was not. Treatment with hot water and NaOH caused fiber defibrillation. NaOH was most effective in promoting both, a decrease in fiber diameter and an increase in fiber surface area. Treatment with Ca(OH)2 led to the formation of a CaCO3 layer deposited on the fiber, preventing defibrillation. The crystalline structure of the fiber was not altered by any of the treatments, maintaining type I cellulose.