Stages Of Mass Loss Research Articles

Effects of pyrolysis temperatures on the oxidation behavior of PIP-processed SiCf/SiC composites

Three kinds of four-step three-dimensional braided silicon carbide fiber-reinforced silicon carbide matrix composites with pyrocarbon interface were prepared through precursor infiltration and pyrolysis under 1100 °C, 1300 °C, or 1500 °C, and they were oxidized at 1300 °C with simulated air. The effects of pyrolysis temperature on the microstructure and oxidation behavior of the composites were investigated. Results indicated that the SiC crystallite size and crystallinity of the as-fabricated composites increased with increasing pyrolysis temperature. During oxidation, the three composites initially underwent similar near-linear mass-loss stages associated with the consumption of carbon component. Subsequently, they exhibited different mass-gain stages associated with the oxidation of SiC component. The composites prepared at 1100 °C followed a linear mass-gain rule, whereas the composites prepared at 1300 °C and 1500 °C followed a two-step parabolic mass-gain rule. The mechanism of mass-gain behavior change was proposed, which might be associated with the pyrolysis-temperature-dependent precursor-derived ceramic SiC microstructure and its evolution during oxidation.

Thermal analysis and hazards evaluation for HTP-65W through calorimetric technologies and simulation

Di-tert-butyl peroxy-hexahydro terephthalate (HTP-65W), a newly developed organic peroxide, has been used in manufacturing acrylonitrile–butadiene–styrene copolymer and as an initiator in the polymerization. However, few studies focus on the thermal hazards of HTP-65W. The purpose of this study was to investigate the thermal decomposition phenomenon of HTP-65W under different conditions via calorimetric technologies and simulation. According to simultaneous thermogravimetric analyzer curves, two mass loss stages were detected at about 79 °C and around 64–72% mass loss happened in the first stage. Furthermore, the real view system was used to observe the apparent physical phenomenon like color and state change in HTP-65W during the reaction. Utilizing accelerating rate calorimeter and adiabatic kinetic method, the exothermic phenomena occurred at around 75 °C. The apparent activation energy (Ea) and rate constant of reaction under adiabatic conditions were 172.0 kJ mol−1 and 4.0 × 1025 mol L−1 s−1. Through differential scanning calorimetry and kinetics simulation, an exothermic peak appeared between 87 and 168 °C caused by the thermal decomposition of HTP-65W, and the Ea calculated using Flynn–Wall–Ozawa and Friedman methods were 143.4 and 128.4 kJ mol−1, respectively. To prevent thermal loss prevention accidents, time to maximum rate under adiabatic condition was obtained as 24 h under 63.9 °C and self-accelerating decomposition temperature was 61 °C for 50 kg package size of HTP-65W. Results of this study can support to prevent the potential thermal hazards of HTP-65W happened during storage, transportation, and manufacturing process.

Thermal decomposition and combustion characteristics of Al/AP/HTPB propellant

Aluminum(Al)/ammonium perchlorate(AP)/hydroxyl-terminated polybutadiene (HTPB) propellant is the most widely used propulsion system currently. Its ignition and combustion processes are fairly complex and need to be better understood. In this study, the thermal decomposition, ignition, and combustion properties of an Al/AP/HTPB propellant were investigated using a thermogravimetry–differential scanning calorimetry and a laser ignition testing system. The morphology and size distribution of the condensed combustion products (CCPs) were analyzed using a laser particle size analyzer and scanning electron microscopy. Results showed that the thermal decomposition process of the propellant consisted of three stages. The first stage (100–430 °C) was a major mass loss stage and exhibited typical features of AP decomposition. The second stage (430–630 °C) was mainly accompanied by the decomposition of remaining HTPB as well as slight oxidation of Al particles. In the third stage, further oxidation of Al particles resulted in a small mass increase. Due to the continuous emission problem, only a few combustion intermediates were identified in the combustion emission spectrum curves. The propellant combustion process could be roughly divided into three stages, and the flame development stage lasted longer than the flame decline stage. As the pressure increased, the propellant ignition delay time decreased and the burning rate increased significantly. The effect of pressure on ignition delay was more pronounced at low pressures. The CCPs consisted of three types. The oxidation of Al particles in the propellant followed the diffusion reaction mechanism. Agglomerates appeared in several different morphologies and had relatively low combustion efficiency under experimental conditions. A 2-D pocket-like structure was observed on the propellant surface.

Characterization and compatibility of dry extract from Annona muricata L. and pharmaceutical excipients

The aim of this study was to characterize and evaluate the compatibility of the dry extract (DE) of leaves of Annona muricata L. with pharmaceutical excipients usually used in the manufacturing of medicines. Characterization of the DE and binary mixtures of the extract and excipients was carried out using scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetry (TG) and Fourier transform infrared attenuated total reflection spectroscopy. Spray drying technique produced extract to form spherical and hollow particles revealed by SEM, with four stages of mass loss in the TG curve. Pre-formulation study showed compatibility between the extract and microcrystalline cellulose, lactose, croscarmellose sodium and sodium starch glycolate. New medicines containing herbal drugs enter the market every year, and our study demonstrates that thermoanalytical techniques can be used in the development and quality control of herbal medicines.

Effect of different BPS concentration on the thermal decomposition and thermal stability properties of GAP curing

ABSTRACTIn order to study the optimal ratio of the degree of bis-propargyl-succinate (BPS) cures Glycidyl azide polymer (GAP), the thermal kinetics of BPS cured system was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG), the thermal stability and mechanical properties were studied. GAP was cured by the reaction of the azide group with BPS through a 1,3-dipolar cycloaddition reaction to form a 1,2,3-triazole network. It was found that the DSC curves of the BPS cured system show an obvious exothermic peak at around 230–260°C for each sample at different heating rates. TG-DTG curves of the BPS/GAP system exhibit two major stages of mass loss for different samples at different heating rates. When the mass ratio of BPS and GAP is 0.4:1, the thermal stability and mechanical properties were optimal. Meanwhile, the activation energy and frequency factor are calculated by Kissinger and Flynn–Wall–Ozawa methods by non-isothermal thermoanalytical data, the kinetic parameters proved that 0.4 BPS sample shows high thermal stability and the parameters are significant for further research of curing system.

Treatment of diesel-contaminated soil using thermal water vapor arc plasma.

Soil pollution with petroleum-based fuels is a serious issue causing environmental problems. Recently, the use of plasma technologies for soil remediation has shown an interest and great potential. The remediation process can be performed in a fast timeframe without adding supplementary chemical reagents or without additional pre-treatment of the polluted soil. As a result, the use of plasma enables to obtain highly effective degradation of pollutants. Thus, in the present experimental research, diesel fuel removal from contaminated soil by utilizing thermal water vapor arc plasma was investigated. It was found that increased concentration of diesel fuel in the soil raised carbon and hydrogen concentrations in the soil. Moreover, soil surface morphology was modified by causing the formation of bigger agglomerates. It was also determined that after the plasma treatment process, soil grains became akin in size and structure to clean soil grains. A complete desorption of carbon, which came from diesel fuel to the soil, and a slight decomposition of organic carbon present in the soil were observed during the soil remediation process. Thermogravimetric analysis showed that regardless of the diesel fuel concentration in the soil, four stages of mass loss were observed: moisture loss, vaporization, and combustion of diesel fuel as well as reduction of volatiles and char in the soil. Producer gas analysis indicated that during soil remediation diesel fuel was mainly converted to synthesis gas, i.e., a mixture of H2, CO, and CO2. Moreover, the decomposition of diesel fuel and the formation of synthesis gas depended on the amount of pollutant in the soil. According to the obtained results, thermal water vapor arc plasma was able to completely remove diesel fuel from polluted soil in the form of synthesis gas with no significant influence on soil's properties.

Heat and mass transfer from a system of closely packed capillaries – Possible choice for wicks

Evaporation characteristics of a radiatively heated (~1000 W/m2 of incident heat flux) unconventional porous medium consisting of closely packed vertical capillaries have been investigated. Three stages of mass loss from a conventional porous medium, consisting of spheres, are well known; high evaporation rate in stage 1 is sustained by capillary liquid films, which transport liquid from lower regions of a porous medium to its exposed top surface. We show that in a bundle of capillaries, stage 1 is sustained by near-zero radii (NZR) of contacts, formed throughout the contact line of two or more touching capillaries, which can theoretically lead to infinite height rise. Some of the evaporative features of these NZR of contacts were recently (Kumar and Arakeri, 2018b) explored. With closely packed capillaries, along with the existence of the NZR of contacts (as in rods’ case), we get an additional advantage of having inner diameter, which we show act as a reservoir for the nearby NZR of contacts. We report extremely high (time) duration of high rates of evaporation from a bundle of capillaries, which is seemingly impossible to achieve in the conventional systems. In passive systems like loop heat pipes and capillary pumped loops, an additional reservoir is not needed in case a wick consisting of closely packed capillaries are used.

Microstructure mechanism of the hydroxyapatite densification process

Hydroxyapatite (HA) is a well-known materials used as biomaterials in various applications. Numerous studied had been done for unlocking the pros and cons of this material. Sintering process has been used for extraction of pure HA that have similar Ca/P ratio to human bone mineral. This study aims to investigate the effect of sintering temperature on the properties of synthetic HA as well as to develop the mechanism of this densification process. Synthetic HA powder (Sigma-Aldrich #04238) was mixed together with binders, namely polyvinyl alcohol (PVA) and polyethene glycol (PEG) in wet mixing condition using ball mill. Pressed HA (15 g, 65 mm x 12 mm) was sintered with temperature ranging from 1000°C to 1200°C with heating rate and cooling rate of 10°C/min. It has been found that, pure HA was obtained when the HA was sintered with temperature ranging from 1000°C to 1200°C. The thermogravimetric analysis showed that there are there were two mass loss stages on the heating process from room temperature to 1250°C; 100-500°C (dehydroxylation) and 680-1080°C (decomposition). From the microstructure data, the mechanism of the densification process of HA was developed.

Combustion behaviors of Pteris vittata using thermogravimetric, kinetic, emission and optimization analyses

Abstract This study aims to assess the combustion efficiency and emissions of both aboveground (PA) and belowground (PB) biomass parts of Pteris vittata. Their combustion process consisted of three major stages, with devolatilization as the main stage of mass loss by 59.06% between 182 and 382 °C for PA, and by 58.24% between 182 and 375 °C for PB. The primary emissions were related to the carbonaceous (90.50% for PA; 90.80% for PB) and N-containing species (6.95% for PA; 6.56% for PB). 172.44% SO2, 137.49% NO2, and 124.48% CO emissions were released more from the PB than PA combustion. Air pollutants were generated between 70 and 500 °C from PA and 60 and 700 °C from PB, with the PB combustion requiring more pollution controls at a higher temperature. The joint optimizations of derivative thermogravimetry, differential scanning calorimetry, remaining mass, and conversion degree indicated 999.2 and 514.6 °C for combustion temperature, 193.6 and 97.1 min for combustion duration, and 40 °C/min for heating rate as the optimum operational schemes for the cleanest production for the PB and PA combustions, respectively. Average activation energy was described using four iso-conversion and integral master-plots methods. The hemicelluloses combustion for PA and PB were best described by the diffusion mechanisms, while the cellulose and lignin + char combustions corresponded to the reaction order mechanisms. Our results contribute to developing the new strategies of cleaner production with the P. vittata combustion.

Evolution of drying kinetics and properties of pyrolusite during microwave heating

Microwave heating is a developing noncontact heating method in dewatering technology. It has been proved to be effective to dewater high moisture content in mineral substance via the application of the dielectric loss of materials. In this study, the effects of microwave power levels (250–550 W) and different sample masses (20–40 g) on microwave drying behavior of pyrolusite have been investigated. For the purpose of the mechanism and morphological changes to the pyrolusite in the process of drying, thermogravimetric analysis, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were used, respectively. The experiment results demonstrated that an increase in the microwave power as well as sample mass was found to increase the drying rate during pyrolusite drying processes, with there are four main mass loss stages from 20 to 900 °C. The SEM-EDS analysis results show that morphological changes with the presence of more pores and appearance in spiral cross-linking way reduced the particle size and the shrinkage of the faces and edges, in which it can been concluded that the microwave drying is an effective method to produce the high-grade pyrolusite. By analysis, the increased pore structure and shrinkage phenomena can be observed, which increase the specific surface area of manganese ore effectively and may benefit the subsequent reduction process of high valence manganese, after the process of microwave heating.

Synthesis, Physicochemical Properties and Anti‐Fatigue Effect of Magnesium, Zinc and Chromium Polygalacturonate Based Composition

AbstractThe present study is focused on the development of a composition based on three pectin metal complexes (NaMg‐PG, NaZn‐PG and NaCr‐PG) at a mass ratio 7:0.3:0.001. It was evaluated by the methods of infrared spectroscopy (IR spectroscopy), atomic force microscopy (AFM), dynamic light scattering (DLS) and TEM‐EDS. The data, obtained by simultaneous thermal analysis and Fourier transform IR spectroscopy, showed that water was the main component of the gas phase at the first stage of mass loss of the specified compounds, whereas further heating led to decarboxylation and degradation. The results of Forced Swim Test (FST) showed that the specified composition at the dose of 50–100 mg/kg contributed to the stimulation of an organism‘s adaptive capacity under intensive physical loads and could be considered as a potential adaptogen and stimulator of erythropoiesis that could normalize metabolism.

Comparative investigation on thermal degradation of flue-cured tobacco with different particle sizes by a macro-thermogravimetric analyzer and their apparent kinetics based on distributed activation energy model

The particle size was an important factor that can affect the thermal degradation behavior of biomass during thermochemical conversion. In this work, the thermal degradation behavior of flue-cured tobacco with different particle sizes for thermochemical conversion was investigated by a self-designed macro-thermogravimetric analyzer (macro-TGA) under inert and oxidative conditions. During pyrolysis and combustion, the thermal degradation behavior could be described by a four-stage and five-stage mass loss reaction, respectively. At the second mass loss stage, for six cut tobaccos, the mass loss rate increased with the decrease in particle size during pyrolysis and combustion. In addition, the combustion character index of cut tobaccos ranging from 3.0480 × 10−7 to 4.4825 × 10−7%2 min−2 °C−3 also increased with the decrease in particle size. Furthermore, the mass change data recorded by the macro-TGA were used to estimate the kinetic parameters, such as the apparent activation energy and the pre-exponential factor, based on distributed activation energy model. For the thermochemical conversion of tobacco materials, it was found that the apparent activation energy increased with the increase in conversion rate for pyrolysis reaction under inert condition, while the apparent activation energy reached a maximum within a certain conversion rate in the middle of combustion reaction under oxidative condition. As well, the kinetic compensation effect was evaluated by the equation $$\ln A = \varphi \times E + \psi$$. The investigation on thermal degradation and apparent kinetics of tobacco revealed the effect of particle size on thermochemical conversion, which can provide a reference for building a more accurate cigarette combustion model.

Thermokinetic characteristics of coal spontaneous combustion based on thermogravimetric analysis

Coal spontaneous combustion (CSC) is a severe threat to coal mining operations. Using thermogravimetric experiments, the contributions of different mechanisms to the mass variation during CSC were analysed. Furthermore, the kinetic mode and kinetic compensation processes were investigated. Among the different mechanisms of coal–oxygen reaction, solid-phase combustion contributes least to mass loss; for coals of high rank, gas-phase combustion makes the greatest contribution. Oxidative decomposition contributes most for coals of low rank. Furthermore, the kinetic mode governing CSC is three-dimensional diffusion in the mass gain stage and changes to random nucleation and subsequent growth in the mass loss stage. The apparent activation energy reaches its maximum near the ignition temperature and indicates a kinetic compensation effect with the pre-exponential factor in each stage. These findings are crucial for understanding the processes involved in CSC.

The simultaneous calcination/sulfation reaction of limestone under oxy-fuel CFB conditions

Using a customized thermogravimetric analyzer, the characteristics of the simultaneous calcination/sulfation reaction of limestone (the simultaneous reaction) under oxy-fuel circulating fluidized bed (CFB) boiler conditions were investigated. The results were compared with the calcination-then-sulfation reaction (the sequential reaction) that has been widely adopted by previous investigators. The sample mass in the simultaneous reaction was higher than that in the sequential reaction. With the increase of SO2 concentration (0–0.9%), the mass difference between the two reaction scenarios increased; while with the increase of temperature (890–950 °C), the difference became smaller. Calcination in the presence of SO2 was slower than that without SO2. With the increase of SO2 concentration, the pore volume of the calcined CaO decreased, and the effectiveness factors of the calcination reaction also declined. This indicates when CaSO4 forms, the pores in CaO were filled or blocked, thus increasing the internal resistance to CO2. Because the simultaneous process is the real one in CFB boilers, and it shows different characteristics from the sequential reaction, all investigations of CaO sulfation in CFB should follow this approach. Also in this work, the effects of SO2 concentration, temperature and H2O on the simultaneous reaction were studied. The sulfation ratio in the simultaneous reaction increased with higher SO2 concentration. Compared with that in the absence of H2O, 8% H2O in flue gas significantly improved sulfation. In the tested range (890–950 °C), the optimum temperature for sulfation was around 890 °C. The sulfation rate in the mass-loss stage was higher than that in the fast sulfation stage, which is likely due to the continuous generation of nascent CaO in this stage.

Study on the kinetic model, thermodynamic and physicochemical properties of Glycyrrhiza polysaccharide by ultrasonic assisted extraction

The extraction process of crude polysaccharides from Glycyrrhiza (GP) by ultrasonic assisted hot water method was established according to the optimized kinetic model based on Fick’s second law of diffusion, and thermodynamic action was analyzed. Physicochemical properties of GP including the apparent viscosity, thermostability and antioxidant activities etc. were determined by ultraviolet spectrophotometry and differential scanning calorimetry (DSC). Characteristic function groups and surface structure also were analyzed by Fourier infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The results showed the extraction kinetic curves of GP showed good linear correlation with the linear correlation coefficients (R2) of equal or greater than 0.90 based on Fick’s second law of diffusion, and the maximum yield of 3.53% was obtained at 343.15 K and ultrasonic power 600 W with material-liquid ratio of 1:15 for 60 min. Gibbs free energy change (ΔGm > 0) indicated that the extraction process was endergonic and not spontaneous. GP was confirmed a kind of acidic pyran polysaccharide with small bubble-like holes internally. The GP viscosity increased with the increase of concentration and then gradually decreased with the enhancement of shear rate. GP showed good thermal stability along with two stages of mass loss by DSC analysis. The antioxidant activity experiments suggested that the higher the concentration of GP, the stronger its reduction power.

Thermogravimetric study of the combustion characteristics of biodiesel and petroleum diesel

The thermal behavior of biodiesel and a comparison with a petroleum diesel combustion process was investigated via thermogravimetric analysis. The investigation was carried out under atmospheric conditions of pure air flow at four different heating rates, reaching a temperature of 700 °C. Beyond the initiation (a fraction of mass loss) stage of the thermograph, the diesel exhibited only one mass loss event, whereas the biodiesel was characterized with two mass loss events. The ignition and burnout temperatures are essential properties of fuel combustion used in their industrial application, and they were evaluated using numerous methods at every heating value. The kinetic parameters were also calculated using the Kissinger method. The values obtained for the main mass loss event I, devolatilization, were 98.8 and 63.4 kJ mol−1, respectively, for the biodiesel and diesel. Additionally, the thermodynamic parameters were calculated including the enthalpy, Gibbs free energy and entropy and found to be 94.3 kJ mol−1, 158 kJ mol−1 and − 0.116 kJ mol−1 for the biodiesel, compared to 59.2 kJ mol−1, 150.5 kJ mol−1 and − 0.117 kJ mol−1 for the diesel, respectively. Results indicate better reactivity in favor of the petroleum diesel. Hence, utilizing biodiesel at 100% for utility burners and internal combustion engine may require some additives to compensate the change and the measured lower heating value (~ ≤ 5%). Therefore, blending has been the simplest practical approach.

A comparative study of the thermal and oxidative stability of moringa oil with olive and canola oils

Moringa oleifera L. is an unconventional source of edible oil. Like olive oil, it is rich in oleic acid (monounsaturated fatty acid) with a high potential to be used in food preparation. The present investigation reports on a study of oxidative stability of moringa oil compared with olive and canola oils, employing the Rancimat and PetroOxy accelerated techniques and Schaal test. The values of induction periods obtained in the Rancimat test showed that moringa oil (23.68 ± 0.54 h) presented an oxidative stability similar to that of olive oil (23.43 ± 0.24 h) and both moringa and olive oils were significantly more stable than canola oil, (7.58 ± 0.33 h), although the PetroOxy test found the highest oxidative stability for moringa oil. Thermal degradation assessment of the oil samples was carried out using a thermogravimetric (TG) analysis. TG curves of the oils showed three stages of mass loss, and the moringa oil showed the higher thermal stability among the studied oils. In addition, the moringa oil remained practically unchanged in the Schaal test, whereas the olive and canola oils had undergone isomerization, evidenced by the absorbance of fatty acids with trans double bonds observed in the infrared spectra. Results obtained showed that moringa oil presented the good thermal and oxidative stability, being indicative that its shelf life would be longer when compared to the other oils evaluated.

Effects of high temperature treatment on physical-thermal properties of clay

High temperature changes the internal microstructure of clay and consequently affects its physical and thermal properties. In this paper, the influence of firing temperature (up to 900 °C) on the thermo-physical properties of clay is analyzed through laboratory tests and the relationship between thermal conductivity and density is revealed. Furthermore, the variation of surface characteristics including clay color and cracking is reported. The results obtained indicate that the thermal conductivity and diffusivity as well as the bulk density of clay decrease rapidly as the temperature increases from room temperature to 200 °C, and then become approximately constant. From the Thermogravimetric Analysis (TG) and Differential Thermal Analysis (DTA) tests it is also shown that there are two significant stages for the clay exposed to high temperature: 25–200 °C and 400–700 °C. The evaporation of adhered water and bound water are proved to be the main reason for the first stage of clay mass loss at 25–200 °C, while the decomposition of minerals is considered as the second stage of mass loss in the temperature range of 400–700 °C. In addition, the combustion of organic matter in clay is the main reason for its darkening at 300–400 °C.

Effects of flame retardants on thermal decomposition of SARA fractions separated from asphalt binder

To better understand effects of flame retardants on thermal decomposition of saturates, aromatics, resins and asphaltenes (SARA) fractions in asphalt binder, different flame retardants were selected to match the thermal decomposition temperature range of each SARA fraction, respectively. Then inhibitory effects of matched flame retardants were discussed and microscopic morphology of combustion residues were observed. The results indicate that the decomposition process of each SARA fraction still includes two thermal mass loss stages after adding the matched flame retardants. However, the thermal decomposition rates are lowered, and the initial decomposition temperatures and maximum decomposition temperatures of each SARA fraction are elevated. Also, the matched flame retardants have few effects on the volatile constituents of four SARA fractions, but show an obvious influence on the release amount of gaseous products. CO2 and H2O are still the two main products of each SARA fraction after adding matched flame retardants. Few chemical reactions between SARA fractions and flame retardants are found during their decomposition. Additionally, the superposed and densified charring layers are formed due to the synergic effects of the composite flame retardants. The thick charring layer prevents the heat from transferring, and hinders the oxygen supply, and inhibits the release of flammable volatiles. Finally, the thermal stability of each SARA fraction is greatly improved by the matched flame retardants. The composite flame retardants show a synergistic flame retarding and smoke suppressing effects. This study is beneficial to develop new composite flame retardants for asphalt binder with a satisfactory flaming retarding and smoke suppressing effects.

O-Acetylated (1→6)-β-D-Glucan (Lasiodiplodan): Chemical Derivatization, Characterization and Antioxidant Activity

β-Glucans are biomacromolecules that present biological properties of medical and pharmacological interest. The chemical modification of the primary structure of these carbohydrate biopolymers is a way to enhance or achieve new biological properties. Acetylated derivatives of (1→6)-β-D-glucan (lasiodiplodan) with different degrees of substitution (0.48, 0.66, 1.03 and 1.26) were obtained and characterized by infra-red and NMR (nuclear magnetic resonance) spectroscopy, thermal analysis, X-ray diffraction and antioxidant capacity. Acetylation was confirmed by FT-IR, and 13C NMR spectroscopy. Thermal analysis indicated that unmodified lasiodiplodan and the O-acetylated -glucan derivative of degree of substitution 0.48 presented three stages of mass-loss, whereas acetylated derivatives of DS (degree of substitution) of 0.66, 1.03 and 1.26 presented four stages of mass-loss. X-ray diffractograms demonstrated that both native and acetylated lasiodiplodan presented crystalline regions in an amorphous polymeric matrix. Scanning electron microscopy revealed that O-acetylation promoted morphologic changes in the biopolymer according to the DS. Acetylation also contributed to improve antioxidant capacity.