Initial Char Research Articles

Fabrication and Performance Investigation of Flame Retardant Flexible Polyurethane Composites via Polyethyleneimine/Phytic Acid LBL Self‐Assembly Coatings

ABSTRACTTo bolster the fire resistance of flexible polyurethane foam (FPUF), and a series of FPUF/polyethylenimine/phytic acid (FPUF/PEI/PA) composites were prepared by layer‐by‐layer self‐assembly strategy. Furthermore, the thermal stability, flame retardancy, combustion properties, and char layer were comprehensively evaluated via thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL‐94 vertical combustion test, microcalorimetry (MCC), scanning electron microscopy (SEM), Raman spectroscopy, and tensile testing. TG analysis revealed that the PEI/PA coatings markedly diminished the initial decomposition temperature (T‐5wt%) and char residue at 800°C. FPUF‐6 extended the burning duration by 20 s, a 80% improvement compared with unmodified FPUF, with an LOI value increased to 19.2 vol%. SEM and Raman analyses of the char residues indicated that the PEI/PA coating promoted graphitization degree of the char layer. This work offered novel insights for the development of high‐performance FPUF composites.

2-D CFD modeling of gasification of a large biomass char particle in CO2 environment

There is a dearth in the literature of simple but robust models for gasification of large biomass particles that can address all important aspects of the reaction. A transient two-dimensional single-particle model of biomass gasification in the CO2 environment was developed in this work that incorporates chemical kinetics and heat transfer resistances, mass transfer inside the particle and boundary layer, non-equimolar counter diffusion including Knudsen diffusion, spatiotemporal variation in specific char surface area and thermophysical properties. The model was validated extensively with experimental results. Detailed simulation was carried out at reactor temperatures of 923–1123 K) using COMSOL Multiphysics software for two biomass samples – casuarina and acacia. Simulated conversion, reaction rate, temperature and gas composition profiles revealed that the reactions initially followed a shrinking core model, shifting subsequently to a shrinking reactive core model. Sensitivity analysis identified the sensitivities of process parameters as: reactor temperature > particle diameter (constant length) > initial specific char surface area > porosity > pore parameter > particle diameter (constant volume). Casuarina was found to be a more reactive and better-suited biomass than acacia for gasification applications. The work has furnished important guidelines for selecting suitable biomass type and process parameters to design an appropriate gasifier for industrial use.

Structural and thermal behavior of a novel phenolic resin and its composite with excellent ablative performance

The heat resistance of existing phenolic resins cannot meet the requirements of the increasingly harsh spaceflight environment. Boron and silicon have been added to phenolic resins to improve the char yields. However, achieving both a high initial decomposition temperature and an outstanding char yield remains challenging. This study presented a strategy to regulate the methylene types of boron-containing phenolic resin (TBPR) by trisilanolphenyl polyhedral oligomeric silsesquioxane (TPOSS) and NaOH. Thermogravimetric analysis (TGA) in nitrogen of cured TBPR displayed remarkable thermal stability with an initial decomposition temperature of 450.0 °C and a char yield of 75.8 %. The effect of TPOSS and NaOH on the TBPR structure were further investigated using nuclearmagneticresonance (NMR) analysis and densityfunctionaltheory(DFT) calculation. The results indicated that TPOSS could attract sodium phenate and formaldehyde through hydrogen bonds, and greatly reduced the energy barrier of the phenol–formaldehyde resin para-addition. The formation of more p-p’ type methylene structures of phenolic resin profoundly contributed to the outstanding initial decomposition temperatures and char yield. TBPR matrix transformed into a stronger protective char layer, forming an effective thermal protection barrier. As a result, the mechanical strength and ablative resistance of the fiber-reinforced CF/TBPR composites were enhanced by the excellent thermal stability of TBPR matrix.

Synergistic Effects of 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-Based Derivative and Modified Sepiolite on Flame-Retarded Poly (Ethylene Oxide)-Poly (Butylene Adipate-Co-Terephthalate) Composites.

A 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based derivative (PN-DOPO) combined with aluminium phosphates-coated sepiolite (Sep@AlPO4) was used to improve the flame retardance, thermal stability and mechanical performances of poly (ethylene oxide) (PEO)/poly (butylene adipate-co-terephthalate) (PBAT) blends. The synergistic effects of PN-DOPO and Sep@AlPO4 on flame-retarded PEO/PBAT composites were systematically discussed. Results indicated that introducing 5 wt% Sep@AlPO4 with 10 wt% PN-DOPO into PEO/PBAT achieved a V-1 rating for the UL-94 test and increased the limiting oxygen index value to 23.7%. Moreover, the peak heat release rate (p-HRR), average HRR and total heat release values of PEO/PBAT/PN10%/Sep5% composites decreased by 35.6%, 11.0% and 23.0% compared with those of PEO/PBAT, respectively. Thermogravimetric analysis (TGA) results confirmed that PN-DOPO/Sep@AlPO4 enhanced the initial thermal stability and char yield of PEO/PBAT matrix, and TGA/Fourier transform infrared spectrometry results revealed that the composites exhibited the characteristic absorption peaks of phosphorous-containing groups and an increase in gas-phase volatiles during thermal degradation. The morphological structures of the residues indicated that PN-DOPO and Sep@AlPO4 mixtures produced a more dense and continuous char layer on the composite surface during burning. Rheological behaviour revealed that higher complex viscosity and modulus values of PEO/PBAT/PN-DOPO/Sep@AlPO4 sample could also promote the crosslinking network structure of condensed phases during combustion. Furthermore, the PEO/PBAT/PN-DOPO/Sep@AlPO4 composites exhibited superior elongation at break and flexural performance than the PEO/PBAT system. All results demonstrated that the PEO/PBAT system modified with PN-DOPO/Sep@AlPO4 showed remarkable flame retardance, and improved thermal stability and mechanical properties, indicating its potential application in areas requiring fire safety.

Chemical and electrical properties of activated carbon from Samui Island young coconut waste

Solid coconut waste has been a chronic issue that can lead to an environmental problem in Samui Island. Therefore, we are interested in processing this waste into a more valuable product. Many previous studies have evaluated the characteristics of activated carbon (AC) using chemical properties, but not electrical properties. In this work, we analyze the electrical properties of AC to identify a wide range of potential applications. The whole coconut with husk was turned into AC under different activation parameters (temperature, impregnation ratio of KOH and time) using one-factor-at-a-time method. The results showed that with higher activation temperature (750-850°C), the iodine adsorption number increased but the yield decreased. Excessive impregnation ratio and longer activation time could lower the iodine adsorption number due to the collapse of micropores into larger pores. The SEM images revealed that after activation process, a well-developed pore structure is achieved. The highest iodine adsorption number was obtained at 1356.80 mg/g at activation condition of 800°C, impregnation ratio of 1:2 and activation time of 2 hrs. The electrical property of activated carbon was remarkably improved from the initial char, in accordance with the iodine number result. The lowest resistivity was also achieved at the same condition as above.

Bismaleimide resin co‐modified by allyl ether of resveratrol and allyl ether of eugenol‐grafted polysiloxane with enhanced toughness, heat resistance, and flame retardancy

AbstractModifying bismaleimide (BMI) resin to improve its toughness and flame retardancy without sacrificing the glass transition temperature (Tg) and thermal decomposition stability is still a challenge. In this study, we employed the allyl ether of resveratrol (AER) and eugenol allyl ether grafted polysiloxane (PMES‐Allyl) to co‐modify BMI resin. For the BMI/AER/PMES‐Allyl (BAPA) resin, the content of PMES‐Allyl was 15 wt%, and the molar ratio of maleimide and allyl groups was controlled as 1:0.8. Compared to commercial 2,2′‐diallyl bisphenol A modified BMI (BD) resin, the BAPA resin exhibited superior thermal properties after curing, due to the role of AER in improving the crosslinking density and chain rigidity of the network. The cured BAPA resin had a Tg more than 380°C, and its initial thermal decomposition temperature (Td5%) and char yield (Y800°C) reached 424.8°C and 46.4%, respectively. Meanwhile, PMES‐Allyl as a rubber phase could effectively improve the toughness of the cured resin. The impact strength of the cured BAPA resin was 15.2 kJ/m2. Moreover, the two modifiers both helped to improve the flame retardancy of the material. Compared with the cured BD resin, the cured BAPA resin showed a decrease of peak heat release rate (PHRR), total heat release (THR), and maximum average rate of heat emission (MARHE) by 25.5%, 35.5%, and 31.5%, respectively. Its total smoke production (TSP) was only 35.6% of that of the cured BD resin. In addition, the cured BAPA resin also displayed a lowered water absorption and improved thermal aging resistance. Therefore, it is suggested to be a promising and high‐performance thermosetting resin for cutting‐edge applications.

Reinforcement of Aminopropyl-Terminated Siloxane-Treated Carbon Nanotubes in Epoxy Thermosets: Mechanical and Thermal Properties.

The synthesis and characterization of aminopropyl-terminated polydimethylsiloxane- treated carbon nanotube (AFCNT)-reinforced epoxy nanocomposites are reported in the current study. The amine functionalization of the CNTs was performed with a reaction to PDMS-NH2. The AFCNTs were homogeneously dispersed in epoxy resin by using an emulsifier and a three-roller mill. The AFCNTs were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The curing behavior of the epoxy/AFCNT was studied using a differential scanning calorimeter (DSC). The tensile and impact strengths of the 2.0 wt.% AFCNT-reinforced epoxy nanocomposite were enhanced by 43.2% and 370%, respectively. Moreover, the glass transition temperature (Tg) was also enhanced by 21 °C. Furthermore, significant enhancements were observed in the initial degradation and char yield values. SEM results confirmed that the AFCNTs were highly dispersed in the polymeric matrix.

Anti‐drip flame retardant poly(urethane‐imide) thin films for high‐temperature applications

AbstractThe present work deals with developing anti‐drip, flame‐retardant, poly(urethane‐imide) copolymer films for potential use in specialized applications. PUI formulations containing varying amounts of different flame retardants were prepared to achieve UL‐94 VTM‐0 rating without any melt‐drip. Thermogravimetric analysis revealed that PUI exhibits multi‐step degradation. The presence of flame‐retardant additives operating through a condensed phase mechanism was found to reduce the initial degradation temperature and increase char yield. SEM imaging of the char residue revealed the intumescent behavior of PUI with APP and PEPA additives. Both these additives were found to be effective flame retardants for PUI films. The addition of 25% APP and 25% PEPA led to VTM‐0 and VTM‐1 ratings, respectively, without melt drip. DOPO, a representative vapor phase flame retardant, was also found to be effective for PUIs, with 25% DOPO introduction resulting in a VTM‐0 rating. Conventional phosphate‐based flame retardants, such as triethyl phosphate, tricresyl phosphate, and triphenyl phosphate, were found to be relatively ineffective for PUI films. Interestingly, the mechanical properties of PUI improved significantly upon the introduction of flame‐retardant additives. High thermal stability, and anti‐drip flame retardant properties, bestows these formulated PUIs excellent candidature as materials for applications where flame retardancy with anti‐drip is mandatory.

A multidimensional numeric study on smoldering-driven pyrolysis of waste polypropylene

The ex-situ smoldering driven pyrolysis reactor can simultaneously remediate the organically contaminated soil/sand and valorize the plastic waste to value-added fuels. This study establishes a multidimensional model to investigate the pyrolysis of polypropylene driven by self-sustained smoldering. The melting and decomposing processes during the pyrolysis of polypropylene have been simulated using the modified apparent heat capacity method and lumped kinetic model. Using a porous structure with high thermal conductivity in the pyrolysis domain proved to be a practical approach to address the non-uniform temperature distribution and low heating rate of plastics during pyrolysis. The research focus of this study is to obtain high-quality plastic pyrolysis liquid (oil, C6–C24) within a reasonable operating time (duration of the plastic pyrolysis process). Also, the operating conditions (Darcy air velocity, initial char concentration, and PP content) determine the yield of pyrolysis products by regulating the temperature and vapor residence time. Therefore, the sensitivity analyses of pyrolysis duration and oil yield to operating conditions have been performed. It is also found that the interface wall (between smoldering and pyrolysis chambers) heat transfer coefficient determines the smoldering chamber's thermal performance. This study provides new insights into the valorization of waste plastics and the remediation of contaminated soil/sand.

Influence of flue gas torrefaction on the fuel properties and pyrolysis characteristics of real components of corn stalk

The aim of this study was to identify the changes in fuel properties and pyrolysis characteristics of the torrefied real components of corn stalk. The isolated components were torrefied with simulated flue gas and nitrogen in a thermogravimetric analyzer at 230, 260 and 290 °C for 30 min. The ultimate analysis indicated that flue gas atmosphere was beneficial to improving the fuel properties of isolated components. Compared to non-oxidative atmosphere, the flue gas had a greater impact on the initial pyrolysis temperature and char yield of the isolated components. The results of mathematical deconvolution analysis (MDA) demonstrated that the pyrolysis weight losses of native mixture could be quantitatively represented by the linear summation of isolated components. The differential thermogravimetric (DTG) characteristic curves could be used to qualitative analyze the changes in relative contents of the structural components of the torrefied biomass.

The Influence of Pore Distribution of Coal Char in the Char Fragmentation and Included Minerals Partitioning: A Percolation Modeling

The processes of char fragmentation, including mineral partitioning and particulate matter (PM) formation during dense and porous char combustion, were observed by a site percolation model. This model simulated the diffusion-controlled regime of char combustion, and the size distributions of included minerals in typical bituminous coal were determined by the computer-controlled scanning electron microscope (CCSEM), and the data were put into the char matrix randomly. The model presents the influence of initial pore distribution on char oxidation and fragmentation, the impact of the char conversion process on the extent of fragmentation, the change of ash distributions with the char conversion, and the particulate matters (PM) size distribution, which is derived from the consequence of the competition between char fragmentation and included minerals partitioning and coalescence. The results indicate that with increasing initial char porosity (φ), the number of large size pores increases but the number of pores decreases, which leads to open pores increasing, close pores decreasing, and the surface reaction area increasing. While φ ≥ 0.4, char fragmentation obviously occurs during the stage in which the rates of char conversion are 0.4–0.6, and it looks as though the maximum value of fragmentation will transfer to an earlier conversion stage if it has a larger φ. The enhanced φ shows a positive effect on the increase in the number and concentration of PM < 10 μm (nominally aerodynamic diameter), this is attributed to char fragments more drastically, and the probability of mineral coalescence reduces a lot.

Self-Heating of Biochar during Postproduction Storage by O2 Chemisorption at Low Temperatures

Biochar is attracting attention as an alternative carbon/fuel source to coal in the process industry and energy sector. However, it is prone to self-heating and often leads to spontaneous ignition and thermal runaway during storage, resulting in production loss and health risks. This study investigates biochar self-heating upon its contact with O2 at low temperatures, i.e., 50–300 °C. First, kinetic parameters of O2 adsorption and CO2 release were measured in a thermogravimetric analyzer using biochar produced from a pilot-scale pyrolysis process. Then, specific heat capacity and heat of reactions were measured in a differential scanning calorimeter. Finally, a one-dimensional transient model was developed to simulate self-heating in containers and gain insight into the influences of major parameters. The model showed a good agreement with experimental measurement in a closed metal container. It was observed that char temperature slowly increased from the initial temperature due to heat released during O2 adsorption. Thermal runaway, i.e., self-ignition, was observed in some cases even at the initial biochar temperature of ca. 200 °C. However, if O2 is not permeable through the container materials, the temperature starts decreasing after the consumption of O2 in the container. The simulation model was also applied to examine important factors related to self-heating. The results suggested that self-heating can be somewhat mitigated by decreasing the void fraction, reducing storage volume, and lowering the initial char temperature. This study demonstrated a robust way to estimate the cooling demands required in the biochar production process.

Development, characterization, and tribological behavior of polymeric carbon nitride/acrylonitrile butadiene styrene nanocomposites

AbstractThis article examines the effect of the addition of nanosheets of polymeric carbon nitride (NPCN) on the frictional, mechanical, thermal, and morphological properties of acrylonitrile butadiene styrene (ABS) system. A series of ABS/NPCN nanocomposites were prepared by varying NPCN concentration using the solution casting and compression molding methods. NPCN were prepared from melamine by thermal treatment and characterized using UV–Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, and transmission electron microscopy. Fourier transform infrared spectroscopy and X‐ray diffraction analysis were utilized to investigate the chemical and crystal structure of NPCN, ABS, and ABS/NPCN composites. The wettability of the composites was analyzed using contact angle studies. The incorporation of NPCN into the ABS matrix improved the thermal stability and tensile strength of the ABS/NPCN composites. The addition of NPCN increased the initial decomposition temperature and char yield of the composites. The frictional analysis results indicated that the presence of NPCN filler significantly influences the friction coefficient (decreased by 35%) and wear loss (reduced by 67%) of the nanocomposites.

Fire retarded polyurethane foam composites based on steel slag/ammonium polyphosphate system: A novel strategy for utilization of metallurgical solid waste

AbstractA series of FR‐RPUF composites were prepared by a one‐step water foaming process with ammonium polyphosphate (APP) and steel slag (SS) as flame retardants. Thermogravimetric analysis (TG), limiting oxygen index (LOI), UL‐94 vertical combustion test, microscale combustion calorimetry (MCC), TG‐Fourier transform infrared spectrometry (TG‐FTIR), scanning electron microscopy (SEM), Raman spectra and FTIR were used to investigate the thermal stability, flame retardancy, combustion performance, gas phase products, and char residue morphology of FR‐RPUF composites. TG test results showed that the initial decomposition temperature (T‐5wt%) and char residue rate at 700°C of RPUF/APP/SS composites were significantly enhanced by the addition of APP and SS, and the thermal stability of the composites was improved. Flame retardant test results confirmed the significantly increased LOI values of RPUF/APP/SS composites with V‐0 rating. TG‐FTIR also confirmed the obviously decreased release of toxic gases and flammable gases in the combustion of RPUF/APP/SS composites. SEM and Raman spectra of char residues for the composites suggested that APP/SS system improved the compactness and graphitization degree of char layer for RPUF/APP/SS composite. The above researches provide a new strategy for the utilization of SS in fire safety engineering.

Effect of calcium ferrites on carbon dioxide gasification reactivity and kinetics of pine wood derived char

Biochar gasification is an essential stage of chemical looping biomass gasification, a promising sustainable source of energy that may limit anthropogenic carbon dioxide emissions. Here, the performance of calcium ferrite oxygen carriers (CaFe2O4, and Ca2Fe2O5) on the CO2 gasification reactivity and kinetics of pine wood char is investigated by a thermogravimetric analyzer. The morphology and graphitization degree of the pine wood derived biochar were characterized by using high-resolution transmission electron microscope (HRTEM) and Raman spectroscopy. A random pore model is established and the best matching structural parameter, Ψ, is used to indicate the pore structure of the initial char samples. Results indicate that the activation energy under biochar with no oxygen carrier, biochar loaded with 10 wt% Fe2O3, 10 wt% Ca2Fe2O5, and 10 wt% CaFe2O4 are 169.76 kJ/mol, 176.03 kJ/mol, 173.81 kJ/mol, and 178.83 kJ/mol, respectively. The introduction of oxygen carriers increases the activation energy for CO2 gasification, potentially due to competition with calcium ferrite reduction, resulting in decreased CO2 partial pressure.

Synthesis and properties of wholly aromatic phosphorus-containing thermotropic liquid crystal copolyesters with excellent fibre formation ability

ABSTRACT In this study, wholly aromatic phosphorus-containing thermotropic liquid crystal polymers (TLCP) derived from 6-hydroxy-2-naphthenic acid (HNA), terephthalic acid (TA) and 10-(2,5-Dihydroxypheny)-10 h-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO-HQ) are successfully synthesised via one pot melt polymerisation method. Although, the resulted copolyesters are amorphous, high glass transition temperature (182–196 °C) is observed due to the existence of kinked DOPO-HQ unit and crankshaft HNA monomer. The nematic liquid crystal behaviour is found for all of the copolyesters under POM at relatively low temperature (190–207 °C). The copolyesters show good thermal stability and high char yield under both nitrogen and air atmosphere, which of the initial degradation temperature (T5%) and char yield are above 450 °C and 50%, 439 °C and 29%, respectively. Dynamic rheology results show that viscous modulus of the obtained copolyesters are much more prominent under both frequency and temperature sweeping mode, indicating have excellent processing ability. The fibres can be easily drawn from the melt, and exhibit well oriented fibrillated structure. The convenient polymerisation method, excellent thermal stability and fibre formation ability of the phosphorus-containing TLCP endow them much potential use in the safety protection field.

Modeling the transient response of a fluidized-bed biomass gasifier

The dynamic response of a bubbling fluidized-bed biomass gasifier (FBG) is examined. A transient model is developed by extending a previous steady-state model to account for key processes occurring during the ramp-up and/or changes in loading of fuel and gasification agent. The model is validated against measurements from transient tests in a laboratory-scale FBG. The model results are also compared with steady-state measurements and previous FBG models from the literature. A sensitivity analysis is performed to identify the most influencing parameters. The model is then used to study the transient response of industrial FBG under different operating conditions. It is shown that for given operational conditions (biomass flowrate, equivalence ratio, initial temperature, and initial char inventory in the bed), there is always an optimal start-up procedure (rate of change in feeding the gasifying agent and/or the fuel) leading to the shortest start-up time and lowest peak temperature. The transient period can be reduced by up to 75% compared to the reference value, in which the transient response can extend for more than an hour, due to the slow change in the inventory of char in the reactor. The model can be used to optimize the operation of hybridized power plants with biomass gasification and thermal energy storage.

Re-examination of Thermogravimetric Kinetic Analysis of Lignite Char Gasification

Kinetic analysis of CO2 gasification by thermogravimetry was examined employing chars from a Victorian lignite. The gasification of char from the rigorously acid-washed lignite was extremely slow. More than 600 min was required for the complete gasification as a result of a near absence of inherent alkali and alkaline earth metallic (AAEM) species. It was nonetheless necessary to strictly choose the following conditions for eliminating the mass transfer effect: an initial mass of char of <1.3 mg, a particle size of char of <125 μm, and a total gas flow rate of ≥1000 mL standard temperature and pressure min–1. Such requirement arose from the inhibition of non-catalytic gasification by CO within the char particle. On the other hand, the char from the original lignite was gasified much faster than the non-catalytic gasification and completed within 50 min by catalysis of the inherent AAEM species. The measured rate of catalytic gasification was, unexpectedly, independent of the initial char mass and particle size and gas flow rate. This was reasonably explained by no or little importance of CO inhibition in the catalytic gasification. This study has also drawn another important conclusion that the non-catalytic gasification obeyed first-order kinetics with respect to the char mass. The rate constant was steady over the entire range of char conversion, while both the specific surface area and carbon-type distribution of the char varied along with the conversion.

Synthesis and thermal properties of silicon-containing benzoxazine

A novel benzoxazine, containing silicon (Si) in the main chain and bonded to two benzene ring, was synthesized from aniline, bis( p-hydroxyphenyl)dimethylsilane, and paraformaldehyde. The structure was characterized by proton nuclear magnetic resonance and Fourier transform infrared (FTIR) spectra. The curing behavior of the benzoxazine was evaluated by differential scanning calorimeter and in situ FTIR. The thermal stability of the resulting polybenzoxazine was studied by thermogravimetric analysis under nitrogen and air atmospheres. The results indicated that the Si-containing polybenzoxazine possessed significantly higher initial degradation temperature and char yield than conventional bisphenol A/aniline-based polybenzoxazine.

Design and preparation of poly(lactic acid) hydroxyapatite nanocomposites reinforced with phosphorus‐based organic additive: Thermal, combustion, and mechanical properties studies

A new phosphorus‐based organic additive (PDA) was designed and successfully synthesized using a three‐component reaction for improvement of the thermal and combustion resistance of polylactic acid (PLA). For compensate for mechanical properties of PLA, hydroxyapatite nanoparticles was modified via in situ surface modification with PDA and was used for preparation of PLA nanocomposites. The structure and morphology as well as thermal, combustion, and mechanical properties of the all PLA systems were investigated. The X‐ray diffraction (XRD) and field‐emission scanning electron microscopy (FE‐SEM) results indicated that the presence of PDA as surface modifier has been necessary for a desirable dispersion of hydroxyapatite (HA) nanoparticles in the PLA matrix. The thermal, combustion, and mechanical properties of the PLA system films were investigated using thermogravimetric analysis (TGA), microscale combustion calorimeter (MCC), and tensile test, respectively. The initial decomposition temperature and char residue of PLA containing 6 mass% of PDA along with 2 mass% HA nanoparticles were increased 20°C and 12% respectively, compared with that of the neat PLA. The peak of heat release rate was decreased from 566 W/g for the neat PLA to 412 W/g for PLA containing 2 mass% of PDA along with 6 mass% HA nanoparticles. By incorporation of only 2 mass% HA nanoparticles and 6 mass% of PDA, the tensile strength was obtained 51 MPa higher than that of the neat PLA.