Initial Weight Loss Temperature Research Articles

Impact of Buriti Oil from Mauritia flexuosa Palm Tree on the Rheological, Thermal, and Mechanical Properties of Linear Low-Density Polyethylene for Improved Sustainability.

Recent advancements highlight the utilization of vegetable oils as additives in polymeric materials, particularly for replacing conventional plasticizers. Buriti oil (BO), extracted from the Amazon's Mauritia flexuosa palm tree fruit, boasts an impressive profile of vitamins, minerals, proteins, carotenoids, and tocopherol. This study investigates the impact of incorporating buriti oil as a plasticizer in linear low-density polyethylene (LLDPE) matrices. The aim of this research was to evaluate how buriti oil, a bioactive compound, influences the thermal and rheological properties of LLDPE. Buriti oil/LLDPE compositions were prepared via melt intercalation techniques, and the resulting materials were characterized through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), mechanical property testing, and contact angle measurement. The addition of buriti oil was found to act as a processing aid and plasticizer, enhancing the fluidity of LLDPE polymer chains. TGA revealed distinct thermal stabilities for buriti oil/LLDPE under different degradation conditions. Notably, buriti oil exhibited an initial weight loss temperature of 402 °C, whereas that of LLDPE was 466.4 °C. This indicated a minor reduction in the thermal stability of buriti oil/LLDPE compositions. The thermal stability, as observed through DSC, displayed a nuanced response to the oil's incorporation, suggesting a complex interaction between the oil and polymer matrix. Detailed mechanical testing indicated a marked increase in tensile strength and elongation at break, especially at optimal concentrations of buriti oil. SEM analysis showcased a more uniform and less brittle microstructure, correlating with the enhanced mechanical properties. Contact angle measurements revealed a notable shift in surface hydrophobicity, indicating a change in the surface chemistry. This study demonstrates that buriti oil can positively influence the processability and thermal properties of LLDPE, thus expanding its potential applications as an effective plasticizer.

Carbon tube‐gypsum reinforced polypropylene: Impact resistance, thermal stability

AbstractThis study investigated the effect of multi‐walled carbon nanotubes (MWCNTs) and reclaimed gypsum of varying contents on the mechanical properties and thermal stability of polypropylene (PP) composite materials. The results indicated that the incorporation of reclaimed gypsum and MWCNTs powder into PP composites could enhance the tensile strength, impact strength, and bending modulus of PP to a certain extent. The above properties of AGY/MWCNTs/PP composites were increased by 14.6%, 131.8%, and 36.2%, respectively, with the impact properties being significantly affected. Univariate analysis of variance revealed that MWCNTs powder and recycled gypsum exerted a significant impact on the mechanical properties of polypropylene composites. Moreover, the initial weight loss temperature of AGY/MWCNTs/PP demonstrated a notable increase, from 318.71 to 398.48°C, while the maximum weight loss temperature exhibited a comparable rise, from 406.85 to 461.54°C.Highlights The impact performance and thermal stability of polypropylene composite materials have been demonstrably augmented. A synergistic effect between reclaimed gypsum and multi‐walled carbon nanotubes in the reinforcement of polypropylene composites was demonstrated. This provides a theoretical framework and practical guidance for the design and preparation of high‐performance and recyclable polymer composites.

Study on the thermal stability of NG/NC/RDX triple-base gun propellants modified by oligomer GAP (Mn = 330)

The thermal stability of gun propellants is related to significant safety issues in their development, production, storage, or transportation. Therefore, the study of improving the thermal stability of propellants has urgent and important practical significance. In this work, glycidyl azide polymer (GAP) with a relative molecular weight of 330 was added to the gun propellant to prepare modified NG-NC-RDX gun propellants containing different contents of oligomeric GAP. The ability of the propellant to cause discoloration of methyl violet test paper due to thermal decomposition, as well as the thermal weight loss and adiabatic decomposition behavior of the propellant, were characterized. And the differential charge density of GAP and NG, as well as the free volume and microstructure of GAP/NC and NG/NC blends, were compared, and the mechanism by which GAP improves the thermal stability of the propellant was discussed. When the content of GAP in the propellant changes from 0% to 16%, the time for the methyl violet test paper to change from purple to orange is prolonged from 87 minutes to 98 minutes. The initial decomposition temperature of thermal weight loss increased from 164.7 °C to 176.4 °C. The maximum temperature rise rate during adiabatic decomposition decreased from 0.95 °C·min−1 to 0.12 °C·min−1. According to MS simulation calculations, GAP provides a larger free volume and improves the uniformity of the mesoscopic phase structure of the propellant. The covalent effect of bond C-N3 in GAP molecules is stronger than that of bond O-NO2 in NG molecules. The thermal stability of the NG-NC-RDX propellant increases with the addition of GAP, and it increases with the increase of GAP content in the propellant. This work provides a scheme for improving the thermal stability of the gun propellant and offers a way to reduce the risk of thermal stimulation.

Microencapsulated phase change n-Octadecane with high heat storage for application in building energy conservation

A novel type of microencapsulated phase change materials (microPCMs) with n-Octadecane core shelled by styrene–divinylbenzene copolymer were synthesized by the suspension polymerization. The morphologies and chemical compositions of the microPCMs with four different shell-to-core ratios were analyzed via the scanning electron microscopy and Fourier transform infrared spectroscopy. Based on the measurements from the thermogravimetric analyzers and differential scanning calorimetry, the thermal characteristics of the different microPCMs were analyzed. The results show that the sample microPCMs with 2:1 shell-to-core ratio (microPCM3) has good thermal stability and high heat storage capability, with melting enthalpy and encapsulation efficiency measured at 111.5 ± 0.7 J/g and 51.4 ± 0.7 %, respectively, which are the highest among all the prepared samples. The initial weight loss temperature of the microPCM3 increases to 160.5 ℃ compared to 115.5 ℃ for the pure n-Octadecane. Furthermore, we prepared four different building boards with different microPCM3 contents (0, 10, 20, or 30 wt%) in cement matrix. Compared to the conventional building material, the board with 30 wt% microPCM3 can store 67.82% more heat energy in the typical temperature range of 10–50 °C. We investigated the passive cooling and heating effects of the boards under extreme temperature conditions (10–70 °C), as well as their thermal regulation performance under multiple consecutive thermal cycling experiments. Compared with the cement board without addition of microPCM3, the board with 30 wt% microPCM3 has reduced temperature fluctuation by 59.0% with maximum temperature fluctuation only 23.5 °C. It has shown excellent thermal regulation and thermal insulation properties and is of great application potential in energy-saving buildings.

Investigation of the catalytic performance of coal gangue char on biomass pyrolysis in a thermogravimetric analyzer and a fixed bed reactor

• Coal gangue rich in metals was used to prepare char-supported catalysts. • Coal gangue char can reduce the activation energy required for pine pyrolysis. • The yield of gas increased with the increase of the coal gangue char mass ratio. • The liquid product yields decreased by 19.01% at PS and CG mass ratio of 1:2. Developing low-cost and high-performance catalysts is an important part of the development of biomass pyrolysis technologies. In this study, the coal gangue rich in metals was used to directly prepare a char-supported catalyst, and metals in coal gangue were hoped to act as catalytic sites for in-situ biomass catalytic pyrolysis and secondary tar cracking. The influence of coal gangue char on pine pyrolysis behavior and kinetics was investigated in the thermogravimetric analyzer and a fixed bed reactor. The thermogravimetric analysis showed that the addition of coal gangue char caused the movement of the initial weight loss temperature and the maximum weight loss peak of the samples to the high-temperature region. With the increase of the coal gangue char mass ratio, lower apparent activation energies of the samples were achieved in the conversion range of 0.2–0.8. Through fixed-bed isothermal pyrolysis experiments, it was found that the yield of gas increased with the increase of the coal gangue char mass ratio, while the tar yield decreased quickly. The yield of H 2 and CO was significantly improved by the coal gangue char, further confirming the catalytic performance of coal gangue char on the cracking of tar molecules.

Biofuel characteristics of chars produced from rapeseed, whitewood, and seaweed via thermal conversion technologies – Impacts of feedstocks and process conditions

Understanding the suitability of different conversion technologies for different types of biomass feedstocks is crucial in delivering the full valorisation of different types of biomass feedstocks. Optimal valorisation pathways can be identified by investigating the formation of products and the most efficient application technologies of these products. This is therefore novel research reporting an extensive comparative study on the biomass processing pathways (hydrothermal conversion, pyrolysis, and torrefaction) for three distinct biomass feedstocks (Rapeseed residue, Whitewood, Seaweed–Laminaria Digitata) to optimise char formation under a wide range of processing conditions and their biofuel characteristics in the bioenergy applications. The results demonstrates that Whitewood gradually decomposes during all three conversion processes to produce chars (hydrochars/biochars) that have a lower O/C-H/C ratio as process temperature increases. The char formation from Whitewood follows the dehydration process in the Van Krevelen diagram. Char formation from Rapeseed residue and L. digitata via pyrolysis also follows a similar dehydration and demethanation pathway at higher temperatures (550 °C for Rapeseed residue and 400 °C for L. digitata). However, char formation from Rapeseed residue and L. digitata via hydrothermal conversion predominantly follows the decarboxylation pathway producing structures with a higher H/C ratio and lower O/C ratio. The intrinsic reactivity analysis of these chars showed that the temperature of initial weight loss and the onset of ignition for the raw biomass sample was shifted to a higher temperature for the chars produced by hydrothermal conversion or pyrolysis, regardless of biomass feedstocks. The chars produced from Whitewood (with hydrothermal conversion, pyrolysis and torrefaction) and Rapeseed residue (with pyrolysis) have a potential application in bioenergy production due to the significant enhancement of char products. However, the chars produced from L. digitata appear less promising for bioenergy applications due to relatively low energy yield, carbon recovery, inferior char structures and a high inherent ash content.

Preparation and structure-properties of crosslinking organic montmorillonite/polyurethane as solid-solid phase change materials for thermal energy storage

In order to solve the leakage problem of commonly used polyethylene glycol (PEG) phase change material (PCM), PEG reacted with 4′ 4-diphenylmethane diisocyanate (MDI) to prepare the polyurethane-based solid-solid phase change material (PU-SSPCM) by the two-step solvent method, and the influence of organic montmorillonite (OMMT) on the phase transition property and crystallization capacity of PU-SSPCM was first studied. The solid-solid phase change polyurethane materials were successfully prepared when the molar ratio of PEG to MDI was 0.75, and the organic montmorillonite acted as a crosslinking heterogeneous nucleating agent to improve the temperature control capacity, the crystallization ability and the thermal stability of the solid-solid phase change polyurethane material. When the addition of OMMT was 0.5 wt%, the phase change enthalpy of PU-SSPCM increased to 106.8J/g from 95.46J/g, a constant temperature platform appeared for about 300 s during both the heating and cooling process, thus demonstrating excellent temperature control ability. The relative crystallinity increased to 74.8% from 66.5% and the initial thermal weight loss temperature was increased from 348 °C to 368 °C. • Organic montmorillonite acted as a crosslinking heterogeneous nucleating agent. • Organic montmorillonite enhanced the temperature control capacity the system. • The composites possessed excellent crystallization ability and thermal stability.

Preparation of MoSi2-modified HfB2-SiC ultra high temperature ceramic anti-oxidation coatings by liquid phase sintering

Liquid-phase sintering combining an in-situ reaction method with a slurry method was used to prepare HfB2-MoSi2-SiC coatings of controllable composition and thickness. The effect of the MoSi2 content on the oxidation protection of HfB2-MoSi2-SiC composite coatings in a dynamic aerobic environment from room temperature to 1500 °C and a static constant temperature at 1500 °C in air was investigated. The relative oxygen permeability was used to characterize the oxidation resistance of the coatings. The results of dynamic oxidation test at room temperature~1500 °C show that the initial oxidation weight loss temperature of the samples is increased from 775 to 821 °C, and the maximum weight loss rate is decreased from 0.9×10−3 to 0.2×10−3 mg·cm−2·s−1 with increasing MoSi2 content, the lowest relative oxygen permeability is reduced to 12.2% with the weight loss of the sample being decreased from 1.8% to 0.21%. The mechanism of MoSi2 improving the oxidation protection of the coatings is revealed. With an increase of the MoSi2 content, the amount of SiO2 glass phase in the coating is increased, and the dispersion of Hf-oxide on the surface is improved so that a Hf-Si-O glass layer with high stability is formed and the weight loss of the sample is reduced from 0.46% to 0.08% after 200 h oxidation at 1500 °C in air.

Study on the characteristics and influencing factors of micron/nano carbon material dust explosions

Because of the wide range of applications of lithium ion batteries, the combustible and explosive carbon material dust of a negative electrode material requires additional attention. Few explosion test data of carbon material dust are available. In this paper, the thermodynamic and explosion parameters of allotropes of carbon dust and the same type of carbon material dust with different particle size distributions were determined. The results showed that the explosion pressure of micron/nano carbon material dust ranged from 0.4 to 0.7 MPa; the maximum deflagration index Kst ranged from 4 to 10 MPa · m/s; and the minimum ignition temperature was approximately 600 °C. The proportion of the small dust particles was an important factor that caused a change in the initial oxidation weight loss temperature and apparent activation energy of the same type of carbon dust. The variation trend among the initial oxidation weight loss temperature, apparent activation energy and particle size distribution of different carbon dust materials was not obvious, and mainly depended on the difference in molecular structures. Different molecular structures resulted in different apparent activation energies of the carbon allotropes. The apparent activation energy played a leading role in the change in the dust deflagration index. The smaller the apparent activation energy was, the smaller the energy required for carbon-carbon chemical bond breaking. The faster the carbon-carbon bond-breaking rate was, the larger the deflagration index. The dust particle size distribution, specific surface area and other characteristics had little influence on the deflagration index. Furthermore, the apparent activation energy had a greater impact on the deflagration index than the explosion pressure. The dust explosion pressure was mainly limited by oxygen in the test equipment, and its maximum value remained relatively constant. The minimum ignition temperature of dust clouds decreased with decreasing activation energy and increasing pre-exponential factor. The lower the initial oxidation weight loss temperature was, the lower the measured dust cloud minimum ignition temperature.

Preparation and research of epoxy modified by carboxyl-terminated polybutylene adipate at room temperature.

In this study, carboxyl-terminated polybutylene adipate (CTPBA) was used to modify epoxy resin, and the modified epoxy resin was cured by a room temperature rapid curing agent (T-31). The effects of CTPBA modification on bonding properties and mechanical properties of epoxy resin adhesive at room temperature were carefully studied. Epoxy-terminated prepolymer was synthesized by pre-polymerization and its structure was characterized. Compared with the addition method of direct blending, the bonding properties and mechanical properties of pre-polymerized epoxy resin adhesive were significantly better. Compared with unmodified epoxy resin, CTPBA modification significantly improved the bonding strength. Furthermore, with the increase of CTPBA content, the shear strength of the material increased first and then decreased, and reached the maximum when the addition amount was 40 phr. This shows that the tensile strength of the material decreased with the increase of CTPBA content, and the elongation at break increased with the increase of CTPBA content. Dynamic mechanical analyzer (DMA) test results showed that the addition of CTPBA reduced the glass transition temperature, but broadened the damping temperature range. TG analysis showed that the thermal stability of the modified epoxy resin was good, and compared with pure epoxy resin, the initial temperature of thermal weight loss and the maximum thermal decomposition rate decreased, but the overall thermal stability was not significantly different. In summary, CTPBA modification of epoxy resin is expected to improve the comprehensive mechanical properties at room temperature.

Development and Performance Evaluation of a High-Permeability and High-Bonding Fog-Sealing Adhesive Material

Herein, the effects of the contents of emulsified asphalt, waterborne epoxy resin emulsion, and curing agent on the permeability, bond shear strength, water stability, and aging resistance of epoxy-emulsified asphalt were studied. A formulation of epoxy-emulsified asphalt as a fog-sealing adhesive material was recommended, and a comparison between the fabricated adhesive material and a traditional Chinese fog-sealing adhesive material was conducted to verify the technical performance of the new material. In addition, the strength formation mechanism of the epoxy-emulsified asphalt was revealed via microcosmic analysis. Results show that the curing agent content mainly affects the permeability of epoxy-emulsified asphalt, and the emulsified asphalt content significantly affects the bond shear strength, water stability, and aging resistance. Moreover, the ratio of waterborne epoxy resin emulsion to the curing agent (epoxy ratio) has a certain effect on the bond shear strength. In the recommended formulation (a high-permeability and high-bonding fog-sealing adhesive material, which can be referred to simply as HPBFA), emulsified asphalt accounts for 80% of the total mass of the mixture, and the epoxy ratio is 2:1–3:1. It can improve air permeability, bond shear strength, water stability and aging resistance. The HPBFA-cured material exhibits a continuous three-dimensional network structure, hydrophobic surface, and large contact angle. Furthermore, the initial thermal weight loss temperature of the HPBFA-cured material is significantly higher than the environmental aging temperature. Additionally, the maximum temperature decomposition range is 0–160 °C, indicating improved strength, wear resistance, permeability, and aging resistance of the material.

Polydimethylsiloxane amino functionalized sponge for adsorption of copper in water

This work describes the preparation and use of a polydimethylsiloxane sponge amino functionalized for the adsorption of copper in water. The sponge was structurally characterized by infrared spectroscopy and solid-state 29Si NMR, which indicated the presence of silsesquioxane units that acted as nodes on the PDMS chains and linked the functional groups to the network. Thermogravimetric analysis of the product showed good thermal stability, with the initial temperature of weight loss at 400 °C. The material displayed a high degree of swelling in polar solvent, presumably due the cavities. The presence of the amino group increases the adsorption of copper onto the surface of the sponge, with adsorption capacity of about 2.0 mmol (127 mg) per gram of material. The sponge shows promising results for environmental remediation with the removal of copper in water, as well as a simple utilization with no need of a separation process after metal adsorption.

Preparation and thermal characterization of n-octadecane/pentafluorostyrene nanocapsules for phase-change energy storage

A novel class of nano-encapsulated phase-change material (NEPCM) was produced using the suspension polymerization method with the core n-octadecane capsulated in the shell of poly(2,3,4,5,6-pentafluorostyrene). The morphology and components of the NEPCM were analyzed by the scanning electron microscopy, the X-ray diffractometer, and the Fourier-transform infrared spectroscopy. The thermal performance of various NEPCM samples was compared based on the measurements of the differential scanning calorimetry, the thermogravimetric analyzer, and the thermal conductivity meter. It is found that the NEPCM4 with shell/core mass ratio 1:2 has the best thermal performance among the tested samples with six different mass ratios. The measured melting enthalpy heat of (171.8 ± 2.2) J•g−1 for the NEPCM4 is the highest among all the tested capsules and the encapsulation efficiency for the NEPCM4 is also maximized at (76.1 ± 1.8)%. Capsule size variation in the prepared samples is small. The average size diameter of the NEPCM4 capsules is measured to be 490 ± 16 nm. The thermogravimetric investigation reveals that the initial weight-loss temperature for the NEPCMs is increased in comparison with that for the pure n-octadecane. The prepared nanocapsules exhibit excellent thermal stability and thermal properties, possessing enormous potentials to enable practical applications in thermal energy storage.

Phthalimido thioureas with high antimicrobial performance as stabilizers for enhancement of the thermal stability of poly(vinyl chloride) loaded with multi‐walled carbon nanotubes

AbstractSome novel phthalimido thiourea stabilizers 1–4 were readily synthesized. Their structure was elucidated by elemental analysis, FTIR, 1H‐NMR, and mass spectroscopy. They showed good antimicrobial activity, in particularly the carboxyl derivative, as judged by their high inhibition zone diameter and low minimum inhibition concentration using the agar well diffusion technique. The results reveal the greater stabilizing efficiency of these stabilizers relative to dibasic lead carbonate, Cd‐Ba‐Zn stearate, and n‐OTM reference thermal stabilizers using TG technique in nitrogen. This is well illustrated by the higher initial decomposition temperature and lower rates of both weight loss and discoloration of the polymer during degradation. Moreover, the stabilizing efficiency is influenced by the nature of the substituent group in these stabilizers. While the methyl stabilizer is characterized by a greater efficiency relative to those of the chloro and carboxyl ones, the non‐substituted stabilizer lies between these two cases. The good disperse‐ability of multi‐walled carbon nanotubes (MWCNTs) into the polymeric material was ascertained using FTIR, XRD, SEM, and TEM. The thermal stability of PVC, which stabilized with 4, has been appreciably improved via loading 1 wt% of MWCNTs into its matrices. Further, PVC nanocomposites showed very high inhibition efficiency against Staphylococcus aureus and Escherichia coli.

Antibacterial Properties of Oregano Essential Oil Encapsulated in Poly(ε-Caprolactone) Nanoparticles

This work describes an outstanding synthesis of poly(ε-caprolactone) nanoparticles of distinct sizes loaded (PCLNP/OEO) or not (PCLNP) with oregano (Origanum vulgare) essential oil (OEO) by the nanoprecipitation method in order investigate the antimicrobial properties against bacteria Escherichia coli and Staphylococcus aureus. OEO antimicrobial activity was achieved by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). FTIR spectra indicated that encapsulation of OEO by PCLNPs was successful. Scanning electron microscopy images revealed that PCLNP and PCLNP/OEO presented spherical shape with diameters around 150 nm, while PCLNP exhibited size distribution raging 158 to 300 nm and zeta potential ranging from -13.8 to -28.5 mV. Thermogravimetric analysis indicated an increase in initial temperature of weight loss for PCLNP/OEO. PCLNP with 80% wt. of OEO has exhibited the highest decrease of growth of bacteria, and MIC against S. aureus and E. coli and MBC only for E. coli, which indicate a promising alternative for designing stable antimicrobial nanoparticles for application in novel food active packaging.

Some Technological Properties of Scotch Pine (Pinus Sylvestris Lipsky) and Eastern Beech (Fagus Orientalis Lipsky) Woods Impregnated with Alpha-X Chemical

This study was performed for the purpose of determining the technological properties of Scotch pine (Pinus sylvestris Lipsky) and Eastern beech (Fagus orientalis Lipsky) woods impregnated with Alpha-X chemicals. The impregnation solution was prepared at 10 % and 20 % concentrations. Alfa-X, a flame-retardant chemical formerly applied to textiles and laminate parquet, was used for the first time in wood work. As a result of the combustion tests, Alfa-X reduced the initial weight loss temperature of the wood material in both samples. However, it has completely raised the combustion temperature gradients in both samples. It is observed that ending temperature increased in eastern beech wood and in scotch pine wood by 117 °C and 50 °C, respectively, with increasing the rate of Alfa-X added into impregnation solution from 0 % to 20 % at deterioration. In addition, the bending and compression strength values ​​of the Scotch pine and Eastern beech wood samples were also examined

Study to improve the properties of polylactic acid by epoxidized crude rubber seed oil

AbstractThe polylactic acid plasticized by epoxidized crude rubber seed oil (EcRSO) was prepared by using a Brabender mixer to improve the ductility of polylactic acid (PLA). The weight ratios of PLA/EcRSO were changed from 100/0 to 90/10. The tensile properties proved that the addition of EcRSO to PLA led to a strong increase in elongation at break (815 %) and a very strong increase in tensile toughness (1370 %), but a decrease in tensile strength. The plasticization of PLA with EcRSO lowered the Tg as well as cold‐crystallization temperature. The initial weight loss temperature grew from 261.8 to 308.8 oC and the weight loss at 380 oC of PLA reduced from 90.9 to 83.2 % with the presence of 5 wt.% EcRSO. Based on the overall results of this investigation, EcRSO could be used as an environmental friendly plasticizer to replace petroleum‐based plasticizers in improvement the overall properties of PLA.

Characterizations of poly-lactic acid/polypropylene filled with bamboo charcoal powder

In this study, polymer blend was prepared in the ratio of Polypropylene (PP) to Polylactic acid (PLA) of 70:30 by weight. Bamboo charcoal powder (BC), at different loading was added to identify its potential use as filler for the PP/PLA blend. The polymer blend and composites were prepared by using a twin screw extruder. The effects of BC content on the mechanical and thermal properties of the PP/PLA blend were investigated. The results of tensile strength and Izod impact strength show a significant decreased with the addition of BC content. The Young modulus of composites was significantly increased (80%) with the addition of 20 wt.% BC content. The SEM results of composites with 20 wt.% BC filler show a brittle fracture surface. TGA results revealed that, blending PP with PLA cause an increase in thermal stability of PLA. However, the incorporation of 20 wt.% BC has shifted the temperature of initial weight loss of PP/PLA blend towards lower temperature. DSC measurement indicates that the melting temperature (Tm) values of the PP/PLA blend decrease with the addition of 20 wt% BC content, from 169 to 164 °C.

Effect on Mechanical and Thermal Properties of Random Copolymer Polypropylene/Microcrystalline Cellulose Composites Using T-ZnOw as an Additive

Four-needle zinc oxide whisker (T-ZnOw) incorporated into microcrystalline cellulose/maleic anhydride grafted polypropylene/random copolymer polypropylene (MCC/PP-g-MA/rPP) composite was prepared by melt blending. 5 wt% PP-g-MA was used as a coupling agent to improve the interfacial compatibility between fillers and rPP. The effect of T-ZnOw on MCC/PP-g-MA/rPP composite was investigated by mechanical testing, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Addition of T-ZnOw enhanced the mechanical properties of composites with tensile and flexural strengths increasing by 10% and 6%, respectively. SEM studies showed an improvement in the compatibility of fracture surfaces, which was evident from the absence of gaps between fillers and rPP. Additionally, initial thermal decomposition temperature and maximum weight loss temperature of T-ZnOw/MCC/PP-g-MA/rPP composite were both higher than those of MCC/PP-g-MA/rPP composite. Thermal degradation kinetics suggested that T-ZnOw has a weak catalytic effect on MCC, resulting in the early degradation of MCC and adhesion to the surface of rPP. Because of the presence of inorganic whiskers, the remaining weight percent was more than that of other composites at the end of the reaction. Crystallization temperature of the T-ZnOw/MCC/PP-g-MA/rPP composite was almost 3~5°C higher than that of MCC/PP-g-MA/rPP composite and close to the crystallization temperature of pure rPP.

Structure and Properties of Polyacrylonitrile/Polystyrene and Carbon Nanoparticle-Based Nanocomposite Foams

Abstract In this study, novel polyacrylonitrile/polystyrene (PAN/PS) blend has been prepared and reinforced with carbon nanoparticle to form polyacrylonitrile/polystyrene/carbon nanoparticle (PAN/PS/CNP) nanocomposite foam. Acid-functional carbon nanoparticle (0.1-3 wt.%) was used as nano-reinforcement for PAN/PS blend matrix. 2’-azobisisobutyronitrile was employed as foaming agent. The PAN/PS/CNP nanocomposite foams have been tested for structure, morphology, mechanical properties, thermal stability, non-flammability, water uptake, and toxic ion removal. Field-emission scanning electron microscopy and transmission electron microscopy exposed unique nanocellular morphology owing to physical interaction between the matrix and functional CNP. PAN/PS/CNP 0.1 Foam with 0.1 wt.% nanofiller had compression strength, modulus, and foam density of 41.8 MPa, 22.3 GPa, and 0.9 mgcm−3, respectively. Nanofiller loading of 3wt.% (PAN/PS/CNP 3 Foam) considerably enhanced the compression strength, modulus, and foam density as 68.2 MPa, 37.7 GPa, and 1.9 mgcm−3, respectively. CNP reinforcement also enhanced the initial weight loss and maximum decomposition temperature of PAN/PS/CNP 3 Foam to 541 and 574 ºC, relative to neat foam (T0 = 411 ºC; T10 = 459 ºC). Nanocomposite foams have also shown excellent flame retardancy as V-0 rating and high char yield of up to 57% were attained. Due to hydrophilic nature of functional carbon nanoparticle, water absorption capacity of 3 wt.% nanocomposite foam was 30% higher than that of pristine foam. Moreover, novel foams were also tested for the removal of toxic Pb2+ ions. PAN/PS/CNP 3 Foam has shown much higher ion removal capacity (166 mg/g) and efficiency (99 %) than that of PAN/PS foam having removal capacity and efficiency of 90 mg/g and 45 %, respectively.