15 results on '"THERMAL properties"'
Search Results
2. The Influence of Urtica dioica and Vitis vinifera Fibers on the Thermal Properties and Flammability of Polylactide Composites.
- Author
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Majka, Tomasz M., Piech, Radosław, Piechaczek, Marcin, and Ostrowski, Krzysztof Adam
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VITIS vinifera , *STINGING nettle , *FLAMMABILITY , *THERMAL properties , *POLYLACTIC acid , *FIRE resistant polymers , *FIBERS - Abstract
This study focuses on examining the influence of bast fibers on the flammability and thermal properties of the polylactide matrix (PLA). For this purpose, Urtica dioica and Vitis vinifera fibers were subjected to two types of modifications: mercerization in NaOH solution (M1 route) and encapsulation in an organic PLA solution (M2 route). In a further step, PLA composites containing 5, 10, and 15 wt% of unmodified and chemically treated fibers were obtained. The results of the tests show that only biocomposites containing mercerized fibers had a nearly 20% reduced flammability compared to that of PLA. Moreover, the biofiller obtained in this way belongs to the group of flame retardants that generate char residue during combustion, which was also confirmed by TGA tests. The M2 modification route allowed to achieve higher mass viscosity than the addition of unmodified and M1-modified fibers. The reason is that fibers additionally encapsulated in a polymer layer impede the mobility of the chain segments. The inferior homogenization of the M2-modified fibers in the PLA matrix translated into a longer combustion time and only a 15% reduction in flammability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
3. Environment friendly biomass composite aerogel with reinforced mechanical properties for thermal insulation and flame retardancy application.
- Author
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Deng, Tao, Li, Hanxin, Li, Yufeng, Jiang, Chongwen, He, Yu, Yang, Tao, Zhu, Lin, and Xie, Le
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THERMAL insulation ,FIREPROOFING ,AEROGELS ,FLAMMABILITY ,HEAT release rates ,THERMAL properties ,PHYTIC acid - Abstract
Biomass aerogels have attracted wide attention due to their excellent thermal insulation properties, but their low mechanical strength and high susceptibility to combustion limit their application. To address these limitations, a novel composite aerogel was prepared by combining chitosan aerogel (CS) and hydroxyapatite nanowires (HAP) via phytic acid (PA) cross‐linking and freeze‐drying. It was found that the maximum compressive strength and modulus of CS/HAP aerogel were 1.13 and 0.67 MPa, respectively. The minimum thermal conductivity of CS/HAP(0.5) composite aerogel was 0.03921 W m−1 K−1, indicating its good thermal insulating property. Moreover, the CS/HAP composite aerogel also showed excellent flame‐retardant properties. The heat release rate (HRR) and total heat release from combustion (THR) were significantly lower than those of the CS aerogel, with values of 35.2 kW m−2 and 3.7 MJ m−2, respectively, compared to 169.6 kW m−2 and 5.4 MJ m−2. The total smoke release (TSR) was also at a low level, reaches 0.4 m2 m−2. Highlights: Propose a novel chitosan aerogel composited with inorganic nano‐reinforced HAP.High mechanical strength of CS/HAP composite aerogel are illustrated.Exhibit excellent thermal insulation performance of CS/HAP aerogel.HAP and PA largely improves the flame retardancy of the chitosan aerogel. [ABSTRACT FROM AUTHOR]
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- 2023
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4. The Influence of Urtica dioica and Vitis vinifera Fibers on the Thermal Properties and Flammability of Polylactide Composites
- Author
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Tomasz M. Majka, Radosław Piech, Marcin Piechaczek, and Krzysztof Adam Ostrowski
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natural fibers ,biopolymer ,biocomposites ,flammability ,thermal properties ,polylactide ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
This study focuses on examining the influence of bast fibers on the flammability and thermal properties of the polylactide matrix (PLA). For this purpose, Urtica dioica and Vitis vinifera fibers were subjected to two types of modifications: mercerization in NaOH solution (M1 route) and encapsulation in an organic PLA solution (M2 route). In a further step, PLA composites containing 5, 10, and 15 wt% of unmodified and chemically treated fibers were obtained. The results of the tests show that only biocomposites containing mercerized fibers had a nearly 20% reduced flammability compared to that of PLA. Moreover, the biofiller obtained in this way belongs to the group of flame retardants that generate char residue during combustion, which was also confirmed by TGA tests. The M2 modification route allowed to achieve higher mass viscosity than the addition of unmodified and M1-modified fibers. The reason is that fibers additionally encapsulated in a polymer layer impede the mobility of the chain segments. The inferior homogenization of the M2-modified fibers in the PLA matrix translated into a longer combustion time and only a 15% reduction in flammability.
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- 2024
- Full Text
- View/download PDF
5. Thermal and flammability behavior of walnut shell reinforced epoxy composites
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Menderes Koyunucu and Göksel Ulay
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thermal properties ,walnut particles ,pumice ,tensile strength ,flammability ,Chemical technology ,TP1-1185 - Abstract
Abstract In this study, walnut shell particles obtained through the grinding of walnut shells were used as a reinforcing material and pumice powder as a filler for developing epoxy-based composites characterized by reduced flammability. Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), and Underwriters Laboratories (UL)-94 vertical tests were carried out for evaluating the effectiveness of these pumice powder treatments. Under the UL-94 vertical test, composites (S1, S2, S3, S4, S5 and S6) with 20% pumice powder (i.e., by mass content of walnut particles were not self-extinguished, and could not be classified. S7 and S8 composites (40wt% and 50%) assigned a V-2 rating, which was the least flammable composite However, the mechanical tensile tests showed that the pumice powder treated composites increased their tensile strength. The morphological analysis showed an enhancement of the interfacial adhesion of the composites achieved by pumice powder.
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- 2023
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6. Thermal Properties and Flammability Characteristics of a Series of DGEBA-Based Thermosets Loaded with a Novel Bisphenol Containing DOPO and Phenylphosphonate Units.
- Author
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Hamciuc, Corneliu, Vlad-Bubulac, Tăchiță, Serbezeanu, Diana, Macsim, Ana-Maria, Lisa, Gabriela, Anghel, Ion, and Şofran, Ioana-Emilia
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BISPHENOL A , *THERMAL properties , *EPOXY resins , *FLAMMABILITY , *DIFFERENTIAL scanning calorimetry , *POLYMER blends , *FIREPROOFING agents , *COMBUSTION kinetics - Abstract
Despite a recent sustained preoccupation for developing biobased epoxies with enhanced applicability, such products have not been widely accepted for industry because of their inferior characteristics compared to classic petroleum-based epoxy thermosets. Therefore, significant effort is being made to improve the flame retardance of the most commonly used epoxies, such as diglycidyl ether-based bisphenol A (DGEBA), bisphenol F (DGEBF), novalac epoxy, and others, while continuously avoiding the use of hazardous halogen-containing flame retardants. Herein, a phosphorus-containing bisphenol, bis(4-(((4-hydroxyphenyl)amino)(6-oxido-6H-dibenzo[c,e][1,2]oxaphosphinin-6-yl)methyl)phenyl) phenylphosphonate (BPH), was synthesized by reacting bis(4-formylphenyl)phenylphosphonate with 4-hydroxybenzaldehyde followed by the addition of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to the resulting azomethine groups. Environmentally friendly epoxy-based polymer thermosets were prepared by using epoxy resin as polymer matrix and a mixture of BPH and 4,4′-diaminodiphenylsulfone (DDS) as hardeners. A hyperbranched phthalocyanine polymer (HPc) and BaTiO3 nanoparticles were incorporated into epoxy resin to improve the characteristics of the final products. The structure and morphology of epoxy thermosets were evaluated by infrared spectroscopy and scanning electron microscopy (SEM), while the flammability characteristics were evaluated by microscale combustion calorimetry. Thermal properties were determined by thermogravimetric analysis and differential scanning calorimetry. The surface morphology of the char residues obtained by pyrolysis was studied by SEM analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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7. A Phosphorous-Containing Bio-Based Furfurylamine Type Benzoxazine and Its Application in Bisphenol-A Type Benzoxazine Resins: Preparation, Thermal Properties and Flammability.
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Zhao, Chunxia, Sun, Zhangmei, Wei, Jixuan, Li, Yuntao, Xiang, Dong, Wu, Yuanpeng, and Que, Yusheng
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FIRE resistant polymers , *FIRE resistant materials , *DYNAMIC mechanical analysis , *FIREPROOFING , *BISPHENOL A , *THERMAL properties , *FLAMMABILITY , *HEAT release rates - Abstract
Polybenzoxazine (PBa) composites based on phosphorous-containing bio-based furfurylamine type benzoxazines (D-fu) and bisphenol-A type benzoxazines (Ba) were developed for flame retardation. The structure of D-fu was analyzed by Fourier transform infrared (FTIR) spectroscopy and 1H-NMR spectroscopy. The curing temperature of Ba/D-fu mixtures was systematically studied by differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) demonstrated the excellent char formation ability of the PBa composites with the addition of phosphorous-containing D-fu. The flame retardancy of the PBa composite materials was tested by the limited oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter (CONE). The LOI and UL-94 level of PBa/PD-fu-5% reached 34 and V0 rate, respectively. Notably, the incorporation of 5% D-fu into PBa led to a decrease of 21.9% at the peak of the heat-release rate and a mass-loss reduction of 8.0%. Moreover, the fire performance index increased, which demonstrated that the introduction of D-fu can diminish fire occurrence. The role of D-fu in the condensed and gas phases for the fire-resistant mechanism of the PBa matrix was supported by SEM-EDS and TGA/infrared spectrometry (TG-FTIR), respectively. Dynamic mechanical analysis (DMA) revealed that the Tg of PBa flame-retardant composites was around 230 °C. Therefore, PBa composites are promising fire-retardant polymers that can be applied as high-performance functional materials. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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8. Effect of borax-boric acid and ammonium polyphosphate on flame retardancy of natural fiber polyethylene composites
- Author
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Ritesh Kumar, Jayshree Gunjal, and Shakti Chauhan
- Subjects
Ammonium polyphosphate ,boric acid-borax ,flammability ,fire retardants ,thermal properties ,wood polymer composite ,Forestry ,SD1-669.5 ,Manufactures ,TS1-2301 - Abstract
Wood fiber filled high density polyethylene composites (WPCs) were prepared using twin screw extruder and maleated polyethylene as a coupling agent. Bamboo fibers were initially treated with alkali (NaOH), boric acid - borax (Ba-Bx) and borax (Bx). The treated and untreated fibers were used in combination with ammonium polyphosphate (APP) to investigate their synergistic effects on thermal stability, flame retardancy and mechanical properties. Alkali pretreatment (5 % NaOH) of fibers showed significant improvement in performance of APP by increasing thermal stability in WPCs. The derivative thermogravimetric (DTG) results indicate significance of Ba-Bx in promoting char induction at lower temperatures (340 ºC) and thereby, improved the thermal stability in WPCs. Flammability decreased with addition of flame retardant additives. As compared to pure WPCs, composites containing APP 10 % / Ba-Bx 5 % exhibited maximum reduction in average heat release rate (HRR) by 69 %, peak heat release rate (PHRR) by 59 %, total heat released rate (THR) by 48 % and also increased time to ignition (TTI) by 62 %. However, no significant difference was found among the combinations i.e., APP with or without compounds towards reducing the flammability of WPCs. The strength properties also reduced significantly when boron compounds were added along with APP. In general, APP alone (15 %) is enough for imparting thermal stability and flame retardancy in WPCs.
- Published
- 2022
9. Development and Characterization of PLA Composites with High Contents of a Brazilian Refractory Clay and Improved Fire Performance
- Author
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Letícia Heldt Rabelo, Rodrigo Amorim Munhoz, Juliano Marini, and Sylma Carvalho Maestrelli
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PLA ,refractory clay ,mechanical properties ,thermal properties ,flammability ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Abstract Aiming to overcome poly(lactic acid) (PLA) limitations regarding flammability and high costs, a highly refractory clay (RC) was employed to produce PLA/RC composites. The composites with clay contents of 0, 2.5, 10 and 15 wt% were produced by extrusion, conformed by injection molding, and characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical analysis, scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), statistical analysis of variance (ANOVA) and flammability tests. The overall thermal stability of the materials was not affected by the incorporation of clay to the polymer matrix; improvements around 25% for Young’s modulus and slight increase in flexural and impact strength, when compared to neat PLA, were obtained; ANOVA showed the possibility of incorporating higher loads of clay, 10-15 wt%, in order to make the final material more cost effective. PLA/RC composites demonstrated self-extinguish behavior for the flame even at a lower clay content.
- Published
- 2021
- Full Text
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10. A phosphorus-containing tertiary amine hardener enabled flame retardant, heat resistant and mechanically strong yet tough epoxy resins.
- Author
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Yang, Qingshan, Wang, Jun, Chen, Xi, Yang, Shuang, Huo, Siqi, Chen, Qiufei, Guo, Pengzong, Wang, Xiao, Liu, Fu, Chen, Wei, Song, Pingan, and Wang, Hao
- Subjects
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EPOXY resins , *FIREPROOFING agents , *TERTIARY amines , *FIREPROOFING , *HEAT release rates , *FIRE prevention , *FLAMMABILITY - Abstract
[Display omitted] • A novel phosphorus-containing tertiary amine hardener (DCM) is synthesized. • DCM endows epoxy resin with desired heat resistance and char-forming capacity. • DCM improves the mechanical stiffness, robustness and toughness of epoxy resin. • DCM imparts superior flame retardancy and smoke suppression to epoxy resin. Although current phosphorus (P)-based hardeners endowed epoxy resins (EPs) with intrinsic flame retardancy, their addition usually reduced thermal and mechanical properties. In this work, a novel phosphorus-containing tertiary amine hardener (DCM) was synthesized using diphenylphosphinic chloride and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), and applied to fabricate high-performance EP/DCM. Introducing P-containing group reduced the reactivity of tertiary amine of DCM, but EP/DCM gelled at 100 °C within 11.3 min, showing modest-temperature curing character. EP/DCM exhibited higher glass-transition temperature (T g) and char yield than virgin EP/DMP-30. Moreover, EP/DCM featured superior mechanical properties, of which the tensile strength, elongation at break and impact strength increased by 61.2%, 72.0% and 198.5%, respectively, relative to those of EP/DMP-30. DCM endowed EP thermosets with remarkable flame retardancy and smoke suppression. The limiting oxygen index (LOI) and UL-94 rating of EP/DCM reached 35.7% and V-0, respectively, with 36.2% and 22.6% reductions in peak heat release rate (PHRR) and peak smoke production rate (PSPR) compared with those of EP/DMP-30. This work pioneers an innovative strategy for creating high-performance EPs with satisfactory heat resistance, fire safety, and mechanical properties by curing with P-containing tertiary amine hardeners. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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11. Development and Characterization of PLA Composites with High Contents of a Brazilian Refractory Clay and Improved Fire Performance
- Author
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Rodrigo Amorim Munhoz, Letícia Heldt Rabelo, Juliano Marini, and Sylma Carvalho Maestrelli
- Subjects
Thermogravimetric analysis ,Materials science ,Mechanical Engineering ,thermal properties ,flammability ,Izod impact strength test ,mechanical properties ,Condensed Matter Physics ,refractory clay ,Differential scanning calorimetry ,Flexural strength ,Mechanics of Materials ,TA401-492 ,PLA ,General Materials Science ,Thermal stability ,Extrusion ,Fourier transform infrared spectroscopy ,Composite material ,Materials of engineering and construction. Mechanics of materials ,Flammability - Abstract
Aiming to overcome poly(lactic acid) (PLA) limitations regarding flammability and high costs, a highly refractory clay (RC) was employed to produce PLA/RC composites. The composites with clay contents of 0, 2.5, 10 and 15 wt% were produced by extrusion, conformed by injection molding, and characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical analysis, scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), statistical analysis of variance (ANOVA) and flammability tests. The overall thermal stability of the materials was not affected by the incorporation of clay to the polymer matrix; improvements around 25% for Young’s modulus and slight increase in flexural and impact strength, when compared to neat PLA, were obtained; ANOVA showed the possibility of incorporating higher loads of clay, 10-15 wt%, in order to make the final material more cost effective. PLA/RC composites demonstrated self-extinguish behavior for the flame even at a lower clay content.
- Published
- 2021
12. Effects of Basalt and Carbon Fillers on Fire Hazard, Thermal, and Mechanical Properties of EPDM Rubber Composites
- Author
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Małgorzata Kuśmierek, Ulugbek Zakirovich Mirkhodjaev, Bolesław Szadkowski, Przemysław Rybiński, Magdalena Śliwka-Kaszyńska, Anna Marzec, and Bartłomiej Syrek
- Subjects
basalt ,Thermogravimetric analysis ,Technology ,Materials science ,polymer composites ,fire hazard ,chemistry.chemical_element ,Carbon nanotube ,Article ,law.invention ,carbon fillers ,mineral fillers ,law ,EPDM rubber ,General Materials Science ,Composite material ,Flammability ,Microscopy ,QC120-168.85 ,thermal properties ,QH201-278.5 ,Engineering (General). Civil engineering (General) ,TK1-9971 ,chemistry ,Descriptive and experimental mechanics ,Basalt fiber ,Electrical engineering. Electronics. Nuclear engineering ,TA1-2040 ,Pyrolysis ,Carbon ,Fire retardant - Abstract
Due to growing restrictions on the use of halogenated flame retardant compounds, there is great research interest in the development of fillers that do not emit toxic compounds during thermal decomposition. Polymeric composite materials with reduced flammability are increasingly in demand. Here, we demonstrate that unmodified graphene and carbon nanotubes as well as basalt fibers or flakes can act as effective flame retardants in polymer composites. We also investigate the effects of mixtures of these carbon and mineral fillers on the thermal, mechanical, and rheological properties of EPDM rubber composites. The thermal properties of the EPDM vulcanizates were analyzed using the thermogravimetric method. Flammability was determined by pyrolysis combustion flow calorimetry (PCFC) and cone calorimetry.
- Published
- 2021
13. Investigations on Epoxy-Carbamate Foams Modified with Different Flame Retardants for High-Performance Applications.
- Author
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Kaysser, Simon T., Bethke, Christian, Romero, Isabel Fernandez, Wei, Angeline Wo Weng, Keun, Christian A., Ruckdäschel, Holger, and Altstädt, Volker
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- *
FIREPROOFING agents , *FOAM , *FIRE resistant polymers , *BLOWING agents , *FLAMMABILITY , *THERMAL properties , *TRANSPORTATION industry - Abstract
In transport sectors such as aviation, automotive and railway, materials combining a high lightweight potential with high flame retardant properties are in demand. Polymeric foams are suitable materials as they are lightweight, but often have high flammability. This study focuses on the influence of different flame retardants on the burning behavior of Novolac based epoxy foams using Isophorone Diamine carbamate (B-IPDA) as dual functional curing and blowing agent. The flame retardant properties and possible modifications of these foams are systematically investigated. Multiple flame retardants, representing different flame retardant mechanisms, are used and the effects on the burning behavior as well as mechanical and thermal properties are evaluated. Ammonium polyphosphate (APP), used with a filler degree of 20 wt.% or higher, functions as the best performing flame retardant in this study. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
14. The Influence of Substituents in Phosphazene Catalyst-Flame Retardant on the Thermochemistry of Benzoxazine Curing.
- Author
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Bornosuz, Natalia V., Korotkov, Roman F., Kolenchenko, Alexander A., Shapagin, Alexey V., Orlov, Alexey V., Gorbunova, Irina Yu., Kireev, Vyacheslav V., and Sirotin, Igor S.
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FLAMMABILITY , *GLASS transition temperature , *THERMOCHEMISTRY , *CURING , *CATALYTIC activity , *THERMAL stability , *THERMAL properties - Abstract
This work is devoted to the influence of phosphazene modifiers with different substituents on the curing process, thermal properties and flammability of benzoxazine resin. Novel catalysts with m-toluidine substituents were introduced. The catalytic activity of studied phosphazene compounds decreased in the row: hexachlorocyclotriphosphazene (HCP) > tetra m-toluidine substituted phosphazene PN-mt (4) > hexa m-toluidine substituted phosphazene PN-mt (6) > hexaphenoxycyclotriphosphazene (HPP), where HPP is totally inactive. Two types of catalysis: basic and acid were proposed. A brief study of resulting properties of polybenzoxazines was presented. The addition of any studied modifier caused the decrease of glass transition temperature and thermal stability of polymers. The morphology of cured compositions was characterized by matrix-dispersion phase structure. All phosphazene containing polybenzoxazines demonstrated the improved flame resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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15. Effects of Water and Chemical Solutions Ageing on the Physical, Mechanical, Thermal and Flammability Properties of Natural Fibre-Reinforced Thermoplastic Composites.
- Author
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Kandola, Baljinder K., Mistik, S. Ilker, Pornwannachai, Wiwat, and Horrocks, A. Richard
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SISAL (Fiber) , *NATURAL fibers , *THERMOPLASTIC composites , *FIBROUS composites , *THERMAL properties , *FLEXURAL modulus , *BIOPOLYMERS , *POLYLACTIC acid - Abstract
Biocomposites comprising a combination of natural fibres and bio-based polymers are good alternatives to those produced from synthetic components in terms of sustainability and environmental issues. However, it is well known that water or aqueous chemical solutions affect natural polymers/fibres more than the respective synthetic components. In this study the effects of water, salt water, acidic and alkali solutions ageing on water uptake, mechanical properties and flammability of natural fibre-reinforced polypropylene (PP) and poly(lactic acid) (PLA) composites were compared. Jute, sisal and wool fibre- reinforced PP and PLA composites were prepared using a novel, patented nonwoven technology followed by the hot press method. The prepared composites were aged in water and chemical solutions for up to 3 week periods. Water absorption, flexural properties and the thermal and flammability performances of the composites were investigated before and after ageing each process. The effect of post-ageing drying on the retention of mechanical and flammability properties has also been studied. A linear relationship between irreversible flexural modulus reduction and water adsorption/desorption was observed. The aqueous chemical solutions caused further but minor effects in terms of moisture sorption and flexural modulus changes. PLA composites were affected more than the respective PP composites, because of their hydrolytic sensitivity. From thermal analytical results, these changes in PP composites could be attributed to ageing effects on fibres, whereas in PLA composite changes related to both those of fibres present and of the polymer. Ageing however, had no adverse effect on the flammability of the composites. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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