Compressive char strength of thermoplastic polyurethane elastomer nanocomposites

Jaramillo, Manuel; Koo, Joseph H.; Natali, Maurizio

doi:10.1002/pat.3287

Cited by 22 publications

(16 citation statements)

References 33 publications

(38 reference statements)

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“…This protective carbonaceous char may act as a thermal barrier to prevent polymer degradation and also avoids the transfer of flammable gases to vapor phase and penetration of oxygen into condensed phases during combustion . Insulation character of char residue can be evaluated from its properties such as cohesion, morphology, thickness, and porosity . Therefore, the remaining carbonaceous residues after cone calorimeter tests were investigated using XRD and Raman spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

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Three in one: β‐cyclodextrin, nanohydroxyapatite, and a nitrogen‐rich polymer integrated into a new flame retardant for poly (lactic acid)

et al. 2018

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Summary A new halogen‐free flame retardant was developed by integrating β‐cyclodextrin, triazin ring, and nanohydroxyapatite (BSDH) into a hybrid system. A β‐cyclodextrin was grafted to a commercially available SABO®STAB UV94 via an aromatic deanhydrate. The BSDH was prepared in situ in the presence of β‐cyclodextrin‐grafted nitrogen‐rich precursor. The resulting hybrid was applied as a flame retardant for poly(lactic acid) (PLA) and compared for performance with ammonium polyphosphate (APP). PLA composites containing BSDH and APP, individually or simultaneously, were examined for thermal degradation and flammability by TGA, cone calorimeter, and pyrolysis‐combustion flow calorimetry. TGA results confirmed enhancement of thermal stability of PLA with assistance of BSDH compared to APP. The gases evolved during thermal degradation were assessed by a thermogravimetric analysis and Fourier infrared spectroscopy device. APP revealed catalytic effect to initiate PLA degradation, while BSDH continued to release some gases at elevated temperatures. The flame retardancy of PLA/APP/BSDH blend containing only 10 wt.% of additives was significantly improved. In cone calorimetric tests, a significant fall in peak of heat release rate was observed for this sample, 49% more than that of neat PLA, which was indicative of more gas and condensed phase reflected in more char residue. The corresponding PLA/APP sample, however, showed 17% improvement, as compared to neat PLA. Also, total heat release rate of PLA/APP/BSDH was 45 MJ.m−2, whereas those of PLA and PLA/APP were 89 and 65 MJ.m−2, respectively. BSDH and APP showed a synergistic effect on improving the flame retardancy of PLA composites.

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Section: Resultsmentioning

confidence: 99%

“…45 Insulation character of char residue can be evaluated from its properties such as cohesion, morphology, thickness, and porosity. 46,47 Therefore, the remaining carbonaceous residues after cone calorimeter tests were investigated using XRD and Raman spectroscopy. Figure 11A).…”

Section: Characterization Of the Residual Charmentioning

confidence: 99%

Three in one: β‐cyclodextrin, nanohydroxyapatite, and a nitrogen‐rich polymer integrated into a new flame retardant for poly (lactic acid)

et al. 2018

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“…Lee et al studied the ablative properties of TPU elastomer with different nano reinforcements and concluded that multiwalled CNT composite is a good choice of ablative reinforcement, whereas carbon nanofiber is not an ideal ablative material. Jaramillo et al put an effort to optimize the formulation of TPU as an EHSM in an SRM along with other EHSMs.…”

Section: A Focus On Ehsms For Srmmentioning

confidence: 99%

Recent developments in elastomeric heat shielding materials for solid rocket motor casing application for future perspective

George

Panda

Mohanty

et al. 2017

Polymers for Advanced Techs

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Catastrophic breakdown that occurs during the flight of supersonic vehicles demands more focused research in the insulation of rocket engines. At present, optimization of polymeric ablatives as viable insulation for solid rocket motor casing has a prominent role in the successful mission of rockets. Among polymers, elastomer serves an imperative part. Comprehensive investigations were disclosed, especially in the elastomeric heat shielding materials with various reinforcing agents. In this paper, research progress of mostly used elastomers is reviewed, and a circumstantial understanding about the features of ablation and insulation has been validated. 2-4 Therefore, to protect the vehicle from miserable failure of spacecraft, some design features are added to cope with the aerodynamic heating. 5Thermal protection system (TPS) materials impart heat shield to protect the structure, aerodynamic surface and the payload of missiles, and those vehicles interacting with the hypersonic environment. 6,7 Polymeric ablative materials serve to effect as TPS that defends space vehicles and probes during the atmospheric entry; they are effective to produce passively cooled rocket combustion chambers 8 and to render insulation to the solid rocket motors (SRMs) at high temperature. [9][10][11] Although some nonpolymeric materials such as inorganic polymers/ceramics or metals have been used as ablative TPS, polymeric ablatives represent the most flexible category of ablatives. In contrast to the inorganic polymers, polymer ablatives have more inborn benefits: high-heat shock resistance, lower density, good mechanical strength, and thermal insulation capabilities. 12The broad range of heat shielding materials (HSMs) for rocket motor casing is produced from reinforced thermosets or elastomers. [13][14][15][16][17][18][19] The most assuring material for the HSM for rocket motors is the elastomers, which can be produced as rubbers, foamed rubbers, or fiber-reinforced composite materials. On the grounds of lightweight, low thermal conductivity, stability in the mechanical and thermal stresses during the operation, elastomeric HSMs (EHSMs) can find relevance in the insulation of SRM casing where thermal insulation is a prime necessity. They do not possess the ability to form cokes without the introduction of special additives due to the linear chain structure of elastomers, thus no solid carbonic residue on thermal decomposition.Also, elastomers have high elongation at break and the capacity to withstand the mechanical and the thermal stresses during the manufacturing and in use. 20This review puts the elastomeric materials as ablative insulators for SRM into frame and would confer the readers the progress that has been attained in developing relatively low surface eroding and ablative insulating systems for SRM. These systems can be used to manufacture variety of ablative TPS systems for rocket motor casing application and would provide an idea regarding the composite system that would behave elastomeric as well as ablative. Scrutini...

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“…Jaramillo et al . developed a compressive char strength to evaluate thermoplastic polyurethane elastomer nanocomposites . Because of its creation, the corrected testing apparatus has served as a novel method for evaluating the properties of char and was once again called upon for this investigation.…”

Section: Introductionmentioning

confidence: 99%

“…This study involves the use of a previously built compressive strength sensor and shear strength sensor at UT Austin. A picture of the shear sensor and a sketch of the shear sensor's set up is presented in Fig.…”

Section: Introductionmentioning

confidence: 99%

Development of a shear char strength sensing technique to study thermoplastic polyurethane elastomer nanocomposites

Lewis

Jaramillo

Koo

2017

Polymers for Advanced Techs

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Ablative materials, such as thermoplastic elastomer nanocomposites (TPUNs) are used as internal insulation materials for solid rocket motors. These TPUNs are thermoplastic elastomer reinforced by montmorillonite nanoclays, carbon nanofibers, and multi‐walled carbon nanotubes. When these TPUN materials are exposed to an extreme heat flux, a char layer forms along the surface as it ablates. This research aims to use the newly developed shear strength sensor to evaluate the shear strength of this char layer, a characteristic that is important to evaluate ablative materials. This device consists of a method to apply a transverse loading on a test specimen, while measuring the reaction force and the induced strain. This device was used on several types of TPUN test specimens to demonstrate its effectiveness. As a means to determine which ablative exhibited the best performance, the energy of destruction or the energy of dissipation was developed. The maximum force was also accounted for as a secondary quantity for determining the char shear strength. This new shear char strength sensor is fully automated to ensure that each test is repeatable. This guaranteed reliability when collecting the data and eliminated the potential for human error. Copyright © 2017 John Wiley & Sons, Ltd.

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Compressive char strength of thermoplastic polyurethane elastomer nanocomposites

Cited by 22 publications

References 33 publications

Three in one: β‐cyclodextrin, nanohydroxyapatite, and a nitrogen‐rich polymer integrated into a new flame retardant for poly (lactic acid)

Three in one: β‐cyclodextrin, nanohydroxyapatite, and a nitrogen‐rich polymer integrated into a new flame retardant for poly (lactic acid)

Recent developments in elastomeric heat shielding materials for solid rocket motor casing application for future perspective

Development of a shear char strength sensing technique to study thermoplastic polyurethane elastomer nanocomposites

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