Evaluation of Filler Effects on the Dynamic Mechanical Behavior of HTPB-Elastomer Used as Binder in Exemplary Composite Formulations

Lemos, Maurício Ferrapontoff; Mußbach, Günter; Bohn, Manfred A.

doi:10.5028/jatm.v9i3.795

Cited by 5 publications

(7 citation statements)

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“…It may be attributed to good dispersion of the particles of fillers, promoting less restrictions for the mobility of polymer chains in the elastomer bulk. [22] Regarding the electrical properties, in Figure 4, it is possible to observe that the dielectric loss values remained nearly constant for every sample throughout the analyzed frequency range. Although the frequency range of GHz is not applied in hydroacoustic transducers, the behavior of the curves can be extrapolated to lower frequencies (range from kHz to MHz), and the comparison between the formulations should remain the same.…”

Section: Resultsmentioning

confidence: 86%

Evaluation of Polyurethane Elastomers for Encapsulation of Hydroacoustic Transducers

Lemos

Lima

Cunha

et al. 2020

Macromolecular Symposia

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Hydroacoustic transducers are devices capable of converting mechanical energy from acoustic waves into electrical energy, and vice versa, through piezoelectric elements connected to electronics that need to be protected from contact with the water. This tightness is provided by the encapsulation of the transducers with elastomers. The use of fillers and chain extenders are known to promote a barrier for water diffusion, but it would inevitably change the other properties of the elastomer. Thus, this work aims to evaluate the effects of filler and chain extender addition on the properties of polyurethane elastomers (PUR) for this application. Thermogravimetric, thermomechanical, glass‐rubber transition temperature, hardness, and dielectric loss analyses are performed. It is observed an increase in the dielectric loss, hardness, and thermal stability with the addition of mineral fillers and carbon black. The addition of chain extender promoted a greater hardness in the final elastomer, but has no measurable effects on the dielectric loss, and decreased the thermal and dimension stability with temperature. Glass‐rubber transition temperatures remain in the range from –78 to –80 °C, which is in the acceptable range for the application as encapsulants.

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Section: Resultsmentioning

confidence: 86%

Evaluation of Polyurethane Elastomers for Encapsulation of Hydroacoustic Transducers

Lemos

Lima

Cunha

et al. 2020

Macromolecular Symposia

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“…Aluminum powder, Al (18 μm mean diameter) and ammonium perchlorate particles, AP (200 μm mean diameter), common fuel and oxidizer in CRP formulation, with different percentages were used in the HTPB based formulations. Samples TS‐50, TS‐52, and TS‐57 were cured in tightly closed glass bottles with periodic turning, see Section 2, to avoid the sedimentation of the filler particles 22,23 . In this way one can recognize the real effect of particle (diameter, mass%) on the shape of tan δ curve, means on the micro level relation of the species due to heterogenous dispersion.…”

Section: Resultsmentioning

confidence: 99%

“…This mechanism enables to get a homogenous distribution of the particles in the binder network, means avoiding the sedimentation. The method is also described and used in the literature 22,23 . One batch with Al, TS‐25, was cured in Teflon mold for comparison and to assess the effect of rotating system on the sedimentation of the particles.…”

Section: Methodsmentioning

confidence: 99%

“…The effect of different isocyanates (TDI, HDI, and IPDI) on the final viscosity of HTPB‐poly(12‐hydroxy‐co‐TMP) ester‐based binder were investigated by Sekkar et al 5 The effect of fillers on the tan δ curve and T g of the polymeric composites were extensively studied 22 . The effect of different energetic plasticizers in a polyol commercially named Desmophen® 2200 (D‐2200®) on the shape of tan δ curves were studied by Lemos et al 22 A detailed survey on the effect of Al content on the tan δ curve of HTPB + IPDI + DOA based binders is investigated by Lemos et al 23 Azoug et al 13,24 applied the design of experiment (DoE) method to analyze the effect of filler fraction, NCO/OH ratio, plasticizer content and the presence of bonding agent on the shape of tan δ curve, 13,24 crosslink density, 25 and sol fraction content 26 through preparing 21 CRPs and binder formulations. They used one set of components in all batches: DOZ as plasticizer with FBBA as bonding agent and IPDI as isocyanate in HTPB based formulations.…”

Section: Introductionmentioning

confidence: 99%

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Effects of four isocyanates and four plasticizers on the thermomechanical and tensile properties of hydroxyl‐terminated polybutadiene elastomers and the effect of solid particle filling

Seyidoglu

Bohn

2020

J of Applied Polymer Sci

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The aim of this study is to analyze effect of four different isocyanates and four different plasticizers in hydroxyl‐terminated polybutadiene (HTPB) based elastomers by quantitative analysis of the shape of the loss factor (tan δ), tensile strength, deformation frequency shift of the maximum temperatures of loss moduli G" and of tan δ. The first part of the study shows intensities of the tan δ curves with the four isocyanates follow the order HDI > IPDI > H12MDI > Desmodur™ E305. By molecular modeling of the isocyanates and the corresponding polyurethane parts the influence of molecular geometry on tan δ are discussed. The second part of the study analyzes HTPB‐IPDI elastomers with the four different plasticizers DOA, DOS, DOZ, and IDP. The IDP provides lowest Tg at about −83°C, while the others provide at about −78°C. In the third part, aluminum (Al‐18 μm) and ammonium perchlorate (AP‐200 μm) are added to HTPB‐IPDI+DOA to analyze the effect of particle size, wt% content and particle type on the shape and intensity of the tan δ curves. From the frequency shift of the two maximum temperatures one receives activation energies Eaf. Their average values without and with plasticizer are with tan δ 178 and 165 kJ/mol and with G" 274 and 248 kJ/mol, respectively.

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“…One of the most common methods used to measure a material's viscoelastic properties is the dynamic mechanical analysis (DMA). Based on DMA it is possible to have information about the temperature-and time-dependent behavior [1,2], as well as aging [3][4][5], degradation [6], glass transition [7][8][9], degree of crosslinking [10][11][12], extent of phase mixing in blends [13,14], crystallinity [15], and interfacial adhesion [16][17][18], among others. Recently, the use of DMA as a characterization technique was applied to investigate mechanical properties of heterogeneous materials [19][20][21][22], spatial distribution of a material's properties [23], and crack healing [24].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Mechanical Analysis of Thermally Aged Fique Fabric-Reinforced Epoxy Composites

et al. 2021

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Dynamic mechanical analysis (DMA) is one of the most common methods employed to study a material’s viscoelastic properties. The effect of thermal aging on plain epoxy and a fique fabric-reinforced epoxy composite was investigated by comparing the mass loss, morphologies, and DMA properties of aged and unaged samples. In fact, thermal aging presents a big challenge for the high-temperature applications of natural fiber composites. In this work, both plain epoxy and fique fabric-reinforced epoxy composite were found to have different molecular mobility. This leads to distinct transition regions, with different changes in intensity caused by external loadings from time-aging. Three exponentially modified Gauss distribution functions (EMGs) were applied to loss factor curves of fique fabric-reinforced epoxy composite and plain epoxy, which allowed identifying three possible mobility ranges. From these results it was proposed that the thermal degradation behavior of natural fibers, especially fique fiber and their composites, might be assessed, based on their structural characteristics and mechanical properties.

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Evaluation of Filler Effects on the Dynamic Mechanical Behavior of HTPB-Elastomer Used as Binder in Exemplary Composite Formulations

Cited by 5 publications

References 0 publications

Evaluation of Polyurethane Elastomers for Encapsulation of Hydroacoustic Transducers

Evaluation of Polyurethane Elastomers for Encapsulation of Hydroacoustic Transducers

Effects of four isocyanates and four plasticizers on the thermomechanical and tensile properties of hydroxyl‐terminated polybutadiene elastomers and the effect of solid particle filling

Dynamic Mechanical Analysis of Thermally Aged Fique Fabric-Reinforced Epoxy Composites

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