Abstract:In the present study, thermoplastic polyurethane elastomers (TPUs) reinforced with multi‐walled carbon nanotubes, Closite 30B nanoplates, and halloysite nanotubes were produced via melt compounding approach and evaluated with many techniques including microscopy, spectroscopy, thermal, and rheological analyses. Following primary analyses, time sweep tests were used to determine the influence of temperature, applied preshear, and type of nanofillers on the micro‐phase separation kinetics of the nanocomposites. … Show more
“…TPAE-6-30 and TPAE-6-50 exhibit higher t (p1/2) values at the isothermal temperature of 170 °C compared to that at the isothermal temperature of 167 °C, indicating a higher microphase separation rate at the lower isothermal temperature. [7,33] This may be attributed to their elevated crystalline rate of PA6 in hard phases at lower temperatures, namely, the crystallization of PA6 increases the separation rate between soft and hard phases at the nanoscale. [7] However, the isothermal microphase separation kinetics curves of TPAE-6-10 and TPAE-6-70 at the isothermal temperatures of 167 °C and 170 °C virtually overlap.…”
Section: Isothermal Microphase Separation Kinetics Of Tpae-6mentioning
The facile characterization of isothermal microphase separation kinetics in polyamide 6 (PA6)‐based thermoplastic elastomers (TPAE‐6) has long posed a challenge for the development of suitable melt spinning processes. In this study, this challenge was addressed through Differential Scanning Calorimetry (DSC) measurements. It was assumed that the enthalpy changes of TPAE‐6 during the isothermal process are a linear superposition of enthalpy changes associated with microphase separation and crystallization of PA6 in hard phases, resembling that of TPAE‐6 without soft segments (TPAE‐6‐0). The study revealed that, as the concentration of soft segments in TPAE‐6 increases, the accelerated dynamics of phase separation become stronger than the dilution of soft segments to PA6 segments during isothermal process, resulting in an increase in the microphase separation rate of TPAE‐6. Furthermore, despite microphase separation, the overall crystallization rate of TPAE‐6 decreased with rising isothermal temperature and varied with increasing soft segment content at different temperatures. Additionally, the crystallization mode of TPAE‐6 followed two‐dimensional, three‐dimensional or a combination of both crystal growth mechanisms, accompanied by a heterogeneous nucleation mechanism.This article is protected by copyright. All rights reserved
“…TPAE-6-30 and TPAE-6-50 exhibit higher t (p1/2) values at the isothermal temperature of 170 °C compared to that at the isothermal temperature of 167 °C, indicating a higher microphase separation rate at the lower isothermal temperature. [7,33] This may be attributed to their elevated crystalline rate of PA6 in hard phases at lower temperatures, namely, the crystallization of PA6 increases the separation rate between soft and hard phases at the nanoscale. [7] However, the isothermal microphase separation kinetics curves of TPAE-6-10 and TPAE-6-70 at the isothermal temperatures of 167 °C and 170 °C virtually overlap.…”
Section: Isothermal Microphase Separation Kinetics Of Tpae-6mentioning
The facile characterization of isothermal microphase separation kinetics in polyamide 6 (PA6)‐based thermoplastic elastomers (TPAE‐6) has long posed a challenge for the development of suitable melt spinning processes. In this study, this challenge was addressed through Differential Scanning Calorimetry (DSC) measurements. It was assumed that the enthalpy changes of TPAE‐6 during the isothermal process are a linear superposition of enthalpy changes associated with microphase separation and crystallization of PA6 in hard phases, resembling that of TPAE‐6 without soft segments (TPAE‐6‐0). The study revealed that, as the concentration of soft segments in TPAE‐6 increases, the accelerated dynamics of phase separation become stronger than the dilution of soft segments to PA6 segments during isothermal process, resulting in an increase in the microphase separation rate of TPAE‐6. Furthermore, despite microphase separation, the overall crystallization rate of TPAE‐6 decreased with rising isothermal temperature and varied with increasing soft segment content at different temperatures. Additionally, the crystallization mode of TPAE‐6 followed two‐dimensional, three‐dimensional or a combination of both crystal growth mechanisms, accompanied by a heterogeneous nucleation mechanism.This article is protected by copyright. All rights reserved
“…Therefore, they discriminately modulate the properties of hard segment and soft segment rich phases. 74,75 Effect of phase separation on polyurethane properties…”
Section: Effect Of Nanoparticles On Polyurethanes Phase Separationmentioning
confidence: 99%
“…Therefore, they discriminately modulate the properties of hard segment and soft segment rich phases. 74,75 Figure 2.Nanoparticles (CNT) effect on PU phase separation. (a) FTIR spectra and (b) degree of phase separation (DPS) of PU/CNT nanocomposites with different CNT concentration.…”
Polyurethanes (PUs) microstructure and characteristics is strongly affected by microphase separation that arises from the thermodynamic immiscibility between the hard and soft segments. The extent of phase separation as well as the morphology and size of the separated phase governs their mechanical, electrical, thermal, and functional properties. This review: (1) provides an insight into how phase separation affects PU properties, (2) explains methods used to study PU phase separation. We review approaches from the simplest one, that is, the transparency measurement, to the more advanced methods including the spectroscopic techniques (infrared, nuclear magnetic resonance spectroscopies and X-ray scattering), rheological instruments ( rheometrics mechanical spectrometer), and thermal analyses (differential scanning calorimetry). We also discuss the theoretical calculations and the molecular modeling used to study PU phase separation.
“…By adjusting the ratio of the matrix, the content of the filler, [9,10] and the particle size of the filler, it is possible to prepare polyurethane materials with different dynamic mechanical properties, mechanical properties, [11,12] and fire resistance performance. Polyurethane has several unique mechanical, physical, biological, and chemical properties due to the strong polar groups in the macromolecule and the micro‐phase separation of the soft and hard segments in the macromolecule, and these unique properties are currently attracting a great deal of scientific attention [13,14] …”
Section: Introductionmentioning
confidence: 99%
“…Polyurethane has several unique mechanical, physical, biological, and chemical properties due to the strong polar groups in the macromolecule and the micro-phase separation of the soft and hard segments in the macromolecule, and these unique properties are currently attracting a great deal of scientific attention. [13,14] Scholars from various countries have conducted extensive research to enhance the damping performance of polyurethane. [15,16] They have found that methods such as blending, copolymerization, adding organic/inorganic fillers, interpenetrating polymer network (IPN) formation, branched structure construction, etc.…”
To improve the noise reduction and fire resistance of marine coating materials, some fire‐resistant polyurethane damping materials were prepared by varying the ratio of esterified branched polyols (EBP) and the 1,4 butanediol (1,4 BD), the content, and the particle size of the mica filler. The effects of branch chain, mica filler content, and particle size in polyurethane structure on the mechanical, dynamic mechanical properties, and fire resistance of polyurethane and its polymerization process were studied. The experimental results showed that the effective damping temperature range of polyurethane material widened from 42.1 °C to 76.6 °C, and then narrowed to 31.2 °C with the increase in EBP ratio. And the maximum loss factor (tanδmax) of these samples is 0.989. The increase of mica content and the decrease of mica particle size in polyurethane damping materials make the dynamic mechanical properties of polyurethane damping materials present a trend of first improving and then impairing. Moreover, the mechanical properties of polyurethane enhanced with the increase of EBP and weakened with the increase of mica mass fraction. This research is expected to advance the development of marine coatings and address noise reduction and fire protection challenges for marine materials.
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