The Influence of Long-Time Storage on the Structure and Properties of Multi-Block Thermoplastic Polyurethanes Based on Poly(butylene adipate) Diol and Polycaprolactone Diol

Gorbunova, M. A.; Anokhin, Denis V.; Abukaev, Ainur F.; Ivanov, Dimitri A.

doi:10.3390/ma16020818

Cited by 5 publications

(4 citation statements)

References 39 publications

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“…Consequently, crystallization conditions can be adjusted to control the crystalline phase fraction and the melting temperature. In previous studies, we observed a similar intricate thermal behavior in semicrystalline polyurethane-urea systems during extended storage [21]. The relative content of concurring polyols affects the total degree of crystallinity.…”

Section: Thermal Transitions and Crystallization Kinetics Of Tpussupporting

confidence: 73%

“…Synthesis of multi-block copolymers was carried out by the three-reactor method developed by us earlier at room temperature (25 • C) [21]. Two crystallizing polydiols were used in different weight ratios PBA/PCL (in wt%) 0/100 for TPU-1(0/100), 50/50 for TPU-2(50/50), 80/20 for TPU-3(80/20), and 100/0 for TPU-4(100/0).…”

Section: Synthesis Of Multi-block Thermoplastic Polyurethane (Tpu)mentioning

confidence: 99%

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Impact of Soft Segment Composition on Phase Separation and Crystallization of Multi-Block Thermoplastic Polyurethanes Based on Poly(butylene adipate) Diol and Polycaprolactone Diol

Gorbunova,

Anokhin,

Abukaev

et al. 2023

Crystals

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In this work, we explore the influence of soft segment structure on the crystallinity and phase separation of semicrystalline multi-block thermoplastic polyurethanes (TPUs) based on poly(butylene adipate) diol, polycaprolactone diol, and their mixture. According to thermal and structural analyses, the crystal growth rate and degree of crystallinity decrease with an increase in the PCL/PBA ratio and reach a minimum at the equimolar composition of polyesters. A reduction in crystal phase content leads to an improvement in elastomeric behavior. TPU samples with high PCL content demonstrate enhanced crystallinity but a lower melting temperature compared to TPU with PBA crystals. Crystallization of TPU below room temperature results in an enhancement of total crystallinity and a change in the phase composition of the PBA block. The difference in semicrystalline morphology and crystallization kinetics can be explained by the efficiency of phase separation and the density of hydrogen bonding between soft and hard segments. Our findings show that the ratio of the two crystallizable polyesters, combined with the choice of crystallization temperature, allows for independent control over the melting temperature and the overall degree of crystallinity of the TPUs. This significantly impacts the mechanical characteristics of the materials. The effect of adding a second crystallizable polyester on the crystallization behavior, phase composition, and mechanical properties of TPU is discussed for the first time.

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Section: Thermal Transitions and Crystallization Kinetics Of Tpussupporting

confidence: 73%

Section: Synthesis Of Multi-block Thermoplastic Polyurethane (Tpu)mentioning

confidence: 99%

Impact of Soft Segment Composition on Phase Separation and Crystallization of Multi-Block Thermoplastic Polyurethanes Based on Poly(butylene adipate) Diol and Polycaprolactone Diol

Gorbunova,

Anokhin,

Abukaev

et al. 2023

Crystals

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“…Two polymers, polycarbonate (PC) and thermoplastic polyurethane (TPU), were chosen for this study because of their contrasting mechanical properties. PC has a high modulus and is an amorphous material, whereas TPU is a relatively softer and semi-crystalline material [ 44 , 45 , 46 ]. To ensure consistent printing conditions, the nozzle size, layer width, air gap, raster angle, print orientation, wall count, print speed, and nozzle/bed temperatures were held constant across all the prints.…”

Section: Materials and Methodsmentioning

confidence: 99%

Exploring the Effect of Specimen Size on Elastic Properties of Fused-Filament-Fabrication-Printed Polycarbonate and Thermoplastic Polyurethane

Chadha,

Olaivar,

Mahrous

et al. 2024

Materials

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Additive manufacturing (AM) is often used to create designs inspired by topology optimization and biological structures, yielding unique cross-sectional geometries spanning across scales. However, manufacturing defects intrinsic to AM can affect material properties, limiting the applicability of a uniform material model across diverse cross-sections. To examine this phenomenon, this paper explores the influence of specimen size and layer height on the compressive modulus of polycarbonate (PC) and thermoplastic polyurethane (TPU) specimens fabricated using fused filament fabrication (FFF). Micro-computed tomography imaging and compression testing were conducted on the printed samples. The results indicate that while variations in the modulus were statistically significant due to both layer height and size of the specimen in TPU, variations in PC were only statistically significant due to layer height. The highest elastic modulus was observed at a 0.2 mm layer height for both materials across different sizes. These findings offer valuable insights into design components for FFF, emphasizing the importance of considering mechanical property variations due to feature size, especially in TPU. Furthermore, locations with a higher probability of failure are recommended to be printed closer to the print bed, especially for TPU, because of the lower void volume fraction observed near the heated print bed.

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“…In our prior research [29,30], we investigated the crystal structure, supramolecular organization, and mechanical properties of TPUs based on PBA and PCL diols, focusing particularly on their evolution during extended storage periods. We emphasized the significance of physical aging and slow crystallization rates in influencing the behavior of these materials.…”

Section: Introductionmentioning

confidence: 99%

Effect of Geometrical Confinement on Ordering of Thermoplastic Polyurethanes with Crystallizable Hard and Soft Blocks

Abukaev,

Gorbunova,

Anokhin

et al. 2023

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A series of multi-block thermoplastic polyurethanes incorporating different soft block structures was synthesized. This was achieved using a poly(butylene adipate) oligomer combined with its macrodiols of both an aromatic and aliphatic nature. The composition of the hard block included 1,6-hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and 1,4-butanediol. For the first time, the structural evolution and phase composition of both the hard and soft segments were analyzed during in situ thermal treatments. A combination of synchrotron small- and wide-angle X-ray scattering, differential scanning calorimetry, thermogravimetric analysis, and Fourier transform infrared spectroscopy was used to determine the influence of the macrodiol’s nature and crystallization conditions on the polymorphic behavior of poly(butylene adipate). Using a new synthesis scheme, a relatively high degree of crystallinity for urethane blocks was achieved, which depended on the diisocyanate type in the structure of the soft segment. The hard segment domains imposed geometrical constraints on poly(butylene adipate), thereby altering its crystallization process compared to the neat oligomer. Thus, crystallization after annealing at a low temperature (80 °C) was fast, predominantly yielding a metastable β-phase. When heated to 180 °C, which was higher than the hard segment’s melting temperature, a phase-separated structure was observed. Subsequent crystallization was slower, favoring the formation of the stable α-PBA modification. The phase separation could be observed even after the hard block melting. Notably slow crystallization from an isotropic melt was documented after the disruption of phase separation at 230 °C.

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The Influence of Long-Time Storage on the Structure and Properties of Multi-Block Thermoplastic Polyurethanes Based on Poly(butylene adipate) Diol and Polycaprolactone Diol

Cited by 5 publications

References 39 publications

Impact of Soft Segment Composition on Phase Separation and Crystallization of Multi-Block Thermoplastic Polyurethanes Based on Poly(butylene adipate) Diol and Polycaprolactone Diol

Impact of Soft Segment Composition on Phase Separation and Crystallization of Multi-Block Thermoplastic Polyurethanes Based on Poly(butylene adipate) Diol and Polycaprolactone Diol

Exploring the Effect of Specimen Size on Elastic Properties of Fused-Filament-Fabrication-Printed Polycarbonate and Thermoplastic Polyurethane

Effect of Geometrical Confinement on Ordering of Thermoplastic Polyurethanes with Crystallizable Hard and Soft Blocks

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