Thermoplastic polyurethanes with varying hard-segment components. Mechanical performance and a filler-crosslink conversion of hard domains as monitored by SAXS

Stribeck, Norbert; Pöselt, Elmar; Eling, Berend; Jokari-Sheshdeh, Farhad; Hoell, Armin

doi:10.1016/j.eurpolymj.2017.07.020

Cited by 31 publications

(36 citation statements)

References 48 publications

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“…By comparing the reported profiles, evident analogies among the samples could be observed. The data confirm that as widely reported in literature for TPU, these samples are characterized by the presence of ordered structures in an amorphous matrix [35]. However, TPU presents stronger small sharp peaks at the top of a broad amorphous halo compared to the composites and these signals are displayed in the 2 ranges 9-11° and 20-30°.…”

Section: Preparation Molecular and Structural Characteristicssupporting

confidence: 90%

Polyurethane-Based Composites: Effects of Antibacterial Fillers on the Physical-Mechanical Behavior of Thermoplastic Polyurethanes

et al. 2020

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The challenge to manufacture medical devices with specific antibacterial functions, and the growing demand for systems able to limit bacterial resistance growth, necessitates the development of new technologies which can be easily produced at an industrial level. The object of this work was the study and the development of silver, titanium dioxide, and chitosan composites for the realization and/or implementation of biomedical devices. Thermoplastic elastomeric polyurethane was selected and used as matrix for the various antibacterial functions introduced during the processing phase (melt compounding). This strategy was employed to directly incorporate antimicrobial agents into the main constituent material of the devices themselves. With the exception of the composite filled with titanium dioxide, all of the other tested composites were shown to possess satisfactory mechanical properties. The best antibacterial effects were obtained with all the composites against Staphylococcus aureus: viability was efficiently inhibited by the prepared materials in four different bacterial culture concentrations.

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Section: Preparation Molecular and Structural Characteristicssupporting

confidence: 90%

Polyurethane-Based Composites: Effects of Antibacterial Fillers on the Physical-Mechanical Behavior of Thermoplastic Polyurethanes

et al. 2020

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“…The average moduli of the various PU films are shown in Figure 7b, and they are 53.8 ± 0.9 MPa, 20.0 ± 1.0 MPa, 21.9 ± 2.6 MPa, and 21.0 ± 0.9 MPa for the 60ES, 100ES, 60ET, and 200ET groups, respectively. The average modulus of the 60ES groups appears to be 2-fold higher than that of the other groups, suggesting that the material is intrinsically different than the others (e.g., crosslinking [53], hard/soft segment ratio [54], or types of hard/soft segments [55]).…”

Section: Resultsmentioning

confidence: 99%

Thermal and Physico-Mechanical Characterizations of Thromboresistant Polyurethane Films

et al. 2019

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Hemocompatibility remains a challenge for injectable and/or implantable medical devices, and thromboresistant coatings appear to be one of the most attractive methods to down-regulate the unwanted enzymatic reactions that promote the formation of blood clots. Among all polymeric materials, polyurethanes (PUs) are a class of biomaterials with excellent biocompatibility and bioinertness that are suitable for the use of thromboresistant coatings. In this work, we investigated the thermal and physico-mechanical behaviors of ester-based and ether-based PU films for potential uses in thromboresistant coatings. Our results show that poly(ester urethane) and poly(ether urethane) films exhibited characteristic peaks corresponding to their molecular configurations. Thermal characterizations suggest a two-step decomposition process for the poly(ether urethane) films. Physico-mechanical characterizations show that the surfaces of the PU films were hydrophobic with minimal weight changes in physiological conditions over 14 days. All PU films exhibited high tensile strength and large elongation to failure, attributed to their semi-crystalline structure. Finally, the in vitro clotting assays confirmed their thromboresistance with approximately 1000-fold increase in contact time with human blood plasma as compared to the glass control. Our work correlates the structure-property relationships of PU films with their excellent thromboresistant ability.

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“…In analogy to previous work on TPU materials, the SAXS is analyzed quantitatively with respect to its information concerning the evolution of the two‐phase morphology. The isotropic scattering curves are transformed into two fundamentally different real‐space representations of the morphology, g 1 ( r ) and g ( r ).…”

Section: Data Evaluationmentioning

confidence: 99%

“…In analogy, a ( T ) v duo is an approximate measure of the volume fraction of the arranged domains which generate the SAXS long period. Related to the parameters directly defined in the model function,

a (T) v_{h} = (W_{s o l o} + W_{d u o}) {\overset{d}{true}}_{h}

with W i being the weight parameters of the fit . The “diameter”

{\overset{d}{true}}_{h}

is, in fact, the number‐average chord length of a hard domain.…”

Section: Data Evaluationmentioning

confidence: 99%

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Melting, Solidification, and Crystallization of a Thermoplastic Polyurethane as a Function of Hard Segment Content

Stribeck¹,

Eling²,

Pöselt³

et al. 2019

Macro Chemistry & Physics

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Thermoplastic polyurethanes (TPU) with varying hard segment contents (HSC) are monitored during melting and solidifying (|T˙| = 20 K/min, Tmax = 220 ° C) by small‐angle and wide‐angle X‐ray scattering (WAXS and SAXS). Hard segments: MDI/BD. Soft segments: PTHF1000. The neat materials are injection‐molded, having small amorphous hard domains (chord length trued¯h < 6 nm). Results indicate complexity of morphology changes. For example, crystals are predominantly produced in freshly segregated, sufficiently large hard domains, while the temperature decreases slowly enough. After the thermal treatment, only the materials with HSC >∼ 35% show sharp Bragg peaks and larger hard domains (trued¯h > 7 nm). When heated, small domains melt, but crystallization in the remaining large domains is not detected. Upon cooling, large agglomerates segregate first, which crystallize immediately. Segregation starts for HSC = 42% at 160 °C and for HSC = 75% at 210 °C. When HSC ≤ 30%, the morphologies before and after are similar, but afterward, many hard blocks are dissolved in the soft phase at the expense of the hard domain fraction. In heating and cooling the melts, multiple homogenization and segregation processes are observed, which are explained by the agglomeration of hard blocks of different lengths in the colloidal fluid.

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Thermoplastic polyurethanes with varying hard-segment components. Mechanical performance and a filler-crosslink conversion of hard domains as monitored by SAXS

Cited by 31 publications

References 48 publications

Polyurethane-Based Composites: Effects of Antibacterial Fillers on the Physical-Mechanical Behavior of Thermoplastic Polyurethanes

Polyurethane-Based Composites: Effects of Antibacterial Fillers on the Physical-Mechanical Behavior of Thermoplastic Polyurethanes

Thermal and Physico-Mechanical Characterizations of Thromboresistant Polyurethane Films

Melting, Solidification, and Crystallization of a Thermoplastic Polyurethane as a Function of Hard Segment Content

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