Castor Oil Polyurethanes as Biomaterials

Medical application of polyurethane (PU) elastomers has been contributed significantly to the quality and effectiveness of health care systems. Applications such as nasogastric catheter, sutures, wound dressing, drug delivery system, and insulation on the leads of electronics pacemakers are already in the market. Properties of polyurethanes such as thermal and chemical stability, mechanical performance, and low degradation rate make an outstanding material for that kind of application. More recently, castor oil as polyol source has been investigated due to the needs of friendly environmental sources. In this chapter, we want to approach the advances in polyurethane area from castor oil for application in medicines. A review of castor oil-based polyurethanes, chemical modification, processing techniques, and applications in tissue engineering and medical devices will be made with the objective to understand the current situation, limitations, challenges, and perspective of this type of material

Hydrolytic stability and biocompatibility on smooth muscle cells of polyethylene glycol-polycaprolactone-based polyurethanes

[EN] Interactions between smooth muscle cells (SMCs) and biomaterials must not result in phenotype changes as this may generate uncontrolled multiplication processes and occlusions in vascular grafts. The aim of this study was to relate the hydrolytic stability and biocompatibility of polyurethanes (PUs) on SMCs. A higher polycaprolactone (PCL) concentration was found to improve the hydrolytic stability of the material and the adhesion of SMCs. A material with 5% polyethylene glycol, 90% PCL, and 5% pentaerythritol presented high cell viability and adhesion, suggesting a contractile phenotype in SMCs depending on the morphology. Nevertheless, all PUs retained their elastic modulus over 120 days, similar to the collagen of native arteries (similar to 10 MPa). Furthermore, aortic SMCs did not present toxicity (viability over 80%) and demonstrated adherence without any abnormal cell multiplication processes, which is ideal for the function to be fulfiled in situ in the vascular grafts.The research and publication were supported by the Universidad de La Sabana (ING-205-2018) and the Minister of Science, Technology, and Innovation of the Republic of Colombia, MINCIENCAS (Contract number 80740-186-2019). M. M-G. would like to thank the Universidad de La Sabana for the scholarship for her master's studies. S. A-A. would like to thank MINCIENCIAS for the doctoral training scholarship (Grant 727-2015). The authors are thankful to Professor Ericsson Coy Barrera and his staff at Nueva Granada Military University for the access to the VarioskanT LUX multimode microplate reader. J. A. S. acknowledges the financial support by MINECO through FIS2017-83295-P, MAT2015-71070-REDC, MAT2016-75586-C4-1/2/3-P and the Ramon y Cajal Fellowship (RYC-201517482). CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.Morales-Gonzalez, M.; Arévalo-Alquichire, S.; Diaz, LE.; Sans-Tresserras, JÁ.; Vilariño, G.; Gómez-Tejedor, J.; Valero, MF. (2020). Hydrolytic stability and biocompatibility on smooth muscle cells of polyethylene glycol-polycaprolactone-based polyurethanes. Journal of Materials Research. 35(23-24):3276-3285. https://doi.org/10.1557/jmr.2020.303S327632853523-24Benrashid, E., McCoy, C. C., Youngwirth, L. M., Kim, J., Manson, R. J., Otto, J. C., & Lawson, J. H. (2016). Tissue engineered vascular grafts: Origins, development, and current strategies for clinical application. Methods, 99, 13-19. doi:10.1016/j.ymeth.2015.07.014Asadpour, S., Ai, J., Davoudi, P., Ghorbani, M., Jalali Monfared, M., & Ghanbari, H. (2018). 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Influence of Polyol/Crosslinker Blend Composition on Phase Separation and Thermo-Mechanical Properties of Polyurethane Thin Films. Polymers, 12(3), 666. doi:10.3390/polym12030666Wu, J., Hu, C., Tang, Z., Yu, Q., Liu, X., & Chen, H. (2018). Tissue-engineered Vascular Grafts: Balance of the Four Major Requirements. Colloid and Interface Science Communications, 23, 34-44. doi:10.1016/j.colcom.2018.01.005Wolf, F., Vogt, F., Schmitz-Rode, T., Jockenhoevel, S., & Mela, P. (2016). Bioengineered vascular constructs as living models for in vitro cardiovascular research. Drug Discovery Today, 21(9), 1446-1455. doi:10.1016/j.drudis.2016.04.017Kotula, A. P., Snyder, C. R., & Migler, K. B. (2017). Determining conformational order and crystallinity in polycaprolactone via Raman spectroscopy. Polymer, 117, 1-10. doi:10.1016/j.polymer.2017.04.006Cunha, F. O. V. da, Melo, D. H. R., Veronese, V. B., & Forte, M. M. C. (2004). Study of castor oil polyurethane - poly(methyl methacrylate) semi-interpenetrating polymer network (SIPN) reaction parameters using a 2³ factorial experimental design. Materials Research, 7(4), 539-543. doi:10.1590/s1516-1439200400040000633. Chang, H.-I. and Wang, Y. : Cell response to surface and architecture of tissue engineering scaffolds. Regen. Med. Tissue Eng. – Cells Biomater. (2012), pp. 569–588.Chen, H., & Kassab, G. S. (2016). Microstructure-based biomechanics of coronary arteries in health and disease. Journal of Biomechanics, 49(12), 2548-2559. doi:10.1016/j.jbiomech.2016.03.023Zhou, C., Zhou, X., & Su, X. (2017). Noncytotoxic polycaprolactone-polyethyleneglycol-ε-poly(l-lysine) triblock copolymer synthesized and self-assembled as an antibacterial drug carrier. RSC Advances, 7(63), 39718-39725. doi:10.1039/c7ra07102gTijore, A., Behr, J.-M., Irvine, S. A., Baisane, V., & Venkatraman, S. (2018). Bioprinted gelatin hydrogel platform promotes smooth muscle cell contractile phenotype maintenance. Biomedical Microdevices, 20(2). doi:10.1007/s10544-018-0274-8Jing, X., Mi, H.-Y., Salick, M. R., Cordie, T., McNulty, J., Peng, X.-F., & Turng, L.-S. (2015). In vitro evaluations of electrospun nanofiber scaffolds composed of poly(ɛ-caprolactone) and polyethylenimine. Journal of Materials Research, 30(11), 1808-1819. doi:10.1557/jmr.2015.117Hou, Z., Xu, J., Teng, J., Jia, Q., & Wang, X. (2020). Facile preparation of medical segmented poly(ester-urethane) containing uniformly sized hard segments and phosphorylcholine groups for improved hemocompatibility. Materials Science and Engineering: C, 109, 110571. doi:10.1016/j.msec.2019.110571Agrawal, A., Lee, B. H., Irvine, S. A., An, J., Bhuthalingam, R., Singh, V., … Venkatraman, S. S. (2015). Smooth Muscle Cell Alignment and Phenotype Control by Melt Spun Polycaprolactone Fibers for Seeding of Tissue Engineered Blood Vessels. 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Functional polymer surfaces for controlling cell behaviors. Materials Today, 21(1), 38-59. doi:10.1016/j.mattod.2017.07.002França de Sá, S., Ferreira, J. L., Matos, A. S., Macedo, R., & Ramos, A. M. (2016). A new insight into polyurethane foam deterioration - the use of Raman microscopy for the evaluation of long-term storage conditions. Journal of Raman Spectroscopy, 47(12), 1494-1504. doi:10.1002/jrs.4984Xie, F., Zhang, T., Bryant, P., Kurusingal, V., Colwell, J. M., & Laycock, B. (2019). Degradation and stabilization of polyurethane elastomers. Progress in Polymer Science, 90, 211-268. doi:10.1016/j.progpolymsci.2018.12.003Uscátegui, Y. L., Arévalo-Alquichire, S. J., Gómez-Tejedor, J. A., Vallés-Lluch, A., Díaz, L. E., & Valero, M. F. (2017). Polyurethane-based bioadhesive synthesized from polyols derived from castor oil (Ricinus communis) and low concentration of chitosan. Journal of Materials Research, 32(19), 3699-3711. doi:10.1557/jmr.2017.371Horakova, J., Mikes, P., Saman, A., Jencova, V., Klapstova, A., Svarcova, T., … Lukas, D. (2018). The effect of ethylene oxide sterilization on electrospun vascular grafts made from biodegradable polyesters. Materials Science and Engineering: C, 92, 132-142. doi:10.1016/j.msec.2018.06.041Liu, X., Xia, Y., Liu, L., Zhang, D., & Hou, Z. (2018). Synthesis of a novel biomedical poly(ester urethane) based on aliphatic uniform-size diisocyanate and the blood compatibility of PEG-grafted surfaces. Journal of Biomaterials Applications, 32(10), 1329-1342. doi:10.1177/0885328218763912Uscátegui, Y., Díaz, L., Gómez-Tejedor, J., Vallés-Lluch, A., Vilariño-Feltrer, G., Serrano, M., & Valero, M. (2019). Candidate Polyurethanes Based on Castor Oil (Ricinus communis), with Polycaprolactone Diol and Chitosan Additions, for Use in Biomedical Applications. 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Polyurethanes from modified castor oil and chitosan. Synthesis, characterization, in vitro degradation, and cytotoxicity

[EN] Polyurethanes (PUs) from castor oil (CO), modified CO (MCO) by transesterification reaction, isophorone diisocyanate (IPDI) in an NCO/OH ratio equal to 1, and chitosan (CS) were synthesized to assess their potential as biomaterials. PUs were characterized by Fourier transform infrared spectroscopy, hydroxyl value (ASTM D1957), thermogravimetric analysis, Shore A hardness (ASTM D2240), and scanning electronic microscopy (SEM). Also, contact angle, water retention and in vitro degradation in PBS, and cell viability on fibroblast were performed. The hydroxyl value confirms CO modification, and IR analysis confirms urethane bond formation. The thermal assay does not show new degradation stages and polyol with a high functionality had better hardness performance due to the increase in cross-linking. The micrograph shows micro-phase separation of both polymers. The contact angle shows the hydrophobic surface with an angle over 65°, and the CS and polyol type do not affect swelling and in vitro degradation due to phase separation between both polymers. The cell viability was over 70% in all cases, and solid polymers and degradation products involve non-cytotoxic effects on the samples. The results suggest a potential for these formulations in the biomedical field.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Universidad de La Sabana under Grant number ING-160-2015. Also, Jose A. Gomez-Tejedor and Ana Valles-Lluch acknowledge the support of the Spanish Ministry of Economy and Competitiveness (MINECO) through the project DPI2015-65401-C3-2-R (including the FEDER financial support).Arévalo-Alquichire, S.; Ramírez, C.; Andrade, L.; Uscategui, Y.; Diaz, LE.; Gómez-Tejedor, JA.; Vallés Lluch, A.... (2018). Polyurethanes from modified castor oil and chitosan. Synthesis, characterization, in vitro degradation, and cytotoxicity. Journal of Elastomers and Plastics. 50(5):419-434. https://doi.org/10.1177/0095244317729578S41943450

Polyurethanes for vascular applications : Effect of polyol blend composition on biomechanics

147 páginasCardiovascular diseases are the lead cause of death around the world. Ischemic heart attacks and stroke are the top pathologies related to the narrowing and occluding of blood vessels. Despite governmental and non-governmental organizations' considerable efforts to improve lifestyle and prevention, surgical interventions are widely performed to repair the damaged vessel. The vascular bypass is a surgical alternative where the broken vein or artery is replaced with another blood vessel (autologous) or prosthesis. Like the saphenous vein, an autologous graft is a gold standard; however, there is a lack of suitable blood vessels in patients due to other blood vessel diseases. On the other hand, the revascularization and compliance mismatch between the native vessel and the graft persist. In the past, polyurethanes were used for vascular grafts because of high compliance and similar mechanical properties to native tissue. The polyurethanes segment made it a special group of heterochain polymers that can be tailored from monomers selection. This thesis proposes studying the polyol composition on the physic properties and biomechanics of polyurethane-based vascular graft. Here, we studied a novel group of polyurethanes synthesized from polycaprolactone diol, polyethylene glycol and, a novel crosslinker, the pentaerythritol, using isophorone diisocyanate. The first section of this dissertation provides a comprehensive description of the physic-chemical properties and the cell-material interaction. Four compositions were selected for further numerical and computational analysis. The four compositions: 5- 90-5, 45-45-10, 46.3-46.3-7.5, 47.5.47.5-5, provide a homogenous phase distribution between segments and the best damping behavior in the experimental space.Las enfermedades cardiovasculares son la principal causa de muerte en todo el mundo. Los ataques cardíacos isquémicos y los accidentes cerebrovasculares son las principales patologías, las cuales están relacionadas con el estrechamiento y la oclusión de los vasos sanguíneos. A pesar de los enormes esfuerzos de las organizaciones gubernamentales y no gubernamentales para mejorar el estilo de vida y la prevención, las intervenciones quirúrgicas se realizan ampliamente para reparar el vaso dañado. El bypass vascular es una alternativa quirúrgica en la que la vena o arteria dañada se reemplaza por otro vaso sanguíneo (autólogo) o prótesis. El injerto autólogo, como la vena safena, es el estándar de oro; sin embargo, hay una falta de vasos sanguíneos viables, en pacientes, debido a otras enfermedades de los vasos sanguíneos. Por otro lado, persisten los desafíos relacionados con la revascularización y el discordancia de compliancia entre el vaso nativo y el injerto. En el pasado, los poliuretanos se usaban para injertos vasculares debido a la alta elasticidad y propiedades mecánicas similares a las del tejido nativo. La estructura segmentada de los poliuretanos lo convirtió en un grupo especial de polímeros de heterocadena cuyas propiedades se pueden adaptar a partir de la selección de monómeros. Esta tesis propone el estudio de la composición del poliol sobre las propiedades físicas y biomecánicas del injerto vascular a base de poliuretano. Aquí, estudiamos un grupo novedoso de poliuretano sintetizado a partir de una mezcla de policaprolactona diol, polietilenglicol y un nuevo reticulante, pentaeritritol, usando diisocianato de isoforona. La primera sección de esta disertación proporciona una descripción amplia de las propiedades físico-químicas y la interacción célula-material donde se seleccionaron cuatro composiciones para el análisis numérico y computacional posterior. Las cuatro composiciones: 5-90-5, 45-45-10, 46.3-46.3-7.5, 47.5.47.5-5 proporcionan una distribución de fase homogénea entre segmentos y el mejor comportamiento de amortiguación dentro el espacio experimental.Doctorado en BiocienciasDoctor en Biociencia

Evaluación mecánica y modelado hiperelástico de poliuretanos para las primeras etapas del diseño de injertos vasculares

17 páginasThe material design of vascular grafts is required for their application in the health sector. The use of polyurethanes (PUs) in vascular grafts intended for application in the body appears to be adequate due to the fact that native tissues have similar properties as PUs. However, the influence of chemical structure on the biomechanics of PUs remains poorly described. The use of constitutive models, together with numerical studies, is a powerful tool for evaluating the mechanical behavior of materials under specific physiological conditions. Therefore, the aim of this study was to assess the mechanical properties of different PU mixtures formed by polycaprolactone diol, polyethylene glycol, and pentaerythritol using uniaxial tensile, strain sweep, and multistep creep-recovery tests. Evaluations of the properties were also recorded after samples had been soaked in phosphate-buffer saline (PBS) to simulate physiological conditions. A hyperelastic model based on the Mooney–Rivlin strain density function was employed to model the performance of PUs under physiological pressure and geometry conditions. The results show that the inclusion of polyethylene glycol enhanced viscous flow, while polycaprolactone diol increased the elastic behavior. Furthermore, tensile tests revealed that hydration had an important effect on the softening phenomenon. Additionally, after the hydration of PUs, the ultimate strength was similar to those reported for other vascular conduits. Lastly, hyperelastic models revealed that the compliance of the PUs showed a cyclic behavior within the tested time and pressure conditions and is affected by the material composition. However, the compliance was not affected by the geometry of the materials. These tests demonstrate that the materials whose compositions are 5–90–5 and 46.3–46.3–7.5 could be employed in the designs of vascular grafts for medical applications since they present the largest value of compliance, ultimate strength, and elongation at break in the range of reported blood vessels, thus indicating their suitability. Moreover, the polyurethanes were revealed to undergo softening after hydration, which could reduce the risk of vascular trauma.El diseño material de los injertos vasculares es requerido para su aplicación en el sector salud. El uso de poliuretanos (PU) en injertos vasculares destinados a su aplicación en el cuerpo parece adecuado debido a que los tejidos nativos tienen propiedades similares a las PU. Sin embargo, la influencia de la estructura química en la biomecánica de las UP sigue estando poco descrita. El uso de modelos constitutivos, junto con estudios numéricos, es una poderosa herramienta para evaluar el comportamiento mecánico de materiales bajo condiciones fisiológicas específicas. Por lo tanto, el objetivo de este estudio fue evaluar las propiedades mecánicas de diferentes mezclas de PU formadas por policaprolactona diol, polietilenglicol y pentaeritritol mediante ensayos de tracción uniaxial, barrido de deformación y recuperación de fluencia de varios pasos. Las evaluaciones de las propiedades también se registraron después de sumergir las muestras en solución salina tamponada con fosfato (PBS) para simular las condiciones fisiológicas. Se empleó un modelo hiperelástico basado en la función de densidad de deformación de Mooney-Rivlin para modelar el rendimiento de las PU en condiciones fisiológicas de presión y geometría. Los resultados muestran que la inclusión de polietilenglicol mejoró el flujo viscoso, mientras que el policaprolactona diol aumentó el comportamiento elástico. Además, las pruebas de tracción revelaron que la hidratación tuvo un efecto importante en el fenómeno de ablandamiento. Además, después de la hidratación de las UP, la resistencia máxima fue similar a la reportada para otros conductos vasculares. Por último, los modelos hiperelásticos revelaron que la complianza de las PU mostró un comportamiento cíclico dentro de las condiciones de tiempo y presión probadas y se ve afectada por la composición del material. Sin embargo, la conformidad no se vio afectada por la geometría de los materiales. Estas pruebas demuestran que los materiales cuyas composiciones son 5–90–5 y 46.3–46.3–7.5 podrían emplearse en los diseños de injertos vasculares para aplicaciones médicas ya que presentan el mayor valor de cumplimiento, resistencia última y elongación a la rotura en el rango de vasos sanguíneos informados, lo que indica su idoneidad. Además, se reveló que los poliuretanos se ablandan después de la hidratación, lo que podría reducir el riesgo de traumatismo vascular

Assessment of the Anti-Thrombogenic Activity of Polyurethane Starch Composites

The increasing morbidity and mortality of patients due to post-surgery complications of coronary artery bypass grafts (CABPG) are related to blood–material interactions. Thus, the characterization of the thrombogenicity of the biomaterial for cardiovascular devices is of particular interest. This research evaluated the anti-thrombogenic activity of polyurethanes–starch composites. We previously synthesized polyurethane matrices that were obtained from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE), and isophorone diisocyanate (IPDI). In addition, potato starch (AL-N) and zwitterionic starch (AL-Z) were added as fillers. The anti-thrombogenic property was characterized by the clot formation time, platelet adhesion, protein absorption, TAT complex levels, and hemolysis. Additionally, we evaluated the cell viability of the endothelial and smooth muscle cells. Statically significant differences among the polyurethane matrices (P1, P2, and P3) were found for protein absorption and the blood clotting time without fillers. The polyurethanes composites with AL-Z presented an improvement in the anti-thrombogenic property. On the other hand, the composites with AL-Z reduced the viability of the endothelial cells and did not significantly affect the AoSCM (except for P1, which increased). These results classify these biomaterials as inert; therefore, they can be used for cardiovascular applications

Evaluación de la actividad antitrombogénica de los compuestos de almidón de poliuretano

13 páginasThe increasing morbidity and mortality of patients due to post-surgery complications of coronary artery bypass grafts (CABPG) are related to blood–material interactions. Thus, the characterization of the thrombogenicity of the biomaterial for cardiovascular devices is of particular interest. This research evaluated the anti-thrombogenic activity of polyurethanes–starch composites. We previously synthesized polyurethane matrices that were obtained from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE), and isophorone diisocyanate (IPDI). In addition, potato starch (AL-N) and zwitterionic starch (AL-Z) were added as fillers. The anti-thrombogenic property was characterized by the clot formation time, platelet adhesion, protein absorption, TAT complex levels, and hemolysis. Additionally, we evaluated the cell viability of the endothelial and smooth muscle cells. Statically significant differences among the polyurethane matrices (P1, P2, and P3) were found for protein absorption and the blood clotting time without fillers. The polyurethanes composites with AL-Z presented an improvement in the anti-thrombogenic property. On the other hand, the composites with AL-Z reduced the viability of the endothelial cells and did not significantly affect the AoSCM (except for P1, which increased). These results classify these biomaterials as inert; therefore, they can be used for cardiovascular applications.La creciente morbilidad y mortalidad de los pacientes debido a las complicaciones posquirúrgicas de los injertos de derivación de arteria coronaria (CABPG) están relacionadas con las interacciones sangre-material. Por tanto, la caracterización de la trombogenicidad del biomaterial para dispositivos cardiovasculares es de particular interés. Esta investigación evaluó la actividad antitrombogénica de los compuestos de poliuretano y almidón. Anteriormente sintetizamos matrices de poliuretano que se obtuvieron a partir de policaprolactona diol (PCL), polietilenglicol (PEG), pentaeritritol (PE) y diisocianato de isoforona (IPDI). Además, se añadieron como cargas almidón de patata (AL-N) y almidón zwitteriónico (AL-Z). La propiedad antitrombogénica se caracterizó por el tiempo de formación del coágulo, la adhesión plaquetaria, la absorción de proteínas, los niveles del complejo TAT y la hemólisis. Además, evaluamos la viabilidad celular de las células endoteliales y del músculo liso. Se encontraron diferencias estáticamente significativas entre las matrices de poliuretano (P1, P2 y P3) para la absorción de proteínas y el tiempo de coagulación de la sangre sin rellenos. Los composites de poliuretano con AL-Z presentaron una mejora en la propiedad antitrombogénica. Por otro lado, los composites con AL-Z redujeron la viabilidad de las células endoteliales y no afectaron significativamente la AoSCM (excepto P1, que aumentó). Estos resultados clasifican a estos biomateriales como inertes; por lo tanto, pueden usarse para aplicaciones cardiovasculares

Influence of Starch on the Structure–Properties Relationship in Polyethylene Glycol/Polycaprolactone Diol Polyurethanes

Improvements in the antithrombogenicity activity of biomaterials for cardiovascular applications are necessary to meet the demand for vascular grafts in the world. Zwitterionic compounds tend to be used due to their anti-fouling properties, which reduce platelet adhesions and protein absorptions. Therefore, in this research, potato starch (AL-N) and zwitterionic starch (AL-Z) (obtained by Williamson etherification) were included as fillers in polyurethane (PU) matrices from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE) and isophorone diisocyanate (IPDI) in order to study their effect in terms of their physicochemical, mechanical and thermal properties. We conducted our evaluation using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), contact angle analysis, swelling behavior, thermogravimetric analysis (TGA), tensile/strain analysis, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), dynamic mechanic analysis (DMA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results showed that AL-N and AL-Z modified these properties, where AL-N improved tensile strength, and AL-Z increased the hydrophilicity of polyurethanes matrices; additionally, AL-N had interactions with the soft segments, and AL-Z had interactions with the hard segments. Finally, both fillers reduced the degree of crystallinity and did not affect the thermal stability of polyurethanes

Influence of Starch on the Structure–Properties Relationship in Polyethylene Glycol/Polycaprolactone Diol Polyurethanes

18 páginasImprovements in the antithrombogenicity activity of biomaterials for cardiovascular applications are necessary to meet the demand for vascular grafts in the world. Zwitterionic compounds tend to be used due to their anti-fouling properties, which reduce platelet adhesions and protein absorptions. Therefore, in this research, potato starch (AL-N) and zwitterionic starch (AL-Z) (obtained by Williamson etherification) were included as fillers in polyurethane (PU) matrices from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE) and isophorone diisocyanate (IPDI) in order to study their effect in terms of their physicochemical, mechanical and thermal properties. We conducted our evaluation using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), contact angle analysis, swelling behavior, thermogravimetric analysis (TGA), tensile/strain analysis, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), dynamic mechanic analysis (DMA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results showed that AL-N and AL-Z modified these properties, where AL-N improved tensile strength, and AL-Z increased the hydrophilicity of polyurethanes matrices; additionally, AL-N had interactions with the soft segments, and AL-Z had interactions with the hard segments. Finally, both fillers reduced the degree of crystallinity and did not affect the thermal stability of polyurethanesEs necesario mejorar la actividad antitrombogenicidad de los biomateriales para aplicaciones cardiovasculares para satisfacer la demanda de injertos vasculares en el mundo. Se tienden a utilizar compuestos zwitteriónicos debido a sus propiedades antiincrustantes, que reducen la adhesión de plaquetas y la absorción de proteínas. Por lo tanto, en esta investigación, se incluyeron almidón de papa (AL-N) y almidón zwitteriónico (AL-Z) (obtenidos por eterificación de Williamson) como cargas en matrices de poliuretano (PU) a partir de policaprolactona diol (PCL), polietilenglicol (PEG), pentaeritritol (PE) y diisocianato de isoforona (IPDI) con el fin de estudiar su efecto en términos de sus propiedades fisicoquímicas, mecánicas y térmicas. Llevamos a cabo nuestra evaluación utilizando espectroscopía infrarroja por transformada de Fourier de reflectancia total atenuada (ATR-FTIR), análisis de ángulo de contacto, comportamiento de hinchamiento, análisis termogravimétrico (TGA), análisis de tracción/deformación, microscopía electrónica de barrido equipada con espectroscopía de rayos X de energía dispersiva (SEM- EDS), análisis mecánico dinámico (DMA), calorimetría diferencial de barrido (DSC) y difracción de rayos X (XRD). Los resultados mostraron que AL-N y AL-Z modificaron estas propiedades, donde AL-N mejoró la resistencia a la tracción y AL-Z aumentó la hidrofilicidad de las matrices de poliuretano; Además, AL-N tuvo interacciones con los segmentos blandos y AL-Z tuvo interacciones con los segmentos duros. Finalmente, ambas cargas redujeron el grado de cristalinidad y no afectaron la estabilidad térmica de los poliuretanos

Surface Response Methodology-Based Mixture Design to Study the Influence of Polyol Blend Composition on Polyurethanes' Properties

17 páginasPolyurethanes are materials with a strong structure-property relationship. The goal of this research was to study the effect of a polyol blend composition of polyurethanes on its properties using a mixture design and setting mathematic models for each property. Water absorption, hydrolytic degradation, contact angle, tensile strength hardness and modulus were studied. Additionally, thermal stability was studied by thermogravimetric analysis. Area under the curve was used to evaluate the effect of polyol blend composition on thermal stability and kinetics of water absorption and hydrolytic degradation. Least squares were used to calculate the regression coefficients. Models for the properties were significant, and lack of fit was not (p < 0.05). Fit statistics suggest both good fitting and prediction. Water absorption, hydrolytic degradation and contact angle were mediated by the hydrophilic nature of the polyols. Tensile strength, modulus and hardness could be regulated by the PE content and the characteristics of polyols. Regression of DTG curves from thermal analysis showed improvement of thermal stability with the increase of PCL and PE. An ANOVA test of the model terms demonstrated that three component influences on bulk properties like water absorption, hydrolytic degradation, hardness, tensile strength and modulus. The PEG*PCL interaction influences on the contact angle, which is a surface property. Mixture design application allowed for an understanding of the structure-property relationship through mathematic models