Polyurethanes
Mostrando 1-12 de 46 artigos, teses e dissertações.
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1. EFECTO DE LA ADICIÓN DE POLÍMEROS DE CADENA CORTA SOBRE LA ESTRUCTURA QUÍMICA, PROPIEDADES MECÁNICAS, TÉRMICAS Y BIOLÓGICAS DE POLIURETANOS SINTETIZADOS CON DIISOCIANATOS ALIFÁTICOS Y ACEITE DE HIGUERILLA
The objective of this research was to synthesize biocompatible polyurethanes, with suitable mechanical properties to be used as biomaterials. Polyurethanes were synthesized with polyols derived from castor oil and isophorone diisocyanate (IPDI), hexamethylene diisocyanate and 4,4’-methylenebis (cyclohexyl isocyanate), with the addition of polycaprolactone/
Quím. Nova. Publicado em: 2021-01
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2. Polyurethanes Obtained by Reacting 1,6-HDI with Monoglycerides from Babassu Oil: A DFT Study
This is a density functional theory (DFT)-based (M06) study on the polyurethane formation from 1,6-hexamethylenediisocyanate (1,6-HDI) reacting with the monoacylglycerol obtained from the babassu oil. As the lauric acid is the most abundant fatty acid in the vegetable oil, the 2-monolaurin was chosen to scrutinize the polyurethane formation. An analysis of t
J. Braz. Chem. Soc.. Publicado em: 2020-09
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3. Weathering Resistance of Waterborne Polyurethane Coatings Reinforced with Silica from Rice Husk Ash
Abstract: Waterborne polyurethanes (WPUs) are interesting materials for coatings when compared to solvent-based polyurethanes, once that reducing the concentration of volatile organic compounds that are harmful for human health and the environment. However, the WPU has low weathering resistance. In order to improve this behavior among others properties, ino
An. Acad. Bras. Ciênc.. Publicado em: 25/11/2019
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4. Lithium catalyst concentration influence on bio-polyols structure and polyurethane adhesives properties
ABSTRACT Polyol structure can be affected by the catalyst used for its synthesis and may affect the curing kinetics and mechanical strength of the final polyurethane (PU). This work aimed to study the influence of catalyst concentration on the structure of bio-based polyols and on the final properties of the polyurethane adhesive obtained from these polyols.
Matéria (Rio J.). Publicado em: 16/09/2019
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5. The role of bondline thickness on mechanical properties of bio-based polyurethane
ABSTRACT Bio-based adhesives have been largely applied on several applications in many industrial areas, including automotive and laminated food packaging. Polyurethanes (PU) occupy a leading position among the most used bio-based polymers due to their large range of properties and application versatility. Recent works reported that PU obtained from castor o
Matéria (Rio J.). Publicado em: 16/09/2019
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6. Alternative use of oily fractions of olive oil
Abstract Oily fractions of olive oil not suitable for human consumption used were: lamp oil (AL), olive pomace oil (OO) and clear oil lees (CB). Polyols were obtained by modifications of epoxidation with subsequent hydrolysis (ALH, OOH, CBH) and transesterification (ALHT, OOHT, CBHT) in order to favor, then, the polymerization reactions. The analysis of the
Polímeros. Publicado em: 18/03/2019
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7. Bonding properties and crystallization kinetics of thermoplastic polyurethane adhesive
ABSTRACT The advantages of heterophasic thermoplastic polyurethanes (TPUs), such as their phase behavior and mechanical properties, make these materials an important class of adhesives. Whereas the amorphous phase contributes to good adhesion properties, the crystalline phase is responsible for the cohesive force of TPU adhesives. This work investigates the
Matéria (Rio J.). Publicado em: 06/12/2018
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8. APLICACIONES BIOMÉDICAS DE POLIURETANOS
Polyurethanes (PUs) are generating increasing interest in the biomedical field due to its characteristic properties. The objective of this article was review general properties of PUs and related with their biomedical applications, also to show the importance of the synthesis of PUs and how each one of the reagents used influences both mechanical properties
Quím. Nova. Publicado em: 2018-04
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9. Hydrocortisone release from tablets based on bioresorbable poly(ether-ester-urethane)s
Abstract Bioresorbable linear poly(ether-ester-urethane)s with different hydrophilic characteristics were synthesized from triblock copolymers of poly(ε-caprolactone)-poly(ethylene oxide)-poly(ε-caprolactone) (PCL-PEO) as macrodiols, and L-lysine diisocyanate (LDI) or hexamethylenediisocyanate (HDI) were used as the required diisocyanates. Macrodiols were
Braz. J. Pharm. Sci.. Publicado em: 20/04/2017
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10. Poliuretanos obtenidos a partir de aceite de higuerilla modificado y poli-isocianatos de lisina: síntesis, propiedades mecánicas y térmicas y degradación in vitro
Biodegradable polyurethanes (PUR) were prepared from polyols derived from castor oil by transesterification of pentaerythritol-modified castor oil and lysine polyisocyanates (LDI and LTI). The polyurethanes obtained were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA).
Quím. Nova. Publicado em: 2014
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11. Aplicações de enzimas na síntese e na modificação de polímeros
Enzymes are biological catalysts that offer great potential for use in the synthesis and modification of polymers, being more specific and greener than chemical catalysts. In this work, enzymes from the classes of hydrolases (lipase, cutinase and protease) and of oxidoreductases (horseradish peroxidase, manganese peroxidase and laccase) were identified as th
Quím. Nova. Publicado em: 2014
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12. Degradación in-vitro de mezclas de poliuretano termoplástico y almidón modificado
The chemical structure of the cassava starch was modified by acylation. Cassava starch modified was mixed with urethane prepolymer based on castor oil modified by transesterification (MCO) and isophorone diisocyanate (IPDI) in order to prepare starch-blended thermoplastic polyurethanes. Polyurethanes were exposed to in-vitro degradation then monitored for ch
Polímeros. Publicado em: 07/06/2013