Urethane
Mostrando 1-12 de 213 artigos, teses e dissertações.
-
1. SYNTHESIS OF TOLUENE DIISOCYANATE URETHANE PREPOLYMER USING CASTOR OIL AND EVALUATION OF MECHANICAL PROPERTIES
This research is the synthesis of urethane prepolymer cast elastomer which had been produced using toluene diisocyanate and castor oil to replace the synthetic polyol, from petroleum origin, and the evaluation of mechanical properties of the polyurethane. The focus was to replace polyol from petroleum to vegetable material looking for renewable resources. Th
Química Nova. Publicado em: 2022
-
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
-
3. Castor polyurethane used as osteosynthesis plates: microstructural and thermal analysis
Abstract Bone fractures to be corrected need stabilization of their extremities, which is achieved with the use of plates and screws. This research aimed to produce castor bean polyurethane (Ricinus communis), to make resorbable plate, structural and thermal analysis. The production was made by the glycerolysis of the triglycerides present in the oil, after
Polímeros. Publicado em: 04/07/2019
-
4. Composite-derived monomers affect cell viability and cytokine expression in human leukocytes stimulated with Porphyromonas gingivalis
Abstract Objectives: Dental composites release unreacted resin monomers into the oral environment, even after polymerization. Periodontal cells are, therefore, exposed to substances that potentially elicit the immune inflammatory response. The underlying molecular mechanisms associated with the interaction between resin monomers and human immune cells found
J. Appl. Oral Sci.. Publicado em: 03/06/2019
-
5. Influence of a hydrophobic monomer on the physical and mechanical properties of experimental surface sealants
Abstract This study evaluated the effect of adding the hydrophobic monomer 1,12 dodecanediol dimethacrylate (DDDMA) to experimental sealants with and without thermocycling on degree of conversion (DC), water sorption (WS), water solubility (WSB), color stability (ΔE), and micro-shear bond strength (μSBS). Five experimental and one commercially available se
Braz. oral res.. Publicado em: 11/10/2018
-
6. Early fragmentation of polyester urethane sheet neither causes persistent oxidative stress nor alters the outcome of normal tissue healing in rat skin
Abstract Silicone breast implant is associated with complications inherent to the surgical procedure. Prosthesis coating with polyurethane, however, commonly reduces the incidence of such complications. In this paper, the authors evaluated the inflammatory histomorphometric profile and oxidative damage associated to the implant of polyester urethane sheets.
An. Acad. Bras. Ciênc.. Publicado em: 26/07/2018
-
7. Ultrasound assisted miniemulsion polymerization to prepare poly(urea-urethane) nanoparticles
Abstract Recently, the physical and chemical effects of ultrasound in polymeric materials synthesis have attracted great attention. This work presents the synthesis of novel polymeric materials by polymerization of isophorone diisocyanate with different polyols. Polymers were synthesized by step miniemulsion polymerizations, using ultrasound bath and thermo
Polímeros. Publicado em: 21/05/2018
-
8. BIODEGRADACION FUNGICA DE POLIURETANO RÍGIDO
Polyurethane (PU) is one of the most widely used polymer materials. This generates a serious environmental problem because of its poor biodegradability since most of the native microorganisms cannot use it as a source of nutrients. Several techniques involving mechanical and chemical processes have been used for its recovery and reuse; however, the problem o
Quím. Nova. Publicado em: 2017-09
-
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
-
10. Effect of S-methyl-l-thiocitrulline dihydrochloride on rat micturition reflex
ABSTRACT Objective: To evaluate the effect of neuronal nitric oxide synthase on the striated urethral sphincter and the urinary bladder. Materials and Methods: A coaxial catheter was implanted in the proximal urethra and another one in the bladder of female rats, which were anesthetized with subcutaneous injection of urethane. The urethral pressure with sa
Int. braz j urol.. Publicado em: 2016-10
-
11. Can intraurethral stimulation inhibit micturition reflex in normal female rats?
ABSTRACT Objective The study was designed to determine the effect of low frequency (2.5Hz) intraurethral electrical stimulation on bladder capacity and maximum voiding pressures. Materials and Methods The experiments were conducted in 15 virgin female Sprague-Dawley rats (220–250g). The animals were anesthetized by intraperitoneal injection of urethane
Int. braz j urol.. Publicado em: 2016-06
-
12. Effect of the loading of organomodified clays on the thermal and mechanical properties of a model dental resin
Experimental dental resins composed of triethyleneglycol dimethacrylate, urethane dimethacrylate, ethoxylated bisphenol-A-dimethacrylate and bisphenol A glycidyl methacrylate containing an organoclay as filler were prepared by photopolymerization. The addition of organoclay fillers results in slower polymerization rates (0.59 and 0.24 mol L-1 min-1, for the
Mat. Res.. Publicado em: 05/02/2016