Phenolic Resins
Mostrando 1-12 de 17 artigos, teses e dissertações.
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1. Study of nanocomposites with carbon nanotubes and their tendency for carbon organization
Abstract The carbon derived from the thermal treatment of modified phenolic resins (PR) tends to organize into graphitic lamellae or turbostratic carbon and is commonly considered non-graphitizable. In this study, nanocomposites were synthesized with modified phenolic resin (Novolac) used as the matrix and oxidized multi-walled carbon nanotubes (NTox) in amo
Cerâmica. Publicado em: 2022
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2. Antileishmanial activity and chemical composition from Brazilian geopropolis produced by stingless bee Melipona fasciculata
ABSTRACT Geopropolis is produced by some stingless bee species such as Melipona fasciculata and consists of a mixture of plant resins, salivary secretions of the bee, wax, and soil. This study evaluated the antileishmanial activity in vitro, cytotoxicity and chemical composition of geopropolis produced by M. fasciculata in the savannah region of Maranhão, B
Rev. bras. farmacogn.. Publicado em: 26/08/2019
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3. Leaf histochemistry analysis of four medicinal species from Cerrado
ABSTRACT Chemical components act in plant defense and protection, but many of them are extracted and used medicinally. For Cerrado, active chemical components are used in the treatment of diseases, which strengthens the necessity for pharmacological studies of plants of that environment. The objective was to evaluate the histochemistry of the leaf blade of B
Rev. bras. farmacogn.. Publicado em: 2016-12
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4. Tensile properties and color and mass variations of GFPR composites under alkaline and ultraviolet exposures
The objective of the present study was to evaluate the influence of two different environmental conditions on the quantitative change of color and mass, tensile strength and modulus of elasticity of glass fiber reinforced polymers (GFRP) produced in Brazil. For this purpose, specimens were taken from pultruded composite profiles with two different matrices (
Matéria (Rio J.). Publicado em: 2016-03
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5. Studies on the Thermal, Mechanical and Chemical Resistance Properties of Natural Resource Derived Polymers
Cardanol-based epoxidized resole resins (ERCF) were synthesized by reacting resole type phenolic resin (RCF) and epichlorohydrin in basic medium, at 120 °C. Resole type phenolic resins were synthesized by reacting cardanol (C) and formaldehyde (F) in the presence of sodium hydroxide, as catalyst, at five different temperatures ranging between 60-80 °C with
Mat. Res.. Publicado em: 03/11/2015
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6. Polyphenolic resin synthesis: optimizing plantain peel biomass as heavy metal adsorbent
AbstractPolyphenolic resol resins were obtained from an ethanolic extraction of green plantain peels (Musa paradisiaca) grown in Colombia. A synthesis was then performed by polycondensation in an alkaline pH solution in order to perform research on phenolic resin production with high mechanical performance. The polymers were characterized by DSC and TGA anal
Polímeros. Publicado em: 2015-08
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7. Synthesis and characterization of polyarylacetylene for use in the monolithic vitreous carbon processing
In this work, polyarylacetylene (PAA) prepolymer obtained from 1,4-diethynylbenzene was evaluated as polymeric precursor of monolithic vitreous carbon (MVC). The monomer 1,4-diethynylbenzene was synthesized and the PAA prepolymer was prepared with 13, 16 and 19 wt % of nickel catalyst. The best percentage of nickel catalyst considered was 13 wt %, due to the
Polímeros. Publicado em: 22/09/2014
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8. Synthesis of a boron modified phenolic resin
Abstract: Phenolic resin has long been used as matrix for composites mainly because of its flame retardant behavior and high char yield after pyrolysis, which results in a self supporting structure. The addition of ceramic powders, such as SiC and B4C, as fillers to the phenolic resin, results in better thermo-oxidative stability, but as drawbacks, it has po
J. Aerosp. Technol. Manag.. Publicado em: 2010-08
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9. Biocomposites of lignin-, tannin- and glyoxal- based polymeric matrices reinforced with natural fibers / Biocompósitos a partir de matrizes poliméricas baseadas em lignina, tanino e glioxal reforçadas com fibras naturais
The present study aimed at developing biocomposites combining polymeric matrices and reinforcement agents, employing the highest possible proportion of materials obtained from natural sources. Phenolic resins are widely known and used due to their excellent properties, such as dimensional and thermal stability, flame resistance and chemical resistance. Howev
Publicado em: 2010
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10. Isolation and identification of formononetin of João Pessoa-PB-Brazil red propolis, seasonal studies and evaluation of their biological activities / Isolamento e identificação de formononetina da propolis de João Pessoa - PB, estudo de sua sazonalidade e avaliação de suas atividades biologicas
Propolis is a resinous substance produced by the honeybee Apis mellifera. Bees use propolis to seal holes and to protect the beehive. To produce propolis the honeybee uses resins of leaf buds and buds, resinous exudates and other parts of plant tissues. Propolis is used as a folk medicine since 3000 BC. Numerous biological properties have been found includin
Publicado em: 2009
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11. Use of raw material obtained from a renewable source in tbhe preparation of phenolic type matrix composites / Utilização de matéria-prima obtida de fonte renovável na preparação de compósitos de matriz tipo fenólica
In the present work phenolic type matrices were prepered, which were reinforced with lignocellullosic fibers (sisal). The tannin-phenolic and phenol-furfural resins, amid other techniques, were characterized by nuclear magnetic resonance (NMR). Model compounds were synthesized specially for the 1H and 13C NMR analysis of phenol-furfural resins. The sisal fib
Publicado em: 2008
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12. Tanino como macromonômero na síntese de polímeros fenólicos visando a preparação de compósitos reforçados com material de origem vegetal / Tannin as substitute of phenols in the formulation of phenolic resins for the processing of composites reinforced with material from renewable source
No presente trabalho, tanino (macromolécula de origem natural) foi utilizado como substituinte de fenol na formulação de matriz fenólica usada na preparação de compósitos, o que é possível devido à presença de anéis fenólicos sua estrutura. Os compósitos de matriz taninofenólica (50% em massa de tanino) apresentaram propriedades mecânicas sup
Publicado em: 2007