Efeito do intemperismo artificial em quatro madeiras tropicais monitorado por espectroscopia de infravermelho (DRIFT)

Pastore, Tereza Cristina Monteiro; Oliveira, Cynara Caroline Kern de; Rubim, Joel C.; Santos, Kelly de Oliveira

doi:10.1590/s0100-40422008000800030

Cited by 24 publications

(17 citation statements)

References 16 publications

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“…Conjuntamente, son identificados otros inconvenientes como la disminución del rendimiento de los productos aplicados a la superficie de la madera (Pastore et al 2008), productos tales como adhesivos y recubrimientos.…”

Section: Introductionunclassified

Color de la madera de dos eucaliptos expuestas al intemperismo natural en tres entornos ambientales diferentes

Delucis

Herrera²,

Labidi³

et al. 2016

Maderas, Cienc. tecnol.

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RESUMENLa degradación superficial en madera de exteriores se debe a una combinación de factores meteorológicos inherentes al entorno de exposición y a la colonización de organismos xilófagos. Desde un punto de vista técnico y económico se trata de uno de los principales problemas para la industria de productos y materiales hechos a partir de la madera. El objetivo del presente trabajo es el de monitorizar la degradación superficial de las maderas de Corymbia citriodora y Eucalyptus tereticornis originarias de plantaciones de rápido crecimiento de Brasil, las cuales han sido expuestas a ensayos de intemperismo natural en tres entornos ambientales distintos. La monitorización de los cambios en el material fue realizada mediante estimaciones del color (método CIEL*a*b*), en ciclos de 45 días, hasta completar un periodo de 360 días de exposición. Los resultados mostraron que el material expuesto al entorno forestal fue menos afectado por los factores ambientales, lo que ha sido probablemente debido al aislamiento térmico y solar que proporciona este tipo de ecosistema. A su vez, se observó que las probetas de madera de Corymbia citriodora presentaron mayor resistencia al deterioro que las probetas de madera de Eucalyptus tereticornis, posiblemente debido a ciertas diferencias en su constitución química.Palabras clave: Biodegradación, biodeterioro, Corymbia citriodora, Eucalyptus tereticornis, fotodegradación. ABSTRACTSurface degradation in outdoor wood and products is due to a combination of inherent climate factors together with colonization of decay organisms. From a technical and economic standpoint it is one of the main problems for the industry of products and materials made from wood. The aim of this work is to track the surface degradation of Corymbia citriodora and Eucalyptus tereticornis timbers originating from fast-growing plantations in Brazil, which have been exposed to outdoor weathering tests in three different environmental conditions. Changes in the material were monitoring using color measurement (CIEL*a*b* method), in cycles of 45 days up to a period of 360 days of exposure. The results showed that timber exposed to a forest ecosystem was less affected by environmental factors; this is probably due to climate insulation provided by these ecosystems. Besides, it was observed that samples of Corymbia citriodora had higher resistance to degradation compared with samples of Eucalyptus tereticornis, possibly due to differences in its chemical constitution.

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Section: Introductionunclassified

Color de la madera de dos eucaliptos expuestas al intemperismo natural en tres entornos ambientales diferentes

Delucis

Herrera²,

Labidi³

et al. 2016

Maderas, Cienc. tecnol.

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“…Aldehydes showed a strong band of carbonyl group (CO) in the range between 1740 and 1725 cm −1 . This band can be attributed to both carbonyl groups of aldehyde functions and unconjugated ketone of the lignins and holocelluloses, as may have been due to the use of glurataldehyde such as a crosslink agent in the final step of the modification . For the three modified materials (TP, PAPA, PAAP) was observed that this band was intensified in comparison to the alkaline material.…”

Section: Resultsmentioning

confidence: 99%

Role of surface chemistry and morphology in the reactive adsorption of metal ions on acid modified dry bean pods (Phaseolus vulgaris L.) organic polymers

Raulino¹,

Silva

Vidal

et al. 2017

J of Applied Polymer Sci

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The present study aimed at verifying the acid surface modification of dry bean pods subjected to alkaline pretreatment using tannic acid, poly(acrylic acid), and poly(acrylamide‐co‐acrylic acid) and evaluate their performances as adsorbents in the metal ions removal. Factorial design was used as a tool to study the variables that affects the modification processes. The results showed that there was an increase in the adsorption capacity after acidic changes, mainly for the tannic acid, achieving 45% increasing of removal of all metal ions. The variable pH had negative significant effect in the modification with tannic acid. When the modifying agent was the poly(acrylic acid), the variable initial concentration presented a positive significant effect. That means more poly(acrylic acid) was immobilized in the surface of the bean pod, resulting in higher capacity of adsorption. Temperature was significant variable in the modification with poly(acrylamide‐co‐acrylic acid), resulting in a strongly negative effect. Analyses of material characterization showed that soluble lipid fraction was removed after the alkaline treatment. Although no morphological changes were observed, there was an improving in the availability of the adsorbents sites after chemical modification. Further, the material exhibited thermal stability up to about 300 °C. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45879.

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“…Spectra of wood are very similar and the assignments of the main bands are well established and described in literature. 30 The spectra of the carbon product shows the following main features: (A) Initially, the intensity of the band around 3400 cm -1 due to the vibrational mode of OH stretching bond in the wood is relatively higher than in charcoal, which suggests loss of the constitution water that is impregnated in the cell wall of wood with an increasing of the temperature. (B) The decomposition of lignin is evident by the reduction of C = C vibrational bands of aromatic rings, in ca.…”

Section: Analysis In the Medium Infraredmentioning

confidence: 99%

“…(C) The non conjugated bonds C=O in 1734 cm -1 assigned to hemicelluloses decreased markedly in intensity. 30 (D) A formation of an aromatic network with the appearance of three bands at low frequencies 880, 820 and 757 cm -1…”

Section: Analysis In the Medium Infraredmentioning

confidence: 99%

Discrimination of native wood charcoal by infrared spectroscopy

et al. 2010

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Recebido em 24/8/09; aceito em 7/1/10; publicado na web em 23/4/10 Brazil is one of the largest producers and consumers of charcoal in the world. About 50% of its charcoal comes from native forests, with a large part coming from unsustainable operations. The anatomic identification of charcoal is subjective; an instrumental technique would facilitate the monitoring of forests. This study aimed to verify the feasibility of using medium and near infrared reflectance spectroscopy to discriminate native (ipê) from plantation charcoals (eucalyptus). Principal Components Analysis, followed by Discriminant Factorial Analysis formed two different groups indicated by Mahalanobis distances of 40.6 and 80.3 for near and mid infrared, respectively. Validation of the model showed 100% efficacy.

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Efeito do intemperismo artificial em quatro madeiras tropicais monitorado por espectroscopia de infravermelho (DRIFT)

Cited by 24 publications

References 16 publications

Color de la madera de dos eucaliptos expuestas al intemperismo natural en tres entornos ambientales diferentes

Color de la madera de dos eucaliptos expuestas al intemperismo natural en tres entornos ambientales diferentes

Role of surface chemistry and morphology in the reactive adsorption of metal ions on acid modified dry bean pods (Phaseolus vulgaris L.) organic polymers

Discrimination of native wood charcoal by infrared spectroscopy

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