Many failures of external walls made of porous buildingmaterials are caused by excessive moisture content,particularly after driving rain and under long duration ofmoist conditions. Lack of sufficient protection againstexposure conditions is one of the reasons for external wallsprematurely demonstrating failures, i.e. properties andperformance above/below critical levels. Silicon-based waterrepellants are increasingly used in order to improve theperformance of both old and new buildings. Water repellants areexpected to prolong the service life and improve the durabilityof wall components by preventing or minimising water ingressinto the structure and thus delaying the deteriorating effectsof the atmosphere. To date, various kinds of water repellantshave been developed. However, only limited research has beencarried out, particularly on the long-term field exposuretesting. Existing research is mainly focused on the performanceof surface treatments of concrete structures and the protectionof historical buildings built of stone, brick and wood, and isprimarily based on short-term laboratory testing. The aim ofthis research work is to study the long-term performance,degradation processes and ageing characteristics of renderedautoclaved aerated concrete (AAC) with and without waterrepellants. Investigations are carried out by physical andchemical analysis of fresh samples, samples naturally weatheredby long-term field exposure and samples artificially aged byshort-term accelerated laboratory tests. Two differentapplication of water repellants are employed: impregnation ofrendering surface with an aqueous product and as additive inpowder form mixed into the fresh rendering mortar. Continuousmoisture and temperature monitoring of naturally exposed testsamples are also included in the study. Wetcorr sensors andresistance-type nail electrodes are used to measure the surfacemoisture and the moisture content in the material,respectively. This thesis describes the experimental set-upand presents the results from site monitoring and laboratorytests of unexposed, naturally and artificially exposed samples(freeze-thaw and UV+water). The results from the continuousmoisture measurements are compared with the results obtainedfrom the full-scale test cabin built within the EUREKA-projectE 2116 DurAAC. The test cabin has the same basic measurementinstruments for continuous monitoring of moisture andtemperature. An attempt has been made to develop methods forlong-term performance assessment of water repellants to be usedin service life prediction. The combination of data obtainedfrom the field measurements with data obtained from thelaboratory tests and analysis may also meet practical needs ofthe end-users.

<p>Many failures of external walls made of porous buildingmaterials are caused by excessive moisture content,particularly after driving rain and under long duration ofmoist conditions. Lack of sufficient protection againstexposure conditions is one of the reasons for external wallsprematurely demonstrating failures, i.e. properties andperformance above/below critical levels. Silicon-based waterrepellants are increasingly used in order to improve theperformance of both old and new buildings. Water repellants areexpected to prolong the service life and improve the durabilityof wall components by preventing or minimising water ingressinto the structure and thus delaying the deteriorating effectsof the atmosphere. To date, various kinds of water repellantshave been developed. However, only limited research has beencarried out, particularly on the long-term field exposuretesting. Existing research is mainly focused on the performanceof surface treatments of concrete structures and the protectionof historical buildings built of stone, brick and wood, and isprimarily based on short-term laboratory testing. The aim ofthis research work is to study the long-term performance,degradation processes and ageing characteristics of renderedautoclaved aerated concrete (AAC) with and without waterrepellants. Investigations are carried out by physical andchemical analysis of fresh samples, samples naturally weatheredby long-term field exposure and samples artificially aged byshort-term accelerated laboratory tests. Two differentapplication of water repellants are employed: impregnation ofrendering surface with an aqueous product and as additive inpowder form mixed into the fresh rendering mortar. Continuousmoisture and temperature monitoring of naturally exposed testsamples are also included in the study. Wetcorr sensors andresistance-type nail electrodes are used to measure the surfacemoisture and the moisture content in the material,respectively. This thesis describes the experimental set-upand presents the results from site monitoring and laboratorytests of unexposed, naturally and artificially exposed samples(freeze-thaw and UV+water). The results from the continuousmoisture measurements are compared with the results obtainedfrom the full-scale test cabin built within the EUREKA-projectE 2116 DurAAC. The test cabin has the same basic measurementinstruments for continuous monitoring of moisture andtemperature. An attempt has been made to develop methods forlong-term performance assessment of water repellants to be usedin service life prediction. The combination of data obtainedfrom the field measurements with data obtained from thelaboratory tests and analysis may also meet practical needs ofthe end-users.</p>

<p>Coatings for exterior wood have two basic functions. One isto give an aesthetically acceptable surface appearance andcolour. The other is to provide protection against wooddegradation by microbiological or physical attack. Theseprotective properties, often called the barrier properties,play an important role in the selection of proper material forsupreme durability. The assessment of these barrier propertiesis of great importance. Within the CEN Technical Committee 139,Working Group 2, Coatings for exterior wood test methods andperformance specifications have been established. Forassessment of water protection efficiency a standard testprocedure, EN 927-5, has been launched. The present work hasfocused on its applicability in assessing water protectionefficiency in relation to the degradation of coatings duringexposure.</p><p>Assessments according to EN 927-5 is shown to givesignificant differences in water absorption values fordifferent types of coatings on wood. The proposed performancespecifications in ENV 927 - 2 for the water absorption valuesfor coatings to be used in different constructions seem to beset at acceptable levels. It has been shown that there is agood correlation between the level of water absorption andpractical experience of the performance of paints inScandinavia. However, it has also been shown that thecombination of a standard procedure for water absorptionmeasurement and an artificial weathering procedure gives moreinformation regarding expected durability and longtermperformance than a single measurement of water absorption onfresh, unweathered coated wood. A combination of waterabsorption measurement and artificial weathering could become auseful tool in product development as well as in benchmarking.Together with statistical tools, such as reliability-basedservice life prediction methodologies for predicting theservice life of coating systems a reduction in testing timesmay be achieved.</p><p>Surface-active substances in coatings have a negative effecton the coatings ability to prevent water ingress, which mostprobably is due to the hydrophilic character of thesesubstances. The presence of these substances, which are commonin waterborne coatings, alters the moisture sorptioncharacteristics of wood. Considering that these substancesoccur in waterborne coatings, may be mobilised during and afterfilm formation and accumulate at the coating/substrateinterface, there is a great probability that these substanceschange the moisture sorption characteristics of the woodsubstrate in an unfavourable way and create unexpected dynamicmoisture conditions at the coating/wood interface.</p><p>Computerized tomography has been found to be a valuable,non-destructive tool for visualising the spatial moisturedistribution of water and moisture in coated wood panels. Themethod is suitable for recurrent testing of a specimen exposedto a series of processes of wetting, drying. This thesis showsthat high moisture contents occur locally at and around cracks.In these areas there is an increased risk of internal tensionand stress resulting in crack initiation and propagation andthat high moisture contents may occur in the first fewmillimetres under waterborne coatings despite intact coatingfilms. Even with good barrier properties of the coating,moisture may accumulate by water-vapour absorption in air gapsbehind the cladding thus causing favourable conditions formicrobiological colonization.</p><p>The work that has been carried out regarding assessment ofthe water protection efficiency shows promising resultsregarding the possibility to use reliability-based service lifeprediction methodology for the assessment. The aim of futurework will be to establish more reliable techniques andprotocols for assessing service life expectancy and durability,especially for waterborne coatings with special focus ontendencies to early failure and robustness of the coatingsystems.</p><p><b>Keywords:</b>Coatings, surfactants, water absorption value,EN 927, paint, additives, moisture dynamics, absorption,desorption, artificial weathering, artificial exposure,computerized tomography, MRI.</p>

Submitted by Bruna Rodrigues (bruna92rodrigues@yahoo.com.br) on 2016-10-13T13:52:59Z No. of bitstreams: 1 DissLHS.pdf: 5329246 bytes, checksum: bf67aefa7ab3954057f79b20b3f10988 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T13:47:37Z (GMT) No. of bitstreams: 1 DissLHS.pdf: 5329246 bytes, checksum: bf67aefa7ab3954057f79b20b3f10988 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T13:47:43Z (GMT) No. of bitstreams: 1 DissLHS.pdf: 5329246 bytes, checksum: bf67aefa7ab3954057f79b20b3f10988 (MD5) / Made available in DSpace on 2016-10-21T13:47:49Z (GMT). No. of bitstreams: 1 DissLHS.pdf: 5329246 bytes, checksum: bf67aefa7ab3954057f79b20b3f10988 (MD5) Previous issue date: 2016-06-30 / Não recebi financiamento / Currently, there has been a search for economically viable and sustainable products in various market segments. Lighter materials that can be recycled have become a strategic issue for many industries. In this sense, the utilization of lignocellulosic fibers in polymeric composites, are becoming increasingly viable as substitutes for inorganic minerals reinforcements, mainly glass fibers. In this study, polypropylene (PP) natural composites reinforced with coir fiber (CF), compatibilized with maleic anhydride grafted polypropylene (PPMAH) and stabilized with a hindered amine (Tinuvin® 791) and UV absorber (Hostavin® ARO 8), were prepared via extrusion. The effect of the additives and their interactions and the influence of 1000 hours exposure in two types of accelerated weathering (Ultraviolet B and xenon arc) in the PP/CF composites were analyzed by mechanical properties (tensile properties), scanning electron microscopy (SEM), differential Scanning Calorimetry (DSC) and colorimetry. The results indicate that the incorporation of coir fiber, in the presence of the compatibilizer, significantly increases tensile strength, but in the absence of the compatibilizer, the coir fiber act as stress concentrators, allowing a lower tensile strength to the sample.The joint presence of Tinuvin® and the compatibilizer has a negative effect on tensile strength and on the compatibility of the natural fiber with the matrix. UV absorber did not affect the compatibility of the PP/CF composites. Post-weathering results indicate that UVB caused more intense degradation than xenon arc. However, decreasing Tinuvin® efficiency evidence were not possible to be confirmed. Through electron micrographs, DSC analysys and tensile tests, it is noted the additive system based on (Tinuvin®+ Hostavin®) as the most effective protection system against the artificial weathering. / Atualmente, tem-se observado a busca por produtos viáveis economicamente e sustentáveis em vários segmentos do mercado. Materiais mais leves e que possam ser reciclados se tornaram uma questão estratégica para muitas indústrias. Neste contexto, a utilização de fibras lignocelulósicas em compósitos poliméricos, estão se tornando cada vez mais viáveis como substitutas de reforços minerais inorgânicos, como a fibra de vidro. Neste trabalho, compósitos naturais de polipropileno reforçados com fibra de coco (FCo), compatibilizados com polipropileno enxertado com anidrido maleico (PPMAH) e estabilizados com uma amina estericamente impedida (Tinuvin® 791) e um absorvedor de UV (Hostavin® ARO 8), foram preparados via extrusão. Os efeitos dos aditivos e de suas interações e a influência de 1000 horas de exposição em duas fontes de intemperismo acelerado (ultravioleta B e arco xenônio) dos compósitos de PP/FCo, foram analisados através das propriedades mecânicas, em tração, microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC) e colorimetria. Os resultados obtidos mostram que a incorporação da fibra de coco, na presença do agente compatibilizante, confere aumentos significativos de resistência à tração, mas que na ausência deste, as fibras de coco se comportam como concentradores de tensões conferindo menor resistência à tração. A presença conjunta de Tinuvin® e agente compatibilizante gera um efeito negativo na resistência à tração e na compatibilidade da fibra natural com a matriz. O absorvedor UV não afetou a compatibilidade dos compósitos PP/FCo. A análise dos resultados pós-intemperismo revelou que a fonte UVB gerou degradação mais intensa que a fonte de arco xenônio. Porém, evidências da diminuição da eficiência do Tinuvin® não foram possíveis de serem confirmadas. Através das micrografias eletrônicas, DSC e ensaios de tração, constata-se o sistema de aditivação composto por Tinuvin®+ Hostavin® como o mais eficaz frente ao intemperismo artificial.

Coatings for exterior wood have two basic functions. One isto give an aesthetically acceptable surface appearance andcolour. The other is to provide protection against wooddegradation by microbiological or physical attack. Theseprotective properties, often called the barrier properties,play an important role in the selection of proper material forsupreme durability. The assessment of these barrier propertiesis of great importance. Within the CEN Technical Committee 139,Working Group 2, Coatings for exterior wood test methods andperformance specifications have been established. Forassessment of water protection efficiency a standard testprocedure, EN 927-5, has been launched. The present work hasfocused on its applicability in assessing water protectionefficiency in relation to the degradation of coatings duringexposure. Assessments according to EN 927-5 is shown to givesignificant differences in water absorption values fordifferent types of coatings on wood. The proposed performancespecifications in ENV 927 - 2 for the water absorption valuesfor coatings to be used in different constructions seem to beset at acceptable levels. It has been shown that there is agood correlation between the level of water absorption andpractical experience of the performance of paints inScandinavia. However, it has also been shown that thecombination of a standard procedure for water absorptionmeasurement and an artificial weathering procedure gives moreinformation regarding expected durability and longtermperformance than a single measurement of water absorption onfresh, unweathered coated wood. A combination of waterabsorption measurement and artificial weathering could become auseful tool in product development as well as in benchmarking.Together with statistical tools, such as reliability-basedservice life prediction methodologies for predicting theservice life of coating systems a reduction in testing timesmay be achieved. Surface-active substances in coatings have a negative effecton the coatings ability to prevent water ingress, which mostprobably is due to the hydrophilic character of thesesubstances. The presence of these substances, which are commonin waterborne coatings, alters the moisture sorptioncharacteristics of wood. Considering that these substancesoccur in waterborne coatings, may be mobilised during and afterfilm formation and accumulate at the coating/substrateinterface, there is a great probability that these substanceschange the moisture sorption characteristics of the woodsubstrate in an unfavourable way and create unexpected dynamicmoisture conditions at the coating/wood interface. Computerized tomography has been found to be a valuable,non-destructive tool for visualising the spatial moisturedistribution of water and moisture in coated wood panels. Themethod is suitable for recurrent testing of a specimen exposedto a series of processes of wetting, drying. This thesis showsthat high moisture contents occur locally at and around cracks.In these areas there is an increased risk of internal tensionand stress resulting in crack initiation and propagation andthat high moisture contents may occur in the first fewmillimetres under waterborne coatings despite intact coatingfilms. Even with good barrier properties of the coating,moisture may accumulate by water-vapour absorption in air gapsbehind the cladding thus causing favourable conditions formicrobiological colonization. The work that has been carried out regarding assessment ofthe water protection efficiency shows promising resultsregarding the possibility to use reliability-based service lifeprediction methodology for the assessment. The aim of futurework will be to establish more reliable techniques andprotocols for assessing service life expectancy and durability,especially for waterborne coatings with special focus ontendencies to early failure and robustness of the coatingsystems. Keywords:Coatings, surfactants, water absorption value,EN 927, paint, additives, moisture dynamics, absorption,desorption, artificial weathering, artificial exposure,computerized tomography, MRI. / <p>NR 20140805</p>

Esta pesquisa teve por objetivo avaliar a suscetibilidade a ensaios de intemperismo acelerado de cinco rochas usadas no patrimônio histórico e cultural das cidades do Rio de Janeiro e São Paulo, para determinar suas resistências frente a: ambientes quimicamente agressivos por meio de exposições em câmaras saturadas de SO2 e NaCl; imersão parcial em soluções ácidas e alcalina (H2SO4, HCl, HNO3 e NaOH); e ciclagens de choque térmico. As rochas abordadas no estudo foram: Granito Itaquera, Granito Cinza Mauá e Monzonito Preto Piracaia, de São Paulo; Gnaisse Facoidal do Rio de Janeiro e um mármore branco do Espírito Santo. Com exceção do mármore, incluído no estudo devido aos diversos monumentos históricos feitos em mármores dos mais variados, todas as rochas tiveram larga utilização na construção de edifícios e monumentos das duas cidades. Nas rochas submetidas às alterações foram feitas determinações, previamente e posteriormente aos ensaios, de suas características físicas: densidade, porosidade, absorção de água, absorção de água por capilaridade, absorção de água por tubo de Karsten, índice de resistência ao carregamento pontual, velocidade de propagação de ondas ultrassônicas, resistência superficial por martelo de rebote (martelo de Schmidt) e cor por espectrofotometria. Foram efetuadas também análises petrográficas das rochas e difratometria de raios X em sais gerados nos corpos parcialmente imersos em soluções. A caracterização das rochas sãs foi catalogada com o intuito de contribuir com estudos de conservação-restauração futuros, considerando que o acesso a pedreiras e disponibilidade das mesmas tendem a diminuir, devido à urbanização e exaustão de pedreiras. Dentre as alterações impostas, a que mais impactou as rochas foi a do choque térmico. As alterações de caráter químico foram mais agressivas sobre o mármore, gerando alterações mais sutis nos outros litotipos, conforme era esperado. Os métodos de velocidade de propagação de ondas ultrassônicas e a resistência superficial por martelo de rebote permitiram inferir que as alterações ocorridas foram predominantemente superficiais, uma vez que ocorreu maior perda de resistência superficial do que redução de velocidade. A rocha que apresenta maior perda de resistência superficial é o Monzonito Preto Piracaia, que em contrapartida apresenta baixa alteração de velocidade ultrassônica. A alteração de cor foi expressiva em todas as rochas, sendo o procedimento de imersão parcial em soluções ácidas o mais agressivo. / The purpose of this research was to evaluate the susceptibility to accelerated weathering tests of five rocks used in the historical and cultural patrimony of the cities of Rio de Janeiro and São Paulo in order to determine their resistance to: chemically aggressive environments through exposure to SO2 and NaCl in saturated chambers; partial immersion in acidic and alkaline solutions (H2SO4, HCl, HNO3 and NaOH); and thermal shock cycling. The rocks covered in the study were: Itaquera Granite, Gray Mauá Granite and Black Piracaia Monzonite, from São Paulo; Augen Gneiss from Rio de Janeiro and a white marble from Espirito Santo. All the rocks have been widely used in the construction of buildings and monuments of the two cities, except for the marble, which was included in the study due to its use in various historical monuments. To the rocks subjected to the artificial weathering, determinations of their physical characteristics were made, before and after the tests: density, porosity, water absorption, water absorption by capillarity, water absorption by Karsten tube, point load strength index, ultrasound pulse velocity, surface resistance by rebound hammer (Schmidt\'s hammer) and color by spectrophotometry. Also, petrographic analyses of the rocks and X - ray diffraction in salts generated in the bodies partially immersed in solutions were carried out. The characterization of unaltered rocks was cataloged with the intention of contributing to future studies of conservation and restoration, considering that the access to quarries and their availability tend to decrease due to the urbanization and exhaustion of quarries. Among the alterations imposed, thermal shock was the one that most affected the rocks. While chemical alterations were more aggressive on the marble, more subtle alterations were observed in the other lithotypes, as expected. The ultrasonic wave propagation velocity methods and the surface resistance by rebound hammer allowed to infer that the alterations occurred were predominantly superficial, since there was a greater loss of surface resistance than reduction of velocity. The rock that presented the greatest loss of surface resistance is the Black Piracaia Monzonite, which in turn has a low ultrasonic velocity change. The color change was significant in all rocks, with the partial immersions in acidic solutions being the most forceful procedure for this characteristic.

Esta pesquisa teve por objetivo avaliar a suscetibilidade a ensaios de intemperismo acelerado de cinco rochas usadas no patrimônio histórico e cultural das cidades do Rio de Janeiro e São Paulo, para determinar suas resistências frente a: ambientes quimicamente agressivos por meio de exposições em câmaras saturadas de SO2 e NaCl; imersão parcial em soluções ácidas e alcalina (H2SO4, HCl, HNO3 e NaOH); e ciclagens de choque térmico. As rochas abordadas no estudo foram: Granito Itaquera, Granito Cinza Mauá e Monzonito Preto Piracaia, de São Paulo; Gnaisse Facoidal do Rio de Janeiro e um mármore branco do Espírito Santo. Com exceção do mármore, incluído no estudo devido aos diversos monumentos históricos feitos em mármores dos mais variados, todas as rochas tiveram larga utilização na construção de edifícios e monumentos das duas cidades. Nas rochas submetidas às alterações foram feitas determinações, previamente e posteriormente aos ensaios, de suas características físicas: densidade, porosidade, absorção de água, absorção de água por capilaridade, absorção de água por tubo de Karsten, índice de resistência ao carregamento pontual, velocidade de propagação de ondas ultrassônicas, resistência superficial por martelo de rebote (martelo de Schmidt) e cor por espectrofotometria. Foram efetuadas também análises petrográficas das rochas e difratometria de raios X em sais gerados nos corpos parcialmente imersos em soluções. A caracterização das rochas sãs foi catalogada com o intuito de contribuir com estudos de conservação-restauração futuros, considerando que o acesso a pedreiras e disponibilidade das mesmas tendem a diminuir, devido à urbanização e exaustão de pedreiras. Dentre as alterações impostas, a que mais impactou as rochas foi a do choque térmico. As alterações de caráter químico foram mais agressivas sobre o mármore, gerando alterações mais sutis nos outros litotipos, conforme era esperado. Os métodos de velocidade de propagação de ondas ultrassônicas e a resistência superficial por martelo de rebote permitiram inferir que as alterações ocorridas foram predominantemente superficiais, uma vez que ocorreu maior perda de resistência superficial do que redução de velocidade. A rocha que apresenta maior perda de resistência superficial é o Monzonito Preto Piracaia, que em contrapartida apresenta baixa alteração de velocidade ultrassônica. A alteração de cor foi expressiva em todas as rochas, sendo o procedimento de imersão parcial em soluções ácidas o mais agressivo. / The purpose of this research was to evaluate the susceptibility to accelerated weathering tests of five rocks used in the historical and cultural patrimony of the cities of Rio de Janeiro and São Paulo in order to determine their resistance to: chemically aggressive environments through exposure to SO2 and NaCl in saturated chambers; partial immersion in acidic and alkaline solutions (H2SO4, HCl, HNO3 and NaOH); and thermal shock cycling. The rocks covered in the study were: Itaquera Granite, Gray Mauá Granite and Black Piracaia Monzonite, from São Paulo; Augen Gneiss from Rio de Janeiro and a white marble from Espirito Santo. All the rocks have been widely used in the construction of buildings and monuments of the two cities, except for the marble, which was included in the study due to its use in various historical monuments. To the rocks subjected to the artificial weathering, determinations of their physical characteristics were made, before and after the tests: density, porosity, water absorption, water absorption by capillarity, water absorption by Karsten tube, point load strength index, ultrasound pulse velocity, surface resistance by rebound hammer (Schmidt\'s hammer) and color by spectrophotometry. Also, petrographic analyses of the rocks and X - ray diffraction in salts generated in the bodies partially immersed in solutions were carried out. The characterization of unaltered rocks was cataloged with the intention of contributing to future studies of conservation and restoration, considering that the access to quarries and their availability tend to decrease due to the urbanization and exhaustion of quarries. Among the alterations imposed, thermal shock was the one that most affected the rocks. While chemical alterations were more aggressive on the marble, more subtle alterations were observed in the other lithotypes, as expected. The ultrasonic wave propagation velocity methods and the surface resistance by rebound hammer allowed to infer that the alterations occurred were predominantly superficial, since there was a greater loss of surface resistance than reduction of velocity. The rock that presented the greatest loss of surface resistance is the Black Piracaia Monzonite, which in turn has a low ultrasonic velocity change. The color change was significant in all rocks, with the partial immersions in acidic solutions being the most forceful procedure for this characteristic.

Submitted by Kamila Costa (kamilavasconceloscosta@gmail.com) on 2015-06-25T21:19:51Z No. of bitstreams: 1 DISSERTAÇÃO-ÉRITON GONÇALO RUBEM.pdf: 2575591 bytes, checksum: d7e93a9078f655ec22ccea74a604b55e (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-07T13:20:15Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO-ÉRITON GONÇALO RUBEM.pdf: 2575591 bytes, checksum: d7e93a9078f655ec22ccea74a604b55e (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-07T13:27:56Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO-ÉRITON GONÇALO RUBEM.pdf: 2575591 bytes, checksum: d7e93a9078f655ec22ccea74a604b55e (MD5) / Made available in DSpace on 2015-07-07T13:27:57Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO-ÉRITON GONÇALO RUBEM.pdf: 2575591 bytes, checksum: d7e93a9078f655ec22ccea74a604b55e (MD5) Previous issue date: 2014-07-14 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / Wood when exposed to sunlight undergoes chemical degradation surface which causes a change of color and weakening its mechanical strength. This process of surface degradation is commonly called weathering process. Although providing satisfactory results, the conventional methods of analysis expose the operator to hazardous environments and / or toxic materials necessary in the analyzes. An alternative to traditional destructive evaluation would be to use non-destructive methods for evaluating properties of wood. As an option to perform the analysis nondestructively technology emerges near infrared Fourier transform (FT-NIR), which gives information about the chemical properties of a sample. The study aimed to evaluate the effects of weathering on the main macroconstituintes wood (cellulose and lignin) through FR-NIR technology. To achieve the proposed objective we chose to use timber waste from three Amazonian forest species: Maçaranduba (Manilkara huberi), Tauari (Couratari stellata) and Marupá (Simarouba amara) chosen for having high, medium and low density respectively and relative insertion timber market in the Amazon region. The samples were subjected to methods of natural and artificial weathering, where the natural weathering test lasted a year and the artificial weathering test lasted 27 weeks. The samples were analyzed weekly with the FT-NIR spectrophotometer over the period of natural and artificial weathering tests. The test results showed changes in spectra during the processes of natural and artificial weathering and UV light prove that the chemical structure of modified wood by decomposition of the chemical constituents and the formation of lignin-related cellulose compounds. In the natural and artificial weathering test maçaranduba takes longer to break down cellulose and lignin, but with the increase in period of weathering, the peaks related to pulp and lignin change and decrease and tend. The rate of decomposition of the wood surface is characteristic of each species. / A madeira quando exposta à radiação solar sofre degradação química superficial que provoca uma mudança de cor e um enfraquecimento da sua resistência mecânica. Esse processo de degradação superficial é comumente chamado de processo de intemperização. Apesar de apresentarem resultados satisfatórios, os métodos de análise convencionais expõem o operador aos ambientes de risco e/ou materiais tóxicos indispensáveis nas análises. Uma alternativa à tradicional avaliação destrutiva seria o uso de métodos não destrutivos para avaliar as propriedades da madeira. Como opção para realização das análises de forma não destrutiva surge a tecnologia de infravermelho próximo com transformada de Fourier (FT-NIR), que permite obter informações sobre as propriedades químicas de uma amostra. O trabalho teve por objetivo avaliar os efeitos do intemperismo nos principais macroconstituintes da madeira (celulose e lignina) através da tecnologia FR-NIR. Para alcançar o objetivo proposto optou-se pela utilização de resíduos madeireiros de três espécies florestais amazônicas: Maçaranduba (Manilkara huberi), Tauari (Couratari stellata) e Marupá (Simarouba amara) escolhidas por apresentarem alta, média e baixa densidade respectivamente e relativa inserção no mercado madeireiro da região Amazônica. As amostras foram submetidas aos métodos de intemperização natural e artificial, onde o teste de intemperização natural teve duração de um ano e o teste de intemperização artificial teve a duração de 27 semanas. As amostras foram analisadas semanalmente com o espectrofotômetro FT-NIR durante o período dos testes de intemperização natural e artificial. Os resultados dos testes mostraram alteração nos espectros durante os processos de intemperização natural e artificial e provam que a luz UV modificou a estrutura química da madeira por meio da decomposição de constituintes químicos da lignina e da formação de compostos relacionados à celulose. No teste de intemperismo natural e artificial a maçaranduba demora mais para decompor a celulose e a lignina, porém com o aumento do período de intemperização, todas as bandas referentes à celulose e à lignina se alteram e tendem e diminuir. A velocidade de decomposição da superfície da madeira é característica de cada uma das espécies estudadas.

Among the materials that can be treated in order to impart superhydrophobic properties are many originally hydrophilic metals. For this, they must undergo a sequential treatment, including roughening and hydrophobic coating. This contribution presents various preparation routes along with various characterization methods, such as dynamic contact angle (DCA) measurements, scanning electron microscopy (SEM) and spectroscopic techniques (FT–IRRAS, XPS, EIS). Micro-rough surfaces of pure and alloyed aluminum were generated most easily by using a modifie Sulfuric Acid Anodization under Intensifie conditions (SAAi). This produces a micro-mountain-like oxide morphology with peak-to-valley heights of 2 μm and sub-μm roughness components. Additionally, micro-embossed and micro-blasted surfaces were investigated. These micro-roughened initial states were chemically modifie with a solution of a hydrophobic compound, such as the reactive f uoroalkylsilane PFATES, the reactive alkyl group containing polymer POMA, or the polymer Teflo ® AF. Alternatively, the chemical modificatio was made by a Hot Filament Chemical Vapor Deposition (HFCVD) of a PTFE layer. The latter can form a considerably higher thickness than the wet-deposited coatings, without detrimental leveling effects being observed in comparison with the original micro-rough surface. The inherent and controllable morphology of the PTFE layers represents an important feature. The impacts of a standardized artificia weathering (WTH) on the wetting behavior and the surface-chemical properties were studied and discussed in terms of possible damage mechanisms. A very high stability of the superhydrophobicity was observed for the f uorinated wet-deposited PFATES and Teflo ® AF coatings as well as for some of the PTFE layer variants, all on SAAi-pretreated substrates. Very good results were also obtained for specimens produced by appropriate mechanical roughening and PTFE coating.

Among the materials that can be treated in order to impart superhydrophobic properties are many originally hydrophilic metals. For this, they must undergo a sequential treatment, including roughening and hydrophobic coating. This contribution presents various preparation routes along with various characterization methods, such as dynamic contact angle (DCA) measurements, scanning electron microscopy (SEM) and spectroscopic techniques (FT–IRRAS, XPS, EIS). Micro-rough surfaces of pure and alloyed aluminum were generated most easily by using a modifie Sulfuric Acid Anodization under Intensifie conditions (SAAi). This produces a micro-mountain-like oxide morphology with peak-to-valley heights of 2 μm and sub-μm roughness components. Additionally, micro-embossed and micro-blasted surfaces were investigated. These micro-roughened initial states were chemically modifie with a solution of a hydrophobic compound, such as the reactive f uoroalkylsilane PFATES, the reactive alkyl group containing polymer POMA, or the polymer Teflo ® AF. Alternatively, the chemical modificatio was made by a Hot Filament Chemical Vapor Deposition (HFCVD) of a PTFE layer. The latter can form a considerably higher thickness than the wet-deposited coatings, without detrimental leveling effects being observed in comparison with the original micro-rough surface. The inherent and controllable morphology of the PTFE layers represents an important feature. The impacts of a standardized artificia weathering (WTH) on the wetting behavior and the surface-chemical properties were studied and discussed in terms of possible damage mechanisms. A very high stability of the superhydrophobicity was observed for the f uorinated wet-deposited PFATES and Teflo ® AF coatings as well as for some of the PTFE layer variants, all on SAAi-pretreated substrates. Very good results were also obtained for specimens produced by appropriate mechanical roughening and PTFE coating.