The work presented in this investigation is concerned with the chemical properties of 5-(4-pyridyl)hydantoin as compared with 5-phenylhydantoin.

Thesis (PhD (Process Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The ongoing trend in papermaking industries is to lower production costs by increasing the low cost filler content in the sheets. However, the disruption of inter-fibre bonding is accompanied by a deterioration of paper stiffness and mechanical properties if filler content exceeds 18 wt%. Polysaccharide solutions, such as starch, are often used as a low cost biodegradable additive to improve internal sheet strength when added to the wet-end of production. The amount of starch that can be added is however limited as only a small percentage will be retained in the paper web. A dual additive multifunctional polysaccharide system was developed to allow higher filler loading levels without detrimental deterioration in paper properties. In order to achieve a larger surface area for fibre/filler interaction and to reduce drainage losses, at least one of these additives was in particulate form. Anionic, cationic, and unsaturated derivatives were prepared using sodium monochloroacetate, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and allyl bromide, respectively. The degree of substitution was determined by 1H-NMR spectroscopy and back titration methods and the interaction of the ionic modified derivatives with paper components was determined using fluorescence microscopy. Anionic modified polysaccharide particles were prepared using techniques such as macrogel ultrasonification, water-in-water emulsification, and in-situ cross-linking and carboxymethylation of granular starch. A process of adding sequential layers of oppositely charged polyelectrolyte layers onto the filler particles was also investigated. A novel approach of preparing modified particles with tailored size and distribution using microfluidics was studied and modelled using response surface methodology. Hand sheets were prepared using the dual additive system and improvements in stiffness, tear resistance, breaking length, and folding endurance were observed. The modified granular maize starch particles had a pre-eminent effect on improving stiffness at higher filler loadings (14% improvement at 30 wt% filler loading), while bulky particles prepared using microfluidics showed a more consistent improvement (between 6% and 10%) across the loading range. Overall improvements gained by the introduction of multi-layered soluble polymers onto fillers suggest that the introduction of nanotechnology to the papermaking process should be of potential benefit to the industry. Furthermore, the dual additive system developed during the course of this study should also be tested on a continuous pilot plant papermaking process. / AFRIKAANSE OPSOMMING: Die papierindustrie neig voortdurend daarna om produksiekostes te verlaag deur die persentasie lae koste vulstof wat gebruik word te verhoog. Aangesien die vulstof vesel kontak belemmer, gaan hoër vlakke (> 18 wt%) egter gepaard met ’n verlaging in papier styfheid en meganiese eienskappe. Polisakkaried oplossings, soos byvoorbeeld stysel, word dikwels gebruik as lae koste vergaanbare bymiddel om papier intern te versterk wanneer dit voor die vormingsproses bygevoeg word. Slegs ’n beperkte hoeveelheid stysel word egter behou in die papier matriks en oormatige oplossings ontsnap tydens dreinering in die afvalwater. ’n Dubbele multi-funksionele polisakkaried bymiddelsisteem was ontwikkel wat ongewensde verwakking in papiereienskappe verminder tydens vulstof verhogings. Ten minste een van die bymiddels was in partikelvorm om sodoende ’n groter oppervlak te bied vir vesel/vulstof interaksie en om dreineringsverliese te verminder. Anioniese, kationiese, sowel as onversadigde derivate was berei deur onderskeidelik gebruik te maak van natrium monochloroasetaat, 3-chloro-2-hidroksiepropieltrimetielammonium chloried, en alliel bromied. Die graad van substitutiese was bepaal met behulp van 1H-KMR spektroskopie sowel as titrasie tegnieke terwyl die ioniese interaksie van die gemodifiseerde stysels met die papierkomponente ondersoek was met behulp van fluoressensie mikroskopie. Anioniese polisakkaried partikels was berei met tegnieke soos makro-jel ultrasonifikasie, water-in-water emulsifikasie, en in-situ kruisbinding en karboksiemetielasie van stysel granulate. ’n Proses was ook ondersoek waar vulstof partikels omhul was in verskeie lae poliëlektroliet oplossings. ’n Nuwe benadering was toegepas waar gemodifiseerde partikels met voorafbepaalde grootte en verspreiding berei is deur gebruik te maak van mikrofluïdika en gemodelleer met behulp van oppervlakte ontwerp metodeleer. Papier toetse was uitgevoer met die bymiddelsisteem en algehele verbetering in styfheid, skeurweerstand, breeklengte, en voulydsaamheid is waargeneem. Die gemodifiseerde stysel granulate het die grootste verbetering in styfheid by hoë vulstofladings getoon (14% verbetering by 30 wt% vulstoflading) terwyl die groter mikrofluïdika-bereide partikels algehele verbetering (tussen 6% en 10%) getoon het oor die hele vulstoflading reeks. Die verbeteringe in styfheid sowel as meganiese eienskappe van papier voorberei met poliëlektroliet omhulde vulstof toon dat aanwending van nanotegnologie in hierdie bedryf potensieel voordelig kan wees. Opskalering van die polisakkaried bymiddels ontwikkel gedurende hierdie studie behoort uitgevoer te word vir verdere toetse op ’n kontinue papier loodsaanleg.

Forest areas are particularly susceptible to fires, which are often manmade. Too-frequent fires are likely to adversely affect the soil properties as well as vegetation composition, and possibly lead to soil erosion and desertification. One of the most fire affected forest regions in the world is the Mediterranean. Libya, in the Mediterranean region, has soils that are considered to be arid except in a small area called Aljabal Alakhdar (Green mountain), which is the geographic area covered by this study. It is the wettest part of Libya, and has an extensive forest and many agricultural crops. Like other forests in the Mediterranean it has suffered extreme degradation. This is mainly due to people removing fire wood, or sometimes converting forested areas to agricultural use, as well as fires which may alter several soil chemical and physical properties. The purpose of this research was to evaluate the effects of fires on the physical and chemical properties of soil of Aljabal Alakhdar forest in the north-east of Libya. The physical and chemical properties of soil following fire in two geographic areas have been determined, with those subjected to the fire compared to those in adjacent unburned areas in one coastal and one mountain site. Physical properties studied were: soil particle size, soil water content, soil porosity and soil particle density; and chemical properties studied were: soil electrical conductivity (EC), soil pH, soluble and exchangeable Na, K, Ca and Mg, cation exchange capacity (CEC), soluble Cl, CO3 and HCO3, SO4, organic matter, total N and total P. For the first time in Libyan soils, the effect of burning on the magnetic susceptibility properties of soils was also tested. The results showed that except for the soil water content and magnetic susceptibility, fire has not had a clear effect on the soils' physical properties, while there has been a strong impact of fire on most of the studied chemical properties. These results have been used to create an index of burning for such soils in each of the geographic areas, as a step towards creating a model which will enable a subset of soil parameters to be used to estimate how recently a site was burned, as well as defining fire severity at a site.

A correlação entre as medidas de condutividade elétrica e propriedades físico-químicas do solo é uma das linhas de estudo que vem sendo exploradas onde os conceitos de agricultura de precisão estão mais avançados. Este estudo teve como objetivo avaliar a eficiência do monitoramento da condutividade elétrica do solo a partir do desenvolvimento de dois sistemas. O primeiro, denominado de Resistência Elétrica do Solo (RES), consiste em definir a condutividade elétrica de um material através de uma amostra de dimensões conhecidas, para medir a sua resistência elétrica utilizando dois eletrodos. O segundo, denominado de Duas Pontas (DP), consiste em definir a condutividade elétrica de um material aplicando uma corrente elétrica em uma amostra para medir a alteração no potencial elétrico, gerado pelo meio em que a corrente elétrica transitou, utilizando dois eletrodos dispostos linearmente. Para a avaliação dos resultados obtidos pelos sistemas desenvolvidos foi utilizado como referência um sistema comercial de origem norte americana e algumas propriedades do solo. Os equipamentos de condutividade elétrica do solo foram aplicados em duas áreas pertencentes à Escola Superior de Agricultura "Luiz de Queiroz" e em época distintas. Na Área 1, com 4,97 ha, o levantamento dos dados foi feito na primeira quinzena de Agosto de 2003 e na Área 2, com 1,3 ha, o levantamento dos dados foi feito na segunda quinzena de Dezembro de 2003. Após a aquisição dos dados experimentais foram feitas análises estatísticas descritivas e exploratórias, análises geoestatísticas, construção de mapas de superfície, análises de correlação e regressão linear múltipla a fim de avaliar os sistemas. De acordo com a metodologia desenvolvida e análises de funcionamento dos equipamentos, foi possível verificar que os sistemas construídos para a coleta, transformação e armazenagem dos dados foram eficientes no levantamento dos pontos amostrais. No entanto os sistemas de condutividade elétrica do solo não apresentaram a eficiência desejada no monitoramento das propriedades do solo em ambas as áreas experimentais. Quando os sistemas desenvolvidos foram comparados ao sistema comercial, também foi possível observar que não houve correlação no monitoramento, o que sugere a necessidade da continuidade e aprofundamento no desenvolvimento desses sistemas. / The correlation between electrical conductivity and physical-chemical properties of the soil is one of the research areas that have been explored where precision agriculture concepts are more advanced. This study had the objective of evaluating the soil electrical conductivity mapping efficiency of different measuring systems. The first one, known as Electrical Resistance of the Soil consists in defining the electrical conductivity of any given material using a sample of known dimensions, to measure its electrical resistance using two electrodes. The second one, the Two Edges method, consists in defining the electrical conductivity of a material applying an electric current in a sample to measure any change on the electric potential, generated by the environment in which the electric current transited through, using two linearly displaced electrodes. To evaluate the results obtained by the developed systems some soil properties and a commercial soil electrical conductivity measuring system where used as guidelines. The soil electrical conductivity equipments mapped two fields, at the Escola Superior de Agricultura "Luiz de Queiroz". In Field 1 (4,97 ha) the data collecting process took place in the first fortnight of august 2003, and, in Field 2 (1,3 ha), the sampling process took place in the second fortnight of December 2003. After the acquisition of the experimental data, descriptive and exploratory statistical and geostatistical analysis were made, electrical conductivity surface maps were obtained and correlation and multiple linear regression analysis, in order to evaluate both systems, were made. In accordance to the developed methodology and analysis of the equipment, it was possible to check that the systems developed to acquire, transform and store the data were efficient in mapping the sampling points. However, the soil electrical conductivity systems did not show the desired efficiency in mapping the soil properties in both experimental fields. When the developed systems were compared to a commercial one it was also possible to observe that there was no correlation in the measurements, which suggests the necessity of new developments on these systems.

O Silicone é um material semi-orgânico, obtido a partir de processos industriais e classificado como polimérico. Ele tem basicamente em sua composição átomos de silício ligados a oxigênio e radicais contendo carbono o que confere ao material, características físico-químicas particulares como inércia química e estabilidade dimensional, mantendo-se íntegro nos mais diversos meios de aplicação. Dentre um sem número de utilizações, o silicone tem indicação na confecção de próteses faciais por apresentar qualidades requeridas de um bom material restaurador. Neste estudo examinamos o comportamento mecânico de amostras de um silicone de indicação em Prótese Buco Maxilo Facial, após processos de envelhecimento acelerado em solução bioquimicamente semelhante ao suor humano e atmosfera saturada de cloreto de sódio, simulando o ambiente da interface silicone/pele do paciente em estado normal e esforço exagerado. Estudamos a resistência mecânica ao rasgamento de amostras de silicone MDX4-4210, de fabricação da Dow Corning Corporation, conforme ASTM 624, após imersão em solução bioquimicamente compatível com o suor humano e exposição à névoa salina, ASTM B 117 Salt Spray (fog) testing, saturada a 5% de cloreto de sódio, em períodos de exposição de 12hs, 36hs e 72 horas. Foram considerados os resultados dos testes de 21 CPs, avaliados estatisticamente, adotado nível de significância de 5% (0,050), e os resultados obtidos permitem-nos concluir que nos dois processos, os valores relativos à resistência ao rasgo foram maiores que os do grupo controle porém, depreende-se também que esta alteração corresponde ao processo de deteriorização do silicone, onde os cristais das soluções alojam-se em poros superficiais,característicos dos elastoméricos, interpondo-se aos seus movimentos intrínsecos, promovendo perda das propriedades originais. / Silicone is a semi-organic material, obtained by industrial processes and is classified as a polymeric. It is composed basically of silicon atoms connected to oxygen and radicals containing carbon witch provides the material with particular fisio-chemical characteristics such as chemical inertia and dimensional stability maintaining its integrity in the most diverse ways of application. Amongst its several utilities, silicone is indicated in confectioning facial prosthesis for it presents the required qualities of a good restoring material. In this study we shall examine the mechanical behavior of silicone sample indications in facial oral prosthesis, after the accelerating ageing in a solution that is bio-chemically similar to human sweat and an environment saturated with sodium Clorets, simulating the silicone/skin interface environment under normal and straining conditions. We studied the mechanical resistance to tearing of the samples of silicone MDX4-4210, fabricated by Dow Corning Corporation, in accordance to ASTM 624 after an immersion in a bio-chemical solution, compatible with the human sweat and exposure to saline fog, ASTM B 117 Salty Spray (fog) testing, saturated at 5% of sodium cloret in periods of 12, 36 and 72 hours exposure testing. Were considered the results of 21 CPs tests, statistically evaluated, adopting the significance level at 5% (0,050) and the results that were obtained allow us to conclude that in both cases the value that relates to the resistance to tearing than those of the group control, all thou it is understood that this value alteration corresponds to the superficial deterioration process of the silicone, where the crystals of the solution sediment in superficial pores, characteristic of the elastomerics, interposing itself to the intrinsic movements promoting lost of the original properties.

Ce travail de recherche consiste à étudier les relations structure-propriétés de mélanges biopolymères à base de poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) et poly(butylène succinate) (PBS). Il est divisé en trois parties. La première partie est consacrée à l'étude des propriétés des mélanges PHBV/PBS préparés par voie fondue en fonction de la composition en termes de morphologie et de propriétés rhéologiques, mécaniques, thermiques et barrières. Les résultats obtenus ont été discutés par rapport aux polymères de base. La deuxième partie est consacrée à la compatibilisation des mélanges PHBV/PBS et l'amélioration des interactions à l'interface. Les effets de l'incorporation de la sépiolite à 5% en masse et du PHBV greffé par de l’anhydride maléique (PHBV-g-MA) à 5% en masse ont été étudiés en termes de changements morphologiques montrant un effet synergique entre le compatibilisant et la nanocharge sur les l’ensemble des propriétés des mélanges PHBV/PBS. Enfin, une étude sur le recyclage a été menée à travers une évaluation des effets du nombre de cycles d'extrusion sur les propriétés des matériaux. Elle révèle qu'après 6 cycles d'extrusion, la dégradation thermo-mécanique du PHBV est significativement réduite en présence du PBS. / The main objective of this work was to study the structure-properties relationships of biopolymerblends based on poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and polybutylene succinate (PBS). The work was devised into three parts. The first part was devoted to the study of the properties of PHBV/PBS blends prepared by melt compounding at different weight ratio in terms of morphology and properties. The results obtained were discussed in terms of properties and compared with the neat polymers. The second part was devoted to the study of compatibility of PHBV/PBS blends aiming to improve the interactions at the interface between the two components. The effects of both sepiolite (5% wt.) and PHBV-g-MA (5% wt.) were studied in terms of properties. The results showed a synergistic effect between the compatibilizer PHBV-g-MA and the nanofiller sepiolite though an increase in thermal, mechanical and rheological properties. The last part dealing with the recyclability of PHBV/PBS through the study of the effects of repeated extrusion cycles on the properties of materials. The results showed that after 6 reprocessing cycles the thermo-mechanical degradation of PHBV is significantly reduced in the presence of PBS.

Orientador: Elias Taylor Durgante Severo / Coorientador: Fred Williams Calogeno / Banca: José Tarcísio da Silva Oliveira / Banca: Claudio Angeli Sansígolo / Resumo: O estudo das propriedades físicas e químicas da madeira possibilita um melhor aproveitamento das suas potencialidades. O aproveitamento da madeira de seringueira Hevea brasiliensis após o declínio da produção de látex tem relevância mundial. Uma parte da madeira da seringueira vem de uma área significativa do fuste submetida ao processo de extração de látex. Esse trabalho tem como objetivo analisar as características químicas e físicas da madeira proveniente da região submetida ao processo de extração de látex e compará-la a madeira originária da região que não sofreu processo de extração de látex. Foram utilizadas árvores de seringueira com 53 anos de idade, submetidas ao processo de extração de látex durante 45 anos ininterruptos. Foram realizadas as seguintes análises químicas: determinação do teor de holocelulose, do teor de lignina e teor de extrativos totais. Foram determinadas as seguintes propriedades físicas: densidade, contração volumétrica, contrações lineares e coeficiente de anisotropia. Não foram encontradas diferenças estatísticas entre as propriedades químicas das duas regiões do fuste analisadas nem entre os diferentes tipos de lenho juvenil e adulto. Em relação às propriedades físicas não foram encontradas diferenças entre as regiões estudadas, mas em relação ao tipo de lenho juvenil e adulto ocorrem diferenças estatísticas entre os coeficientes de contrações lineares e contração volumétrica / Abstract: The study of physical and chemical properties of wood allows a better use of its potential. The use of wood from rubber tree Hevea brasiliensis after the decline of the production of latex has global significance. A portion of the rubber wood is a significant area of the stem submitted to the extraction process latex paper aims to analyze the chemical and physical characteristics of the wood from the region subjected to the process of extracting latex and compares it to wood originally from the region that has not undergone the process of extraction of latex. Rubber trees were used with 53 years old, subject to the latex extraction process for 45 consecutive years. We made the following chemical analysis: determination of holocellulose, lignin content and the content of total extractives. We determined the following properties: density, volumetric shrinkage, linear shrinkage and coefficient of anisotropy. There were no statistical differences between the chemical properties of both the stem region analyzed or between different types of juvenile and adult wood. Regarding the physical properties no differences were found between the regions studied, but in relation to the type of juvenile wood and adult wood statistical difference between the coefficients of linear shrinkage and shrinkage were found / Mestre

A correlação entre as medidas de condutividade elétrica e propriedades físico-químicas do solo é uma das linhas de estudo que vem sendo exploradas onde os conceitos de agricultura de precisão estão mais avançados. Este estudo teve como objetivo avaliar a eficiência do monitoramento da condutividade elétrica do solo a partir do desenvolvimento de dois sistemas. O primeiro, denominado de Resistência Elétrica do Solo (RES), consiste em definir a condutividade elétrica de um material através de uma amostra de dimensões conhecidas, para medir a sua resistência elétrica utilizando dois eletrodos. O segundo, denominado de Duas Pontas (DP), consiste em definir a condutividade elétrica de um material aplicando uma corrente elétrica em uma amostra para medir a alteração no potencial elétrico, gerado pelo meio em que a corrente elétrica transitou, utilizando dois eletrodos dispostos linearmente. Para a avaliação dos resultados obtidos pelos sistemas desenvolvidos foi utilizado como referência um sistema comercial de origem norte americana e algumas propriedades do solo. Os equipamentos de condutividade elétrica do solo foram aplicados em duas áreas pertencentes à Escola Superior de Agricultura “Luiz de Queiroz” e em época distintas. Na Área 1, com 4,97 ha, o levantamento dos dados foi feito na primeira quinzena de Agosto de 2003 e na Área 2, com 1,3 ha, o levantamento dos dados foi feito na segunda quinzena de Dezembro de 2003. Após a aquisição dos dados experimentais foram feitas análises estatísticas descritivas e exploratórias, análises geoestatísticas, construção de mapas de superfície, análises de correlação e regressão linear múltipla a fim de avaliar os sistemas. De acordo com a metodologia desenvolvida e análises de funcionamento dos equipamentos, foi possível verificar que os sistemas construídos para a coleta, transformação e armazenagem dos dados foram eficientes no levantamento dos pontos amostrais. No entanto os sistemas de condutividade elétrica do solo não apresentaram a eficiência desejada no monitoramento das propriedades do solo em ambas as áreas experimentais. Quando os sistemas desenvolvidos foram comparados ao sistema comercial, também foi possível observar que não houve correlação no monitoramento, o que sugere a necessidade da continuidade e aprofundamento no desenvolvimento desses sistemas. / The correlation between electrical conductivity and physical-chemical properties of the soil is one of the research areas that have been explored where precision agriculture concepts are more advanced. This study had the objective of evaluating the soil electrical conductivity mapping efficiency of different measuring systems. The first one, known as Electrical Resistance of the Soil consists in defining the electrical conductivity of any given material using a sample of known dimensions, to measure its electrical resistance using two electrodes. The second one, the Two Edges method, consists in defining the electrical conductivity of a material applying an electric current in a sample to measure any change on the electric potential, generated by the environment in which the electric current transited through, using two linearly displaced electrodes. To evaluate the results obtained by the developed systems some soil properties and a commercial soil electrical conductivity measuring system where used as guidelines. The soil electrical conductivity equipments mapped two fields, at the Escola Superior de Agricultura “Luiz de Queiroz”. In Field 1 (4,97 ha) the data collecting process took place in the first fortnight of august 2003, and, in Field 2 (1,3 ha), the sampling process took place in the second fortnight of December 2003. After the acquisition of the experimental data, descriptive and exploratory statistical and geostatistical analysis were made, electrical conductivity surface maps were obtained and correlation and multiple linear regression analysis, in order to evaluate both systems, were made. In accordance to the developed methodology and analysis of the equipment, it was possible to check that the systems developed to acquire, transform and store the data were efficient in mapping the sampling points. However, the soil electrical conductivity systems did not show the desired efficiency in mapping the soil properties in both experimental fields. When the developed systems were compared to a commercial one it was also possible to observe that there was no correlation in the measurements, which suggests the necessity of new developments on these systems.

O sucesso do tratamento endodôntico a longo prazo depende do preparo químico mecânico e também da obturação dos sistemas de canais radiculares, que tem como objetivo prover o preenchimento de forma tridimensional com um material inerte. Um cimento endodôntico ideal deve ser biocompatível, ter tempo de presa adequado, estabilidade dimensional, união à dentina, baixa solubilidade, fácil manuseio e ser radiopaco. Para estabelecer um padrão nas pesquisas de materiais odontológicos algumas especificações são determinadas pela ISO e ANSI/ADA, onde são determinados os testes a serem realizados para cada tipo de material a ser avaliado. O objetivo desse estudo foi avaliar as propriedades físico-químicas de um novo cimento à base de silicato de cálcio tendo como fonte de comparação um cimento à base de resina epóxi. Para a avaliação do pH e liberação de cálcio, tubos de polietileno de 1mm de diâmetro interno e 10 mm de comprimento foram preenchidos com os cimentos e imersos em 10 ml de água deionizada. Após os períodos experimentais de 1, 24, 72 e 168 horas as amostras foram avaliadas quanto ao pH e a liberação de cálcio em um medidor de pH e espectrofotômetro colorimétrico respectivamente. Na análise da radiopacidade, solubilidade e tempo de presa foram confeccionados anéis com 10mm de diâmetro e 1mm de espessura do cimento; o valor da radiopacidade foi determinado de acordo com a densidade radiográfica (mm Al). Para a solubilidade os espécimes foram imersos em 50ml de água destilada por 7 dias, onde foi aferida a massa inicial (antes da imersão) e a final (após a imersão e desumidificação). A avaliação do tempo de presa foi realizada com agulhas Gilmore de 100g e 456,3g. O escoamento foi realizado com base na ISO 6876:2001. Os dados foram analisados por análise de variância e teste de Tukey (P<0,05). Os resultados encontrados nesse estudo, para valores de pH e Ca- foram significativamente maiores para o cimento Biosealer quando comparados ao AH Plus (P<0,05). Nos testes de escoamento, radiopacidade e tempo de presa o cimento biocerâmico demonstrou valores inferiores ao AH Plus (P<0,05). O Biosealer demonstrou uma alta solubilidade comparativamente ao AH Plus (P<0,05). É lícito concluir que, o cimento Biosealer demonstrou boas propriedades físico-químicas tais como; pH, liberação de cálcio, escoamento, radiopacidade e tempo de presa. Essa nova formulação de cimento endodôntico apresentou uma maior solubilidade do que a prevista na ISO 6876:2012. / The success of long-term endodontic treatments depend on mechanical and chemical preparation, as well as on the root canal fillings, the purpose of which being providing filling in a three-dimensional fashion using inert material. The ideal endodontic cement must be biocompatible, have an appropriate setting time, dimensional stability, dentin bond strength, low solubility, be easy to manipulate and radiopaque. In order to set up a standard for research involving dental materials, some specifications are set forth by ISO and ANSI/ADA, in which the tests to be carried out for each material to be assessed are provided for. The goal of this study is to assess the physical and chemical properties of a new calcium silicate-based cement, to be compared with an epoxy resin-based cement. In order to assess calcium release and pH levels, polyethylene tubes with internal diameter of 1 mm and 10 mm in length have been filled with the cements and immersed in 10 ml of deionized water. After trial periods of 1, 24, 72 and 168 hours, the samples were assessed with regard to their calcium release and pH levels, using a colorimetric spectrophotometer and a pH mete, respectively. In order to assess radiopacity, solubility and setting time, rings with 10 mm in diameter and 1 mm in thickness were manufactured using the cements; the radiopacity levels were calculated in accordance with their radiographic density (mm Al). In order to assess solubility, the items were immersed in 50 ml of distilled water for seven days, with the initial mass (before immersion) and final mass (after immersion and dehumidification) being measured. The setting time assessment was carried out using Gilmore needles weighing 100 g and 456.3 g. Yield test was carried out based on ISO 6876:2001. The data obtained were analyzed through analysis of variance and Tukey test (P<0.05). The results found in this study with regard to pH e Ca- levels were significantly higher for the Biosealer cement, when compared with AH Plus (P<0.05). In the yield, radiopacity and setting time tests, the results for the bioceramic cement were lower when compared with AH Plus (P<0.05). The results for the Biosealer indicated higher solubility levels, when compared with AH Plus (P<0.05). It is conceivable to conclude that the Biosealer has shown good physical-chemical properties, such as pH, calcium release, yield, radiopacity and setting time. This new endodontic cement formulation has shown a higher solubility when compared with the level set forth in ISO 6876:2012.

O presente estudo teve como objetivo avaliar a influência do protocolo de secagem com álcool isopropílico à adesividade dos cimentos AH Plus, Hybrid Root Seal e Epiphany SE à dentina radicular. Oitenta raízes de caninos foram submetidas ao preparo biomecânico e distribuídas em 2 grupos de acordo com a secagem, previamente a obturação: I- Secagem cone de papel absorvente e II- Secagem com álcool isopropílico 70%,e posteriormente distribuídas em 8 grupos (n=10): IA e IIA cimento AH Plus; IB e IIB - cimento Hybrid Root Seal; IC e IIC- cimento Epiphany SE com guta percha e ID e IID cimento Epiphany SE com Resilon. Após a obturação, 80 raízes foram seccionadas transversalmente obtendo-se 3 slices de 1,0 mm de espessura para cada terço radicular. Um slice de cada terço foi submetido ao teste de push out e tipo de falha analisado por meio de lupa estereoscópica. Os dois slices restantes foram submetidos à MEV para análise da interface adesiva e superfície do material obturador. A análise de variância evidenciou haver diferença estatisticamente significante (p<0,05) entre os materiais obturadores, o protocolo de secagem do canal radicular e a interação destes fatores. AH Plus/ guta percha obteve os maiores valores médios de resistência de união (3,83 ± 0,45 MPa), sendo estatisticamente diferente (p<0,05) dos demais. O Hybrid Root SEAL/ guta percha (3,24 ± 0,46 MPa) obteve valores intermediários, sendo estatisticamente diferente dos demais (p<0,05). O cimento obturador Epiphany SE quando associado à guta percha (0,45 ± 0,10 MPa) ou ao Resilon (0,31 ± 0,09 MPa) obteve os menores valores de adesividade, sendo estatisticamente semelhantes entre si (p>0,05) e diferentes dos demais (p<0,05). O cimento AH Plus obteve os maiores valores de adesividade independente do protocolo de secagem utilizado. Na comparação entre os protocolos, o protocolo que utilizou álcool isopropílico 70% obteve maiores valores médios de adesividade. / The purpose of the present study was to evaluate the influence of the drying protocol with isopropyl alcohol on the adhesion of the sealers AH Plus, Hybrid Root Seal and Epiphany SE to intraradicular dentin. Eighty root canals of canines were subjected to biomechanical preparation and were allocated to receive one of the following drying protocols (n=40) prior to root canal filling: I- Drying with absorbent paper point and II- Drying with 70% isopropyl alcohol. Thereafter, 8 groups (n=10) were formed according to the filling material: IA and IIA AH Plus sealer; IB and IIB - Hybrid Root Seal sealer; IC and IIC- Epiphany SE sealer with gutta-percha; and ID and IID Epiphany SE sealer with Resilon. After filling, the 80 roots were sectioned transversally to obtain three 1.0-mm-thick slices from each root third. The first slice of each third was subjected to a push-out test and the failure mode was determined with a stereoscopic lens. The other two slices were prepared for SEM to examine adhesive interface and the surface of the filling materials. Analysis of variance revealed statistically significant difference (p<0.05) among the filling materials, between the root canal drying protocols as well as for the interaction of these factors. AH Plus/gutta-percha had significantly higher (p<0.05) bond strengths (3.83 ± 0.45 MPa) than the other materials. Hybrid Root SEAL/gutta-percha (3.24 ± 0.46 MPa) had intermediate values and differed significantly from the other materials (p<0.05). Epiphany SE combined with either gutta-percha (0.45 ± 0.10 MPa) or Resilon (0.31 ± 0.09 MPa) presented the lowest bond strengths without statistically significant difference (p>0.05) from each other, but with significant difference (p<0.05) from the other materials. AH Plus present the highest bond strengths regardless of the drying protocol. Comparing the two protocols, drying of root canals with 70% isopropyl alcohol was associated with the highest bond strength values to intraradicular dentin.