Adhesion promoters are traditionally used to improve the durability between an adhesive or any other organic phase, such as a sealant or a paint, and a metallic substrate. There are many different types of molecules which will act as adhesion promoters, but one class which has attracted considerable attention is that based on the organosilanes, such as y-aminotriethoxysilane, or y-glycidoxypropyl trimethoxysilane. Applications of such adhesion promoters are to be found in sealants, rubbers, primers in packaging and primers for coatings and adhesives. Organosilanes as adhesion promoters are widely used in industry, and until recently have been included in adhesive formulations in an empirical way, because it has been observed that the adhesive properties and hydrolytic stability can be improved. However recent work is leading to an understanding of how the silane molecules specifically interact with metallic and inorganic substrates. Little is known at the present time regarding the mode of operation of such molecules when applied to polymeric substrates. The purpose of the current work was to probe interaction of these molecules with low energy polymer substrates, for example, poly(methyl methacrylate) (PMMA) and poly(ethylene terephalate) (PET), using surface analysis techniques. Two factors which have been identified as controlling the adsorption of the organosilanes onto low energy substrates are the solution chemistry and the surface energy of the polymer. Both have been investigated extensively within this project. The latter was identified by means of investigating a series of substrates, with increasing polar contribution towards the surface free energy. The highest polar component was displayed by corona treated PET, which also displayed the highest levels of adsorption of organosilanes. Investigation of the adsorbed layer of the organosilane on the corona discharge treated PET has led to an understanding of the mechanism of the interaction of the molecules with all of the low energy substrates, and models for such interactions are proposed on the basis of spectroscopic observations.

Les polymères thermosets sont largement employés dans les revêtements, les composites et les adhésifs du fait de leurs excellentes propriétés mécaniques et thermiques. Malheureusement, ils ne peuvent pas être recyclés et génèrent des déchets non réutilisables, ce qui doit être amélioré pour s'adapter aux nouvelles directives environnementales. Notamment, l’utilisation d’adhésifs démontables permettrait un meilleur recyclage de ses substrats, ce qui est particulièrement intéressant pour la fin de vie des véhicules, ou des pièces électroniques. Une grande partie des adhésifs sont formulés à partir de polyuréthanes (PUs). De manière classique, les PUs sont obtenus par polymérisation entre poly-isocyanates et polyols, et la plupart de temps, ils sont réticulés pour donner un collage irréversible. Le démontage du collage peut se faire par intégration de liaisons clivables sur réponse à un stimulus donné, la température étant préféré dans l'industrie. La réaction de Diels-Alder (DA) et la retroDiels-Alder (rDA) est un système thermoréversible bien connu et déjà utilisé dans de nombreux travaux. La réaction de DA produit un adduit qui peut se dissocier sous traitement thermique pour donner le diène et le diénophile de départ. Le couple furane/maleimide est choisi pour leur excellente réactivité. Toutefois, la rDA commence souvent à des températures inférieures à 100°C, ce qui est trop bas pour certaines applications. Par ailleurs, la rDA ne se produit pas lorsque l'adduit est sous forme solide (sauf dans des conditions critiques). Nous avons cherché à augmenter la température de rDA en utilisant un adduit de DA solide à haut point de fusion. Pour s'assurer de la miscibilité de l'adduit dans les formulations industrielles, l'adduit est intégré de manière covalente dans des structures PPG par polymérisation, ou bien en ajoutant un segment PPG sur le composé furanique. Ainsi, plusieurs oligomères diols intégrant le motif adduit solide sont synthétisés pour être polymérisés avec des isocyanates au centre de recherche de l'entreprise. De plus, une nouvelle voie d'accès simple et en une étape à des structures bismaleimides a été développée. Ces bismaleimides ont été fonctionnalisés et formulés dans des formulations industrielles donnant des adhésifs PU dont les propriétés thermiques sont étudiées. Par ailleurs, les isocyanates sont dangereux pour la santé humaine et l'environnement. La synthèse de polyhydroxyuréthanes (PHUs) par polymérisation de cyclocarbonates avec des amines, s'est imposé comme une alternative prometteuse. Dans une étude préliminaire, des PHUs linéaires intégrant des adduits de DA sont synthétisés, soit par polymérisation d'adduit dicyclocarbonate avec une diamine, soit par polyaddition de DA d'un hydroxyuréthane bisfuranique et d'un bismaleimide. Il a été démontré que la chaine polymère est coupée par la rDA lors de traitement thermique. Puis des adduits de DA sont intégrés dans des PHU réticulés à différentes positions dans le réseau. Il a été montré que cette position influence grandement les propriétés thermiques du polymère. Finalement, une classe de matériaux originaux, des polyuréthanes sans isocyanates réticulés thermo-démontables, a été développée et a donné des résultats prometteurs. / Thermosetting polymers are greatly used in coatings, composites and adhesives due to their good mechanical and thermal properties. They cannot be recycled, which constitutes a great deal for environmental concern. It has been pointed out that using remendable adhesives would enable to better recycle adhesives substrates. This is especially required for vehicles end-of-life or electronic waste. For adhesive applications, polyurethanes (PUs) are widely used because of their versatility. PUs are typically obtained by reaction between diisocyanates and diols and most of the time they are chemically cross-linked which makes the resulting adhesion irreversible. In order to reprocess cross-linked networks, reversible bonds which can break on demand are integrated within them. Industrially, temperature is the most practical stimulus. Diels-Alder (DA) and retroDiels-Alder (rDA) are a well-known thermoreversible system and already studied in various works. Indeed DA reaction leads to an adduct which can dissociate under thermal treatment to turn back into the previous diene and dienophile compounds (rDA). Here the furan/maleimide couple was chosen as diene/dienophile because of its (catalyst-free) good reactivity. Yet, rDA often begins under 100°C which can be problematic for some applications, but also, rDA cannot take place at solid state (). So we aimed to increase rDA temperature using a solid DA adduct with high melting point. To ensure its miscibility in industrial formulation, it was integrated within PPG structures by polymerization or by adding a PPG-spacer on furanic compound. Several oligomer diols with this solid DA adduct unit were synthetized and polymerized with isocyanates at Bostik research center. Furthermore, a novel pathway to easily access to bismaleimide structures was investigated. These bismaleimides were reacted to give diol adducts which were formulated into industrial formulations and their thermal behaviors were studied.Besides, diisocyanates are harmful for human health and its environment. Thus, the synthesis of polyhydroxyurethanes (PHUs) by step-growth polymerization of cyclocarbonates with amines is a promising alternative. In a preliminary study, linear PHUs integrating DA adducts have been synthetized by polymerization of a dicyclocarbonate adduct with an amine, and by DA polyaddition of a bisfuranic PHU and a bismaleimide. It was demonstrated that rDA split-up the polymeric chains. Then crosslinked PHUs integrating DA adducts at different places were studied.. It was shown that DA adduct position influences greatly polymer thermal behavior. As a result, an original class of thermoremendable isocyanate-free crosslinked polyurethane has been developed and gave promising results.

Doctor of Philosophy / Department of Grain Science and Industry / X. Susan Sun / Oilseed protein is a promising renewable source to be used as the replacement of petroleum-based materials for adhesion purpose, and it has drawn increasing attention since soy-based adhesives were developed for wood glues. However, soy protein comprises a portion of humans’ diets, thereby creating competition between utilization of soy protein for protein-based products or human food. Therefore, alternative bio-resources must be discovered. Proteins from camelina sativa provide such potential. Similar to other protein-based polymers, low mechanical strength and poor water resistance are the major drawbacks limiting camelina protein’s further applications. In this research, camelina protein (CP) was modified by unfolding, crosslinking, and co-polymerization treatment for improved flow-ability, adhesion properties and water resistance, which facilitates the industrialization of camelina as an alternative to soy-based adhesives. The physicochemical properties and microstructures of CP were also investigated. To increase the reactivity of CP adhesive, the first step is to denature the folded structure of native proteins. Camelina protein was extracted from defatted camelina meal through alkali solubilization and acid precipitation and modified with varying amount of NaHSO₃ (0-12% of the protein dry base) and Gdm.Cl (0-250% of the protein dry base). NaHSO₃ treatment broke the disulfide bonds of the CP and thus increased its free sulfhydryl content and surface hydrophobicity. As NaHSO₃ concentration increased, the viscosity, elastic modulus (G') and water resistant of NaHSO₃-modified camelina protein (SMCP) dispersion decreased, and the protein became hydrophobic. Gdm.Cl treatment broke the CPI’s hydrogen bonds but decreased their surface hydrophobicity. Similarly, viscosity, G', and water resistant of Gdm.Cl-modified camelina protein (GMCP) dispersions decreased as Gdm.Cl increased and protein became to aggregate. The reducing effect of NaHSO₃ was more obvious than Gdm.Cl to disrupt CPI’s intermolecular protein interaction but less obvious than Gdm.Cl to reduce the viscosity and water resistant. To further increase the CP’s water resistance, a coupling agent, Ethyl-3-(3-dimethyl-aminopropyl-1-carbodiimide) (EDC), was applied to stabilize the protein structure by crosslinking the free carboxyl groups and amino groups. The cross-linked CP exhibited increased molecular weight and particle size. Microstructures of modified CP also became rigid and condensed. Accordingly, CP’s increased intermolecular protein interaction resulted in its higher elastic modulus, viscosity and water resistance. The ultrasound pretreatment further increased the crosslink degree of CP, which resulted in protein’s increased aggregation behaviors and compact micro-structures. Consequently, the elastic modulus, viscosity, and water resistance of CP increased accordingly. Copolymerization with hydrophobic enhancers was also an effective method to improve CP’s water resistance. In this study, kraft lignin was oxidized by H₂O₂ and then copolymerized with CP as wood adhesives, which exhibited increased wet strength. In the presence of ultrasound irradiation, the H₂O₂-depolymerized kraft lignin exhibited reduced particle size, thermal stability and increased content of hydroxyl groups. Fluorescence spectroscopy analysis revealed that after coupling with pristine or de-polymerized lignin, CP exhibited increased hydrophobicity due to lignin’s increased reactivity with camelina protein. Accordingly, the water resistance of CP-based adhesives improved. In the optimized condition, when CP was copolymerized with ultrasound-induced oxidized lignin, it had increased wet shear adhesion strength from 0.28 MPa to 1.43 MPa, with wood panels passing the three-cycle water soaking test.

Orientador: Luiz Andre Freire Pimenta / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-07-24T01:11:58Z (GMT). No. of bitstreams: 1 Saboia_VicentedePauloAragao_M.pdf: 3642627 bytes, checksum: 3810c206c50b67463e5e76e570894df6 (MD5) Previous issue date: 1998 / Resumo: O objetivo deste trabalho foi verificar os efeitos remoção do colágeno na resistência ao cisalhamento de dois sistemas adesivos de frasco único e examinar a micromorfologia da dentina, antes e após o teste de cisalhamento, em lupa estereoscópica e MEV. Foi usado como substrato dentina planificada de terceiros molares recém-extraídos e armazenados em formal a 10% (pH neutro). Foram usados os adesivos Prime & Bond 2.1 (PB-Dentsply) e Single Bond (SB-3M). Nos grupos controle (1 e 3), após aplicação da ácido fosfórico a 37%, os adesivos foram aplicados de acordo com as instruções do fabricante, enquanto que nos grupos experimentais (2 e 4), após o condicionamento ácido, foi aplicada uma solução de hipoclorito de sódio a 10% (H), por 1 minuto, para remover o colágeno exposto pelo condicionamento ácido. Foram cqnfeccionados cilindros de 3 mm de diâmetro por 5 mm de altura com resina composta Z-100 (3M). Após 24 horas em ambiente úmido a 37 °e, foi realizado o teste mecânico de cisalhamento com velocidade de 0,5 mm/min. Os resultados explorátórios e do Teste de Kruskal-Wallis podem ser observados na tabela abaixo. ... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: The purpose of this study was to evaluate the effect of removing collagen using Single Bond-3M (SB) according to the manufacturer's to four groups and on the shear bond strength for two single-bottle adhesives systems and to examine the dentin surfaces after shear test. The buccal and lingual surfaces of 80 extracted human third molars were ground to expose dentin, then polished with 320, 400 and 600-grit aluminum oxide. Teeth were randomly assigned received the following treatments: group 1, samples were conditioned with 37% phosphoric acid , rinsed and left moist, Prime & Bond 2.1-Dentsply (PB) adhesive was applied according to manufacturer's directions, and restorative Z100 (3M) composite resin was bonded to the dentin surface; group 2, the same procedures were followed as for group 1 except the surfaces were treated with 10% NaOCI for 1 minute, after acid conditioning; group 3, the same technique was followed as for group 1 , recommendations; group 4, the same procedure was followed for group 2, using Single Bond. The specimens were stored. in humidity at 37°C for 24 hours and tested in a shear mode at a crosshead speed of 0,5 mm/minute. The median of results were: G2=21,84, G3=15,99, G1=15,02 and G4=13,82. The Kruskal-Wallis test and multiple comparisons were used for statistical analysis of the data. A 1 minute exposure of dentin to 10% NaOCI following acid conditioning resulted in significant increase on the dentin shear bond strength for Prime & Bond 2.1 (group 2). The same treatment for Single Bond (group 4) resulted in significant reduction on the values of adhesion. Groups 1 and 3 were not statistically different from each other. Group 2 showed more dentin-cohesive failures than the other groups. Under SEM observations, there were morphological differences between the groups treated with NaOCI and those that did not received this treatment / Mestrado / Dentística / Mestre em Clínica Odontológica

Orientador: Fernanda Miori Pascon / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T04:03:41Z (GMT). No. of bitstreams: 1 Girotto_AlineCarvalho_M.pdf: 1616855 bytes, checksum: 11bb1dc52c1940120b0da6f0e2d4b9db (MD5) Previous issue date: 2015 / Resumo: O objetivo foi avaliar o efeito de uma solução antioxidante (tiossulfato de sódio a 5%) na resistência da união (RU) da dentina da câmara pulpar tratada com duas concentrações de hipoclorito de sódio (NaOCl) e diferentes sistemas adesivos. Quarenta e oito dentes bovinos foram selecionados, seccionados, para remoção das raízes e exposição da câmara pulpar, e foram divididos aleatoriamente em 16 grupos de acordo com o tratamento da superfície dentinária: NaOCl a 1%; NaOCl a 1% + tiossulfato de sódio a 5%; NaOCl a 5,25%; NaOCl a 5,25% + tiossulfato de sódio a 5% e do sistema adesivo: Single Bond UniversalTM (3M/ESPE) - técnica convencional, Single Bond UniversalTM (3M/ESPE) - técnica autocondicionante, Adper ScotchbondTM Multi-Purpose (3M/ESPE) e ClearfilTM SE Bond (Kuraray). As soluções irrigadoras foram utilizadas por 30 minutos e a solução antioxidante por 1 minuto, após a irrigação. Os dentes foram seccionados no sentido mésio-distal, resultando em duas hemi-espécimes que foram restauradas com compósito Filtek- Z350TM (3M/ESPE). Após 24 horas, os corpos-de-prova foram submetidos à microtração e foram avaliados em microscopia eletrônica de varredura (75x), quanto ao padrão de fratura (falhas adesivas; coesivas em dentina; coesivas em resina; mistas). Os dados foram convertidos em Mpa e submetidos aos testes Shapiro-Wilk, ANOVA três fatores e teste de Tukey (?=5%). Para o grupo tratado com NaOCl a 1%, maiores valores de RU foram observados para o ClearfilTM quando comparado aos demais adesivos (p<0,01). Quando associou-se a solução antioxidante, o grupo ScotchbondTM apresentou maiores valores de RU comparados aos demais grupos (p?0,01). Após tratamento com NaOCl a 5,25%, não houve diferença entre os sistemas adesivos (p>0,05). A aplicação do antioxidante após o tratamento com NaOCl a 1% e 5,25% associado ao ScotchbondTM, foi capaz de aumentar significativamente a RU. Para o sistema adesivo Single Bond UniversalTM (técnica convencional) os maiores valores de RU foram observados para o grupo tratado com NaOCl a 1% associado ao tiossulfato. (p<0,05). Entretanto, para Single Bond UniversalTM (técnica autocondicionante) e para ClearFilTM, maiores valores de RU foram observados quando da utilização do NaOCl a 1%, diferindo significativamente dos grupos tratados com NaOCl a 5,25% (p<0,01). Com relação ao ScotchbondTM, maiores valores foram observados após o tratamento com NaOCl a 1% associado ao antioxidante, seguido dos grupos: NaOCl a 1% e NaOCl a 5,25% associado ou não ao antioxidante. NaOCl a 5,25% utilizado sozinho apresentou os menores valores de RU. Maior porcentagem de falha adesiva foi observada para os grupos tratados com NaOCl a 1% + Single Bond UniversalTM, em ambas as técnicas, NaOCl a 1% + antioxidante + Single Bond UniversalTM na convencional e NaOCl a 5,25% + todos os sistemas adesivos. Para Single Bond UniversalTM - técnica autocondicionante, ClearfilTM e ScothBondTM foram observadas maiores porcentagens de falhas mistas. Conclui- se que o efeito do tiossulfato de sódio a 5% na RU da dentina da câmara pulpar, tratada com NaOCl foi dependente do sistema adesivo utilizado, sendo que para ambas as concentrações o tiossulfato foi capaz de aumentar a RU quando o sistema adesivo ScotchbondTM foi utilizado / Abstract: The aim of this study was to evaluate the effect of an antioxidant solution (5% sodium thiosulfate) on the microtensile bond strength (µTBS) between the pulp chamber dentin treated with two concentrations of sodium hypochlorite (NaOCl) and different adhesive systems. Forty eight bovine incisors were selected, sectioned horizontally to remove the roots and expose the pulp chamber and randomly divided into 16 groups according to dentin surface treatment: 1% NaOCl; 1% NaOCl + 5% sodium thiosulfate; 5.25% NaOCl; 5.25% NaOCl + 5% sodium thiosulfate and to the adhesive system: Single Bond UniversalTM - etch-and-rinse technique, Single Bond UniversalTM - self-etch technique (3M/ESPE), Adper ScotchbondTM Multi- Purpose (3M/ESPE) and ClearfilTM SE Bond (Kuraray). The irrigation solutions were applied for 30 minutes and the antioxidant solution for 1 minute, after irrigation. The teeth were sectioned into mesial-distal direction, resulting in two halves that were restored with the composite resin Filtek-Z350TM (3M/ESPE). After 24 hours, sticks were obtained and submitted to the µTBS test and they were evaluated by scanning electron microscopy (x75), and classified according the failure pattern (adhesive failure, cohesive in dentin, cohesive in resin and mixed). Data were converted to Mpa and submitted to Shapiro-Wilk, three-way ANOVA and Tukey tests (a=5%). In the group treated with 1% NaOCl, higher µTBS values were observed for ClearfilTM when compared to other adhesive systems (p<0.01). When 5% sodium thiosulfate was used after 1% NaOCl, ScotchbondTM showed higher µTBS compared to other groups (p?0.01). After treatment with 5.25% NaOCl, there was no difference between the adhesive systems (p>0.05). The application of the antioxidant after treatment with 1% NaOCl and 5.25% associated to ScotchbondTM was able to significantly increase the µTBS. For the Single Bond UniversalTM (etch-and-rinse technique) highest µTBS were observed when using 1% NaOCl with the antioxidant (p<0.05). However, for Single Bond UniversalTM (self-etching technique) and ClearFilTM highest µTBS were observed when using the 1% NaOCl, differing significantly from the groups treated with 5.25% NaOCl (p<0.01). With respect to ScotchbondTM, higher µTBS values were observed following treatment with 1% NaOCl associated with the antioxidant, followed by groups: 1% NaOCl, 5.25% NaOCl associated with the antioxidant. NaOCl 5.25% used alone had the lowest. Higher percentage of adhesive failure was observed for the groups treated with 1% NaOCl + Single Bond UniversalTM in both techniques, 1% NaOCl + antioxidant + Single Bond UniversalTM etch-and-rinse technique, and 5.25% NaOCl + all adhesive systems. To Single Bond UniversalTM - self-etching technique, ClearfilTM and ScothBondTM were observed higher percentages of mixed failures. It could be concluded that the effect of 5% sodium thiosulfate, in the µTBS of pulp chamber dentin treated with NaOCl, it was adhesive system dependent and for both NaOCl concentrations, the thiosulfate was able to increase µTBS when ScotchbondTM adhesive system was used / Mestrado / Materiais Dentarios / Mestra em Materiais Dentários

Uma das técnicas para viabilizar a utilização de madeira de reflorestamento é a fabricação de Madeira Laminada Colada (MLC), que consiste na colagem de lâminas de madeira. Essas lâminas são obtidas da união de peças, por meio de emendas dentadas coladas. Para um bom desempenho de estruturas de MLC, a escolha do adesivo é fundamental. Atualmente, o Cascophen é o adesivo mais utilizado. Nesse contexto, o objetivo dessa pesquisa foi avaliar a eficiência, quanto à resistência à tração de emendas dentadas, de adesivos (Cascophen, Wonderbond, Cascorez, Melaminauréia formaldeído e Poliuretano à base de óleo de mamona) na colagem de madeira da espécie Pinus hondurensis, utilizando um padrão de emenda com perfil vertical. Também foram feitas comparações entre os perfis vertical e horizontal usando apenas o adesivo Cascophen. Os trabalhos experimentais foram baseados em ensaios de tração em peças com dimensão estrutural. Foram testadas 150 peças emendadas e 25 peças sem emendas (para comparações), com dimensões nominais de 3,5 x 7 x 200 cm. As principais análises feitas foram as comparações entre todos os adesivos com perfil vertical e entre os perfis vertical e horizontal, e uma análise dos modos de ruptura e suas relações com a porcentagem de madeira de inverno e o módulo de elasticidade. A comparação entre todos os adesivos com perfil vertical revelou que apenas o Cascophen e o Cascorez não possuem diferenças estatísticas. O adesivo que mais se destacou foi o Wonderbond, que teve desempenho superior ao do Cascophen, inclusive. Também se concluiu que não existe diferença estatística significativa na resistência à tração dos perfis vertical e horizontal / One of the techniques to allow for the use of reforestation lumber is the production of glued laminated timber (glulam), which consists of the gluing of lumber laminas. Those laminas are obtained of the union of pieces, through glued finger joints. For a good performance of glulam structures, the choice of the adhesive is fundamental. Traditionally, Cascophen is the most adhesive used in the production of glulam. In that context, the aim of the present research is to evaluate the efficiency, with relation to the strength, of adhesives (Cascophen, Wonderbond, Cascorez, Melamine urea formaldehyde and castor oil Polyurethane) in the gluing of Pinushondurensis lumber, using a joint pattern with vertical profile. Comparisons between the vertical and horizontal profiles using only Cascophen adhesive were made. The experimental analyses were based on tensile tests in pieces with structural dimension. For this purpose, 150 joint pieces and 25 pieces without joints (for comparisons) with nominal dimensions of 3,5 x 7,0 x 200 cm were tested. The main analyses performed were the comparison among all the adhesives with vertical profile, the comparison between the vertical and horizontal profiles for the Cascophen adhesive and, finally, an analysis of the failure modes and their relations with both latewood percentage and elasticity modulus. The comparison among all the adhesives with vertical profile revealed that Cascophen and Cascorez do. Not have statistical differences. The best adhesive was Wonderbond, which had a better performance than Cascophen. Concerning the vertical and horizontal profiles, no significant statistical difference was found in the tensile strength

No description available.

Phenol-formaldehyde adhesives are important adhesives known to have superior water resistance capacity and high mechanical strength when utilized in wood-based applications. Due to unsustainability and environmental issues associated with the use of fossil fuels, there is an urgent need to look for alternative raw materials, which are renewable in nature. Pinyon-juniper biomass has been found to be a suitable replacement for petroleum-based phenol because it is renewable, abundant, and readily available. In this thesis, bio-oil produced from the pyrolysis of pinyon-juniper biomass using red mud alumina catalyst was used to produce wood adhesives. The characterization of pinyon-juniper bio-oil showed the presence of phenolics, aromatic hydrocarbons, aliphatic hydrocarbons, carboxylic acids, ethers, ketones, aldehydes, and aliphatic alcohols. Resol synthesis parameters such as formaldehyde-to-phenol molar ratio (1.8 and 2), catalyst loading (0.25, 0.63, and 1.25 g of NaOH), reaction time (60 minutes), and reaction temperature (95°C), were investigated in the production of pinyon-juniper adhesives. Based on the results obtained, the extent of phenol substitution with pinyon-juniper bio-oil was dependent on the amount catalyst used during the synthesis process. The maximum phenol substitution of 80% was achieved using a catalyst loading of 1.25 g of NaOH while the minimum phenol substitution of 50% was obtained at a catalyst loading of 0.25 g of NaOH. Dry shear strength (8.99 to 12.73 MPa) and wet shear strength of (5.16 to 7.36 MPa) for both pure phenol-formaldehyde resols and pinyon-juniper substituted resols were comparable and exceeded the minimum requirement of 0.66 MPa for plywood. Finally, the chemical structure of pure phenol-formaldehyde resols showed the presence of more phenolic OH groups compared to pinyon-juniper substituted resols. This observation was corroborated by the higher concentration of free phenol in pure phenol-formaldehyde adhesives compared to pinyon-juniper substituted resols.

No description available.

Thesis: M.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980 / Includes bibliographical references. / by Dennis P. Orgill. / M.S. / M.S. Massachusetts Institute of Technology, Department of Mechanical Engineering