A organização dos bivalves em geral sempre foi muito confusa e, em se tratando de ostreídeos, a variação intraespecífica dificulta ainda mais a identificação das distintas espécies que ocorrem no litoral brasileiro. Neste caso, as ostras do gênero Crassostrea são um bom exemplo. Este trabalho visa a revisão taxonômica das espécies do Brasil, Crassostrea rhizophorae e C. brasiliana, e das espécies exóticas C. gigas, cultivada no sul do país, e C. virginica. Foram aplicadas técnicas de análise e comparação de anatomia detalhada, através de dissecções. Por serem economicamente importantes, a diferenciação entre as espécies é fundamental, o que garante conhecimentos para uma melhor produção. As diferenças morfo-anatômicas encontradas em quase todas as estruturas foram suficientes para a separação entre as quatro espécies, duas nativas e duas exóticas. A ocorrência da espécie africana C. gasar no Brasil não foi confirmada. O material testemunho de artigos que fizeram tal citação foi examinado, evidenciando tratar-se de C. brasiliana de ambiente estuarino. A distribuição geográfica das espécies estudadas é a seguinte: C. rhizophorae ocorre do Caribe ao Rio Grande do Sul, exclusiva de manguezais. C. brasiliana endêmica da costa brasileira, ocorrendo tanto em costões rochosos quanto em manguezais, do Maranhão a Santa Catarina. C. virginica ocorre da costa Atlântica do Canadá até o Caribe. C. gigas, é originária de todo o Indo-Pacífico, mas é cultivada no sul do Brasil. Material de várias regiões da distribuição das espécies nativas do Brasil foi estudado. / The organization of the bivalves in general has always been very confused, and in the case of the ostreidae, the intra-specific variation makes even harder the identification of the distinct species that occur in the Brazilian seashore. In such case, the oysters of the Crassostrea genus are good examples. This work aims at the taxonomic review of the Brazilian species Crassostrea rhizophorae and C. brasiliana, and the exotic species C. gigas, cultivated in the Southern region of the country, and C. virginica. Techniques of detailed anatomy analysis and comparison have been applied through dissections. By being economically important, the differentiation between species is critical, which ensures the knowledge for a better production. The morphoanatomical differences found in almost all structures were sufficient for the seggregation among the four species, two native and two exotic. The occurrence of the African species C. gasar in Brazil was not confirmed. The testimonial material of articles that made such mention was examined, evidencing that it is a C. brasiliana of estuarine environment. The geographic distribution of the studied species is the following: C. rhizophorae occurs from the Caribbean to the State of Rio Grande do Sul, only in mangroves. C. brasiliana is endemic of the Brazilian coast, occurring both in rocky coasts and mangroves, from the States of Maranhão to Santa Catarina. C. virginica appears from the Atlantic coast of Canada to the Caribbean. C. gigas is originating from the whole Indian-Pacific, but is cultivated in the Southern region of Brazil. Material of several distribution regions of the Brazilian native species was studied.

A organização dos bivalves em geral sempre foi muito confusa e, em se tratando de ostreídeos, a variação intraespecífica dificulta ainda mais a identificação das distintas espécies que ocorrem no litoral brasileiro. Neste caso, as ostras do gênero Crassostrea são um bom exemplo. Este trabalho visa a revisão taxonômica das espécies do Brasil, Crassostrea rhizophorae e C. brasiliana, e das espécies exóticas C. gigas, cultivada no sul do país, e C. virginica. Foram aplicadas técnicas de análise e comparação de anatomia detalhada, através de dissecções. Por serem economicamente importantes, a diferenciação entre as espécies é fundamental, o que garante conhecimentos para uma melhor produção. As diferenças morfo-anatômicas encontradas em quase todas as estruturas foram suficientes para a separação entre as quatro espécies, duas nativas e duas exóticas. A ocorrência da espécie africana C. gasar no Brasil não foi confirmada. O material testemunho de artigos que fizeram tal citação foi examinado, evidenciando tratar-se de C. brasiliana de ambiente estuarino. A distribuição geográfica das espécies estudadas é a seguinte: C. rhizophorae ocorre do Caribe ao Rio Grande do Sul, exclusiva de manguezais. C. brasiliana endêmica da costa brasileira, ocorrendo tanto em costões rochosos quanto em manguezais, do Maranhão a Santa Catarina. C. virginica ocorre da costa Atlântica do Canadá até o Caribe. C. gigas, é originária de todo o Indo-Pacífico, mas é cultivada no sul do Brasil. Material de várias regiões da distribuição das espécies nativas do Brasil foi estudado. / The organization of the bivalves in general has always been very confused, and in the case of the ostreidae, the intra-specific variation makes even harder the identification of the distinct species that occur in the Brazilian seashore. In such case, the oysters of the Crassostrea genus are good examples. This work aims at the taxonomic review of the Brazilian species Crassostrea rhizophorae and C. brasiliana, and the exotic species C. gigas, cultivated in the Southern region of the country, and C. virginica. Techniques of detailed anatomy analysis and comparison have been applied through dissections. By being economically important, the differentiation between species is critical, which ensures the knowledge for a better production. The morphoanatomical differences found in almost all structures were sufficient for the seggregation among the four species, two native and two exotic. The occurrence of the African species C. gasar in Brazil was not confirmed. The testimonial material of articles that made such mention was examined, evidencing that it is a C. brasiliana of estuarine environment. The geographic distribution of the studied species is the following: C. rhizophorae occurs from the Caribbean to the State of Rio Grande do Sul, only in mangroves. C. brasiliana is endemic of the Brazilian coast, occurring both in rocky coasts and mangroves, from the States of Maranhão to Santa Catarina. C. virginica appears from the Atlantic coast of Canada to the Caribbean. C. gigas is originating from the whole Indian-Pacific, but is cultivated in the Southern region of Brazil. Material of several distribution regions of the Brazilian native species was studied.

Pressure-sensitive adhesives (PSAs) are complex macromolecular-based blend formulations that, in dry form will adhere permanently to diverse surfaces with the application of mere finger pressure. This thesis addresses the bonding and debonding mechanisms of coated films of different commercially available PSAs by systemically investigating the film characteristics on multiple levels. The methods implemented involve a novel procedure in investigating viscoelastic properties with Dynamic Mechanical Analysis, film surface chemistry with Time-of-flight Secondary Ion Mass Spectrometry and film morphology, modulus and bonding characteristics with Atomic Force Microscope. The theoretical aspect invoked rubber elasticity, viscoelasticity and thermodynamic concepts in representation of film morphology with corresponding adhesion nature. The results indicate that the bonding and debonding behaviour of PSA films are of a viscoelastic nature, dictated mainly by two fundamental morphological elements. These elements are; (1) the formation of phase-separated self-assembly of polystyrene-richcopolymer nano-domains within the adhesive matrix and (2) the inter-linking of the nanodomains by elastically active elastomer segments into a physical crosslinked network system that is highly efficient in dissipating large strain energy. These morphological factors are manifested through a profound contribution to the peel strength of the adhesive films when either coated at high temperatures or annealed. Increasing the content of the polystyrene endblock-tackifier in the adhesive blend formulation increased the PSA’s performance sensitivity to the film coating temperature. Meanwhile increasing the cis-C=C bond concentration in the formulation reduced the film’s performance sensitivity to coating temperature, as polydienes are premised to promote the entropy-elasticity of the film matrix by contributing to the nano-domain interconnections. This thesis generates many qualitative similarities, despite the significantly different adhesive blends investigated and hopefully the results reported here are more universal than one might expect.