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Título: METROLOGICAL EVALUATION OF THE MEASUREMENT OF THE MODULUS OF ELASTICITY OF POLYMERIC MATERIALS BY ATOMIC FORCE MICROSCOPY, IN THE PEAK FORCE TAPPING MODE
Autor: JUAN DAVID CAICEDO VASQUEZ
Colaborador(es): MAURICIO NOGUEIRA FROTA - Orientador
OMAR GINOBLE PANDOLI - Coorientador
Catalogação: 01/SET/2020 Língua(s): PORTUGUESE - BRAZIL
Tipo: TEXT Subtipo: THESIS
Notas: [pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio.
[en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio.
Referência(s): [pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=49224&idi=1
[en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=49224&idi=2
DOI: https://doi.org/10.17771/PUCRio.acad.49224
Resumo:
Over the past few decades, more intensely, atomic force microscopy (AFM) has been used in research and development activities, notably for the characterization of materials. Despite the advances and sophistications of the technique, the determination of the modulus of elasticity of polymeric materials remains a challenge given the complexity of characterizing complex materials, commonly generating significant spread in the measurement results. This research presents mappings of the morphology and measurements of the elasticity modulus of commercial cellulose (bamboo and eucalyptus fibers) and lignocellulosic, referenced to already characterized synthetic polymeric materials (considered as standard). Atomic force microscopy (AFM), in the peak force tapping mode, alternatively based on the Derajaguin-Muller-Toporo model, DMT (which is the model incorporated by Bruker in its AFM software) and the Johnson-KendallRobert model, JKR (proposed in this work, using a Matlab algorithm), was used as a technique for measuring the elasticity module of the investigated materials. From the tests performed, it was possible to evaluate the measurement method based on metrological criteria and determine the most appropriate calculation model for the characterization of the investigated materials. For the standard materials used as a reference, whose elasticity modulus values are reported by the respective suppliers (E equal 2.7 more or less 0.1 GPa, for polystyrene and E equal 1.8 GPa, for polyamide), the JKR model proved to be most suitable to support the calculation of the modulus of elasticity. While the JKR model reproduced the manufacturer s value with 6.3 percent, for the case of polystyrene (E equal 2.540754 more or less 0.056 GPa) and with 12.5 percent, for the case of polyamide (E equal 1.680050 more or less 0.041 GPa), the DMT model produced results with deviations greater than 50 percent from the reference value taken as standard reference values. Based on these DMT and JKR models, the work evaluated the elasticity module of other materials, more specifically: (i) cellulose film extracted from eucalyptus; (ii) commercial microfiltered cellulose film; (iii) microfibrillated cellulose film, deposited in the laboratory by and ultrasound technique and (iv) samples of bamboo (Dendrocalamus Giganteus), extracted from the external and internal section of the bamboo stem. The results are discussed in accordance with the metrological rigor of the stochastic and deterministic components of the uncertainty associated with the measurements performed, confirming that the atomic force microscopy (AFM), in the peak force tapping mode, presents itself as a promising technique to be used as a metrological tool for the characterization of polymeric materials at the nanoscale.
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