Desenvolvimento de compósitos híbridos de blendas de PLA/PHBV com carbono vítreo e nanoplacas de grafeno
Data
2022-12-20
Autores
Oyama, Isabela Monteiro Cesar [UNIFESP]
Orientadores
Passador, Fabio Roberto [UNIFESP]
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Materiais poliméricos são muito utilizados para a produção de carcaças de equipamentos eletrônicos, devido à facilidade de processamento, baixa massa específica, propriedades térmicas e mecânicas que atendem a essa aplicação. Entretanto, os polímeros comerciais são isolantes elétricos, e para atuar como protetor de componente eletrônico, o material deve possuir baixa resistividade elétrica. Uma alternativa para diminuir a resistividade elétrica dos polímeros é por meio da adição de cargas condutoras, destacando-se as cargas carbonosas como as nanoplacas de grafeno (GNP) e o carbono vítreo (CV). Além disso, a sinergia por meio da mistura dessas cargas pode ser uma possibilidade para utilização de menores quantidades individuais desses materiais contribuindo para a diminuição da massa específica do material. Visando a sustentabilidade ambiental, biopolímeros biodegradáveis, como o poli(ácido láctico) (PLA) e o poli(3-hidroxibutirato-co-3-hidroxivalerato) (PHBV), podem ser alternativas ao uso de polímeros convencionais. Neste contexto, compósitos híbridos de blendas de PLA/PHBV com adição de diferentes teores de CV e GNP foram preparados por extrusão de dupla rosca seguido de conformação de corpos de prova. A blenda de PLA/PHBV e compósitos de blendas de PLA/PHBV com adição de diferentes teores das cargas individuais (0,1, 0,3 e 0,5 % em massa de CV e 1, 3 e 5% em massa de GNP) e mistura das cargas (híbridos) também foram estudados e processados visando compreender o efeito de cada material carbonoso nos compósitos. As amostras foram submetidas a ensaios de biodegradação em meio sólido. As amostras foram caracterizadas por ensaios térmicos, mecânicos, elétricos, eletromagnéticos e análises morfológicas. As amostras após os ensaios de biodegradação foram caracterizadas por análise visual e perda de massa. O compósito contendo 0,5% em massa de CV e o compósito híbrido contendo 0,5% em massa de CV e 5% em massa de GNP apresentaram redução na resistividade elétrica (1,1 x 105 e 2,0 x 105 Ω.m, respectivamente) e obtenção de propriedades de EMI SE, com atenuação total igual a 4 e 4,5 dB, respectivamente.
Polymeric materials are widely used for the production of electronic component housing due to their unique properties such as ease of processing, low density, and attractive thermal and mechanical properties. However, commercial polymers are insulators and to act as an electronic component protector, the material must have low electrical resistivity. An alternative to decrease the electrical resisitivity is the addition of conductive fillers such as graphene nanoplatelets (GNP) and glassy carbon (GC). In addition, synergy through the mixing of these fillers may be a possibility for the use of smaller individual amounts of these materials, contributing to the reduction of the density of the material. Aiming at environmental sustainability, biodegradable biopolymers, such as poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), can be alternatives to the use of conventional polymers. In this context, hybrid composites of PLA/PHBV blends with the addition of different GC and GNP contents were prepared using twin screw extrusion followed by the conformation of standardized specimens. PLA/PHBV blend and PLA/PHBV blends-based composites with the addition of different contents of individual fillers (0.1, 0.3, and 0.5 wt% of GC and 1, 3, and 5 wt% of GNP) and the hybrids composites were also processed, and studied as to understand the effect of each carbonaceous material on the composites. The samples were submitted to biodegradation tests in a solid medium. The samples were characterized by thermal tests, mechanical, morphology evaluation, electrical, and electromagnetic. The samples after the biodegradation tests were characterized by visual analysis and mass loss. The composite with 0.5 wt% of GC and the hybrid composite containing 0.5 wt% of GC and 5 wt% of GNP presented reduction in electrical resistivity (1.1 x 105 and 2.0 x 105 Ω.m, respectively) and obtaining EMI SE properties, with total attenuation equal to 4 and 4.5 dB, respectively.
Polymeric materials are widely used for the production of electronic component housing due to their unique properties such as ease of processing, low density, and attractive thermal and mechanical properties. However, commercial polymers are insulators and to act as an electronic component protector, the material must have low electrical resistivity. An alternative to decrease the electrical resisitivity is the addition of conductive fillers such as graphene nanoplatelets (GNP) and glassy carbon (GC). In addition, synergy through the mixing of these fillers may be a possibility for the use of smaller individual amounts of these materials, contributing to the reduction of the density of the material. Aiming at environmental sustainability, biodegradable biopolymers, such as poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), can be alternatives to the use of conventional polymers. In this context, hybrid composites of PLA/PHBV blends with the addition of different GC and GNP contents were prepared using twin screw extrusion followed by the conformation of standardized specimens. PLA/PHBV blend and PLA/PHBV blends-based composites with the addition of different contents of individual fillers (0.1, 0.3, and 0.5 wt% of GC and 1, 3, and 5 wt% of GNP) and the hybrids composites were also processed, and studied as to understand the effect of each carbonaceous material on the composites. The samples were submitted to biodegradation tests in a solid medium. The samples were characterized by thermal tests, mechanical, morphology evaluation, electrical, and electromagnetic. The samples after the biodegradation tests were characterized by visual analysis and mass loss. The composite with 0.5 wt% of GC and the hybrid composite containing 0.5 wt% of GC and 5 wt% of GNP presented reduction in electrical resistivity (1.1 x 105 and 2.0 x 105 Ω.m, respectively) and obtaining EMI SE properties, with total attenuation equal to 4 and 4.5 dB, respectively.