Carlos Alberto de Oliveira Couto

Universidade Federal de São Paulo

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Fábio Roberto Passador

Universidade Federal de São Paulo

Bruna Cristina da Silva

Universidade Federal de São Paulo

Eduardo Henrique Backes

Universidade Federal de São Carlos

S. Ribeiro

Universidade de São Paulo

Caroline Martins dos Santos

Universidade Federal de São Paulo

Cooperative Institutions

Universidade Federal de São Paulo

Departamento de Ciência e Tecnologia

Universidade Federal de São Carlos

Universidade de São Paulo

Hospital Universitário da Universidade de São Paulo

Recaltech (Brazil)

Faculdade Brasil

Universidade Estadual do Paraná

Universidade Estadual Paulista (Unesp)

Federal Institute of São Paulo

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Evaluation of Aging Resistance in UHMWPE/LLDPE Blend-Based Carbon Nanotubes Nanocomposites

Macromolecular Symposia (2019)

Bruna Cristina da Silva Caroline Martins dos Santos Carlos Alberto de Oliveira Couto Eduardo Henrique Backes Fábio Roberto Passador

Ultra high molecular weight polyethylene (UHMWPE)/linear low density polyethylene (LLDPE) blend‐based carbon nanotubes nanocomposites with different contents of LLDPE are prepared using a high speed homogenizer. Samples of the materials are thermally treated to understand the correlation between the degree of crystallinity of the treated samples and their impact resistance. Promising results are obtained for the nanocomposite with 10 wt% of LLDPE that shows similar behavior to neat UHMWPE, with the advantage of this nanocomposite being produced by conventional thermoplastic processing methods.

Linear low-density polyethylene

Low-density polyethylene

Homogenizer

10.1002/masy.201700079

Cite

Citations (7)

Mechanical and thermal properties of UHMWPE / LLDPE / CNT blends and nanocomposites for ballistic application

Figshare (2018)

Carlos Alberto de Oliveira Couto Bruna Cristina da Silva Eduardo Henrique Backes Fábio Roberto Passador

ABSTRACT The purpose of developing UHMWPE/ LLDPE/ CNT nanocomposite plates is to obtain a material that can be applied in laminated ceramic/polymer structures for high-impact ballistic protection. The polymer nanocomposite is used in the backing plate of the armor structure to absorb the residual kinetic energy of the projectile and shards from the ceramic material after impact. The polymer nanocomposite must have high fracture toughness, high mechanical strength and controlled deformation, in order to comply with these requirements. For instance, extreme deformations of the backing plate may cause injury to users of ballistic protective vests. In this work, a blend of linear low-density polyethylene (LLDPE) and ultra-high molecular weight polyethylene (UHMWPE) was prepared, using a high-rotation homogenizer with subsequent hot pressing, in order to facilitate the manufacturing process of the polymer nanocomposite plates. Furthermore, carbon nanotubes (0.5, 1.0 and 2.0 wt%), functionalized with nitric acid, were added to the polymer blend, in order to improve the mechanical properties of the resulting material. The mechanical and thermal properties of the polymer blend and the polymer nanocomposite were compared with each other. The polymer blends and polymer nanocomposites were submitted to mechanical tests such as Shore D hardness and uniaxial tensile tests. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed to evaluate thermal stability of the various compositions. Finally, scanning electron microscopy (SEM-FEG) was performed to evaluate the morphology of the nanocomposites.

Linear low-density polyethylene

10.6084/m9.figshare.7453040

Cite

Citations (2)

Propriedades mecânicas e térmicas das blendas e nanocompósitos de UHMWPE/LLDPE/CNT para aplicação balística

Matéria (Rio de Janeiro) (2018)

Carlos Alberto de Oliveira Couto Bruna Cristina da Silva Eduardo Henrique Backes Fábio Roberto Passador

RESUMO O desenvolvimento de placas do nanocompósito de UHMWPE/LLDPE/CNT tem como objetivo a obtenção de um material para aplicação em blindagem balística híbrida de alto impacto em forma de multicamadas de cerâmica/polímero. O compósito polimérico é utilizado na base da blindagem com a função de absorver a energia cinética residual do projétil e dos estilhaços da cerâmica após o impacto. Para atender a estes requisitos o compósito polimérico precisa ter alta tenacidade à fratura, alta resistência mecânica e deformação controlada. Uma deformação exagerada da placa polimérica pode causar lesões aos usuários de coletes balísticos de proteção pessoal, por exemplo. Neste trabalho foi realizada a mistura de polietileno linear de baixa densidade (LLDPE) com polietileno de ultra alta massa molecular (UHMWPE) utilizando um homogeneizador de alta rotação com posterior prensagem a quente com a finalidade de melhorar a mistura dos componentes fundidos e facilitar o processo de fabricação das placas poliméricas. Para compensar as perdas de propriedades mecânicas das blendas em relação ao UHMWPE puro foram produzidos compósitos com adição de 0,5; 1,0 e 2,0 % em massa de nanotubos de carbono funcionalizados com ácido nítrico. Os valores das propriedades mecânicas e térmicas dos compósitos foram comparados com as blendas poliméricas sem adição de nanotubos de carbono. As blendas poliméricas e nanocompósitos foram submetidos aos ensaios mecânicos de dureza Shore D e ensaio de tração uniaxial. Para avaliação da estabilidade térmica foram realizadas análises de calorimetria exploratória diferencial (DSC) e análise termogravimétrica (TGA), e para a avaliação morfológica dos nanocompósitos foi utilizado microscopia eletrônica de varredura (FEG-MEV).

10.1590/s1517-707620180004.0599

Cite

Citations (1)

Effect of carbon nanotubes reinforcement on the mechanical properties of alumina and ZTA composites for ballistic application

Cerâmica (2018)

Carlos Alberto de Oliveira Couto S. Ribeiro Fábio Roberto Passador

Abstract Toughened and hardened alumina/carbon nanotubes and zirconia-toughened alumina (ZTA)/carbon nanotubes nanocomposites were developed by conventional ceramics route using pressureless sintering for the ballistic application. The multiwall carbon nanotubes (CNT) were functionalized with nitric acid oxidation reaction. Moreover, the surfactants sodium dodecyl sulphate and gum arabic were used to promote a homogeneous distribution of CNT in the ceramic matrix. Ceramic powders were prepared with pure alumina, alumina with the addition of 20 wt% of tetragonal zirconia/yttria, alumina/CNT and ZTA/CNT with the addition of 0.1 and 0.5 wt% of CNT. The morphology of nanocomposites was characterized by SEM-FEG. The mechanical properties of sintered samples were evaluated by flexural bending, Vickers microhardness and fracture toughness by SEVNB method. The addition of CNT in the ceramic and composite caused a general increase in densification, hardness, flexural strength and fracture toughness. ZTA composite with the addition of 0.1 wt% of CNT yielded the best results.

Ceramic matrix composite

10.1590/0366-69132018643722475

Cite

Citations (19)