Ionized‐Air‐Treated Curaua Fibers as Reinforcement for Phenolic Matrices

Trindade, Wanderson G.; Paiva, Jane Maria Faulstich de; Leão, Alcides Lopes; Frollini, Elisabete

doi:10.1002/mame.200800016

Cited by 23 publications

(23 citation statements)

References 27 publications

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“…Para a determinação do teor de umidade da fibra a norma ABNT (NBR9656) foi seguida [33,34] . O teor de umidade encontrado para a fibra de curauá no presente trabalho foi de 8,0 ± 0,2% [32] .…”

Section: Caracterização Da Fibraunclassified

“…O teor de umidade encontrado para a fibra de curauá no presente trabalho foi de 8,0 ± 0,2% [32] . O teor de lignina foi determinado pelo método Klason [35] , fundamentado na hidrólise ácida dos polissacarídeos e, conseqüente separação e determinação gravimétrica da lignina insolúvel em ácido sulfúrico (72%) [33,34] . O teor de lignina Klason total presente na fibra em estudo foi de 5,2 ± 0,1% [32] .…”

Section: Caracterização Da Fibraunclassified

“…O teor de lignina Klason total presente na fibra em estudo foi de 5,2 ± 0,1% [32] . Para determinar o teor de cinzas da fibra de curauá, esta foi previamente extraída em cicloexano/etanol e em seguida com H 2 O, sendo então a norma TAPPI T211 om-85 [ASH,1991] seguida [33,34] . O teor de cinzas na fibra de curuá foi de 0,50 ± 0,1% [32] .…”

Section: Caracterização Da Fibraunclassified

“…A determinação do teor de holocelulose (celulose + hemicelulose) foi realizada de acordo com o método descrito na norma TAPPI T19 om-54, o qual é baseado na eliminação de lignina via reação com clorito de sódio. As fibras de curauá utilizadas foram previamente submetidas à extração com cicloexano/etanol [33,34] . A determinação do teor de celulose foi realizada com as amostras resultantes da determinação do teor de holocelulose.…”

Section: Caracterização Da Fibraunclassified

“…Secou-se a celulose obtida em estufa de circulação de ar (105 °C) até massa constante. O teor de α-celulose foi calculado pela diferença de massa, antes e após o tratamento da amostra com solução de NaOH 17,5% [33,34] . O teor de hemicelulose (29,6 ± 0,2%) e α-celulose (63,4 ± 0,9) encontrados no presente trabalho são superiores ao da fibra utilizada em trabalhos prévios [32] .…”

Section: Caracterização Da Fibraunclassified

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Preparação e caracterização de biocompósitos baseados em fibra de curauá, biopolietileno de alta densidade (BPEAD) e polibutadieno líquido hidroxilado (PBHL)

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Resumo: Neste trabalho, foram utilizadas fibras de curauá como reforço de matriz termoplástica de biopolietileno de alta densidade. O polietileno foi obtido por polimerização de eteno, gerado do etanol de cana de açúcar. Este polímero é também chamado de biopolietileno (BPEAD), por ser preparado a partir de material oriundo de fonte natural. Desta forma, pretendeu-se contribuir para desenvolver materiais que, dentre outras propriedades, causem menor emissão de CO 2 para a atmosfera na sua produção, utilização e substituição, comparativamente a outros materiais. Adicionalmente, polibutadieno líquido hidroxilado (PBHL) foi acrescentado à formulação do compósito, visando a um aumento na resistência à propagação da trinca durante impacto. Os compósitos e as fibras foram caracterizados por várias técnicas, tais como microscopia eletrônica de varredura (MEV), Calorimetria Exploratória Diferencial (DSC), Termogravimetria (TG), além da caracterização dos compósitos quanto à Análise Térmica Dinâmico-Mecânica (DMTA), propriedades mecânicas (impacto e flexão) e absorção de água. A presença das fibras de curauá diminuiu algumas propriedades do BPEAD, como resistência ao impacto. A análise de DMTA mostrou que as fibras geram material mais rígido. Pode-se considerar que a introdução de PBHL na formulação do material foi eficiente, levando a uma resistência ao impacto do compósito BPEAD/PBHL/Fibra maior do que a do compósito BPEAD/Fibra. Palavras-chave: Biocompósito, fibra de Curauá, HDPE. Preparation and Characterization of Biocomposites Based on Curaua Fibers, High-density Biopolyethylene (HDBPE) and Liquid Hydroxylated Polybutadiene (LHPB)Abstract: In this work, curaua fibers were used in the reinforcement of a high-density (HDPE) thermoplastic matrix. The polyethylene used was obtained by polymerization of ethene produced from sugarcane ethanol. This polymer, also called high-density biopolyethylene (HDBPE), was prepared from a natural source material. The aim was to contribute to developing materials which could lead to smaller release of CO 2 into the atmosphere in comparison to other materials. Additionally, liquid hydroxylatedpolybutadiene (LHPB) was added to the composite formulation, aiming at improving resistance to crack spreading during impact. The fibers and their composites were characterized by several techniques, such as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermal gravimetry (TG). The composites were also characterized by dynamic mechanical thermal analysis (DMTA), mechanical properties (flexural and impact strength), and water absorption. The presence of curaua fibers reduced some of the properties of HDBPE, such as flexural and impact strength. DMTA indicated a more rigid material with the fibers incorporated. The addition of LHPB to the formulation was efficient, leading to greater impact strength for the HDBPE/LHPB/Fiber composite, as compared to the HDBPE/Fiber composite.

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Section: Caracterização Da Fibraunclassified

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Preparação e caracterização de biocompósitos baseados em fibra de curauá, biopolietileno de alta densidade (BPEAD) e polibutadieno líquido hidroxilado (PBHL)

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Phenolic Resins and Composites

Frollini

Castellan

2012

Wiley Encyclopedia of Composites

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One of the major contributions of phenolic resins is their use as a matrix in fiber‐reinforced composites to prepare materials with low fire‐smoke toxicity coupled with favorable economics and excellent properties. New formulations became available in the 1980s and were developed mainly to meet requirements of the mass‐transit fire code, which allowed the application of phenolic composites in new areas, such as in mass‐transit car interiors and architectural and marine components. These facts, along with their properties, led to a favorable conjunction for phenolic composites, making them widely used when the requirements of both public and worker safety are of primary importance. Currently, there are basically three types of phenolic resins: the traditional resoles and novolacs and the more recent polybenzoxazines. Lignin, a phenolic biopolymer present in wood and non‐wood plants, is a by‐product of the pulp and paper industry. The growing number of biorefineries in many countries, aiming to convert lignocellulosic wastes into fuels and chemical raw materials, will lead to the availability of large quatities of lignin, which gives it strategic importance as a substitute of phenol in phenolic resins. Aside from lignins, the condensed tannins, also obtained from renewable sources, are suitable to prepare a phenolic‐type polymeric matrix because of the presence of phenolic rings with a larger number of free positions where the electrophilic attack can occur. To decrease the dependence of phenol–formaldehyde (PF) resins on formaldehyde, and hence their formaldehyde emissions, phenolic–furfural (PFu) resins have been developed. In addition, the low vapor tension and low toxicity of glyoxal (OHC–CHO) solutions represent some of the advantages of using glyoxal instead of formaldehyde for many applications. Concerning the reinforcement of phenolic‐type composites, the properties required for a particular application, along with other questions such as cost, define the fiber to be used as reinforcement. The prerequisites for a given application define the fiber length, the diameter, and the need for surface modifications of the fiber, among other characteristics. In addition to the traditional fibers used (as glass, carbon, aramids), agro‐fibers can be mentioned, going by the growing interest this material has aroused. Lignocellulosic fibers are particularly interesting as plastic reinforcements because of their low cost, low density, process flexibility, and modest equipment requirement. These fibers are renewable, widely grown, moldable, anisotropic, nonabrasive, porous, viscoelastic, biodegradable, compostable, and reactive. Lignocellulosic fibers have many hydroxyl groups on the surface, mainly from cellulose and lignin, which may interact easily with the phenolic or lignophenolic polar matrices. The use of nanofibers or nanoparticles as reinforcement can be highlighted, as they can improve several properties of the related composite, such as thermal, flame, chemical, and moisture resistance, and decreased permeability. The set of properties of phenolic‐type matrices, as well as both the flexibility to make changes in their formulations and possible use of different reinforcements, in addition to their favorable cost/performance characteristics, place these materials in a prominent position in relation to other thermoset matrix composites.

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Composites based on renewable materials: Polyurethane‐type matrices from forest byproduct/vegetable oil and reinforced with lignocellulosic fibers

Ramires

Oliveira

Frollini

2013

J of Applied Polymer Sci

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The use of products and byproducts from the agro-industry and forest biorefinery is essential for the development of value-added and low environmental-impact materials. In this study, polyurethanes were prepared using sodium lignosulfonate (NaLS) and castor oil (CO) as reagents and were used to prepare composites reinforced with lignocellulosic fibers, namely, curaua and coir fibers (30 wt %, 3 cm length, and randomly oriented). The SEM images of fractured surfaces of the composites revealed excellent adhesion at the fiber/matrix interface of both coir and curaua composites, which probably resulted from the favorable interactions between polar groups, as well as amid low polarity domains that are present in both the matrix and the reinforcements. The composites exhibited different impact/flexural and strength/flexural moduli (NaLS/CO/Curaua ¼ 465 Jm À1 /44 MPa/2 GPa; NaLS/CO/Coir ¼ 180 Jm À1 /25 MPa/1 GPa). The higher tensile strength/aspect ratio of the curaua fibers (485 MPa/259) compared with that of the coir fibers (120 MPa/130) most likely contributes to the enhanced performance of its composite.

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Ionized‐Air‐Treated Curaua Fibers as Reinforcement for Phenolic Matrices

Cited by 23 publications

References 27 publications

Preparação e caracterização de biocompósitos baseados em fibra de curauá, biopolietileno de alta densidade (BPEAD) e polibutadieno líquido hidroxilado (PBHL)

Preparação e caracterização de biocompósitos baseados em fibra de curauá, biopolietileno de alta densidade (BPEAD) e polibutadieno líquido hidroxilado (PBHL)

Phenolic Resins and Composites

Composites based on renewable materials: Polyurethane‐type matrices from forest byproduct/vegetable oil and reinforced with lignocellulosic fibers

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