Formation of hydrogels from cellulose nanofibers

Abe, Kentaro; Yano, Hiroyuki

doi:10.1016/j.carbpol.2011.03.028

Cited by 126 publications

(61 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Nanofibra é um termo geral que classifica a celulose que possui pelo menos uma de suas dimensões em escala nanométrica [16] . Um dos tipos de nanofibra, a celulose nanofibrilada (NFC), também é chamada de celulose microfibrilada, microfibrila, nanofibras de celulose, celulose nanofibrilar ou microfibras, são agregados de fibras longas e flexíveis compostas de regiões amorfas e cristalinas com diâmetro de 10 a 100 nm e com comprimento de vários micrometros, possuem elevada área superficial e elevada razão de aspecto [16][17][18][19][20] . Este tipo de nanofibra é obtido, geralmente, por processo mecânico, sendo que outros processos auxiliares podem ser empregados, tais como processo enzimático, oxidação mediada por N-oxil-2,2,6,6-tetrametilpiperidina (TEMPO), carboximetilação ou acetilação [19,21] .…”

Section: Introductionunclassified

“…O processo mecânico com o uso de moagem por fricção ultrafina é um método de uma única etapa e de alto rendimento, no entanto, possui alto consumo energético para sua operação e é realizado com suspensões aquosas celulósicas de 1% a 3% (m/m) [18,[22][23][24] . Um equipamento utilizado para obtenção de NFC é o moinho fibrilador de moagem ultrafina e seu funcionamento é baseado na passagem da suspensão celulósica entre pedras de moagem, enquanto que uma das pedras é estacionária, a outra é mantida a rotações entre 1500 e 3000 rpm e o material a ser moído é submetido a forças cisalhantes de corte que causam o rompimento da estrutura individualizando as fibras, obtendo NFC [17][18][19][20][21][22]25] . Para utilização da NFC em materiais poliméricos, como ela geralmente é processada como uma suspensão aquosa, é necessário realizar a secagem dessa fibra celulósica.…”

Section: Introductionunclassified

See 1 more Smart Citation

Obtenção de espumas flexíveis de poliuretano com celulose de Pinus elliottii

et al. 2017

View full text Add to dashboard Cite

ResumoNeste trabalho foram desenvolvidas espumas flexíveis de poliuretano com a adição de celulose de Pinus nas concentrações de 0,5; 1 e 2% (m/m). A celulose foi submetida ao processo de fibrilação mecânica e posterior secagem por aspersão (spray dry) sendo caracterizada quanto a sua morfologia por MEV e MET. As espumas foram produzidas pelo método de batelada (one-shot) com a adição e mistura da fibra junto ao poliol. As espumas foram caracterizadas por MEV, densidade aparente e resistência à compressão. Os principais resultados indicam que a fibrilação mecânica promove a obtenção de fibras em escala nanométrica, porém durante a secagem, ocorre aglomeração ocasionando aumento para escala micrométrica. As propriedades mecânicas da espuma obtiveram acréscimos de 40 e 50% na resistência à compressão com a adição de 0,5 e 1% de celulose, respectivamente, evidenciando seu potencial como aditivo alternativo para o desenvolvimento de espumas de poliuretano. Palavras-chave: celulose, espuma, fibrilação, poliuretano, spray dry. AbstractIn this work, flexible polyurethane foams were developed with the addition of Pinus cellulose at concentrations of 0.5; 1 and 2 wt%. The cellulose was subjected to mechanical fibrillation process and subsequent dried by spray dry process. It was characterized morphologically by SEM and TEM. The foams were produced by one-shot method by adding and mixing the fiber with the polyol. The foams were characterized by SEM, apparent density and compression strength. The main results indicate that the mechanical fibrillation promotes the obtainment of nanoscale fibers, but during the drying process, agglomeration occurs causing an increase reaching the micrometer scale. The mechanical properties of the foam increased by 40 and 50% in compressive strength with the addition of 0.5% and 1% of cellulose, respectively, showing its potential as an alternative additive for the development of polyurethane foams.

show abstract

Section: Introductionunclassified

Obtenção de espumas flexíveis de poliuretano com celulose de Pinus elliottii

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Many initial difficulties are now overcame and advances have been made concerning their obtention, surface modification and processing [5] . Derivated from natural fibers, bacteria or algaes, cellulose nanomaterials are versatiles materials that are now applied in nanopapers [6] , hydrogels [7] , composites [8] , electronic [9] , biomedicine [10] , etc. Being a versatile material, cellulose processing can be adjusted to provide different materials as, for example, cellulose nanofibril (CNF) or cellulose nanocrystal (CNC).…”

Section: Introductionmentioning

confidence: 99%

Cellulose nanomaterials: size and surface influence on the thermal and rheological behavior

2018

View full text Add to dashboard Cite

ObstractCellulose nanocrystals (CNC) and nanofibrils (CNF) were obtained by acid hydrolyzis and mechanical treatment, respectively, of cellulosic fibers from paper. Additionally, surface modification was performed for CNC by neutralization (NaOH) and oxidation (TEMPO). The thermal stability, surface properties and rheological behavior of these nanomaterials were compared. A clear difference in CNC surface was found upon neutralization and oxidation treatments, leading to distinct thermal behaviors. Optical and rheological properties were found to be predominantly by the particles size, being strongly affected by inertial effects.

show abstract

“…Cellulose molecular structure is extremely strong as a pile of nanoscale crystalline region [11,12]. It is a linear homopolysaccharide composed of D-glucopyranose units linked together by b-1,4-glycosidic bonds.…”

Section: Introductionmentioning

confidence: 99%

A feasibility study on semi industrial nozzleless electrospinning of cellulose nanofiber

et al. 2015

View full text Add to dashboard Cite

The current study focuses on the production of cellulose nanofiber through semi-industrial nozzleless electrospinning process. The cellulose biopolymer used for spinning process was extracted from rice straw as renewable, abundant, and inexpensive natural resource. The electrospinning device comprising one needle is extremely inefficient because of low productivity level of about 0.3 g/h. Thus, using the nozzleless electrospinning system guarantees the high productivity of nanofiber web for diverse applications. The successful electrospinning process is accomplished through systematic control of the surface tension, viscosity, and electric conductivity of aqueous solutions of cellulose. Moreover, a design expert software was used for providing experimental plan for the investigation of the influence of the operational conditions on the spinning properties of the selected solution. The polyvinyl alcohol with a weight ratio of 60 % relative to cellulose content was used as a biocompatible polymer to facilitate electrospinning process for producing the aqueous cellulose solution of 0.63 wt%. Based on the scanning electron microscopy images, and various selected parameters, namely, the drum rotation rate of 9 rpm, high voltage range of ±55 kV, the spinning temperature of 41°C, and 10-cm distance between drum and collector an average diameter of 89 ± 1 nm was arrived. The composite nanofibers used for filter production and their performance were evaluated by porosity analysis and permeability tests. Results show the negative impact of the weak mechanical strength as an obstacle in Penetration test. (It promotes by higher electrospinning time and reaching proper stiffness in web layer.) The permeability tests show a maximum value of 3.5 cm 3 /cm 2 /s at the maximum pressure of 120 Pa.

show abstract

Formation of hydrogels from cellulose nanofibers

Cited by 126 publications

References 22 publications

Obtenção de espumas flexíveis de poliuretano com celulose de Pinus elliottii

Obtenção de espumas flexíveis de poliuretano com celulose de Pinus elliottii

Cellulose nanomaterials: size and surface influence on the thermal and rheological behavior

A feasibility study on semi industrial nozzleless electrospinning of cellulose nanofiber

Contact Info

Product

Resources

About