Investigation of the relationships between the chain organization and rheological properties of atactic poly(vinyl alcohol) hydrogels

Ricciardi, Rosa; Gaillet, Christine; Ducouret, Guylaine; Lafuma, F.; Lauprêtre, F.

doi:10.1016/s0032-3861(03)00246-5

Cited by 92 publications

(99 citation statements)

References 19 publications

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“…Our neutron scatting data for isotropic samples support the picture developed by Kanaya 22,23 using SANS and Willcox et al 20 using SAXS, TEM, and 13 C NMR, and recently extended by Ricciardi et al [25][26][27][28][29][30] using SANS, XRD, and solid-state 1 H NMR, that the PVA hydrogel is composed of two distinct phases: a somewhat homogeneous polymer-rich phase (polymer mesh) formed of swollen amorphous regions (nanopores) of size 15-30 nm cross-linked by smaller PVA crystallites, surrounding polymer-poor domains (micropores) with a characteristic length scale of >100 nm, which is presumably the pore structure left behind by melted ice created during the freeze-thaw process. The small value of the correlation length ∼ 3 nm relative to the characteristic mesh length scale (∼18 nm) determined from our data indicates a low degree of order (i.e., random crystallite sites).…”

Section: Discussionsupporting

confidence: 88%

SANS Characterization of an Anisotropic Poly(vinyl alcohol) Hydrogel with Vascular Applications

et al. 2007

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Poly(vinyl alcohol) (PVA) hydrogels are formed by physical cross-linking through freeze/thaw cycles. By controlling the stress applied during the freeze/thaw process, anisotropic PVA hydrogels can be produced. An anisotropic PVA hydrogel conduit that mimics the nonlinear and anisotropic mechanical properties displayed by porcine aorta was developed. Preliminary structural characterization of isotropic and anisotropic PVA samples using small-angle neutron scattering reveals a polymer mesh cross-linked by crystallites spaced by about 18 nm and, most importantly, that the anisotropic properties are due to large-scale (>100 nm) structures alone; the geometry of the polymer mesh and crystallites remains largely unaltered. Controlling the properties of these anisotropic PVA hydrogels promises a broad range of potential applications in biomedical devices, such as coronary bypass grafts, where compliance mismatch between the implanted synthetic graft and the surrounding tissue has been identified as a major cause of failure.

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Section: Discussionsupporting

confidence: 88%

SANS Characterization of an Anisotropic Poly(vinyl alcohol) Hydrogel with Vascular Applications

et al. 2007

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“…The similar tendency of G# varying with the frequency was found, but G# showed weak dependency of frequency. Storage modulus (G') is a good measure of material stiffness [50], the larger G' reflects the larger strength of the material [51,52]. Figure 4a showed that the incorporation of PVP increased the G' much when compared with pure PVA hydrogels.…”

Section: Compressive Mechanical Properties 341 Unconfined Uniaxialmentioning

confidence: 99%

Effects of polymerization degree on recovery behavior of PVA/PVP hydrogels as potential articular cartilage prosthesis after fatigue test

Yan¹,

Xiong²,

Peng³

et al. 2016

Express Polym. Lett.

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Abstract. Poly (vinyl alcohol)/poly (vinyl pyrrolidone) (PVA/PVP) hydrogels with various polymerization degrees of PVA were synthesized by a repeated freezing-thawing method. The influence of polymerization degree on microstructure, water content, friction coefficient, compressive fatigue and recovery properties of PVA/PVP hydrogels were investigated. The results showed that higher polymerization degree resulted in larger compressive modulus and lower friction coefficient. The fatigue behaviors of PVA/PVP hydrogels were evaluated under sinusoidal compressive loading from 200 to 800 N at 5 Hz for up to 50 000 cycles. The unconfined uniaxial compressive tests of PVA/PVP hydrogels were performed before and after fatigue test. During the fatigue test, the height of the hydrogel rapidly decreased at first and gradually became stable with loading cycles. The compressive tangent modulus measured 0 h after fatigue was significantly larger than the values obtained before test, and then the modulus recovered to its original level for 48 h after test. However, the geometry of hydrogels could not return to the original level due to the creep effects. PVA/PVP hydrogels prepared with lower polymerization degree showed better recovery capability than that prepared with high polymerization degree.

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“…O padrão de difração do PVA foi analisado com base na estrutura monoclínica para a célula unitária (a=7,81 Å; b=2,52 Å; c=5,51 Å e =91 o 42'). [9][10][11] A quitosana foi avaliada segundo a estrutura ortorrômbica (a=8,9Å, b=10,25Å e c=17,0Å) e monoclínica com =88 o .…”

Section: Difração De Raios-xunclassified

Preparação e caracterização de blendas de quitosana/poli(álcool vinílico) reticuladas quimicamente com glutaraldeído para aplicação em engenharia de tecido

Junior¹,

Mansur²

2008

Quím. Nova

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Recebido em 3/10/07; aceito em 14/3/08; publicado na web em 1/9/08 PREPARATION AND CHARACTERIZATION OF CHITOSAN/POLY(VINYL ALCOHOL)BLEND CHEMICALLY CROSSLINKED BY GLUTARALDEHYDE FOR TISSUE ENGINEERING APPLICATION. In this study, novel Chitosan/PVA based films were chemically crosslinked by glutaraldehyde, under pH=(4,00 ±0,05), in order to achieve structures tailored for wound tissue engineering applications. Both precursors and developed films were characterized by FTIR, SEM and XRD in order to determine the presence of chemicals groups and nanostructural order, respectively. The results have shown that the glutaraldehyde crosslinking have altered the crystallinity of pure chitosan and the increase on the C=N bands and simultaneous decrease on NH 2 bands suggested that Chitosan/GA crosslinking has preference to occur in carbon-2 of the saccharide ring by the Schiff's base reaction. Also, FTIR spectroscopy clearly showed that crosslinking has also taken place with blends of PVA and chitosan. The mechanical properties presented high degree dependence with on the increase of the content of chitosan and glutaraldehyde. The results have indicated that, by controlling the ratio [PVA]/[chitosan] in the blends and the extent of chemical crosslinking, it was possible to tailor the hybrid network produced aiming to obtain properties of interest for the specific application.Keywords: chitosan; poly(vinyl alcohol); crosslinking. INTRODUÇÃONum sentido amplo a engenharia de tecidos visa fabricar partes de órgãos e tecidos de organismos vivos para sua substituição. Esse ramo do conhecimento tem se desenvolvido devido à crescente demanda por órgãos e tecidos em função de acidentes e/ou tratamentos de enfermidades diversas.1 De forma a suprir essa necessidade, as blendas de polímeros naturais e sintéticos têm se mostrado uma alternativa viável, pois é possível trabalhar diversas propriedades a fim de viabilizar as características específicas de cada aplicação.A quitosana (QUI) é um polímero obtido principalmente a partir da desacetilação alcalina da quitina, a qual é o segundo polí-mero natural mais abundante depois da celulose e é encontrado nos exoesqueletos de artrópodes e alguns fungos. Ela tem propriedades interessantes para aplicação em engenharia de tecido, tais como biocompatibilidade, biodegradabilidade, acelera a recuperação de lesões, reduz o nível do colesterol sanguíneo, estimula os efeitos do sistema imunológico, além de ter se mostrado um composto bacteriostático e fungistático, 2 bem como os resultados de sua degradação em organismos vivos que são as glicosaminas, substâncias não tóxicas. Uma das características mais importantes deste polissacarídeo é o seu grau de desacetilação (GD) que representa a proporção de resíduos acetilados ainda presentes no mesmo, após o processamento para sua obtenção. A quitosana se degrada pela hidrólise enzimática e apresenta cinética de degradação aparentemente relacionada ao grau de cristalinidade que é controlado principalmente pelo GD, 3 entretanto sua resistência mecânica e s...

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Investigation of the relationships between the chain organization and rheological properties of atactic poly(vinyl alcohol) hydrogels

Cited by 92 publications

References 19 publications

SANS Characterization of an Anisotropic Poly(vinyl alcohol) Hydrogel with Vascular Applications

SANS Characterization of an Anisotropic Poly(vinyl alcohol) Hydrogel with Vascular Applications

Effects of polymerization degree on recovery behavior of PVA/PVP hydrogels as potential articular cartilage prosthesis after fatigue test

Preparação e caracterização de blendas de quitosana/poli(álcool vinílico) reticuladas quimicamente com glutaraldeído para aplicação em engenharia de tecido

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