Polymeric Hydrophilic Hydrogels with Flexible Hydrophobic Chains. Control of the Hydration and Interactions with Water Molecules

Vázquez, Blanca; Román, Julio San; Péniche, Carlos; Cohen, Ma Eugenia

doi:10.1021/ma970863l

Cited by 88 publications

(57 citation statements)

References 26 publications

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“…Hydration degree of the copolymers richer in EHA was around 0.8%, that is, in the order of that presented in commercial intracorneal ring devices. Water contact angle of the copolymers increased up to 79°but in all cases remained lower than values reported for MMA/EHA copolymers of 40/60 to 60/ 40 M ratios, which presented angles around 90° [41], very close to that of the homopolymer [42]. Values of surface energy of solid for copolymers hardly changed with respect to that of PMMA, and they were higher than 31.0 mN m À1 reported for PEHA [40], indicating scarce hydrophobic modification on the surface of the Immunolocalization of a-SMA (red) and DAPI (blue) in hen corneas after materials.…”

Section: Groups/ Treatmentmentioning

confidence: 69%

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

et al. 2010

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a b s t r a c tThe objective of this work was to evaluate the potential use of less stiff materials based on acrylic copolymers of methyl methacrylate/2-ethylhexyl acrylate (MMA/EHA) as devices to correct, stabilize and improve the effect of poly(methyl methacrylate) (PMMA) intracorneal ring segments. MMA/EHA and PMMA intracorneal ring segments were surgically implanted in the corneas of Lohmann Classic hens. The effects of the intracorneal ring segments were assessed by optical measurements and corneal tolerance was evaluated through biomicroscopic examination over a 90-day observation period and by conventional histology. The experimental results demonstrated that the intracorneal ring segments made of MMA/EHA copolymers provided a significant change in the corneal curvature and an improved in vivo response compared to those obtained for PMMA rings, which was attributed to the higher flexibility of the copolymeric materials, indicating that these systems might be considered suitable as an alternative to those currently used, for application in clinical practice.

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Section: Groups/ Treatmentmentioning

confidence: 69%

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

et al. 2010

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“…The swelling properties of the hydrogels were studied using conventional gravimetric method (Vazquez et al, 1997). The swelling behavior of dried hydrogels was monitored as a function and was determined by immersing the completely dried (60°C for 24 h) hydrogel samples in double-distilled water at 37°C.…”

Section: Swelling Property Of Silk Hydrogelmentioning

confidence: 99%

Preparation, characterization and in vitro study of biocompatible fibroin hydrogel

Sah¹,

Pramanik²

2011

Afr. J. Biotechnol.

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In this study, Bombyx mori silk based hydrogels were prepared and their biorelevant properties like physical, chemical and thermal properties were studied. Firstly, silk fibroin aqueous solution was prepared and the molecular weight of fibroin protein was determined followed by particle size analysis for the confirmation of study. Silk fibroin hydrogels were prepared by treating a 12% (w/v) silk fibroin aqueous solution at 4°C (thermgel) and lyophilized. The swelling and thermorheological behaviour of fibroin hydrogels were studied. The morphology and crystalline structure of lyophilized hydrogels were investigated by scanning electron microscopy (SEM) and wide-angle diffractometry, respectively while the surface functional groups were analyzed by FT-IR. The thermal behavior was also studied by means of differential scanning calorimetry and gravimetric method. The cytocompatibility of the hydrogels was evaluated through three-dimensional culture with human peripheral blood mononuclear cells. Lyophilized fibroin gel of high strength and high thermal stability were obtained. The β-crystelline structure of lyophilized fibroin hydrogel has shown excellent swelling capacity to mimic the living tissues. The surfaces of these hydrogels were found supporting to cell adherence and proliferation. hMNCs could survive and proliferate in the gel within 3 weeks, and the gel had good cytocompatibility. It was concluded that fibroin hydrogel not only has interpenetrating network structure but also has good cytocompatibility and could be used as injectable scaffolds able to promote in situ bone regeneration.

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“…Para ello, inicialmente se determinan los incrementos (decrementos) en masa húmeda de un grupo de mezclas autofraguantes usando técnicas gravimétricas clásicas (7,(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) , análogas a las empleadas en el registro del incremento en peso de una muestra de material absorbente en interacción con un absorbato gaseoso para estudios de absorción y difusión en polímeros (7,(10)(11)(12) , vidrios y dieléctricos (13,14) , zeolitas (15 -18) y sólidos inertes (19) en general. Mediante comparación de los incrementos porcentuales en masa húmeda de equilibrio para las diferentes mezclas estudiadas se comparan los poderes higroscópicos de las mismas y se analiza la influencia de sus diferentes constituyentes en la capacidad higroscópica de ellas.…”

Section: La Difusión Transcurre En Un Medio Semiinfinitounclassified

Difusión de humedad en mezclas de moldeo para machos de fundición

Ruiz¹,

Valencia-Morales²,

Villar-Cociña³

et al. 2002

Bol. Soc. Esp. Ceram. Vidr.

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Se describe la difusión de humedad en mezclas de moldeo utilizadas en los procesos de fundición. Empleando técnicas gravimétricas se registra el comportamiento de la cinética de humectación de diferentes tipos de mezclas de moldeo para machos de fundición. La higroscopicidad de las mezclas es comparada usando el criterio del incremento porcentual en masa húmeda. El estudio cinético se concluye con los cálculos de los coeficientes efectivos de difusión del agua atmosférica en las mezclas a distintas intemperies. Para este propósito se emplean métodos de ajuste no lineal. También se analiza la influencia de los materiales aglutinantes y desarenantes en las propiedades higroscópicas de estas mezclas.Palabras claves: Humedad, difusión y mezclas de moldeo. Moisture diffusion in molding mixtures for cores of foundingThe moisture diffusion in molding mixtures employing in foundry processes is described. Using gravimetric techniques the humectation kinetic behavior of different types of molding mixtures for foundry cores were registered. The mixture higroscopicity is compared using the porcentual increase in wet mass. The kinetic study is ending with the calculations effective coefficients of diffusion of the atmospheric water in the mixtures to different bleakness. For this goal the fitting through non lineal methods was used. The influences of the agglutinative and draw materials in the hygroscope properties of these were analyzed too. INTRODUCCIÓNYa desde los años 70 son múltiples las ventajas que hacen retomar la práctica de los moldes de arena frente a las nuevas tecnologías que surgían en las fundiciones de hierro, dado entre otros factores por sus inferiores costos y ausencia de contaminación del medio ambiente (1,2) . Entre las limitaciones de esta práctica se encuentra el deterioro de mezclas para moldes y machos por concepto de su incremento en masa húmeda, como consecuencia de las prolongadas exposiciones a la intemperie (3) . Por ello, la mejora de la calidad en las producciones fundidas, que emplean moldes y machos de arena es un problema necesario y actual.El incremento porcentual en masa húmeda de equilibrio para una mezcla dada a una determinada intemperie puede ser usado como medida del grado de hidratación de la mezcla (4) . Sin embargo, esto es una descripción incompleta del problema. La caracterización integral de la cinética de humectación del material incluye el cálculo de los coeficientes efectivos de difusión del agua ambiental en la mezcla de moldeo (3) . La solución del problema difusivo depende de la geometría que se seleccione (3,5,6) . Por un problema de simplicidad se requiere la elección de las muestras experimentales con geometrías lo más sencillas y apropiadas para los cál-culos.Si una muestra tipo pastilla finita, permeable por una cara e inicialmente seca se expone a una intemperie con humedad constante (3) , se pueden presentar dos situaciones (3,5) : 1. La difusión transcurre en un medio finito, LA DIFUSIÓN TRANSCURRE EN UN MEDIO SEMIINFINITOLa solución del primer problema de contor...

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Polymeric Hydrophilic Hydrogels with Flexible Hydrophobic Chains. Control of the Hydration and Interactions with Water Molecules

Cited by 88 publications

References 26 publications

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

Preparation, characterization and in vitro study of biocompatible fibroin hydrogel

Difusión de humedad en mezclas de moldeo para machos de fundición

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