Polyurethane–unsaturated polyester interpenetrating polymer networks: thermal and dynamic mechanical thermal behaviour

Ramis, Xavier; Cadenato, A.; Morancho, J. M.; Salla, Josep María

doi:10.1016/s0032-3861(01)00492-x

Cited by 74 publications

(51 citation statements)

References 35 publications

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“…A similar peak in the loss factor for the 90% copolymer content was also observed for the composition using the 1400 g·mol -1 PTMG, as well as broader transitions for samples containing <90 weight percentages of copolymer. This suggests that several different relaxation mechanisms are present in the produced network, and they may be related to the nano-heterogeneity of the system [10,17]. In the case of the TEGDMA-based graft-IPNs, all samples presented broad transitions, also suggesting a high level of heterogeneity in the system.…”

Section: Thermo-mechanical Characterizationmentioning

confidence: 94%

“…As shown in Table 2, the storage modulus values for the system using the 1400 g·mol -1 PTMG are inferior to those of the 650 g·mol -1 . This reduction in the storage modulus may be explained by the higher mobility that a longer macrodiol provides to the PU network [10]. When analyzing the storage modulus of the TEGDMA-based samples (see Table 2), it can be seen that the substitution of a single double bond monomer (MMA) in the copolymer for a monomer with two double bonds (TEGDMA) had a major impact on the storage modulus.…”

Section: Thermo-mechanical Characterizationmentioning

confidence: 99%

“…Nevertheless, IPNs usually present some degree of phase separation at some stage of the synthesis. For instance, it has been observed that synthesis of IPNs by simultaneous method results in phase separation [10]. Phase separation in sequential polymerization has also been observed, here, the entropy of mixing is lost during the second polymerization, due to the increase in size of the molecules as the polymerization continues [4].…”

Section: Introductionmentioning

confidence: 99%

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Sequential graft-interpenetrating polymer networks based on polyurethane and acrylic/ester copolymers

Ballestero¹,

Sundaram²,

Tippur³

et al. 2016

Express Polym. Lett.

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Abstract. Highly transparent and tough graft-interpenetrating polymer networks (graft-IPNs) were synthesized using an elastomeric polyurethane phase (PU) and a highly stiff acrylate-base copolymer phase. The grafting points between the two networks were generated with the purpose of minimizing the phase separation process of the polymeric systems. In order to generate the grafting between the networks, an acrylic resin capable of undergoing both free radical and poly-addition polymerization was employed. The thermo-mechanical properties, fracture toughness properties as well as network and surface phase morphology of the graft-IPNs synthesized were evaluated in this work. Data obtained suggested that the minimization of the phase separation was achieved by the generation of crosslinking points between both networks. High transparency was obtained in all samples as an indication of the high level of interpenetration achieved. The relative high values obtained for the fracture toughness tests suggest that generating chemical crosslinks between networks is a good approach for increasing the fracture toughness of polymeric materials.

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Section: Thermo-mechanical Characterizationmentioning

confidence: 94%

Section: Thermo-mechanical Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sequential graft-interpenetrating polymer networks based on polyurethane and acrylic/ester copolymers

Ballestero¹,

Sundaram²,

Tippur³

et al. 2016

Express Polym. Lett.

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“…The balance between the surface hydrophilic and hydrophobic properties is important for achieving an enhanced biocompatibility of polyurethanes. Plasma treatments or other types of stimuli may alter the surface energy of most polymers, thus changing their surface polarity, hydrophilicity and adhesiveness, (Desai et al, 2000;Ozdemir et al, 2002;Ramis et al, 2001). In Table 1 The measurement methods used for determination of surface tension are based on contact angles between the liquid meniscus and the polyurethane surface.…”

Section: Wwwintechopencommentioning

confidence: 99%

Natural-Based Polyurethane Biomaterials for Medical Applications

Macocinschi¹,

Filip²,

Vlad³

2011

Biomaterials Applications for Nanomedicine

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“…La densidad de entrecruzamiento de los poliuretanos se obtuvo usando la siguiente Ecuación de Flory-Rehner. [12][13][14] (4) vc = Número efectivo de cadenas entrecruzadas; V 1 =Volumen molar del solvente; x 12 = Parámetro de interacción solvente-polímero; V = V 0 /V donde V 0 = Volumen del polímero sin hinchar (seco) y V = Volumen del polímero hinchado en el punto de equilibrio.…”

Section: Caracterización De Elastómeros De Poliuretanounclassified

Poliuretanos elastoméricos obtenidos a partir de aceite de ricino y almidón de yuca original y modificado con anhídrido propiónico: síntesis, propiedades fisicoquímicas y fisicomecánicas

Valero¹,

Pulido²,

Ramírez³

et al. 2010

Quím. Nova

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Recebido em 28/5/09; aceito em 9/11/09; publicado na web em 23/3/10 POLYURETHANE ELASTOMERS FROM CASTOR OIL AND CHEMICALLY MODIFIED YUCCA STARCH: SYNTHESIS AND PHYSICAL-CHEMICAL, PHYSICAL-MECHANICAL AND THERMICAL PROPERTIES. Chemical modification of cassava starch was conducted through an acylation reaction by using pyridine and propionic anhydride to replace the functional groups of starch. Polyurethane elastomers were prepared using suspensions of the mixture obtained from castor oil and yucca starch that was modified by a propionic anhydride reaction. The suspensions were characterized by means of tests based on The Fourier Transform Infrared Spectroscopy and the Hydroxyl Index. The castor oil-AMP suspensions were used for the PU synthesis. The PUs were characterized by their physical-mechanical properties like tension-deformation and Shore A. hardness, thermal gravimetric analysis and swelling test. The density cross-linking of from swelling tests was determined by applying the Flory-Rehner equation.Keywords: polyurethane elastomers; cassava starch; acylation. INTRODUCCIÓNLa síntesis de elastómeros de poliuretano (PU) y el estudio de sus propiedades ha recibido notable atención. Recientes desarrollos de mezclas de polímeros con almidón modificado y sin modificar muestran que las propiedades de los PUs cambian debido a la incorporación de esta molécula en la matriz de PU.1 Desai y colaboradores utilizaron el almidón como agente entrecruzante en elastómeros de PU.2 El principal problema que hallaron al adicionar almidón al PU fue el carácter hidrofílico de la molécula en contraste con el carácter hidrofóbico de la estructura de PU. Este contraste produce una baja adhesión interfacial entre los gránulos de almidón y la matriz de PU. Santayanon y Wootthikanokkhan incorporaron almidón de yuca modificado por reacción de acilación con anhídrido propiónico a un sistema de PU previamente sintetizado.3 Este estudio reveló que la molécula de almidón modificado tuvo mayor afinidad con la estructura de PU de carácter hidrofóbico, debido a que al modificar el almidón los grupos hidroxilo de carácter hidrofílico presentes cambiaron a grupos éster de carácter hidrofóbico.Trabajos previos realizados en el grupo de investigación utilizando almidón de yuca sin modificar en sistemas de poliuretano obtenidos a partir del aceite de ricino original y modificado por transesterificación, revelaron que el esfuerzo máximo y la elongación de ruptura aumentan. Este efecto se debe primordialmente a que el almidón actuó como relleno reforzante del material. Es decir, la densidad de entrecruzamiento no varía, por que el almidón refuerza la red pero no hace parte de ella. [4][5][6] En este trabajo se modificó el almidón de yuca por medio de una reacción de acilación, usando como reactivo anhídrido propiónico y piridina como catalizador. Las variables del diseño fueron la temperatura de preactivación, el tiempo de preactivación y la temperatura de acilación. El proceso se llevó a cabo usando un diseño de experimentos factorial 2 3 . El objet...

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Polyurethane–unsaturated polyester interpenetrating polymer networks: thermal and dynamic mechanical thermal behaviour

Cited by 74 publications

References 35 publications

Sequential graft-interpenetrating polymer networks based on polyurethane and acrylic/ester copolymers

Sequential graft-interpenetrating polymer networks based on polyurethane and acrylic/ester copolymers

Natural-Based Polyurethane Biomaterials for Medical Applications

Poliuretanos elastoméricos obtenidos a partir de aceite de ricino y almidón de yuca original y modificado con anhídrido propiónico: síntesis, propiedades fisicoquímicas y fisicomecánicas

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