The properties of polyurethanes with mixed chain extenders and mixed soft segments

Ahn, Tae Oan; Jung, Soonuk; Jeong, Han Mo; Lee, Sang Won

doi:10.1002/app.1994.070510105

Cited by 51 publications

(25 citation statements)

References 10 publications

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“…All the prepared polymers have a single loss modulus peak, which cor responds to the glass transition of soft segments T gs [6]. As is seen, the T gs of PEE is lower than that of PBIs, this phenomena could be attribute to the introduction of PEG segments in the PBIs, which shows a higher glass transition temperature than PTMG [24,25]. Besides, the T gs of PBIs showed a shift to a higher value as the concentration of the branching increased.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Synthesis and characterizations of branched poly(butylene isophthalate)-co-poly(tetramethylene glycol)-co-poly(ethylene glycol) fibers with excellent low temperature elastic recovery

2015

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To improve the low temperature elastic recovery and tensile properties of the traditional poly(ether ester), a series of randomly branched poly(ether ester)s consisting of poly(butylene isophthalate) as hard segment, poly(tetramethylene glycol) and poly(ethylene glycol) as mixed soft segment, and trimeth ylolpropane as trifunctional monomer were synthesized. The structure and composition of the samples were characterized by 1 H NMR and FTIR spectroscopy. The tensile strength, elongation at break and the low temperature elastic recovery were used to characterize the mechanical properties of the synthetic polymers.The results indicate that the branched poly(ether ester) showed an increment of mechanical and thermal properties with the increasing content of branching agent in the polymer matrix. Moreover, the low temper ature elastic recovery and tensile properties of branched poly(ether ester) were superior comparing to the tra ditional poly(ether ester)s.

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Section: Mechanical Propertiesmentioning

confidence: 99%

Synthesis and characterizations of branched poly(butylene isophthalate)-co-poly(tetramethylene glycol)-co-poly(ethylene glycol) fibers with excellent low temperature elastic recovery

2015

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“…20 The strain level applied to remove the PU part surface can be compromised. The defects introduced by microgels can be overcome by perwill depend on the device geometry.…”

Section: Tensile Experimentsmentioning

confidence: 99%

Molding of biomedical segmented polyurethane delamination events and stretching behavior

Abraham

Frontini

Cuadrado

1998

J. Appl. Polym. Sci.

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Segmented polyurethane devices for medical applications are generally processed by the solution-casting technique. The processing parameters in the molding and demolding stages strongly affect the physicochemical properties of the finished articles. Thus, the solution concentration, immersion cycle and drying temperature, type of mold (material and geometry), additives, and the drying time between the casting of successive layers define the surface and bulk properties of the manufactured articles. In this work, new commercially available medical-grade segmented polyurethanes were processed by two techniques to obtain multilayer films. Processing parameters were chosen to ensure the generation of a coating with the desired structural and surface characteristics. In the solution-casting technique, multiple dipping of the preshaped former into the polymer solution were used to obtain proper film thickness. Thin and uniform plaques were produced by the spin-casting technique. The two materials selected have different chemical compositions: one is an aromatic poly(ether urethane urea) (Biospan TM ) and the other an aromatic ether-free polyurethane (Chronoflex TM ). An analysis of the possibility of delamination events, considering the influence of surface-modifying additives and drying times, is presented. The freeze-fracture surface appearance is qualitatively described by SEM. In addition, tensile properties are determined and their influence on demolding and assembling procedures are also discussed.

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“…This network proves to be more stable in the case of elevated temperatures, to mechanical loading and to low‐molecular‐mass liquids, as compared with labile networks of inter‐chain physical bonds . Significant amounts of various hydrogen‐bonded associates in polyurethanes, formation of micro‐dispersive hard phases and the use of soft segments with various structures in these materials create prerequisites to control the properties of polyurethane materials …”

Section: Introductionmentioning

confidence: 99%

New diurethane plasticizers for polyurethane thermoplastics and perspective functional composites

Tereshatov

Senichev

2014

J of Applied Polymer Sci

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A method to synthesize low‐molecular‐mass diurethane compounds via reaction between diisocyanates and various primary and secondary alcohols was presented. A number of diurethanes with the melting points below 100oC were revealed. These diurethanes can be used as fusible plasticizers for thermoplastic polyurethanes (TPU) and for high‐filled composites based thereupon. TPU based on oligotetramethyleneoxide diol and on 4,4′‐diphenylmethane diisocyanate and containing 30% of fusible diurethanes were produced. In the presence of such plasticizers, a 3‐order increase in magnitude of the melt flow index was demonstrated. Data evincing significantly larger strength values of TPU and of tungsten‐containing high‐filled composites (94.2 wt %), comparing with thermoplastics plasticized with low‐molecular‐mass liquids, were presented. The mechanism of this phenomenon attributed to the partial crystallization of diurethanes in TPU compositions was described. Samples of low‐toxic thermoplastic polyurethane having density value of 9.4 g/cm3 and meant for protection of various facilities from radioactive radiation, instead of highly toxic metallic, lead, were prepared. Issues of improving the frost resistance of this new type of TPU were considered. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41481.

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The properties of polyurethanes with mixed chain extenders and mixed soft segments

Cited by 51 publications

References 10 publications

Synthesis and characterizations of branched poly(butylene isophthalate)-co-poly(tetramethylene glycol)-co-poly(ethylene glycol) fibers with excellent low temperature elastic recovery

Synthesis and characterizations of branched poly(butylene isophthalate)-co-poly(tetramethylene glycol)-co-poly(ethylene glycol) fibers with excellent low temperature elastic recovery

Molding of biomedical segmented polyurethane delamination events and stretching behavior

New diurethane plasticizers for polyurethane thermoplastics and perspective functional composites

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