Elasticity and inelasticity of thermoplastic polyurethane elastomers: Sensitivity to chemical and physical structure

Morphological features and thermal and mechanical response in segmented polyurethane elastomers based on mixtures of isocyanates

“…9 As a general observation for the materials studied, on first loading, the tensile modulus and the strain energy recovery on cycling (hysteresis) at 300% strain were found to increase significantly with increase in hard phase degree of crystallinity, achieved primarily by use of DBDI, with ethylene glycol (EG) or butylene glycol as chain extenders, instead of the conventional rigid 4,4-diphenylmethane diisocyanate (MDI) as diisocyanate. As shown, the origin of these effects was intimately related to the nanoscale structure of the elastomers through the degree of phase segregation and the size and perfection of the hard domains.…”

“…The present work is part of a wider study [8][9][10][11][12] of the effects on constitutive response of systematically varying the key structural variables: hard segment, soft segment and crosslinking. Such variations in composition lead to significant changes in the key mechanical properties of the elastomer, such as stiffness, strain recovery and strain energy recovery.…”

“…The latter is a novel diisocyanate, also now available commercially, first synthesized in our (Romanian) laboratory. [8][9][10][11][12] Rotation around the central -CH 2 -CH 2 -bond in DBDI allows alignment of successive aromatic rings thus favoring the tendency of crystallization which involves the DBDI hard phase. [9][10][11][12] The chain extender EG and the soft segment macrodiol polyethylene adipate (PEA) of molar mass 2000 g mol À1 were considered.…”

Cyclic stress-strain behavior of polymeric nonwoven structures for the use as artificial leaflet material for transcatheter heart valve prostheses

“…Polyurethanes, in particular, have been applied in view of their relatively low thrombogenicity and good blood compatibility characteristics [2]. Thermoplastic polyurethanes are randomly segmented copolymers composed of hard and soft segments forming a two-phase microstructure [4][5][6]. The presence of hard domains in segmented polyurethanes is very important regarding mechanical properties.…”

Procesado, modelización y caracterización de mezclas industriales de SEBS con materiales con cambio de fase (PCM) para la mejora del confort térmico en aplicaciones de ortopedia y puericultura

“…Boukakri estudia el impacto del envejecimiento del material sobre sus propiedades mecánicas, así como la afección por radiación ultravioleta. Buckley [Buckley, et al, 2010] analiza la sensibilidad del TPU a nivel elástico en base a la estructura del mismo. Lawandy propone un análisis para la optimización del proceso de inyección del TPU basado en la temperatura, por medio del fallo a fatiga y el esfuerzo de deformación.…”