Polyurethane Elastomers

Introduction.The past and the present of polyurethanes (PUs).Chapter 1Chemistry of PUs1.1.Macrodiols1.2.Chain Extenders (diols and diamines)1.3.Diisocyanates1.3.1Conventional model rigid diisocyanates1.3.1.1.Diisocyanates reactivity with alcohols1.3.1..2.Diisocyanates reactivity with diols1.3.1.3. Secondary reactions of diisocyanates group during polyurethane formation1.3.1.4. Methods to investigate the mechanism of polymer crystallization1.3.2. 4ovel flexible diisocyanates: their versatility to polyaddition processes1.4. PUs preparation methods. The effect of reaction conditions on structure heterogeneityChapter 2Hydrogen bonding in polyurethanes2.1. Hydrogen bond influence on polyurethane formation2.2. Effect of hydrogen bonding on phase separation2.3. Effect of the hard segment nature (crystallizing or not) on hydrogen bonding2.4. Effect of hydrogen bonding on mechanical propertiesChapter 3PUs morphology and thermal behaviour. Crystallinity and phase segregation as revealed by:3.1. Structural studies (WAXS, SAXS, SANS)3.2. Thermal methods (DCS, DMA, TGA, thermal creep)3.3. Morphology (IR dichroism; SEM)3.4.IR spectroscopy3.4. A comparison between conventional PUs based on rigid, hard segments (not crystallizing) and novelPUs derived from the flexible DBDI giving hard segments of constitutional mobility (crystallizing or not).Chapter 4PUs Mechanical Properties4.1.General considerations4.1.1. Influence of Hydrogen bonding on the mechanical properties. (A comparison between PUs withhydrogen bonding and analogous structures but achieved without hydrogen bonding)4.1.1.1. Hydrogen substitution with Deuterium. Deuterated PUs.4.1.1.1.1 Deuterated PUs achieved with deuterated chain extenders.4.1.1.1.2.Deuterated PUs achieved with deuterated macrodiols.4.1.1.2. Hydrogen substitution with inert (-CH3) groups4.1.1.2.1. Partial Hydrogen substitution.4.1.1.2.2. Total Hydrogen substitution4.1.1.Influence of the type of soft segment macrodiol4.1.2. Influence of hard segment nature (crystallizing or not)4.1.3. Influence of the type chain extender.4.1.4. Influence of the polyaddition procedure.4.2. Elasticity and inelasticity. Inelasticity measures.4.2.1 Tensile Modulus.4.2.2 Hysteresis: work input and unrecovered strain.4.2.3.Mullins effect4.3. Creep and Stress RelaxationChapter 5.Sensitivity of elasticity to PUs chemical and physical structure5.1. Variation of cyclic tensile responses with PUs degree of crystallinity5.2. Variation of cyclic tensile responses with PUs degree of phase separation.Chapter 6.PUs strain induced orientation and crystallization6.1. Orientation of structure under tensile deformation as revealed by WAXS and SAXSmeasurements6.2. Orientation and crystallization of PU microstructure as revealed by dichroic measurementsConclusionsPerspectives