Polyurethanes. Mark F. Sonnenschein

the reactants into a transition state geometry for ur...FIGURE 2.48 World (a) capacity and (b) production of isocyanates for polyure...FIGURE 2.49 World toluene production and portion used for manufacturing TDI ...FIGURE 2.50 Simplified block diagram for TDI production.FIGURE 2.51 Preparation of nitrotoluenes from toluene and nitric acid with a...FIGURE 2.52 Pathways and product distributions of dinitrotoluene from mononi...FIGURE 2.53 Preparation of toluenediamines from nitrotoluenes by catalytic h...FIGURE 2.54 Phosgenation of toluene diamines to produce toluene diisocyanate...FIGURE 2.55 First step of the phosgenation process forming the dicarbamoyl c...FIGURE 2.56 Thermolysis of the dicarbamoyl chloride to form the isocyanate a...FIGURE 2.57 Preparation of TDI by reaction of toluene diamines with dimethyl...FIGURE 2.58 Preparation of dimethyl carbonate.FIGURE 2.59 Process for reductive decarbonylation for nonphosgene production...FIGURE 2.60 Simplified proposed mechanism for Pd‐catalyzed reductive carbony...FIGURE 2.61 Nonphosgene preparation of isocyanates via the Curtius rearrange...FIGURE 2.62 Illustrative structures of MDI and pMDI.FIGURE 2.63 Nitration of benzene to nitrobenzene followed by hydrogenation t...FIGURE 2.64 Global usage of aniline in 2018. The vast majority is used for m...FIGURE 2.65 Simplified block diagram for the production of monomeric, polyme...FIGURE 2.66 Structures of 4,4′‐methylene bisphenyldiamine and the MDA polyme...FIGURE 2.67 Mechanism for the production of polymeric and monomeric MDA by r...FIGURE 2.68 1,3,5‐Triphenylhexahydritriazine formed by trimerization of the ...FIGURE 2.69 Phosgenation of MDA and pMDA to form MDI and pMDI.FIGURE 2.70 Side reaction in MDI production between MDA and MDI to form a ur...FIGURE 2.71 Formation of APA – a common impurity in pMDI, usually quantified...FIGURE 2.72 Formation of uretdione, a common undesired side reaction resulti...FIGURE 2.73 Measured percentage molar conversion of MDI monomer to dimer per...FIGURE 2.74 Oxidation processes of isocyanates leading to color in polymers....FIGURE 2.75 Global consumption of major commercial aliphatic isocyanate in 2...FIGURE 2.76 Structures of common and commercially available aliphatic isocya...FIGURE 2.77 Process to produce hexamethylene diamine from adiponitrile.FIGURE 2.78 Phosgenation of hexamethylene diamine to hexane diisocyanates.FIGURE 2.79 Trimerization of acetone to form isophone [161].FIGURE 2.80 Conversion of isophorone to isophorone nitrile, hydrogenation to...FIGURE 2.81 Conversion of MDA to hydrogenated MDA.FIGURE 2.82 Trimerization of aliphatic isocyanates commonly preceding their ...FIGURE 2.83 Conversion of isophorone diamine to isophorone diisocyanates usi...FIGURE 2.84 Ethylene glycol chain extender (in boxes) linking isocyanates th...FIGURE 2.85 Hydrogen bonding between chain‐extended urethane hard segments. ...FIGURE 2.86 Illustration of the origin of the greater stabilization of hard ...

      3 Chapter 3FIGURE 3.1 Urethane structure.FIGURE 3.2 Generally accepted transition state for the uncatalyzed formation...FIGURE 3.3 FTIR spectroscopy of a polyetherpolyol focusing on the OH stretch...FIGURE 3.4 Common catalysts for urethane and urea formation. Trade names are...FIGURE 3.5 Examples of bond polarization mechanisms of catalyst action.FIGURE 3.6 Proposed mechanism of Lewis acid catalysis of urethane formation....FIGURE 3.7 Proposed mechanism of Bismuth carboxylate urethane catalysis. Coo...FIGURE 3.8 Energy‐minimized interaction between water and pentamethylene dip...FIGURE 3.9 Trimerization of isocyanate to isocyanurate.FIGURE 3.10 Proposed mechanism of isocyanurate formation using highly nucleo...FIGURE 3.11 Dynamic mechanical analysis of an aromatic polyurethane showing ...FIGURE 3.12 The reaction of isocyanate and water, forming an amine.FIGURE 3.13 The reaction of amine with an isocyanate to form a urea.FIGURE 3.14 Formation of an allophanate by reaction of a urethane with an is...FIGURE 3.15 Formation of a biuret linkage by reaction of urea with isocyanat...FIGURE 3.16 Dimerization of isocyanate to form the uretdione.FIGURE 3.17 Catalyzed dimerization of isocyanate to form carbodiimide.FIGURE 3.18 Phospholene‐catalyzed formation of carbodiimide.FIGURE 3.19 Proposed trimerization of carbodiimide occurring during high‐tem...FIGURE 3.20 Proposed reaction of carbodiimide to form a six‐member ring duri...FIGURE 3.21 Reaction of carbodiimide and isocyanate to form the industrially...FIGURE 3.22 Reaction of aliphatic isocyanate and carboxylic acid to form the...

      4 Chapter 4FIGURE 4.1 Hard and soft polyurethane segments make for a multiblock copolym...FIGURE 4.2 Representations of polyurethane final structures. (a) An idealize...FIGURE 4.3 Scanning electron micrograph of a 20%/80% (w/w) blend of cross‐li...FIGURE 4.4 Tapping‐mode atomic force microscopy of a thermoplastic polyureth...FIGURE 4.5 Polyurethane elastomer of the same composition as the polyurethan...FIGURE 4.6 Illustrative phase diagram of a polyurethane capable of exhibitin...FIGURE 4.7 Illustrative phase diagram for polyurethane phase decomposition t...FIGURE 4.8 Transmission electron microscopy of a cast polyurethane elastomer...FIGURE 4.9 Graphical representations of the Kerner and Davies equations usin...FIGURE 4.10 Graphical representation of the Budiansky equation using a soft‐...FIGURE 4.11 Graphical representation of the Halpin–Tsai equation (Equation 4...FIGURE 4.12 Graphical representation of the modulus predictions based on a p...FIGURE 4.13 Diagram of the categories of phase‐separated polyurethanes that ...FIGURE 4.14 Illustrative stress–strain curve for a polyurethane elastomer ch...FIGURE 4.15 Illustrative stress–strain curves for polyurethane elastomers of...FIGURE 4.16 Illustrative stress–strain curve for a polyurethane elastomer wi...FIGURE 4.17 The equivalent box model for calculating large strain properties...FIGURE 4.18 Graphical representation of Equation 4.17 calculating the maximu...FIGURE 4.19 Graphical representations of Equations 4.18 and 4.24 showing the...FIGURE 4.20 Graphical representation of the Fox equation (Equation 4.25) rel...FIGURE 4.21 Graphical representation of the Gordon–Taylor equation for varyi...FIGURE 4.22 Graphical representation of the Kwei equation, keeping k at or n...

      5 Chapter 5FIGURE 5.1 Anhydride derivatization of polyols prior to titration of acid en...FIGURE 5.2 ATR Fourier transform infrared (FTIR) spectroscopy of polyethylen...FIGURE 5.3 Integrated OH absorbance versus percentage OH measured. Example c...FIGURE 5.4 Cast polyurethane elastomer: dark areas are hard segment. See Fig...FIGURE 5.5 Illustrative scanning electron micrographs of (a) open cell polyu...FIGURE 5.6 Illustrative TEM images of polyurethanes. (a) Oriented rod‐like h...FIGURE 5.7 Simplified illustration showing sample and signal detection contr...FIGURE 5.8 Potential diagram of attractive and repulsive forces influencing ...FIGURE 5.9 A piece of the foam was embedded in epoxy and then cured. The cur...FIGURE 5.10 ATR‐FTIR spectroscopy of isocyanurate foam. These foams are made...FIGURE 5.11 ATR‐FTIR spectroscopy of flexible foams showing the sensitivity ...FIGURE 5.12 Transmission FTIR spectroscopy of TDI–polyurethane