Structural engineering of polyurethane coatings for high performance applications

A mean-field phase diagram for conformationally symmetric diblock melts using the standard Gaussian polymer model is presented. Our calculation, which traverses the weak- to strong-segregation regimes, is free of traditional approximations. Regions of stability are determined for disordered (DIS) melts and for ordered structures including lamellae (L), hexagonally packed cylinders (H), body-centered cubic spheres (QIm3m), close-packed spheres (CPS), and the bicontinuous cubic network with Ia3d symmetry (QIa3d). The CPS phase exists in narrow regions along the order−disorder transition for χN ≥ 17.67. Results suggest that the QIa3d phase is not stable above χN ∼ 60. Along the L/QIa3d phase boundaries, a hexagonally perforated lamellar (HPL) phase is found to be nearly stable. Our results for the bicontinuous Pn3m cubic (QPn3m) phase, known as the OBDD, indicate that it is an unstable structure in diblock melts. Earlier approximation schemes used to examine mean-field behavior are reviewed, and compa...

Unifying Weak- and Strong-Segregation Block Copolymer Theories

Vegetable oils are excellent but very heterogeneous renewable raw materials for polyols and polyurethanes. This review discusses the specific nature of vegetable oils and the effect of their structures on the structure of polyols and polyurethanes. One section is dedicated to polyols for rigid and flexible foams and methods of their preparation such as direct oxidation of oils, epoxidation followed by ring opening, hydroformylation, ozonolysis, and transesterification. The next section deals with preparation and structure‐property relationships in polyurethanes from different groups of polyols, different isocyanates, and different degrees of crosslinking. The final section covers the environmental aspects of bio‐based polyurethanes, i.e., thermal stability, hydrolytic stability, and some aspects of biodegradability.

Polyurethanes from Vegetable Oils

A review of current chemorheological techniques and measurement systems is presented for unfilled and filled thermoset resins. The specific measurement techniques for the kinetics, chemorheology, and modeling of these systems are presented, with particular emphasis on the chemorheological techniques and measuring systems. These techniques and measurement systems provide a greater understanding of traditionally complex thermoset processes, provide effective quality control measures for these processes, and will reduce design and operating costs in associated industries.

Chemorheology of thermosets—an overview

Effect of the degree of soft and hard segment ordering on the morphology and mechanical behavior of semicrystalline segmented polyurethanes

Model butanediol–MDI–polypropylene oxide polymers have been synthesized to explore the structure–property relationships in urethane/polyether polymers. The results of mechanical, thermal, and spectroscopic analyses agree remarkably well. The phase mixing in these polymers decreases with increasing hard-segment length, while the hard-segment stability increases with increasing hard-segment length. This is demonstrated clearly by dynamic mechanical, differential scanning calorimetry, infrared, and NMR studies. The importance of hydrogen bonding to the stability of the hard segment is strongly supported by the variable-temperature infrared experiments. The critical hard-segment size for phase segregation was shown to be two butanediols per hard segment. The temperature limit of the flatness of the storage modulus was tied to the thermal stability of the hard-segment hydrogen bonding which is controlled largely by the length of the hard segment and the extent of the hydrogen bonding.

Model MDI/butanediol polyurethanes: Molecular structure, morphology, physical and mechanical properties

Integrated processes of preparing industrial chemicals starting from seed oil feedstock compositions containing one or more unsaturated fatty acids or unsaturated fatty acid esters, which are essentially free of metathesis catalyst poisons, particularly hydroperoxides; metathesis of the feedstock composition with a lower olefin, such as ethylene, to form a reduced chain olefin, preferably, a reduced chain α-olefin, and a reduced chain unsaturated acid or ester, preferably, a reduced chain α,ω-unsaturated acid or ester. The reduced chain unsaturated acid or ester may be (trans)esterified to form a polyester polyolefin, which may be epoxidized to form a polyester polyepoxide. The reduced chain unsaturated acid or ester may be hydroformylated with reduction to produce an α,ω-hydroxy acid or α,ω-hydroxy ester, which may be (trans)esterified with a polyol to form an α,ω­polyester polyol. Alternatively, the reduced chain unsaturated acid or ester may be hydroformylated with reductive amination to produce an α,ω-amino acid or α,ω-amino ester, which may be (trans)esterified to form an α,ω-polyester polyamine.

Integrated chemical processes for industrial utilization of seed oils

An energy absorbing article having a direction in which impact resistance is desired is formed of extruded thermoplastic foam exhibit anisotropic compressive strength. The extrusion direction of the thermoplastic foam is aligned substantially parallel with the direction in which impact resistance is desired to provide an energy absorbing article exhibiting a high ratio of compressive strength to weight.

Energy absorbing articles of extruded thermoplastic foams

We describe a new modeling approach to prediction of Young's modulus of segmented polyurethanes. This approach combines micromechanical models with thermodynamic considerations based on the theory of block copolymers. The resulting model predicts both the equilibrium morphology and the “ideal” Young's modulus of a segmented polyurethane polymer as a function of its formulation (hard segment chemical structure, hard segment weight fraction, soft segment equivalent weight) and temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2123–2135, 2007

Theoretical modeling of the relationship between Young's modulus and formulation variables for segmented polyurethanes

The invention is a catalytic device comprised of a catalyst support of fused ceramic grains and a catalyst that is surface-bound to at least a portion of the ceramic grains, incorporated into at least a portion of the ceramic grains or combinations thereof, wherein the grains and catalyst form a surface structure that has a box counting dimension of greater than 1.00 or the box counting dimension has at least one step change when measured from a box size “d” of at least about 1 micrometer to at most about 1 millimeter. The invention is particularly useful in making a catalytic converter or catalytic converter-soot trap.

Christopher P. Christenson

Papers

Model MDI/butanediol polyurethanes: Molecular structure, morphology, physical and mechanical properties

Integrated chemical processes for industrial utilization of seed oils

Energy absorbing articles of extruded thermoplastic foams

Theoretical modeling of the relationship between Young's modulus and formulation variables for segmented polyurethanes

Catalytic devices and method of making said devices