Thermoplastic Polyurethane Elastomer UV Stabilization

Abstract

Germany m the Main Scientific Laboratories first, of I. G. Farbenindustrie and then Farbenfabriken Bayer has spawned a giant industry which continues to proliferate today. In the course of this development the chemical industry has built great capacity to produce various di-and poly-isocyanates and polyols as well as added capacity to produce certain diamines, glycols, and urethane polymerization catalysts.Everything considered, polyurethane elastomer formation by the poly-addition process must be termed unique among commercial polymerization reactions. It is perhaps the most obviously dependent on the broad precepts of stoichiometric organic chemistry, responding predictably to steric, electronic, functional group, and catalyst effects through a variety of known chemical reactions. This rich chemistry promises to provide important opportunities to the polyurethane chemist for years to come. It produces segmented (block structured) polymer chains which result in heterophase solid polymers having morphology-dependent properties. This morphology is both composition and process-dependent and is capable of regulation by the polymer scientist.It proceeds at moderately rapid rates in bulk or in solution without excessive heat evolution or monomer explosion hazard.It is not an unduly sensitive polymerization and proceeds reasonably well even in the presence of minor reactive impurities and in the absence of ideal stoichiometry. Of course, gross deviations from optimum polymerization conditions are not tolerated. This relative insensitivity enables the production of reasonably stable, terminally reactive, low molecular weight liquid &dquo;prepolymers&dquo; which can be handled by practical methods in air without the absolute exclusion of moisture, to provide cast vulcanizates. Sensitivity to catalysis although high is still reasonable and concentration dependent.The foregoing polymerization characteristics mark the polyurethanes as materials of versatile processability and enable their utilization by casting, thermo-J.

The Inhibition Effects of Wood Light Induced Discoloration Coating with Water-Based Acrylic Varnish

“…Chinese scholars processed the research of light resistance of transparent coating material, the result showed that the light resistance of alkyd varnishes coating material was the best, polyurethane varnish coating material was in the middle, and nitro varnish coating material was the worst [5]. Among them, the aromatic amino acid esters in Aromatic polyurethane varnish would produce quinone of imide derivatives (quinine imides) structure, made aromatic polyurethane varnish film etiolated [6]. But after varnish film etiolated, it could form protective film, filter the light, had a good inhibitory effect of wood light induced discoloration [7].…”

Organic–Inorganic Polyureas with POSS Cages in the Main Chains via Polycondensation of Diamines with Carbon Dioxide

“…Polyurethanes (PUs) are a class of important materials, which are widely applied as thermoplastic elastomers, foams, adhesives, and coatings. − In general, PUs are synthesized via isocyanate routes, i.e., polyaddition of diisocyanate with polyols or polyamines. For multisegmented PUs, a two-step approach is generally used.…”

Organic–Inorganic Linear Segmented Polyurethanes Simultaneously Having Shape Recovery and Self-Healing Properties

“…Polyurethanes (PUs) have widespread applications owing to their versatile properties. − In terms of processing properties, PUs can be divided into thermosets and thermoplastics. Thermoset PUs have been extensively applied owing to their excellent mechanical strengths.…”