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Showing 1 to 20 of 98 for “"Isocyanate"”.
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Non-isocyanate routes to urethane-polymers
The conventional synthetic route to urethane polymers involves the use of hazardous dflsocyanates which are synthesised using phosgene, the use of which produces a significant chlorine-waste stream. The processing of high molecular mass specialty polyurethanes regularly requires the use of organic …
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Characterization of the wood/isocyanate bondline
Polymeric diphenylmethane diisocyanate, pMDI, is a wood adhesive that provides excellent composite board properties. Much is unknown about the specific mechanism of pMDI/wood adhesion under conditions that are typical of wood gluing operations. The present research describes the use of ¹⁵N …
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Stabilisation of isocyanate cross linked polybutadiene binder
Isocyanate cross-linked hydroxy terminated polybutadiene is used as a binder for solid rocket propellant. Rocket motors containing this propellant require a storage life of at least 20 years. During storage it has been found that the important rubbery properties of the binder can be lost due to …
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Characterization of PF Resol/Isocyanate Hybrid Adhesives
… PF, and organic polymeric methylenebis(phenylisocyanate), pMDI, are the two primary choices for the manufacture of exterior grade wood-based composites. This work addresses simple physical blends of pMDI dispersed in PF as a possible hybrid wood adhesive. Part one of this study examined the …
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Wood/Polymeric Isocyanate Resin Interactions: Species dependence
The performance of polymeric diphenylmethane diisocyanate (PMDI) resin is known to be highly dependent on the wood species. This species dependence may be due to differences in: cure chemistry, interphase morphology, or both of these factors. This study addresses aspects of the cure chemistry and …
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Studies of PF Resole / Isocyanate Hybrid Adhesives
… (PF) resole and polymeric diphenylmethane diisocyanate (PMDI) are two commonly used exterior thermosetting adhesives in the wood-based composites industry. There is an interest in combining these two adhesives in order to benefit from their positive attributes while also neutralizing some of …
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Crosslinking of cotton cellulose by lignin-isocyanate copolymer
… carbamate by reacting phenol and Tolylene diisocyanate (TDI) in a 1:1 mole ratio. Reaction of the above prepolymer with the modified lignin (HP- EL) using a mole ratio of 1:20 to form a lignin carbamate. The lignin carbamate finish was crosslinked to cotton cellulose fabric through carbamoyl …
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Isocyanate-derived organic aerogels: polyurethanes, polyureas, polyamides and polyimides
… by organic aerogels derived from multifunctional isocyanates through reaction with (a) alcohols (polyurethanes); (b) water (polyureas); (c) carboxylic acids (polyamides); and, (d) acid anhydrides (polyimides). All processes are invariably single-step, one-pot and take place at room temperature or …
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Optimization and characterization of asphalts modified with isocyanate modifier
… as reactive mono- and oligomeric aromatic diisocyanate. Besides the formation of covalent bonds with polar species present in asphalt, the conversion of B2last into polymer could also be anticipated. In this thesis, a soft conventional asphalt was modified by B2last. The development of …
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Structure-property relationships of lignin-based isocyanate and amine adhesives for wood
… were reacted with polymeric methylene diphenyl diisocyanate (PMDI) and hexamethoxy-methyl-melamine (HMMM) to form polyurethane and polyether wood adhesives respectively. Adhesive performance in shear block tests indicated: (a) that the combination of lignin and PHDI reduced the adhesive strength …
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Determination of the molecular structure of Sulphonyl Chloride Isocyanate using microwave spectroscopy
… was used to determine whether sulphonyl chloride isocyanate (SO₂CINCO) exists as a mixture of 71° and 110° isomers or as a single 94° isomer where the angle is the dihedral angle between the S-Cl bond and N = C bond, and whether the NCO group is linear or not. The microwave spectrum of SO₂CINCO …
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Synthesis and Characterization of methylene bis (p-cyclohexyl isocyanate)-poly (tetramethyl oxide) based Polyurethane Elastomers
… characterization of methylene bis (p-cyclohexyl isocyanate/butanediol) (HMDI/BD) based polyurethanes used in connection with surface-active anti-microbial polyurethanes. Previously studied polyurethanes having an isophorone diisocyanate/butanediol (IPDI/BD) hard block contaminated water during …
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Addition of carbonyl fluoride to organic and inorganic nitriles
… to form the corresponding α,α-difluoroalkyl isocyanate, perfluoroalkyl isocyanate, or α,α,ω,ω-tetrafluoro- α,ω-diisocyanatoalkane. With acetonitrile the reaction proceeded slowly in anhydrous hydrogen fluoride or hydrogen chloride to yield a clear colorless liquid which was identified by …
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Preparation and Cycloaddition Reactions of Oxazoline Nitrogen Oxides
… and the related pyrroline N-oxides with phenyl isocyanate, dimethyl acetylenedicarboxylate, methyl phenylpropiolate, phenylpropiolonitrile, methyl acrylate, and acrylonitrile were carried out. The reaction of 4,4-dimethyl-2-phenyloxazoline N-oxide with acetylenic dipolarophiles in concentrated …
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Synthesis and Structure Assignments of Novel Azolinone Ribonucleosides
… rings onto 2,3,5-tri-O-benzoylribofuranosyl isocyanate. Reaction of 2,3,5-tri-O-benzoylribofuranosyl isocyanate with (alpha)-aminoacetaldehyde diethyl acetal gave N-(2,2-diethoxyethyl)-N'-(beta)-D-(2,3,5-tri-O-benzoylribofuranosyl)-4-imidazolin-2-one in the presence of acid. Addition of …
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Morphology of water-blown flexible polyurethane foams
… content was varied from 2 to 5 pph at a constant isocyanate index of 110. A portion of each foam was thermally compression molded into a plaque. The morphology of the foams and plaques was investigated using DMS, DSC, FTIR, TEM, SEM, swelling, WAXS, and SAXS. A high degree of phase separation …
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Cure studies of network-forming polyurethanes
… with polymeric methylene diphenyl diisocyanate (MDI) was studied via dynamic mechanical thermal analysis (DMTA). HPC/MDI and HPL/MDI resins flow at 30°C and proceed to cure at 50°C. The latter has excellent thermal stability over the former. Crosslinking of HPL and HPC with MDI follow …
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Hindered urea bond for the design of dynamic materials
… and allows reversible dissociation of HUB to isocyanate and hindered amine. The dynamic properties of HUB enables the design of self-healing polymeric elastomers/malleable thermosets through bond exchange and hydrolyzable polymers through quenching of dissociative intermediate – isocyanate. …
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Preparation and properties of N-pentafluorosulfanylamido derivatives
… was prepared from pentafluorosulfanyl isocyanate and aniline. Attempts to prepare the mixed urea from pentafluorosulfanylamine and phenyl isocyanate failed. A possible product from a reaction of thiazyl trifluoride and aniline was either ΦN=S(F₂) ≡ N. Attempts to prepare …
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Microencapsulation of reactive amines and isocyanates and their application to self-healing systems
… failed to recover. Microcapsules containing isocyanate are also prepared by means of interfacial polyurea condensation. These capsules are also isolated and analyzed for content, and shown to contain reactive isocyanate. No healing was observed with these capsules, however, due to problems …
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