Showing papers on "Polytetrahydrofuran published in 2009"

Concentration Fluctuations, Local Order, and the Collective Structure of Polymer Nanocomposites

Abstract: A combined theory−experiment analysis of adsorbing polymer mediated structural reorganization of silica nanoparticles in equilibrated and miscible poly(ethylene oxide) (PEO) and polytetrahydrofuran (PTHF) nanocomposites is presented. Quantitative comparison of microscopic liquid state theory calculations with small-angle X-ray scattering experiments demonstrate the theoretical approach properly accounts for the effects of adsorbed polymer layers on nanoparticle concentration fluctuations over all length scales for a wide range of volume fractions and interfacial cohesion strengths. The mixture total packing fraction is increased as particles are added to the polymer melt in order to account for equation-of-state effects which are important at very high filler loadings. A distinctive microphase separation like peak in the collective polymer structure factor is predicted. Nanoparticle potential of mean force calculations suggest a criterion for the onset of depletion or bridging induced kinetic gelation whi...

Synthesis and characterization of shape-memory polyurethane films with blood compatibility

Abstract: Shape memory polyurethane with different hard and soft segment based on aromatic diisocyanate (MDI) and polytetrahydrofuran (PTHF) or Polyethylene glycol (PEG) were synthesized by the prepolymer method. Glass transition temperature was tested by DSC. XRD results showed that the series of shape memory polyurethane has no crystallinity. And the shape memory behavior was also discussed. The results showed that the shape memory polyurethane made up of TMP-PTHF(1000)-MDI (2:1:5) performs better. It can recover 80% of original shape within one more second in the range of 37-45°C. SMPU films with PTHF as soft segment have good blood compatibility.

Aqueous coating material, a method for the production thereof and the use thereof

Abstract: The invention relates to an aqueous coating material, containing at least one polyurethane, which is saturated, unsaturated and/or grafted with olefinically unsaturated compounds and stabilized ionically and/or non-ionically, characterized in that the coating material contains between 0.5 and 30% by weight of polytetrahydrofuran, based on the total weight of the coating material.

Preparing polyurethane foam, useful as a cleaning sponge for e.g. cleaning tubes, comprises mixing and reacting polyisocyanate, blowing agent (water) and optionally chain extenders, catalyst, and other auxiliaries and/or additives

Abstract: Preparation of a polyurethane foam (I) with a density of 70-300 g/dm 3>and 1-20 cells/cm, comprises mixing and reacting polyisocyanate obtained by reacting diisocyanates e.g. methanediisocyanate, with non-polar polyetherols obtained by alkoxylation of 2 to 4-hydric alcohols with propylene oxide and/or butylene oxide, and/or polytetrahydrofuran, and polar polyetherols obtained by alkoxylation of 2- to 4-hydric alcohols with ethylene oxide and propylene oxide, a blowing agent comprising water, and optionally chain extenders, a catalyst, and other auxiliaries and/or additives to form (I). Preparation of a polyurethane foam (I) with a density of 70-300 g/dm 3>and 1-20 cells/cm, comprises mixing and reacting polyisocyanate obtained by reacting diisocyanates comprising methanediisocyanate and/or naphthalene diisocyanate, with non-polar polyetherols obtained by alkoxylation of 2 to 4-hydric alcohols with propylene oxide and/or butylene oxide and/or polytetrahydrofuran, and polar polyetherols obtained by alkoxylation of 2- to 4-hydric alcohols with ethylene oxide and propylene oxide, where the proportion of oxyethylene units, based on all oxyalkylene units, is at least 15 wt.%, and the isocyanate content of the polyisocyanate is 3-14%, a blowing agent comprising water, and optionally chain extenders, a catalyst, and other auxiliaries and/or additives to form (I) An independent claim is included for the polyurethane foam made by the method.

High-solid content polyurethane resin composition and preparation method thereof

Abstract: The invention relates to a polyurethane resin composition and a preparation method thereof Formula of raw materials of the composition expressed by weight percentage comprises: polyglycol butylene glycol adipate diol as polyester polylol, polytetrahydrofuran diol as polyether glycol, ethylene glycol as a chain-extension agent, toluene diisocynate as polyisocyanate, and ethyl acetate as solvent; during the process of synthesizing and preparing the polyurethane resin composition, ethanol solution of hydrogen chloride as a sealer is added after pre-polymer is synthesized and before the chain-extension agent is added for chain extension reaction The chain extension reaction is suspended and restrained by the sealer, so no curing happens during the preparation of the polyurethane resin composition in the technical scheme, the viscosity is low, fluidity is good, and coating process for preparing synthetic leather is not affected; on the other hand, the product system is easy to store for good stability, and no crystallization during storage

SYNTHESIS AND CHARACTERIZATION OF POLY(AMINO ACID-UREA)S COMPRISING NOVEL TRIBLOCK COPOLYMERS OF POLY(TETRAHYDROFURAN) AND POLY(γ-BENZYL L-GLUTAMATE)S

Abstract: A kind of novel triblock copolymers of poly(γ-benzyl L-glutamate)-b-poly(tetrahydrofuran)-b-poly(γ-benzyl L-glutamate)s (PBLG-b-PTHF-b-PBLG) was synthesized by using bis(3-aminopropyl) terminated polytetrahydrofuran to initiate the ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride (BLG-NCA). The corresponding multiblock poly(amino acid-urea)s were prepared in one-pot protocol from the chain extension of PBLG-b-PTHF-b-PBLG with MDI. The resulting triblock and multiblock copolymers were characterized by FTIR, 1H-NMR, 13C-NMR and GPC techniques. It is demonstrated that the chain extension has taken place to give rise to the copolymers with the well-defined block composition and narrow molecular weight distribution. A distinct Tg arising from the hard-segments was observed in all the copolymers. Their mechanical properties showed an increasing trend with the molecular weight enhancement of the prepolymers.

Multiblock copolymer sequence of dihydroxytelechelics comprising at least one polytetrahydrofuran block and at least two polymer diol blocks, useful for preparing polyurethanes, which is useful as a binder for energetic materials

Abstract: Multiblock copolymer sequence of dihydroxytelechelics (A) comprising at least one polytetrahydrofuran block and at least two polymer diol blocks, where the polymer diol contains primary hydroxyl function, is claimed. Multiblock copolymer sequence of dihydroxytelechelics (A) comprising at least one polytetrahydrofuran block and at least two polymer diol blocks, where the copolymer has polytetrahydrofuran-polyethylene oxide structure of formula (HO-pOE-b-pTHF-b-pOE-OH) (I); and the polymer diol contains primary hydroxyl function, is claimed. pTHF : polytetrahydrofuran block; and pOE : poly(ethylene oxide) block. An independent claim is included for a process for preparing (A) comprising: cationic polymerization of tetrahydrofuran under anhydrous inert atmosphere, in the presence of at least one primer that generates two reactive ends to the macromolecule, to obtain a polytetrahydrofuran difunctional oxonium (a); and reaction of at least one polymer diol having primary hydroxyl functions with (a).

Polyether type polyester hot melt adhesive and production technology thereof

Abstract: The invention discloses a polyether type polyester hot melt adhesive and production technology thereof. The polyether type polyester hot melt adhesive comprises the following components: 40 to 50 percent of terylene, 30 to 45 percent of dihydric alcohol containing ether bonds, and 8 to 15 percent of zinc acetate. The production technology for the polyether type polyester hot melt adhesive comprises the steps of: A, alcoholyzing, namely the terylene, polytetrahydrofuran and the zinc acetate are mixed; B, adding ethane diacid, and performing an esterification reaction on paratoluenesulfonic acid; C, adding tetrabutyl titanate and triphenyl phosphite for a copolycondensation reaction; and D, discharging, pelletizing, then performing cold grinding at a temperature of 120 DEG C below zero, and finally sizing, inspecting, packaging and entering a warehouse. The production technology has the advantages that the production technology adopts the terylene to substitute dihydric alcohol as a main raw material (the terylene can be leftovers during the production of polyesters, some leftovers during spinning tabletting of polyester fiber and waste terylene products in daily life), effectively reduces production cost, and protects ecological environment at the same time.