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1845 results about "Melt viscosity" patented technology

Liquid crystalline thermosets from ester, ester-imide, and ester-amide oligomers

Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and were end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The resulting reactive end-capped liquid crystal oligomers exhibit a variety of improved and preferred physical properties. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. These properties make the end-capped liquid crystal oligomers highly processable by a variety of melt process shape forming and blending techniques including film extrusion, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injection (RFI), powder molding, pultrusion, injection molding, blow molding, plasma spraying and thermo-forming. Once processed and shaped, the end-capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures. The resulting thermosets display many properties that are superior to their non-end-capped high molecular weight analogs.
Owner:NASA

Ethylene copolymer and process for producing the same, resin composition containing the copolymer, and uses of these

The present invention is intended to provide an ethylene copolymer having excellent mechanical properties and moldability, a process for preparing the copolymer, a resin composition containing the copolymer and uses thereof. The ethylene copolymer has the following properties: the copolymer comprises 90 to 99% by mol of ethylene constituent units and 1 to 60% by mol of C3-20 alpha-olefin constituent units; the ratio (Mz / Mw) of a Z average molecular weight (Mz) to a weight-average molecular weight (Mw), each molecular weight being measured by GPC, is in the range of 10 to 30, and said ratio (Mz / Mw) and the ratio (Mw / Mn) of a weight-average molecular weight (Mw) to a number-average molecular weight (Mn), each molecular weight being measured by GPC, satisfy the relation (Mz / Mw)>(Mw / Mn); the intrinsic viscosity is in the range of 0.5 to 9 dl / g; the ratio (n*0.01 / n*8) of a melt viscosity (eta*0.01) at a shear rate of 0.01 rad / sec, as measured at 190° C., to a melt viscosity (eta*8) at a shear rate of 8 rad / sec, as measured at 190° C., and the intrinsic viscosity (eta) satisfy the relation (eta*0.01 / eta*8)>=0.893x(eta)+1.0; and the absolute value of an activation energy (Ea) of a shift factor of melt viscoelasticity is not more than 4x104 J / mol.K.
Owner:MITSUI CHEM INC

Inorganic powder highly filled polyvinyl alcohol composite material and preparation method thereof

The invention discloses an inorganic powder highly filled polyvinyl alcohol composite material, which consists of the following components in parts by weight: 10-60 parts of polyvinyl alcohol, 30-80 parts of inorganic powder, 5-30 parts of plasticizing agent and 5-15 parts of flow modifying agent. Further, the composite material has the tensile strength of 17.0-75.0 MPa and the breaking elongation of 70-450%, and the melt viscosity is 1.0*10<2> to 5.0*10<3> Pa s at 180 DEG C when the shearing rate is 10<2>-10<3> s<-1>. The invention further discloses a preparation method of the inorganic powder highly filled polyvinyl alcohol composite material. By using the inorganic powder highly filled polyvinyl alcohol composite material and the preparation method, not only can inorganic powder highly filled polyvinyl alcohol be realized, the cost of the composite material be greatly reduced, but also the flowability of the composite material can be guaranteed; the favorable thermoplastic processing of the composite material is realized; the obtained composite material is excellent in combination property; products such as a fiber, a sheet and a thin film can be prepared through a routine thermoplastic processing method; and the inorganic powder highly filled polyvinyl alcohol composite material is used for the fields of writing paper, printing paper, instrument and meter packaging films, wallpaper, heat-insulating gaskets, toys and the like. The preparation method provided by the invention is simple in process and short in flow and industrial production is easy to realize.
Owner:SICHUAN UNIV

Method to prepare processable polyimides with reactive endogroups using 1,3-bis(3-aminophenoxy)benzene

InactiveUS6288209B1Improved solvent resistance and modulus and elevated use temperatureImproved melt processabilityNon-fibrous pulp additionSynthetic resin layered productsPolymer scienceBackbone chain
Polyimide copolymers were obtained containing 1,3-bis(3-aminophenoxy)benzene (APB) and other diamines and dianhydrides and terminating with the appropriate amount of reactive endcapper. The reactive endcappers studied include but should not be limited to 4-phenylethynyl phthalic anhydride (PEPA), 3-aminophenoxy-4'-phenylethynylbenzophenone (3-APEB), maleic anhydride (MA) and nadic anhydride (5-norbornene-2,3-dicarboxylic anhydride, NA). Homopolymers containing only other diamines and dianhydrides which are not processable under conditions described previously can be made processable by incorporating various amounts of APB, depending on the chemical structures of the diamines and dianhydrides used. By simply changing the ratio of APB to the other diamine in the polyimide backbone, a material with a unique combination of solubility, Tg, Tm, melt viscosity, toughness and elevated temperature mechanical properties can be prepared. The copolymers that result from using APB to enhance processability have a unique combination of properties that include low pressure processing (200 psi and below), long term melt stability (several hours at 300° C. for the phenylethynyl terminated polymers), high toughness, improved solvent resistance, improved adhesive properties, and improved composite mechanical properties. These copolyimides are eminently suitable as adhesives, composite matrices, moldings, films and coatings.
Owner:NASA

Method to prepare processable polyimides with reactive endgroups using 1,3-bis (3-aminophenoxy) benzene

Polyimide copolymers were obtained containing 1,3-bis(3-aminophenoxy)benzene (APB) and other diamines and dianhydrides and terminating with the appropriate amount of reactive endcapper. The reactive endcappers studied include but should not be limited to 4-phenylethynyl phthalic anhydride (PEPA), 3-aminophenoxy-4'-phenylethynylbenzophenone (3-APEB), maleic anhydride (MA) and nadic anhydride (5-norbornene-2,3-dicarboxylic anhydride, NA). Homopolymers containing only other diamines and dianhydrides which are not processable under conditions described previously can be made processable by incorporating various amounts of APB, depending on the chemical structures of the diamines and dianhydrides used. By simply changing the ratio of APB to the other diamine in the polyimide backbone, a material with a unique combination of solubility, Tg, Tm, melt viscosity, toughness and elevated temperature mechanical properties can be prepared. The copolymers that result from using APB to enhance processability have a unique combination of properties that include low pressure processing (200 psi and below), long term melt stability (several hours at 300 DEG C. for the phenylethynyl terminated polymers), high toughness, improved solvent resistance, improved adhesive properties, and improved composite mechanical properties. These copolyimides are eminently suitable as adhesives, composite matrices, moldings, films and coatings.
Owner:NAT AERONAUTICS & SPACE ADMINSTRATION NASA THE
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