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Showing 1 to 18 of 18 for “"Poly(amic acid)"”.
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Synthesis and Characterization of Wholly Aromatic, Water-Soluble Polyimides and Poly(amic acid)s Towards Fire Suppression Foams
Polyimides epitomize one of the most versatile high-performance engineering polymers. Polyimides are inherently mechanically robust, chemically inert, and thermooxidatively stable to 400+ °C depending on their chemical structure, enabling their function in numerous aerospace, electronic, medical, …
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The preparation of high performance polymers for composites and blends: A) thermally stable ion containing polymers B) epoxy and hydroxy functional polyolefin macromers
… or soluble high performance ion containing polymers to be used as composite system interfacial modifiers and processing aids. In the first approach, thermally stable pyridine containing poly(ary/ene ether)s were designed which could be ionized by protonation in acidic aqueous media. A novel …
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Siloxane modified engineering polymers: synthesis and characteristics
Novel, polyand weight, randomly coupled, poly(imide siloxane) segmented copolymers were prepared and characterized. The copolymers were synthesized in two steps, the first involving the generation of soluble poly(amic acid) intermediates through reaction of various aromatic dianhydrides and …
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Synthesis and characterization of poly-(p-phenylene pyromellitamic acid)
<p>"Poly-(p-phenylenepyromellitamic acid)s have been synthesized over the weight average molecular weight range from 8,000 to 22,000 by reaction of pyromellitic dianhydride and p-phenylenediamine in dimethylformamide. The polymers were recovered as amorphous yellow powders having planar dimensions …
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Synthesis and characterization of high performance polyimide homopolymers and copolymers
Polyimides are generally formed by combining a dianhydride and a diamine monomer in a polar aprotic solvent to form a poly(amic acid). The poly(amic acid) is then cyclodehydrated by either thermal or solution imidization at high temperatures to give the fully cyclized polyimides. This research …
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Adhesion of novel high performance polymers to carbon fibers: fiber surface treatment, characterization, and microbond single fiber pull-out test
… of carbon fibers to several high performance polymers, including a phosphorus-containing bismaleimide, a cyanate ester resin, and a pyridine-containing thermoplastic, was evaluated using the microbond single fiber pull-out test. The objective was to determine the chemical and mechanical …
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Structure-property behavior of polyimide homopolymers, copolymers, and blends
Fully imidized, high molecular weight polyimide homopolymers and random segmented poly(siloxane imide) and poly(aryl ether imide) copolymers were prepared for use as environmentally stable, tough structural matrix resins, structural adhesives, and dielectric materials. Although polyimides are well …
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The application of siloxane modified polyimides as high performance textile coatings
Novel poly(imide siloxane) copolymers were prepared and developed as high performance fiber coatings. These copolymers were synthesized and characterized extensively as a function of chemical composition. The polyimides were then utilized to coat prototype fibers which were subsequently evaluated …
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Photocrosslinkable polyimide and poly(imide siloxane) homo- and copolymers: synthesis and characterization
… glass transition temperature, photocrosslinkable polyimide and poly(imide siloxane) homo- and segmented copolymers were prepared and characterized. The polyimides were synthesized by the classical two step method of first preparing soluble poly(amic acid) prepolymers by the reaction of various …
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Synthesis and Characterization of High Performance Polymers for Gas Separation and Water Purification Membranes and as Interfacial Agents for Thermplastic Carbon Fiber Composites
… and characterization of high performance polymers, specifically polybenzimidazoles (PBIs) for gas separation applications and polyimides (PI) for water purification and as interfacial agents for thermoplastic carbon fiber composites. Two methods for improving the gas transport properties …
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The synthesis and characterization of semicrystalline polyimides
Polyimides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]-hexafluoropropane (BDAF) and pyromellitic dianhydride (PMDA) displayed a glass transition temperature (Tg) at 306°C and a melting point (Tm) near 470°C as measured by differential scanning calorimetry (DSC) with a heating rate of 10°C/min. …
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Cresol Novolac/Epoxy Networks: Synthesis, Properties, and Processability
… and using an excess of formaldehyde. A dynamic equilibrium reaction was proposed to occur which allowed the targeted molecular weight to be obtained. A 2000 g/mol ortho-cresol novolac resin was crosslinked by a diepoxide oligomer and by an epoxidized phenolic oligomer in defined weight …
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Structure-property behavior of novel high performance thermoplastic and thermoset structural adhesives and composite matrix resins
Soluble, thermally stable phosphorus containing polyimides have been synthesized to controlled molecular weights and well-defined phthalimide endgroups via solution imidization. They were characterized by intrinsic viscosity, DSC, TGA, and thermomechanical measurements. Molecular weight control was …
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Synthesis and characterization of high Tg nanofoams based on pyromellitic dianhydride and 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane polyimide block and graft copolymers
Thermally stable polyimide block and graft copolymers with labile con1ponents (especially polypropylene oxide), have been prepared and investigated as low dielectric materials that afford desirable thermal, mechanical and electrical properties. Polyimide nanofoams based upon the controlled …
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Synthesis and Characterization of Thermosetting Polyimide Oligomers for Microelectronics Packaging
… has been prepared in either fully cyclized or amic acid precursor form. Soluble oligomers have been synthesized with controlled molecular weights ranging from 2- to 12 Kg/mol. Molecular weight characterization was performed using SEC (size exclusion chromatography) and 13C-NMR, revealing good …
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Synthesis and Characterization of Poly(siloxane imide) Block Copolymers and End-Functional Polyimides for Interphase Applications
End-functional poly(ether amic acid)s and poly(siloxane imide) multiblock copolymers, comprised of 2,2'-Bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) / meta-phenylene diamine (MPDA) and hexafluoroisopropylidene-2-bis(phthalic acid anhydride) (6FDA) / meta-phenylene diamine (MPDA) …
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Advancing Vat Photopolymerization of Photosensitive Polyimides: Process-Structure-Property Relationships
Vat photopolymerization (VPP) is a robust additive manufacturing (AM) technology which can produce products with high resolution features, smooth service finish, and at relatively high throughput. These advantages are leveraged in applications like jewelry manufacturing as well as dental and …
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Design and synthesis of novel nanometallic catalysts and electrode materials for green fuel cells
… carbon electrode. The catalyst was tested in acidic media. The typical SEM images showed the near spherical Pt structures with diameters in a range of 50–120 nm. The general size of the PtCr nanoparticles were determined to be around 105 nm and the surface aggregates were from 400 nm to 1µm at …