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Showing 1 to 20 of 36 for “"imidization"”.
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Siloxane modified engineering polymers: synthesis and characteristics
… the imidized homo- and copolymers. The first imidization process, conducted on solution cast poly(amic acid) films, employed stepwise heating cycles to 300°C. Quantitative thermal imidization was also achieved in solution at temperatures in the 140 to 170°C range. This novel method of …
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Kinetic and mechanistic investigations of polyimide formation and characterization of their blends with polybenzimidazoles
… based upon polyimides and polybenzimidazole. Imidization kinetics were successfully followed by the quantitative non-aqueous titration of the amic acid functional groups as a function of reaction conditions. The homogeneous solution imidization processes were described by auto-acid catalyzed …
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Synthesis of poly(arylene ether sulfone)-polyimide segmented copolymers
… copolymers were synthesized using a solution imidization procedure with NMP as the solvent and o-dichlorobenzene as the azeotroping agent. The polysulfone oligomers were reacted into the system via the diamine oligomer. The segmented copolymers demonstrated good solubility characteristics, …
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Structure-property behavior of polyimide homopolymers, copolymers, and blends
… method involved the utilization of a solution imidization technique in converting the poly(amic acid) intermediate to the fully cyclized polyimide. Another important method was the incorporation of a monofunctional reagents to obtain controlled endgroups and molecular weights. Structural …
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Characterization of modified polyimide adhesives
… copolymers prepared by bulk and solution thermal imidization were investigated as structural adhesives for titanium. The solution thermal imidization procedure was found to result in favorable adhesive characteristics while the presence of siloxane segments in the polymer backbone improved the …
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Synthesis and characterization of perfectly alternating segmented copolymers comprised of poly(dimethylsiloxane)s and engineering thermoplastics
… and poly(arylene ether sulfone)) or by solution imidization using a controlled excess of the diamine monomer. A solution imidization method was developed for the segmented copolymerization that simplified the typically two-step, two-solvent method into a one-step approach with a single solvent. …
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Investigation of the heating and curing rate of polymeric materials with thermal energy, continuous and pulsed microwave radiation
… as the agitation rate was increased, the rate of imidization of poly(amic acids) with microwave radiation approached the rate of thermal imidization, at constant temperature. However, more research is required to clarify this complex phenomenon.
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A process simulation model for the manufacture of composite laminates from fiber-reinforced, polyimide matrix prepreg materials
… through the composite microstructure during the imidization reaction. The volatile formation model can be used to predict the vapor pressure profile and volatile mass flux. The second part of the simulation model, the consolidation model, can be used to determine the degree of crosslinking, resin …
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Synthesis and Characterization of Novel Polyimide Gas Separation Membrane Material Systems
… using either the two-step ester-acid solution imidization or the high temperature solution imidization routes. High molecular weight soluble fully cyclized polyimides were successfully synthesized using a 1:1 molar ratio of dianhydride to diamine. The polyimides were film forming and were …
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Manipulation of Carbon Nanostructures for Multifunctional Composite Materials
… (PAA) solution at 100 psi followed by thermal imidization to obtain fibers reinforced with polyimide (PI). The tensile strength was increased form 68 to 215 MPa for SWCNT fibers after VPI and imidization. Surfactant-wrapped chemically converted graphene (CCG) sheets obtained from the hydrazine …
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Novel high performance thermosetting polyimides
… oligomers were synthesized via solution imidization techniques, using the ester-acid derivatives of various dianhydrides and various aromatic diamines. A "one pot" procedure utilizing NMP as the solvent and o-dichlorobenzene as the azeotroping agent reproducibly exhibit fully imidized …
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Structure-property behavior of novel high performance thermoplastic and thermoset structural adhesives and composite matrix resins
… well-defined phthalimide endgroups via solution imidization. They were characterized by intrinsic viscosity, DSC, TGA, and thermomechanical measurements. Molecular weight control was successful and these polyimides were thermally stable via dynamic TGA up to 500°C. Flame resistance was suggested …
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Synthesis of functional polyimide and its application in nanostructured films
… treatment at lower temperature than typical imidization temperature. Less dense Langmuir-Blodgett films can be fabricated with modified polyimide followed by thermal treatment. Silver nanoparticles/ polyimide composite Langmuir-Blodgett films were fabricated successfully using immersion …
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Donor-Sigma-Acceptor (D-sigma-A) Molecules With Perylenebisimide Acceptors Having Alkyl or Peg Swallowtails With Sulfur or Hydroxyl Anchors: Synthesis and Applications in Langmuir-Blodgett Films, Single Molecule Spectroscopy (SMS), G-Quadruplex Studies and Passivation of Gold Nanoparticles
… Williamson ether synthesis and simultaneous imidization as key reactions. A dozen different swallowtail amines were attached to the perylenetetracarboxylic acceptor by imidization to make unsymmetrical perylene bisimides (PBI 's). Several donors, with different ionization energies, have been …
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Synthesis and characterization of soluble, high temperature aromatic polyimides
… synthetic route utilizing solution imidization techniques and diester-diacid derivatives of various commercially available dianhydrides. "One pot" syntheses were conducted using a solvent system of N-methylpyrrolidinone and σ-dichlorobenzene at temperatures of 170°C to 180°C and …
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Adhesion study of thermoplastic polyimides with Ti-6Al-4V alloy and PEEK-graphite composites
… number of diamines and dianhydrides via solution imidization, polydimethylsiloxane segment incorporation and molecular weight control with non-reactive phthalimide end-groups. The adhesive bond performance of these polyimides was investigated as a function of molecular weight, siloxane …
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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
… bases to form poly(amic acid) salts. The imidization conditions, and chemistry of the conversion of the poly(amic acid) salts to imide were studied, with the aim of maintaining the targeted molecular weight distribution and properties analogous to a control polyimide. For the above …
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Polymer-Metal–Organic Framework (MOF) Mixed-Matrix Membranes for Gas Separation Applications
… of covalently tethered oligomers through various imidization routes. Upon embedding these post-synthetically modified (PSM) MOFs in high molecular weight polymers, defect-free MMMs were formed, revealing synergistic improvements in both permeability and selectivity due to enhanced interfacial …
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Photocrosslinkable polyimide and poly(imide siloxane) homo- and copolymers: synthesis and characterization
… polyimides were obtained by use of a solution imidization procedure which utilized a cosolvent system of N-methyl-2-pyrrolidinone and N-cyclohexyl-2-pyrrolidone at temperatures of approximately 170°C. The fully imidized polyimides were soluble in a variety of solvents. The homo- and copolymers …
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Synthesis and characterization of high performance polyimide homopolymers and copolymers
… cyclodehydrated by either thermal or solution imidization at high temperatures to give the fully cyclized polyimides. This research focuses on the development of a low temperature solution polymerization route utilizing a transimidization method to make fully cyclized polyimide homopolymers and …
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