- Bis(azobenzene) diamines and photomechanical polymers made therefrom
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Bis(azo-benzene) diamine monomers and a method of synthesizing the monomers are provided. The bis(azo-benzene) diamine monomers, in combination with amine reactive monomers, form polymers, such as polyimides and copolyimides, having photomechanical and thermomechanical properties.
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- Method for preparing 2,2-bis[4-(4-aminophenoxy)phenyl] propane
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The invention belongs to the technical field of polyimide materials and epoxy curing agents and specifically discloses a method for preparing 2,2-bis[4-(4-aminophenoxy)phenyl] propane with low metal ion content. The method comprises the following steps: carrying out a synthetic reaction of nitride 2,2-bis[4-(4-nitrophenoxy)phenyl] propane on 2,2-bis(4-hydroxyphenyl)propane, parachloronitrobenzene and anhydrous potassium carbonate in a system taking N,N-dimethyl formamide as a solvent and taking xylene as a dehydrating agent; taking absolute ethyl alcohol as a solvent, taking Ni-B/C as a catalyst, taking hydrazine hydrate as a reducing agent, and reducing the 2,2-bis[4-(4-nitrophenoxy)phenyl] propane into a target initial product 2,2-bis[4-(4-aminophenoxy)phenyl] propane; and finally, removing the metal ions by using a complex-precipitation method, thereby obtaining the target product. The method disclosed by the invention is low in production cost, high in product purity, low in metal ion content and high in yield, and the electronic grade monomer standard can be met.
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Paragraph 0026; 0027; 0030; 0031; 0035; 0037
(2017/08/28)
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- Multivalent photo-crosslinkable coumarin-containing polybenzoxazines exhibiting enhanced thermal and hydrophobic surface properties
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In this study, mono-, bi-, and trivalent coumarin-containing benzoxazine monomers (mono-, di-, and tri-coumarin BZ) were synthesized in high yield and purity by facile Mannich reactions of 4-methyl-7-hydroxycoumarin and paraformaldehyde with aniline, bisphenol A-NH2, and 1,3,5-tri(4-aminobenzene), respectively, in 1,4-dioxane. 1H and 13C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and high resolution mass spectroscopy support the chemical structures of these three benzoxazine monomers. Differential scanning calorimetry (DSC) and FTIR spectroscopy were used to investigate the curing polymerization behavior and photodimerization ([2π + 2π] cycloaddition) of the coumarin units of mono-, di-, and tri-coumarin BZ to form poly(mono-coumarin BZ), poly(di-coumarin BZ), and poly(tri-coumarin BZ), respectively. DSC measurement revealed that the thermal polymerization temperature of coumarin-containing benzoxazine monomers was lower than that of the model compound 3-phenyl-3,4-dihydro-2H-benzooxazine (263°C) which was attributed to the catalytic effect of the coumarin moiety and a strong electron withdrawing electron conjugated CC bond in the coumarin unit. In addition, the glass transition and thermal decomposition temperatures of poly(tri-coumarin BZ) (Tg = 240°C; Td5 = 370°C) were higher than poly(di-coumarin BZ) and poly(mono-coumarin BZ), consistent with the former's higher crosslinking density. In addition, the water contact angles of poly(tri-coumarin BZ) polymers prepared with and without photo-dimerization prior to thermal curing (112 and 110°, respectively) were higher than the corresponding poly(mono-coumarin BZ) and poly(di-coumarin BZ), presumably because of greater degrees of intramolecular hydrogen bonding between the CO units of the coumarin moieties and the phenolic OH units of the benzoxazine rings, resulting in lower surface free energies. Thus, the presence of multivalent photo-crosslinkable coumarin units enhanced the thermal and hydrophobic surface properties of these polybenzoxazines.
- Lin, Ruey-Chorng,Mohamed, Mohamed Gamal,Hsu, Kuo-Chih,Wu, Jia-Yu,Jheng, Yu-Ru,Kuo, Shiao-Wei
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p. 10683 - 10696
(2016/02/09)
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- Thermo-mechanical and surface properties of POSS reinforced structurally different diamine cured epoxy nanocomposites
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In the present study three structurally different diamines namely bisphenol-A based ether diamine, octane diol based ether diamine, and capron based diamine were synthesized and characterized using FT-IR, 1H-NMR and 13C-NMR spectra. These diamines were used to cure DGEBA epoxy resin and were reinforced with NH2-POSS in different weight percentages (1%, 3% and 5% wt) to obtain epoxy matrices and composites. Data obtained from thermo-mechanical, dielectric and surface studies were compared with those of neat epoxy matrix cured with diamino diphenyl methane (DDM). The surface morphology was ascertained from the XRD and SEM analysis and the presence of POSS in the composites was ascertained from the TEM images. The capron based diamine cured epoxy matrix shows better improvement in tensile strength and impact strength of 39.8% and 137.0% respectively than those of neat epoxy cured with diamino diphenyl methane (DDM). The value of contact angle (91.3°) of the capron based diamine cured epoxy composites infers that the epoxy matrix becomes hydrophobic nature. Data obtained from different studies suggest that the capron diamine cured epoxy matrix can be used in the form of a coating, encapsulant, or a sealant for different industrial and engineering applications for better performance and improved longevity. This journal is
- Sethuraman,Prabunathan,Alagar
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p. 45433 - 45441
(2015/01/09)
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- Impact of backbone rigidity on the photomechanical response of glassy, azobenzene-functionalized polyimides
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Azobenzene-functionalized polyimide materials can directly transduce light into mechanical force. Here, we examine the impact of polymer backbone rigidity on the photomechanical response in a series of linear, azobenzene-functionalized polymers. The rigidity of the backbone was varied by the polymerization of five dianhydride monomers with a newly synthesized diamine (azoBPA-diamine). The azobenzene-functionalized linear polymers exhibit glass transition temperatures (Tg) ranging from 276 to 307 C and maintain excellent thermal stability. The photomechanical response of these materials was characterized by photoinduced cantilever bending as well as direct measurement of photogenerated stress upon exposure to linearly polarized, 445 nm light. Increasing the rigidity of the polymer backbone increases the magnitude of stress that is generated but decreases the angle of cantilever deflection.
- Wang, David H.,Wie, Jeong Jae,Lee, Kyung Min,White, Timothy J.,Tan, Loon-Seng
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p. 659 - 667
(2014/02/14)
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- METHOD FOR PREPARING A POLY(ETHER SULFONIMIDE OR -AMIDE) COPOLYMER USING CYCLIC OLIGOMERS
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Disclosed is a method for preparing a poly(ethersulfonimide or ethersulfonamide) copolymer using cyclic oligomers, and more particularly, to a method for preparing a poly(ethersulfonimide or ethersulfonamide) copolymer by preparing a cyclic ether sulfone oligomer and a cyclic imide or amide oligomer and subjecting the cyclic ether sulfone oligomer and the cyclic imide or amide oligomer to ring-opening copolymerization in the presence of an alkali metal fluoride catalyst.
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- Synthesis and thermal studies of bisphenol-A based bismaleimide: Effect of nanoclays
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The compound 2,2-bis[4-(4-maleimidophenoxy phenyl)]propane was prepared by the imidization of bisamic acid of 2,2-bis(4-aminophenoxy phenyl)propane. Various nanoclays were blended with this bismaleimide and thermally cured. The structural characterization of the synthesized materials and the thermal properties of the bismaleimide and their blends were investigated through FTIR, 1H and 13C NMR, differential scanning calorimetry and thermo gravimetric analysis. Among the various clays investigated, Cloisite 15A shows strong influence on the cure exotherm of bismaleimide. Introduction of clay mineral into bismaleimide shifts the onset of curing exotherm to higher temperature and is nearly 40 °C. The thermal stability of the clay loaded cured bismaleimide increases and the presence of clay particles in the cured bismaleimide matrix enhances the char formation.
- Vijayakumar, Chinnaswamy Thangavel,Surender, Rajendran,Rajakumar, Kumaraswamy,Alam, Sarfaraz
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p. 693 - 699
(2011/04/23)
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- Functionalized Photoreactive Compounds
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The present invention concerns functionalized photoreactive compounds of formula (I), that are particularly useful in materials for the alignment of liquid crystals. Due to the adjunction of an electron withdrawing group to specific molecular systems bearing an unsaturation directly attached to two unsaturated ring systems, exceptionally high photosensitivities, excellent alignment properties as well as good mechanical robustness could be achieved in materials comprising said functionalized photoreactive compounds of the invention.
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- Thermoplastic resin composition and a method of molding the same
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This invention provides a thermoplastic resin composition comprising a thermoplastic resin and 0.1 to 100 parts by weight, per 100 parts by weight of the thermoplastic resin, of an imide compound prepared, e.g., by dehydration condensation of 1,2,3,4-butanetetracarboxylic acid or a monoanhydride or a dianhydride thereof with a primary amine, and a method of molding the resin composition.
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- Synthesis of phthalonitrile resins containing ether and imide linkages
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Imide-containing phthalonitrile monomers are prepared from a phthalonitrile and an aromatic dianhydride. The monomer and a method for preparing the monomer is disclosed. These monomers are synthesized into heat resistant polymers and copolymers with aromatic ring structure incorporating imide and ether linkages. The synthesis of the high temperature thermosetting polymers and copolymers is also disclosed.
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- Melt-fusible polyimides
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Melt-fusible polyimides based on pyromellitic dianhydride and at least one defined aromatic diamine are useful in making low-void composites and thermoplastic tapes, which can be fabricated into articles such as, for example, aircraft and autobody panels, printed circuit boards, etc. Some of these polyimides are melt-processible and can be fabricated by conventional procedures such as extrusion and injection molding.
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