The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Single-walled carbon nanotube (SWCNT)/epoxy composites with a high nanotube loading up to ∼39.1 wt% are fabricated by combining the mixed-curing-agent assisted layer-by-layer method and the hot press process. This combined method is an efficient and effective approach for making composite sheets in practical applications since the hot press process makes it possible and easy to readily prepare thick...
In this paper, the effect of solvent selectivity on the transition between crystallization and microphase separation of the semicrystalline diblock copolymer polystyrene-b-poly(ethylene oxide) (PS-b-PEO) thin films was investigated. Square-shaped crystals formed due to lower barrier of crystalline nucleation in both poor and good solvent vapor for PEO. However, in poor solvent (cyclohexane) vapor...
Epoxy resins are widely applied in cryogenic engineering and their cryogenic mechanical properties as important parameters have to be improved to meet the high requirements by cryogenic engineering applications. Carbon nanotubes (CNTs) are regarded as exceptional reinforcements for polymers. However, poor carbon nanotube (CNT)–polymer interfacial bonding leads to the unexpected low reinforcing efficiency...
Epoxy resins are increasingly used in cryogenic engineering areas due to rapid developments of spacecraft and superconducting cable technologies as well as large cryogenic engineering projects (e.g., International Thermonuclear Experimental Reactor). Cryogenic mechanical properties are important parameters for epoxy resins to be employed in such areas. In this paper, a traditional reactive aliphatic...
Improvements in mechanical properties at low temperatures are desirable for epoxy resins such as diglycidyl ether of bisphenol A (DGEBA) that are often used in cryogenic engineering applications. In this study, a hydroxyl functionalized hyperbranched polymer (H30) is employed to improve the mechanical properties of a DGEBA epoxy resin at liquid nitrogen temperature (77K). The results show that the...
A surface-initiated ring-opening polymerization approach was used to functionalize multi-walled carbon nanotubes (MWNTs) with linear poly(l-lysine) (PLL). The oxidized MWNTs, which resulted from the treatment of MWNTs with mixed concentrated sulfuric acid and nitric acid, were converted into amino-functionalized MWNTs (MWNT-NH 2 ) by the amidation of carboxylic group on MWNT surface with excess...
Diglycidyl ether of bisphenol A (DGEBA) is one of the most widely used epoxy resins for many industrial applications, including cryogenic engineering. In this paper, diethyl toluene diamine (DETD) cured DGEBA epoxy resin has been modified by two flexible diamines (D-230 and D-400). The cryogenic mechanical behaviors of the modified epoxy resins are studied in terms of the tensile properties and Charpy...
Two series of novel polyimides (5a–g and 6a–g) containing flexible ether linkages and pendent trifluoromethyl (CF 3 ) groups were synthesized from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (3a) and 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride (3b) with various CF 3 -substituted aromatic bis(ether amine)s (4a–g) via ring-opening polyaddition to poly(amic acid)s, followed...
A series of organosoluble and light-colored polyimides (III) was prepared from 2,3,3′,4′-biphenyltetracarboxylic dianhydride (α-BPDA) with various fluorinated aromatic bis(ether amine)s via two-step method with thermal or chemical imidization of poly(amic acid)s yielded polyimides. The III series had inherent viscosity of 0.74–1.01dl/g and showed excellent solubility in a variety of organic solvents...
A series of polyimides III a–h characterized by colorlessness, high transparency, high solubility, and good mechanical property, was synthesized from the aromatic dianhydride, 2,5-bis(3,4-dicarboxyphenoxy)-t-butylbenzene dianhydride (I), and various aromatic diamines (II a–h ) with pendent trifluoromethyl group via polyaddition, chemical imidization, and direct cast films. The III...
New aromatic diamine with cyclohexane cardo group substituted with trifluoromethyl group in the side chain, 1,1-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]cyclohexane (II), was prepared through the nucleophilic substitution reaction of 1,1-bis(4-hydroxyphenyl)cyclohexane and 2-chloro-5-nitrobenzotrifluoride in the presence of potassium carbonate, to yield the intermediate dinitro compound I, followed...
Fluorinated diimide-dicarboxylic acid (DIDA, Code: IV), 1,4-bis(4-trimellitimido-2-trifluoromethylphenoxy) benzene, synthesized by reacting 1,4-bis(4-amino-2-trifluoromethyl phenoxy)benzene (I) with trimellitic anhydride in polar solvents (PSv), was found to crystallize easily in amide-type solvents, such as N-methyl-2-pyrrolidinone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc),...
A novel fluorinated bis(ether amine) monomer, 2,3-bis(4-amino-2-trifluoromethylphenoxy)naphthalene, was prepared through the nucleophilic aromatic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 2,3-dihydroxynaphthalene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. A series of new fluorine-containing polyimides having inherent viscosities...
A novel fluorinated diamine monomer, 4,4'[hyphen]bis(4[hyphen]amino[hyphen]2[hyphen]trifluoromethylphenoxy)[hyphe n]3,3',5,5'[hyphen]tetramethylbiphenyl, was prepared by a nucleophilic chloro[hyphen]displacement reaction of 3,3',5,5'[hyphen]tetramethyl[hyphen]4,4'[hyphen]biphenol with 2[hyphen]chloro[hyphen]5[hyphen]nitrobenzotrifluoride and subsequent reduction of the intermediate dinitro compound...
The diimide-diacid monomer, N,N'-bis(3-carboxyphenyl)-4,4'-oxydiphthalimide (I), was prepared by azeotropic condensation of 4,4'-oxydiphthalic anhydride and m-aminobenzoic acid at a 1:2 molar ratio in polar solvent and toluene. A series of organosoluble and colorless poly(amide-imide)s with inherent viscosities ranging from 0.95 to 1.70dl/g were synthesized from diimide-diacid I and various aromatic...
A new diimide dicarboxylic acid, 1,2-bis(4-trimellitimidophenoxy)-4-t-butylbenzene (I), was prepared by the condensation of 1,2-bis(4-aminophenoxy)-4-t-butylbenzene (1,2-BAP-tBB) and trimellitic anhydride (TMA) at 1:2 molar ratio. The diamine 1,2-BAP-tBB was first synthesized from 4-t-butylcatechol and p-chloronitrobenzene in the presence of potassium carbonate (K 2 CO 3 ) and then...
4-tert-Butyl-1,2-bis(4-carboxyphenoxy)benzene (2a) and 1,2-bis(4-aminophenoxy)-4-tert-butylbenzene (2b) were synthesized through the aromatic nucleophilic substitution reaction of 4-tert-butylcatechol with p-fluorobenzonitrile or p-chloronitrobenzene in the presence of potassium carbonate in N,N-dimethylformamide. Two series of polyamides with flexible main-chain ether linkages and ortho-phenylene...
Alternate copoly(amide-imide) was synthesized from two aromatic diamines and trimellitic anhydride (TMA). When the diamine was m-phenylenediamine (m-PDA), the resulted poly(amide-imide) [P(A-alt-I)] was found to be of light colour. Specifically, when m-PDA was located between two amide groups in the P(A-alt-I) chain, the P(A-alt-I) was colourless. Using triphenyl phosphite (TPP) and pyridine as condensing...
The primer of double electrodeposition coating is formed by electrically depositing a thermosetting quaternary ammonium-epoxy resin adduct on the metallic material, and then the topcoat, a self-crosslinkable acrylic resin, is formed upon the wet primer, by electrodeposition again. It is observed that the quaternary ammonium-type adduct, used as the primer, can lead to thicker topcoat film, than the...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.