• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.999-1004
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• 2001

(1-Chloro-2,2-dicyanovinyl)benzene or 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene was reacted with 2-amino-phenol to give the model compound, hydroxy enaminonitrile, which was found to undergo thermal cyclization reaction to form the corresponding benzoxazole. This intramolecular cyclization reaction is expected to occur through nucleophilic attack to electropositive enamine carbon by ortho-hydroxy group on the phenyl ring, which is accompanied by the release of neutral malononitrile through rearrangement. From each bifunctional monomer, o-hydroxy substituted polyenaminonitrile was prepared and characterized as a new precursor polymer for well-known aromatic polybenzoxazole. Also the unusual macrocyclic dimer formation from the 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane polymerization reaction system was discussed. The thermal cyclization reactions and the properties of polymers were investigated using FT-IR and thermal analysis (DSC & TGA).

• Bulletin of the Korean Chemical Society
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• v.20 no.5
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• pp.567-572
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• 1999

5-Nitro-2-(2'-vinyloxyethoxy)benzylidenemalononitrile (2a), methyl 5-nitro-2-(2'-vinyloxyethoxy)benzylidenecyanoacetate (2b), 3-nitro-4-(2'-vinyloxyethoxy)benzylidenemalononitrile (4a), methyl 3-nitro-4-(2'-vinyloxyethoxy)benzylidenecyanoacetate (4b), 2-nitro-5-(2'-vinyloxyethoxy)benzylidenemalononitrile (6a), and methyl 2-nitro-5-(2'-vinyloxyetboxy)benzylidenecyanoacetate (6b) were prepared by the condensation of 5-nitro-2-(2'-vinyloxyethoxy)benzaldehyde (1), 3-nitro-4-(2'-vinyloxyethoxy)benzaldehyde (3), and 2-nitro-5-(2'-vinyloxyethoxy)benzaldehyde (5) with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 2a-b, 4a-b, and 6a-b were polymerized with boron trifluoride etherate as a cationic initiator to yield poly(vinyl ethers) 7-9 having oxynitrobenzylidenemalononitrile and oxynitrobenzylidenecyanoacetate, which is effective chromophore for second-order nonlinear optical applications. Polymers 7-9 were soluble in common organic solvents such as acetone and DMSO. Tg values of the resulting polymers were in the range of 67-83 ℃. Electrooptic coefficient (r33) of the poled polymer films were in the range of 15-27 pm/V at 633 nm. Polymers 7-9 showed a thermal stability up to 300 ℃ in TGA thermograms, which is acceptable for NLO device applications.

• Bulletin of the Korean Chemical Society
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• v.21 no.6
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• pp.613-617
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• 2000

p-(2-Vinyloxyethoxy)benzylidenemalononitrile (4a), methyl p-(2-vinyloxyethoxy)benzylidenecyanoacetate (4b), 3,5-dimethoxy-4-(2'-vinyloxyethoxy)benzylidenemalononitrile (5a), methyl 3,5-dimethoxy-4-(2'-vinyloxy-ethoxy) benzylidenecyanoacetate (5 b), o-(2 -vinyloxyethoxy)benzylidenemalononitrile (6a), methyl o-(2-viny-Ioxyethoxy) benzylidenecyanoacetate (6b), 1,3-di-(2',2'-dicyanovinyl)-5-methyl-2-(2'-vinyloxyetioxy)benzene (7a), l,3-di-(2'-carbomethoxy-2'-cyanovinyl)-5-methyl-2-(2'-vinyloxyethoxy)benzene (7b), 2,3,4-tri-(2'-viny-Ioxyethoxy) benzylidenemalononitrile (8a), methyl 2,3,4-tri-(2'-vinyloxyethoxy)benzylidenecyanoacetate (8b), 2,4,6-tri-(2'-vinyloxyethoxy)benzylidenemalononitrile (9a), and methyl 2,4,6-tri-(2'-vinyloxyethoxy)benzyl-idenecyanoacetate(9b) were prepared by the condensation of the corresponding benzaldehyde 1-3 with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 4, 6, and 8 polymerized readily with radical initiators to yield crosslinked polymers 10, 12, and 14. However, compounds 5, 7, and 9 were inert to radical initiators due to the steric hindrance. The resulting polymers 10, 12, and 14 were not soluble in common solvents showing a thermal stability up to $300^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.307-313
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• 1999

2,4-Di-(2'-vinyloxyethoxy)benzylidenemalononitrile (la), methyl 2,4-di-(2'-vinyloxyethoxy)benzylidenecyanoacetate (lb), 3,4-di-(2'-vinyloxyethoxy)benzylidene malononitrile (2a), methyl 3,4-di-(2'-vinyloxyethoxy)benzylidenecyanoacetate (2b), 2,5-di-(2'-vinyloxyethoxy)benzylidenemalononitrile (3a), methyl 2,5-di-(2'-vinyloxyethoxy)benzylidenecyanoacetate (3b), 2,3-di-(2'-vinyloxyethoxy)benzylidenemalononitrile (4a), and methyl 2,3-di-(2'-vinyloxyethoxy)benzylidenecyanoacetate (4b) were prepared by the condensation of 2,4-di-(2'-vinyloxyethoxy)benzaldehyde, 3,4-di-(2'-vinyloxyethoxy)benzaldehyde, 2,5-di-(2'-vinyloxyethoxy) benzaldehyde, and 2,3-di-(2'-vinyloxyethoxy)benzaldehyde with malononitrile or methyl cyanoacetate, respectively. Trifunctional divinyl ether monomers 1-4 were polymerized readily with boron trifluoride etherate as a cationic initiator to give optically transparent swelling poly(vinyl ethers) 5-8 havina oxybenzylidenemalononitrile and oxycyanocinnamate, which is presumably effective chromophore for second-order nonlinear optical applications. Polymers 5-8 were not soluble in common organic solvents such as acetone and DMSO due to crosslinking. Polymers 5-8 showed a thermal stability up to 300 ℃ in TGA thermograms, which is acceptable for electrooptic device applications.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.155-159
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• 1998

o-(2-Vinyloxyethoxy)benzylidenemalononitrile (4a), methyl o-(2-vinyloxyethoxy)benzylidenecyanoacetate (4b), m-(2-vinyloxyethoxy)benzylidenemalononitrile (5a), methyl m-(2-vinyloxyethoxy)benzylidenecyanoacetate (5b), p-(2-vinyloxyethoxy)benzylidenemalononitrile (6a), and methyl p-(2-vinyloxyethoxy)benzylidenecyanoacetate (6b) were prepared by the condensation of o-(2-vinyloxyethoxy)benzaldehyde (1), m-(2-vinyloxyethoxy)benzaldehyde (2), and p-(2-vinyloxyethoxy)benzaldehyde (3) with malononitrile or methyl cyanoacetate, respectively. Bifunctional vinyl ether monomers 4a-b and 6a-b polymerized readily with cationic initiators to give polymers with the NLO-chromophores o- and p-oxybenzylidenemalononitrile or o- and p-oxybenzylidenecyanoacetate in side chain at -60 ℃, while meta-isomers 5a and 5b gave lower yields of polymers under the same conditions. The resulting polymers 7-9 were soluble in common organic solvents and the inherent viscosities of polymers were in the range of 0.20-0.30 dL/g in acetone. Solution-cast films were clear and brittle, showing Tg values in the range of 40-70 ℃.

• Journal of the Korean Applied Science and Technology
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• v.24 no.1
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• pp.31-46
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• 2007

This study was focused on the maximization of flame-retardancy of polyesters by a synergism of simultaneously introduced chlorine and phosphorus into polymer chains of modified polyesters. To prepare modified polyesters, reaction intermediates, TD-adduct (prepared from trimethylolpropane/2,4-dichlorobenzoic acid (2,4-DCBA)) and TMBO (prepared from tetramethylene bis(orthophosphate)), were prepared first, then condensation polymerization of the prepared intermediates, adipic acid, and 1,4-butanediol were carried out. In the condensation polymerization, the content of phosphorus was fixed to be 2%, and the content of 2,4-DCBA that provides chlorine component was varied to be 10, 20, and 30wt%, and we designated the prepared modified polyesters containing chlorine and phosphorus as ABTT-10C, -20C, -30C. Two-component PU flame-retardant coatings (ABTTC, ABTTC-10C, ABTTC-20C, ABTTC-30C) were prepared by the curing of synthesized ABTTs with a curing agent of allophanate/trimer at room temperature. To examine the film properties of the prepared PU flame-retardant coatings, film specimens were prepared with the prepared coatings. The film properties of ABTTC, ABTTC-10C and ABTTC-20C, which contain 0, 10 and 20wt% 2,4-DCBA, respectively, were proved to be good, whereas the film properties of ABTTC-30C, which contains 30wt% 2,4-DCBA, was proved to be a little bit poor. Two kinds of flame retardancy tests, $^{\circ}45Meckel$ burner method and LOI method were performed. With the $^{\circ}45Meckel$ burner method, three flame-retardant coatings except ABTTC showed less than 3.4cm of char length, and showed less than 2 seconds of afterflaming and afterglow. From this result, the prepared flame-retardant coatings were proved to have the 1st grade flame retardancy. With the LOI method, the LOI values of the coatings containing more than 10wt% 2,4-DCBA were higher than 30%, which means that the coatings possess good flame retardancy. From these results, it was found that synergistic effect in flame retardancy was taken place by the introduced phosphorus and chlorine.

• Applied Microscopy
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• v.28 no.2
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• pp.193-205
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• 1998

The Urechis unicinctus sperm and spermatogenic cells prepared from the testis are investigated to identify $\alpha-tubulin$ of axoneme microtubules using mouse monoclonal $anti-\alpha-tubulin$ as the first Ab and Gold(10nm) conjugated goat anti-mouse IgG as the Ab marker. The Ag-Ab reaction analyzed excellently the localization of $\alpha-tubulin$ and the gold particles incorporated with the proximal and distal centrioles, manchette microtubules, and flagellum. The gold particles can be also observed in the spermatogenic cells while the cells are still in sperm ball which is composed of a somatic cell and spermatogenic cells. The sperm ball is the functional unit of sperm production in U unicinctus testis. The spermatids are developed from the spermatogenic cells in the sperm ball and released into the testis cavity through a cortical cytoplasmic opening. The spermatid architectures are similar with the mature sperm of the testis cavity in aspects of shape of discoid acrosome, degree of nuclear condensation and ring type of mitochondrion. However, the distal centriole connecting with the flagella can be observed from the mature sperm while the both proximal and distal centrioles reveal only in the spermatids. The proximal centriole is directly connected with nuclear outer membrane during the stage of nuclear condensation and oriented perpendicularly to the distal centriole whose axis coinciding with the longitudinal axis of the spermatozoon. There are indications that the distal centriole is intimately associated with the polymerization of the flagellum. The manchette microtubules appear during spermatid development but the mature sperm have round head and no conspicuous middle piece.

• Resources Recycling
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• v.17 no.6
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• pp.34-42
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• 2008

The properties of sodium silicate solution were surveyed by using the yellow silicomolybdic method, and the formation of silica sol from sodium silicate solution and the growth of silica sol were investigated in this study. The $SiO_2$ content of 2 wt% in sodium silicate solution was proper to oxidize sodium silicate with sulfuric acid. After the removal of sodium ions in sodium silicate solution, the pH of silicate solution had to be controlled above 9 for the stabilization of silicate solution. The condensation between silicic acid species and silica nuclei surfaces has been studied at $20{\sim}80^{\circ}C$ and pH 10 in silicate solutions with silica nuclei. The reaction falls into two kinetics regimes, limited at high silicic acid species concentration by polymerization, but at lower concentration by a process whereby deposited silicic acid species condenses further to silica. The overall condensation is first-order in silicic acid species concentration, proceeded toward to pseudo equilibrium concentration, $C_x$, rather than the solubility of amorphous silica. The heat of solution of amorphous silica was 3.34 kcal/mol and exhibits an Arrhenius temperature dependence with an apparent activation energy of 3.16 kcal/mol in the range of $20{\sim}80^{\circ}C$.

• Membrane Journal
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• v.26 no.5
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• pp.391-400
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• 2016

In this work, novel thin film composite (TFC) forward osmosis (FO) membranes are developed via interfacial polymerization on the polysulfone (PS) substrate, using TEOS as the a sol-gel reagent to form hydrophilic interlayer polymer between PS and polyamide (PA). The PS substrate was cast on a very thin polyester nonwoven to reduce membrane resistance. With the incorporation of TEOS (tetraethoxy silane) polymer in the interface between PS and PA, the formed TFC FO membrane exhibits better hydrophilicity and improved water flux, and therefore superior membrane performance. By changing the polymerization sequence of PA interfacial polymerization and TEOS sol-gel condensation, the surface properties and performance of FO membranes are changed significantly. The permeability of FO membranes were estimated using the bench-scale FO test equipment. The distribution of the polysiloxane on composite membrane and morphology are also studied with FE-SEM and EDAX. The PS_PA_TEOS membrane showed highly enhanced water flux (79.2 LMH) but reverse salt flux (RSF) value (7.10 GMH) also increased. However, the flux of PS_TEOS_PA membrane increased moderately (54.1 LMH) without increasing RSF value (1.60 GMH) compare with PS_PA membrane.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1451-1456
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• 2012

A novel tetrathiafulvalene (TTF)-based main-chain polymer (6TTF-polymer) was successfully synthesized via a condensation polymerization between a newly synthesized dihydroxy TTF derivative and a malonyl chloride, and its chemical structure was characterized by spectroscopic techniques. Molecular weight of the 6TTF-polymer (9,030 g/mol by gel permeation chromatography) was large enough to form the ductile film. The electrochemical and optical properties of the 6TTF-polymer were further estimated by cyclic voltammetry, ultraviolet and photoluminescence spectroscopes. The highest occupied molecular orbital level ($E_{HOMO}$=-4.79 eV) and band-gap energy ($E_g$=1.91 eV) of the 6TTF-polymer suggested that TTF-based polymer could act as a good electron donating material for the optoelectronic applications.