• Macromolecular Research
• /
• v.16 no.4
• /
• pp.360-366
• /
• 2008

Poly(dialkoxyphenylene 1,3,4-oxadiazole)s were conveniently synthesized to compare their material properties of solvent solubility, thermal stability and molecular alignment with respect to alkyl chain length and meta/para-phenylene structure. All prepared polymers exhibited good solubility in co-solvents containing various volume levels of chloroform to trifluoroacetic acid. Meta-polymers showed slightly better solubility than para-polymers. All polymers produced were thermally stable up to $320^{\circ}C$. Photoluminescence of polymer films was observed with blue light emission at around 450 nm. X-ray diffraction patterns of all polymers indicated that they were composed of stacked molecular sheets with the same layer-to-layer distance of $3.4\;{\AA}$. However, side chain-to-side chain and main chain-to-main distances within the layers increased with increasing alkyl chain lengths. The meta-polymer chains were separated more than the para-polymer chains.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.5
• /
• pp.1443-1454
• /
• 2011

Methods to prepare novel second-order nonlinear optical (2O-NLO) materials composed of all-silica zeolite (silicalite-1) and a series of 2O-NLO molecules having high second order hyperpolarizability constants (${\beta}$ values) are reviewed. These methods include the development of novel methods to incorporate a series of hemicyanine (HC) molecules into the channels of silicaite-1 films in uniform orientations. The first method is to incorporate HC molecules tethered with long alkyl chains (octadecyl or longer) into the silicalite-1 channels with the long alkyl chain side first through the hydrophobic-hydrophobic interaction between the long alky chains and the silicalite-1 channels. The second method is to incorporate the HC molecule tethered with a medium length alkyl chain (nonyl) into the silicalite-1 channels with the medium length alkyl chain side first through hydrophobic-hydrophobic interaction between the medium length alky chain in the photoexcited state and the silicalite-1 channels. The third method is to incorporate the HC molecule tethered with propionic acid into the silicalite-1 channels with the propionic acid side last mediated by a tetrabultylammonium cation ion-paired to the propionate unit. A method to prepare a novel third-order nonlinear optical (3O-NLO) material composed of zeolite-Y and PbS or PbSe quantum dots is also reviewed. This Account thus describes a promising new direction to which the search for highly sensitive 2O-NLO and 3O-NLO materials has to be conducted and a new direction to which zeolite research and applications have to be expanded.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.1009-1011
• /
• 2009

Nano-structured conducting polypyrroles were synthesized in the ionic liquids (ILs) based on 1-alkyl-3-methylimidazolium family with tetrachloroferrate as an anion ($C_n\;mim\;[FeCl_4]\;with\;n\;=\;4,\;8,\;and\;12$). The polypyrrole nanostructures synthesized in ILs were formed as spherical shapes. For ionic liquids with alkyl side chain length $C_4,\;C_4\;mim\;[FeCl_4]$, the size of particles was ranged around 60-nm with a relatively narrow size distribution. As the length of alkyl chain increases, the particle sizes become larger and their distributions become wider. The self-assembled local structures in the solvent ionic liquids are likely to serve as templates of highly organized nano-structured polymers. The length of the alkyl chain in ionic liquids seems to affect these local structures.

• Food Science and Biotechnology
• /
• v.17 no.1
• /
• pp.176-179
• /
• 2008

Amylose contents and amylopectin chain architecture of sorghmn and waxy sorghum starches were determined and compared with those of other common cereal and tuber starches. Also, in vitro digestibility of sorghum starch was estimated using a novel methodology. The absolute amylose content of sorghum starch was similar to that of com and wheat starches. The side chain length distribution patterns for sorghum and waxy sorghum amylopectin were very similar to those of com and waxy com, respectively. The $k_{cat}/K_m$ values for sorghum and potato amylopectin did not show a significant difference. The kinetic parameters could be used as novel indicators for starch digestibility.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.9
• /
• pp.2679-2683
• /
• 2014

Mechanisms underlying the impacts of interactions between carbon nanoparticles (CNPs) and ionic liquids (ILs) on the physicochemical behavior of CNPs need to be more full worked out. This manuscript describes a theoretical investigation at multiple levels on the interactions of fullerene $C_{60}$ with 21 imidazolium-based ILs of varying alkyl side chain lengths and anionic types and their impacts on $C_{60}$ dispersion behavior. Results show that ${\pi}$-cation interaction contributed to mechanism of the $C_{60}$-IL interaction more than ${\pi}$-anion interaction. The calculated interaction energy ($E_{INT}$) indicates that $C_{60}$ can form stable complex with each IL molecule. Moreover, the direction of charge transfer occurred from IL to $C_{60}$ during the $C_{60}$-IL interaction. Quantitative models were developed to evaluate the self-diffusion coefficient of $C_{60}$ ($D_{fullerene}$) in bulk ILs. Three interpretative molecular descriptors (heat of formation, $E_{INT}$, and charge) that describe the $C_{60}$-IL interactions and the alkyl side chain length were found to be determinants affecting $D_{fullerene}$.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.2
• /
• pp.178-183
• /
• 1998

Carbon-13 CP-MAS NMR techniques were used to investigate dynamics of new combined type liquid crystalline polymers, poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] and poly[oxy-1,4-phenyleneoxy-2-{10-(4-(4-butylphenylazo)phenoxy)decyloxy}terephthaloyl]. Noticeable mobility change of either aromatic groups or methylene groups is not detected between 25 ℃ and 82 ℃ from 13C spinlattice relaxation time in the rotating frame (T1ρ(C)) and contact time array experiments. However, line shape analysis shows the increase of mobility of methylene carbons in poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] at higher temperature. The dynamics of side chanis does not seem to be affected in our experimental temperature range by the length of aliphatic chain which is connecting the side chain group to the main chain.

• Applied Chemistry for Engineering
• /
• v.29 no.4
• /
• pp.405-412
• /
• 2018

Three types of bis[3-(dialkyloxylphosphorothionyl) thio-2-methylpropanyloxy]alkane (BAPA) drived from alkane diol were synthesized. The principal chain of each BAPA had a different carbon number, i.e., 6, 9, and 11. The three types of synthesized BAPA were compared to zinc dialkyl dithiophosphates (ZDDPs) in terms of abrasion resistance. A four-ball test was conducted to evaluate the anti-abrasion performance of the synthesized BAPA according to the length of the principal carbon chain. Each product was added to an additive at a concentration of 1% of the base oil weight, and the wear scar diameter (WSD) was measured as 0.472, 0.459, and 0.480 mm, respectively. Among the BAPA compounds, dialkyl dithiophosphoric acid (DDP), which is the side chain of bis[methacryloyloxy] nonane (BMOO9), was synthesized by varying the carbon number, i.e., 4, 8, and 12, and subsequently the 4-ball test was carried out. The WSD was determined as 0.537, 0.459, and 0.531 mm, respectively. As a result, it was found that when a side chain is short, a thin film is formed. In contrast, a long side chain hindered the formation of a film, and hence the best result was achieved when the carbon number was 8. As for the ZDDPs, the WSD was determined to be 0.563 mm, when measured under the same conditions. The measurements confirm that the synthesized BAPA compounds are superior to the ZDDPs as abrasion resistance additives.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3060-3065
• /
• 2009

A series of wholly aromatic Poly(ether-ether-ester)s with flexible side chain was synthesized by direct polycondensation from ether linkaged triad diol and 2,5-dialkoxyterephthalic acid. The chemical structures and physical properties of these polymers were investigated by using $^1H$-NMR, FT-IR, DSC and TGA. As results of investigations, the inherent viscosities($\eta$inh) measured at $40^{\circ}C$ in 1,1,2,2-tetrachloroethane(TCE) were 0.45~0.86 dl/g and initial decomposition(Td) in TGA occurred at 378~418 $^{\circ}C$ in N2 gas. The majority of these polymers were soluble in organic solvents used in this experiments at elevated temperatures. Melting temperatures(Tm) decreased with increasing the length of the side chain and showed odd-even effects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.583-585
• /
• 2004

In this paper, we synthesized a new photo-crosslinkable polyitaconimide containing cinnamoyl moiety by radical polymerization. Also, the NLC alignment capabilities on these photopolymer surfaces were studied. Good LC alignment with W exposure on the polyitaconimide surfaces can be obtained. A homogenous alignment using UV exposure on the polyitaconimide with 1-carbon chain cinnamoyl group and 4-carbon chain cinnamoly group can be obtained. However, the homeotripic alignment using UV exposure was observed on polyitaconimide with 6-carbon chain cinnamoyl. The LC aligning ability on the polyitaconimide depends on the side chain length of photopolymer.

• Polymer(Korea)
• /
• v.26 no.4
• /
• pp.439-444
• /
• 2002

Several monomeric benzilidene anhydrides (2a~d) haying n-alkyloxy groups with various n-alkyl chain lengths were prepared by Stobbe condensation of diethyl succinate with 4-(n-alkyloxy)benzaldehyde (1a,b) followed by hydrolysis by the succinates and cyclodehydration of the benzilidenated succinic acids. Configurational isomerism of the monomer was investigated by spectroscopic means. It was found that monomers (2a~d) exist in (Z,Z)-isomeric structure. Polymerization was carried out in bulk at 150~$210^{\circ}C$ range in nitrogen flow. The chemical structure and thermal properties of the polymers were characterized by spectroscopic means, TGA and DSC. Their properties highly depended on their chemical structures in accordance with a side chain length.