• Journal of Pharmacopuncture
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• v.25 no.4
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• pp.317-325
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• 2022

Polymers are the major constructive material of pharmaceutical formulations that play a prime role in designing effective drug-delivery systems and releasing drugs at their sites of application. Polymers are composed of multiple repeating units of high molecular mass components with attendant properties. Most synthetic polymers are non-biocompatible, expensive, and extremely inclined to deliver adverse impacts. Meanwhile, edible polymers obtained from natural sources have gained remarkable recognition for their promising use in modern medicine. Moreover, polymers derived from natural sources are generally preferred due to certain of their unique features such as abundant availability, biocompatibility, nontoxicity, economical, safe, and effective functions that fit the purpose. Polysaccharides including starch, cellulose, hemicellulose, pectin, and mucilage are identified as a major class of naturally obtained molecules that have a substantial role as functional polymers. This review summarizes the potential role of polysaccharides derived from vegetable sources such as adhesives, anticaking agents, binders, disintegrants, emulsifiers, film-framing agents, and thickeners. This is simply an opportunity to abandon synthetic excipients that hurt our bodies and think back to nature from where we originate.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.216-216
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• 2006

A special group of polymers, those from renewable resources, has attracted an increasing amount of attention over the last two decades, due to two major reasons: environmental concerns and the limitations of our finite petroleum resources. Generally, polymers from renewable resources (PFRR) can be classified into three groups: (1) natural polymers, such as starch, protein and cellulose; (2) synthetic polymers from natural monomers, such as polylactic acid (PLA); and (3) polymers from microbial fermentation, such as polyhydroxybutyrate (PHB). Like many other petroleum based polymers, various properties of PFRR are also vastly improved through blending and composites formation.

• The Journal of Natural Sciences
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• v.5 no.1
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• pp.59-65
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• 1992

In this study, new photosensitive polymers bearing acyloxyimino(AOI) group were prepared and the relationship between photochemical reactions of the polymers and changes of their physical properties was investigated. It was found that main reaction of these copolymers depended on the structure of polymer mainchain. From the view point of amino groups formation, acryl type polymers were superior to methacryl type polymers. On the other hand, in the case of mathacryl type polymers, mainchain scissions and formation of double bonds occurred very effectively. Applications of these copolymers to photofunctional polymers were also discussed.

• Macromolecular Research
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• v.8 no.5
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• pp.199-208
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• 2000

The recent development of biodegradable polymers for drug delivery system (DDS) has been investigated. The biodegradable polymers for DDS are mainly discussed in two categories: one category is natural biodegradable polymers such as polysaccharides, modified celluloses, poly(${\alpha}$-amino acid)s, modified proteins, and microbial biodegradable polymers; the other is synthetic biodegradable polymers such as poly(ester)s, poly(ortho ester)s, poly(phosphazene)s, poly(anhydride)s, poly(alkyl cyanoacrylate)s, and multiblock copolymers. The bioconjugate polymeric drug delivery systems have been also proposed for the design of biocompatible polymeric controlled drug delivery.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.2017-2022
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• 2012

Three isostructural lanthanide coordination polymers, $[Ln(L)_3(H_2O)_2](H_2O)_3$ {Ln = Eu (1), Tb (2), Gd (3); L = $trans$-3-(3-pyridyl)acrylate, (3-py)-CH=CH-COO}, were prepared from HL, lanthanide nitrate, and NaOH in $H_2O$ by microwave heating. In all coordination polymers, the metal is bonded to eight oxygen atoms, and all pyridyl nitrogen atoms do not coordinate to the metals. All polymers have a 1-D loop-connected chain structure. The hydrogen atoms in the aqua ligands and lattice water molecules all participate in the hydrogen bonds of the O-$H{\cdots}O$ or O-$H{\cdots}N$ type. The hydrogen bonds connect the 1-D chains to create a 2-D network. Polymer 1 exhibited red luminescence in the solid state at room temperature.

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1649-1654
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• 2003

We have investigated substituent effect on the stabilization energies, and nucleus-independent chemical shifts of pentafulvalenes and on the electronic structures of the corresponding polypentafulvalenes to design environmentally stable semiconductive or conductive polymers. Geometrical optimizations of the molecules were carried out at the density functional level of theory with B3LYP hybrid functional and 6-311+G(d) basis set. Stabilization energies were estimated using isodesmic and homodesmotic reactions. As a criterion of aromaticity nucleus-independent chemical shifts of the molecules were computed using GIAO approach. For the polymers the geometrical parameters were optimized through AM1 band calculations and the electronic structures were obtained through modified extended Huckel band calculations. It is found that strong electronwithdrawing substituents increase isodesmic and homodesmotic stabilization energies of pentafulvalene, though it does not increase the aromaticity. Nitro-substituted pentafulvalene is estimated to have stabilization energy as much as azulene. However, substitution either with electron-donating groups or with electronwithdrawing groups does not significantly affect the electronic structures of polypentafulvalene and poly (vinylenedioxypentafulvalene).

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.176-180
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• 2005

The liquid crystalline properties of a series of main chain liquid crystalline polymers and four series compounds consisting of aromatic type Schiff base mesogenic units and polymethylene flexible spacers were studied. The thermal and liquid crystalline properties were investigated by differential scanning calorimetry and on the hot stage of a polarizing microscope. The nature of the liquid crystalline phase of the polymers and compounds depended greatly on the length of the central polymethylene spacer and on the terminal alkoxy groups. Polymers I and Series III exhibited an even-odd effect in melting and isotropization temperatures but Series II and Series IV exhibited an even-odd effect in isotropization temperatures. They formed nematic and smectic mesophases in melts as judged by their optical textures observed through a polarizing microscope.

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.89-93
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• 1997

Polyorganophosphazenes bearing various hydrophilic and hydrophobic side groups were synthesized. These polymers were crosslinked by three methods. The side groups were (2-methoxyethoxy)ethoxy, 2,2,2-trifluoroethoxy, phenyloxy, ethyl ester of alanin. Polymers synthesized in this study were crosslinked by gamma ray irradiation, UV irradiation, and UV irradiation in the presence of crosslinker and photosensitizer. Polymers crosslinked by UV irradiation in the presence of crosslinker and photosenitizer yielded hydrogels of highest elasticity. All hydrogels had lower critical separation temperature behavior.

• Bulletin of the Korean Chemical Society
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• v.21 no.3
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• pp.321-327
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• 2000

Polynucleotide analogues containing pyrimidine (uracil and thynime) bases, $poly[(1'{\beta}-uracil-1-yl-2'.5'-dideoxy-D-glycero-pent-4'-enofuranose)-alt-(maleic$ acid)] (12) and $poly[(1'-{\beta}-thymin-1-yl-2'5'-dideoxy-D-glycero-pent-4'-enofuranose)-alt-(maleic$, acid)] (15), were synthesized by the altermating copolymerization of relevant nucleosied derivatives and maleic anhydride, and the subsequent hydrolysis. The polymers had quite similar structures to the natural polymes and were soluble in water, They showed high hypochromicities up to 49% and excimer fluorescence due to the base stacking, and polyelectrolyte behavior. Since the polymers had compact structrures, depyrimidinations, the release of pyrimidine bases from the polymer backbone, occurred in aqueous solutions with higher rates compared with those of the natural polymers.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.464-468
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• 1999

The effectiveness of current biodegradation test methods for degradable polymers under controlled composting conditions was studied in regards to the test temperature and compost condition. When biodegradability tests for the natural (starch, cellulose, PHB/HV) and synthetic (PCL, SG, PLA) polymers were conducted at temperature levels of 35 and $55^{\circ}C$ with compost cured at ambient temperature, the degradations of cellulose and starch were higher at $35^{\circ}C$ because of the priming effect. On the other hand, degradations of other polymers were higher at $55^{\circ}C$. In the biodegradation test at $55^{\circ}C$, compost harvested right after the thermophilic degradation stage showed higher biodegradation activities than the cured compost for both the synthetic aliphatic polyester (SG) and a natural polymer, cellulose. These results suggest that the biodegradation test conducted at $55^{\circ}C$ with the compost, harvested right after the thermophilic degradation stage during composting, showed the highest biodegradation activity under controlled composting conditions.