• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.351-351
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• 2006

The possible interactions between cyclodextrins and biodegradable polyesters were investigated. The hydrophobicity of cyclodextrin could be varied with the methyl substitution of host CD, and the possibility of IC formation and the types of interaction between respective CDs and polyesters were subsequently changed. Further, the effect of cyclodextrins on the morphological change of biodegradable polymer was shown to depend on the degree of IC formation between cyclodextrin and biodegradable polymer as well as on the type of interaction between respective CDs and polyesters. That is, the enhancement and/or the restriction of the crystallization of P(3HB) were observed by the incorporation of various kind of cyclodextrins with different cavity size and hydrophobicity.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.209-210
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• 2003

The durability and anti-microbial stability of plastics, which have been thought to be favorable characteristics, cause ecoloical problems due to non-degradation after disposal. For a possible solution of these ecological and environmental problems, the biodegradable polymers. especially aliphatic polyesters, have been widely investigated. Poly(tetramethylene succinate)(PTMS) is one of the most promising biodegradable polyesters. (omitted)

• Polymer(Korea)
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• v.29 no.3
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• pp.314-319
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• 2005

Four kinds of new aliphatic diols were synthesized by the ring opening reaction of glycolide with 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, or 1,4-cyclohexanedimethanol, a difunctional initiator, in the presence of stannous octoate catalyst. The resulting diols were melt-polymerized with succinic acid, adipic acid, or suberic acid at 170, 190, or $220^{circ}C$ to produce new sequentially ordered aliphatic polyesters and their corresponding polyesters with random structure. Their glass transition temperatures ($T_g$) ranged from -40 to $30^{circ}C$, The sequentially ordered polyesters prepared at $170^{cir}C$ had higher $T_g$ of 5 to $10^{circ}$ than the polyesters with rand()m structure produced at higher temperature. From in-vitro degradation test the sequentially ordered polyesters was shower in the rate of hydrolysis in a buffer solution than the polymers with random molecular structure.

• Applied Chemistry for Engineering
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• v.3 no.3
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• pp.377-385
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• 1992

• Bulletin of the Korean Chemical Society
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• v.19 no.6
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• pp.680-685
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• 1998

Two kinds of new aliphatic diols were synthesized by the ring-opening reaction of lactide and glycolide with 1,4-butanediol, a difunctional initiator, in the presence of stannous octoate. The resulting aliphatic diols were melt-polymerized with D-tartaric acid at 150 ℃ to produce new crosslinkable polyesters. They were reacted with hexamethylene diisocyanate in THF at 65 ℃ in a teflon mold for 24 h to prepare sequentially ordered crosslinked polyesters (BD/LT/GL/D-tartarate). Degradation of the prepared yellow crosslinked films was carried out in a buffer solution in order to examine the effect of time, pH, temperature and crosslinking degree on their degradation rate and mechanism. The rate of degradation increased with an increase in pH and temperature, but it decreased with increasing degree of crosslinkage incorporated into the crosslinked polyesters. We also found that the crosslinked polymers were converted into the acidic compounds such as lactic, glycolic, and D-tartaric acids during the degradation.

• Proceedings of the Korean Fiber Society Conference
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• 1997.04a
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• pp.328-332
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• 1997

Hot stretching focused on the improvement of properties of poly(L-lactic acid) fiber. Some aliphatic polyesters are biodegradable under microbial attack and the new unique applications are expected. Generally, these materials have a somewhat low melting temperature and low mechanical properties compared with the aromatic polyesters. In this study, melt-spinning of poly(L-lactic acid) was conducted. We investigated effects of the stretching and the molecular orientation of aliphatic polyester fibers on the change of fine-structure. Glass transition temperature, molecular orientation and crystallinity increased according to the increase of stretching ratio.

• Journal of Biomedical Engineering Research
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• v.16 no.1
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• pp.9-16
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• 1995

Biodegradable poly (I ,4-butanediol succinate) (PBS) was synthesized from 1,4-butanediol and succinic anhydride. The glass transition temperature of poly (I, 4-butanediol succinate) was revealed at $73^{\circ}C$. The crystallization and cold crystallization of the polymers were investigated as a function of holding time in melt state, cooling rate. reheating, and molecular weight. Chain scission and/or cmsslinking did not occur in the melt state at var.ious holding times. Slower scanning rate can allow more times for nucleation, rearrangement, and packing of the polymer chain, so the onset temperature of crystallization from the melt was increased. PBS crystallized from the melt was found to have spherulitic structure. The degradation behavior of PBS was studied under basic conditions and with microorganisms using the modified ASTM method. In the basic solution. PBS lost up to 85% of its mass within two days. Based upon visual observation, the crystalline structure of films composed of larger molecular weight polymers retained their crystallinity longer than similar structures in low molecular weight samples.

• Clean Technology
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• v.8 no.4
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• pp.223-228
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• 2002

The biodegradable Properties of various polyester resins with different chemical structures have been studied by applying the controlled compost test and soil burial test. Celluose was taken as a fully biodegradable reference resin while PVC and PE were empolyed as non-biodegradable reference chains or ester group were rather easily degraded by hydrolase, meanwhile copolymer type polyesters which contain aromatic rings showed relatively low biodegradability. According to the results from controlled compost test, cellulose(the positive reference) showed 70.6% degradation after 45 days, whereas synthetic poly(butylene adipate-co-succinate), poly(butylene succinate), poly(butylene adipate-co-succinate-co-terephthalate) showed 44.0%, 32.0% and 23.4% degradation respectively. In this regard, it was concluded that biodegradable properties of polymers are largely dependant on the chemical structures constituting the polymers.

• Polymer Science and Technology
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• v.18 no.5
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• pp.436-443
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• 2007

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.357-357
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• 2006

Many industrial sources of proteins can be used as raw materials to produce films, molded materials, and various hollow items either by "casting" techniques or by "thermoplastic processing". Combining proteins with natural fibbers, paper or biodegradable polyesters is very promising to form biodegradable composites witch take advantage of the barrier and mechanical properties of each component. Using nano-fillers to form nanocomposites has also been shown to be interesting to improve properties. Production, with low transformation cost, of protein based materials to form biodegradable materials with controlled functional properties for food uses, medical uses, packaging, agriculture, controlled release systems, etc. is discussed.