• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.123-128
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• 1993

The polyesters (polyhydroxyalkanoates; PHAs) production capability in a two-step cultivation of Alcaligenes eutrophus H16(ATCC 17699) was investigated by using various organic carbon sources. The carbon sources used included linear $C_2~C_10$ monocarboxylic acids, $C_3~C_10$ dicarboxylic acids, crotonic acid, and several linear vicinal and $\omega$-diols. The polyesters synthesized were characterized by 500 MHz $^1 H-NMR$ spectroscopy, intrinsic viscosity$[\eta]$ measurement in chloroform and differential scanning calorimetry (DSC). The PHAs synthesis data showed that the use of C-odd ($C_3, C_5, and C_7$) monocarboxylic acids resulted in poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(3HB-co-3HV) (3HV content ranging 40 to 70 mol%) while the use of $C_9$ substrate gave the copolyester containing only 4 mol% of 3HV. All culture products obtained on $C_3$~C$_{10}$ dicarboxylic acids gave exclusively P(3HB). 500 MHz $^1 H-NMR$ analysis showed that all polyesters synthesized generally contained 1~2 mol% 3HV even for the unrelated substrates such as the carboxylic acids with even number of carbon. When $\alpha, \omega$-diols with even number of carbon were used as substrates, 4-hydroxybutyrate(4HB) was inserted into the polyester chain composed of P(3HB-co-4HB). Vicinal diols were generally not utilized by the bacterium for polyester production.n.

• Polymer(Korea)
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• v.37 no.2
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• pp.167-176
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• 2013

Linear and cross-linked waterborne polyurethanes (WPUs) based on isophorone diisocyanate and mixed diols of poly(tetramethylene glycol)/hydroxyethyl-terminated polydimethylsiloxane (PDMS-OH) were synthesized with dimethylol propionic acid as an anionic component, trimethylolpropane as a cross-linking agent, and butanediol as a chain extender and characterized. The hydrophobicity, $T_g$, stress-strain behaviors of the linear or cross-linked siloxane-containing WPU (WPU-Si) films with different PDMS content were analyzed by using water contact shape analyzer, energy dispersive spectrometer, dynamic mechanical analyzer, and universal testing machine. The results reveal that as the PDMS content increased, the hydrophobicity of WPU-Si films increased, $T_g$ moved to higher temperature, the breaking stress increased, and the breaking strain decreased.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.341-349
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• 1996

To improve the dyeability of polyurethane (PU) resin, low molecular weight diols containing dye site in the molecular structure was added as a chain-extender. PU resin were synthesized with the variations in the chain extender, polyol type, and hard segment/soft segment (HS/SS) ratio. When HS/SS ratio is 1.4 and dimethylolpropionic acid(DMPA) or N-butyldiethanolamine (BDEA) was used as a chain extender, because of heterogeneity of reaction mechanical properties were diminished. But when N-methyldiethanolamine (MDEA) was used as a DCE, and HS/SS ratio lowed to 1.3, mechanical properties and dyeability improved. In particular, when linear type 1,4-BD was formulated with MDEA, hydrolysis resistance and mechanical properties of PTMG type PU was improved. And initial elasticity, tensile strength and elongation could be controlled by the variation of HS/SS ratio, DCE mixing ratio of 1,6-HD or NPG.