• Polymer(Korea)
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• v.24 no.6
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• pp.810-819
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• 2000

Poly(p-hydroxybenzoate) (PHB)/poly(ethylene terephthalate) (PET) 8/2 thermotropic liquid crystalline copolyester, poly(ethylene 2,6-naphthalate) (PEN), and PET ternary blend was spun to fiber by melt spinninB process, and tensile properties of the fibers were measured. The matrix of the fibers, PET and PEN, were dissolved in ο-chlorophenol at 55$^{\circ}C$ for 2 hours, and the liquid crystalline polymer fibrils were observed using a scanning electron microscope. Halpin-Tsai equation for modulus calculation of short fiber reinforced composite and the rule of mixture for continuous reinforcement composite were modified, and the tensile modulus were calculated and compared with experimental modulus. To minimize difference between the theoretical and the experimental moduli, dimensionless viscosity constant (K) was given and used to modify two equations. The theoretical tensile modulus using the newly modified equations presentel a similar to the experimental tensile modulus of composite, and the modified equations presented a unique way to determine the tensile modulus of the liquid crystalline polymer reinforced thermoplastic composites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3653-3659
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• 2015

This paper describes the reactive compatibilization of blends of a wholly aromatic thermotropic copolyester liquid crystalline polymer (TLCP) with random copolymers of ethylene and acrylic acid (EAA) and their salts. Blends were prepared by melt mixing in an intensive batch mixer, and the formation of a graft copolymer due to acidolysis between the TLCP and the acrylic acid group of the ionomer was evaluated. Chemical reaction was assessed by torque measurement during melt mixing and by thermal analysis and morphological observation. The Na-salt of the EAA ionomers was especially effective at promoting a grafting reaction. The extent of reaction depended not only on the cation, but also composition of the ionomer and reaction time. The product of the grafting reaction between the TLCP and a sodium-neutralized ionomer proved to be an effective compatibilizer for TLCP and EAA ionomers.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.435-442
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• 2001

Poly(3-hydroxy-5-phenylvalerate) [P(3HPV)] was efficiently accumulated from 5-phenylvalerate (5PV) in Pseudomonas putida BM01 in a mineral salts medium containing butyric acid (BA) as the cosubstrate. A nove aromatic copolyester, poly(5 mol% 3-hydroxy-4-phenylbutyrate-co- 95 mol% 3-hydroxy-6-phenylhexanoate) [P(3HPB-co-3HPC)] was also synthesized from 6-phenylhexanoate (6PC) plus Ba. The two aromatic polymers, P(3HPV) and P(3HPB-co-3HPC), were found to be amorphous and showed different glass-transition temperatures at $15^{\circ}C$ and $10^{\circ}C$, respectively. When the bacterium was grown ina medium containing 20 mM 5PV as the sole carbon source for 140 h, 0.4 g/l of dry cells was obtained in a flask cultivation and 20 wt% of P(3HPV) homopolymer was accumulated in the cells. However, when it was grown with a mixture of 2 mM 5PV and 50 mM BA for 40 h, the yield of dry biomass was increased up to 2.5 g/l and the content of P(3HPV) in the dry cells was optimally 56 wt%. This efficient production of P(3HPV) homopolymer from the mixed substrate was feasible because BA only supported cell growth and did not induce any aliphatic PHA accumulation. The metabolites released into the PHA synthesis medium were analyzed using GC or GC/MS. Two $\beta$-oxidation derivatives, 3-phenylpropionic acid and trans-cinnamic acid, were found in the 5V-grown cell medium and these comprised 55-88 mol% of the 5PV consumed. In the 6PC-grown medium containing Ba, seven ${\beta}$-oxidation and related intermediates were found, which included phenylacetic acid, 4-phenylbutyric acid, cis-4-phenyl-2-butenoic acid, trans-4-phenyl-3-butenoic acid, trans-4-phenyl-2-butenoic acid, 3-hydroxy-4-phenylbutyric acid, and 3-hydroxy-6-phenylhexanoic acid. Accordingly, based on the metabolite analysis, PHA synthesis pathways from the two aromatic carbon sources are suggested.

• Korean Journal of Microbiology
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• v.38 no.2
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• pp.144-151
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• 2002

For elucidating the relationship between the biosynthetic pathways for polyhydroxyslkanoates (PHAs) and 5-aminolevulinic acid (ALA), culture conditions for the production of these two biomaterials by Rhodopseudomonas sp. KCTC 1437 were investigated. Of the carbon substrates tested, acetic acid was the best carbon source for cell growth and PHA biosynthesis. When succinic acid was added as a co-substrate into culture medium, cell growth and PHA production were greatly increased up to 2.5 g/ι and 73% of dry cell weight, respectively. The PHA obtained from the carbon substrates tested was homopolyester of 3-hydroxybutyrate, while valeric acid was only effective for the production of copolyester consisting of 3-hydroxybutyrate and 3-hydroxyvalerate. Anaerobic light culture condition was better for PHA production and cell growth than anaerobic dark or aerobic dark culture condition. The organism was capable of synthesizing ALA when glycine and succinic acid were added to the culture medium. ALA was produced to ca.400 mg/ι when levulinic acid, soccinic acid, and glycine were repeatedly added with a reductant (sodim thioglycolate). However, the presence of glycine, levulinic acid and sodium glycolate inhibited the cell growth and the conversion of carbon substrates to PHA. From these results it is apparent that the production yields of PHA and ALA could not be increased simultaneously because the optimal conditions for the production of PHA and ALA are opposed to each other.