• Journal of Life Science
• /
• v.22 no.9
• /
• pp.1187-1193
• /
• 2012

This study was conducted to evaluate effects of halogenated compounds on in vitro rumen fermentation characteristics and methane emissions. A fistulated Holstein cow of 650 kg body weight was used as a donor of rumen fluid. Five kinds of halogenated compounds (bromochloromethane (BCM), 2-bromoethane sulfonic acid (BES), 3-bromopropanesulfonic acid (BPS), chloroform (CLF), and pyromellitic diimide (PMDI) known to inhibit methyl-coenzyme M reductase activity were added to an in vitro fermentation incubated with rumen fluid. The microbial population including bacteria, protozoa, and fungi were enumerated, and gas production including methane and fermentation characteristics were observed in vitro. The pH values ranged from 6.25 to 6.72 in all the treatments, and these showed a similar level at 48 hr. The total gas production in the treatments showed a similar pattern with C at 48 hr, whereas methane production in the treatments was lower (p<0.05) than C. Concentrations of total volatile fatty acids (VFAs) and propionic acid were higher (p<0.05) in the treatments than in C at 12 hr. Therefore, halogenated compounds (BCM, BES, BPS, CLF, and PMDI) inhibited in vitro methane emissions by inhibiting methanogens in the rumen. Further studies on safety are needed.

• Elastomers and Composites
• /
• v.47 no.4
• /
• pp.355-363
• /
• 2012

A series of poly(hydroxyamide)s (PHAs) having trifluoromethyl group were prepared by direct polycondensation of aromatic diimide-dicarboxylic acids with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane by thionyl chloride and triethyl amine in N-methyl-2-pyrrolidinone (NMP). The PHAs exhibited inherent viscosity in the range of 0.54-0.96 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs were readily soluble in a variety of organic solvents, whereas the polybenzoxazoles (PBOs) were quite insoluble except partially soluble in sulfuric acid. PHAs were converted to PBOs by thermal cycling reaction with heat of endotherm. The maximum weight loss temperature of the PHAs occurred in the range of $559-567^{\circ}C$. The PBOs showed relatively high char yields in the range of 47-59%. Pyrolysis Combustion Flow Calorimeter (PCFC) results of the PBOs showed 12-19 W/g heat release rate (HRR), and 2.7-3.6 kJ/g total heat release (total HR). The HRR of PBO 1 showed the lowest value of 12 W/g, which was 37% lower than that of PBO 3 (19 W/g).