Post consumer pet depolymerization by acid hydrolysis

The reaction of post-consumer poly(ethylene terephthalate) with aqueous solutions of sulfuric acid 7.5M was investigated in terms of temperature, time and particle size. The reaction extent reached 80% in four days at 100 degrees C and 90% in 5 hours at 135 degrees C. TPA obtained was purified and considered in the same level of quality of the commercial one after tests of elemental analysis, particle size and color. It was concluded that the hydrolysis occurred preferentially at the chain ends and superficially, having as controller mechanism the acid diffusion into the polymer structure. The shrinking-core model can explain the reaction kinetics.

Metacromasia para identificação de basófilos sanguíneos em surubim híbrido: contribuição metodológica

Padua S.B. & Ishikawa M.M. [Metachromasia for blood basophils identification in hybrid surubim catfish: methodological contribution]. Metacromasia para identificacao de basofilos sanguineos em surubim hibrido: contribuicao metodologica. Revista Brasileira de Medicina Veterinaria, 33(3):147-150, 2011. Centro de Aquicultura da Unesp/Jaboticabal Rod. Paulo Donato Castellane, s/n Bairro Rural, Jaboticabal, 14884-900, SP. Brasil. E-mail: santiagopadua@live.comDifferent protocols of fixation and hydrolysis of blood smears of hybrid surubim catfish for metachromasia to marking blood basophils were evaluated. For this reason, methanol, acid-alcohol and formalin vapor were tested as fixatives. For hydrolysis of blood smears, HCl, citric acid and 2-Mercaptoethanol + Urea + NaCl solutions was evaluated. After procedures, the blood smears was stained with toluidine blue (0.025%) diluted in McIlvaine buffer (pH 4). The different protocols for fixation and hydrolysis of blood smears for metachromasia influenced the quality of the reaction. Hydrolysis with 2-Mercaptoethanol + Urea + NaCl solutions provided negative results when using methanol and acid-alcohol as fixatives. The fixation with acid-alcohol associated with citric acid hydrolysis provides highest quality reason.