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Recebido em 19/7/06; aceito em 9/3/07; publicado na web em 24/7/07 STUDY OF THE PROPERTIES AND BIODEGRADABILITY OF POLYESTER/STARCH BLENDS SUBMITTED TO MICROBIAL ATTACK. This work deals with the biodegradation of blends of poly(β-hydroxybutyrate)/starch and poly(β-hydroxybutyrate-cohydroxyvalerate)/starch. The blends were obtained by evaporation of the solvent in the mixture of the polymers in chloroform. Tests were carried out in presence of micro-organisms which acted as biodegradation agents. The blends were consumed as carbon substrate and the production of CO 2 was evaluated in the process. In addition, the polyesters' mechanical properties were reduced by the incorporation of starch in its structure.( 1 H) NMR and infrared spectroscopy detected some characteristic polyester degradation groups in the polyesters' chemical structure, thus confirming the alteration suffered by it.Keywords: biodegradation; fungi; blends. INTRODUÇÃOO desenvolvimento na segunda metade do século XX foi profundamente marcado pelo surgimento dos materiais poliméricos e plásticos, os quais constituem atualmente boa parte dos materiais utilizados pelo homem.Os plásticos têm papel fundamental na sociedade moderna, mas devido ao fato de algumas aplicações destes materiais serem de descartabilidade muito rápida, associado à grande dificuldade de degradação no ambiente, podendo demorar séculos para se degradar e ocupando grande volume na área dos aterros, têm despertado fortes preocupações nos dias atuais [1][2][3][4][5][6][7] . O aumento no interesse científico pela área ambiental, atraído pelo crescimento explosivo do consumo de polímeros ou plásticos e pela disposição final destes resíduos sólidos urbanos, tem tornado cada vez mais necessária, a produção de substitutos ambientalmente sustentáveis, importantes no gerenciamento de resíduos, os chamados polímeros ou plásticos ambientalmente degradáveis (PADs), compostos por um vasto grupo de materiais poliméricos, naturais e sintéticos, que sofrem alterações químicas sob a influência de fatores ambientais 8 . Devido à preocupação mundial em não agredir o meio ambiente, um tipo de material polimérico vem merecendo atenção, os polidroxialcanoatos, principalmente o poli(β-hidroxibutirato) -PHB e seu copolímero poli(hidroxibutirato-co-valerato)-PHB-HV. A produção desses biopolímeros em grande escala acontece por um processo de fermentação bacteriana, sendo ainda um processo relativamente caro 9,10 . As blendas poliméricas usando o amido, em mistura com os polímeros biodegradáveis e polímero sintético, surgem como uma boa alternativa para minimizar os custos dos polímeros biodegradáveis, bem como aumentar a biodegradação dos polímeros sintéticos. Além disso, o amido é um material de baixo custo com valor estimado de US$ 0,50/kg 11 , sendo uma matéria-prima abundante que permite o desenvolvimento de produtos recicláveis e quando biodegradado ou incinerado libera CO 2 para a atmosfera 12 . Acredita-se que a mistura do plástico convencional com o polímero biodegradável possa resultar em um materi...

-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one JT69; 3-(4-phenyl-benzyl)-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one

Galvanized steel has been widely applied in different applications and the industry significantly increased its production in recent years. Some galvanized structures can be completely or partially buried, such as transmission tower footings. The corrosion of these metallic structures is related to the soil chemical and physicochemical properties, which define the aggressiveness of the environment. To assess the effect of the soil moisture on galvanized steel corrosion, a comparative study was carried out. Carbon steel coupons, with or without galvanization, were buried in clay soil collected from an industrial region in the northeast of Brazil. The chemical, physicochemical and microbiological characteristics of the soil were determined. The thickness of the galvanized coating was measured by scanning electron microscopy (SEM). Corrosion tests were conducted in different soil moisture conditions using the following techniques: potentiodynamic polarization curves and gravimetric tests. The results showed the influence of soil moisture on corrosion rates. The electroplating decreased corrosion rates, especially when the coupons were exposed to low moisture soil.

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zolidinediones. -The title compounds (III) and (VI) are prepared by a nucleophilic addition of cyanoacrylates to the corresponding thiazolidinediones. Derivatives (III) demonstrate glucose and triglyceride lowering activities. -(MOURAO, R. H.; SILVA, T. G.; SOARES, A. L. M.; VIEIRA, E. S.; SANTOS, J. N.; LIMA, M. C. A.; LIMA, V. L. M.; GALDINO, S. L.; BARBE, J.; PITTA*, I. R.; Eur.

High-strength low-alloy steel is used in pipelines, which transport oil/gas and also produced water in the process of the secondary recovery of oil. This paper investigates the corrosion of X80 steel after immersion in static systems (biotic and abiotic). The corrosion rate, the corrosion morphology and the hardness of the coupons were investigated. The corrosion products were determined by SEM/EDS and XRD. The corrosion rates of the coupons in the biotic system were moderate and had an agressive pit morphology, while those of the coupons in the abiotic system were low with less aggressive pit. The hardness of the coupons after exposure to the systems of produced water was not changed compared with that of the control coupons. The corrosion products formed in the biotic system were Fe(OH) 3 , Fe(OH) 2 , FeOOH, Fe 3 O 4 , FeS 2 , FeCl 3 , and in the abiotic system, NaCl, CaCl 2 and SrSO 4 . BaSO 4 and CaCO 3 were identified in both systems.