The present work investigates the aquatic biodegradation of poly(3-hydroxybutyrate) (PHB)/nanoclay bionanocomposites containing PP-g-MA as compatibilizing agent. Both pristine and organically modified (Cloisite20A®) montmorillonite clay were used as fillers in different content (1 and 3 wt%). The bionanocomposites were prepared by melt intercalation in a single screw extruder. There after films (50x50x0.5mm) were prepared by compression and assessed by X-ray diffraction. Aquatic biodegradation of the films was appraised by visual inspection, optical microscopy, counting and identification of bacteria. Results proposed that the water of the Parnaíba River in the city of Teresina (Piauí, Brazil) has microorganisms (Pseudomonas putida and Pseudomonas aeruginosa) capable of degrading these bionanocomposite films, particularly the films with 3 wt% organoclay. Our data indicated the bacteria Pseudomonas aeruginosa degraded dexterously all the films. This work collaborates with the preservation of the environment and expands the use of bionanocomposites in expendable items with the development of films with properties favorable to biodegradation in aquatic environments. It is believed that PHB/clay/PP-g-MA films emerge as a promising alternative for the packaging industry.

This work developed ternary films based on Poly(Lactic Acid) (PLA), Cloisite 30B (C30B) and Oregano Essential Oil (OEO) as proposal to be applied in food packaging. The films thus manufactured were unscathed, with reduced surface defects. Their thickness and moisture content varied according to the composition and content of each component in the formulation. Optical micrographs indicated a homogeneous morphology, with good distribution of clay in the matrix. FTIR data confirms the incorporation of OEO into the films. TGA analysis indicated that the thermal stability of the films was not significantly affected by the incorporation of C30B and OEO. OEO incorporation did not promote an efficient antimicrobial action which is probably due to its retention by the clay. Further studies are needed to confirm this hypothesis. The combination between C30B and OEO in the PLA polymeric matrix is a promising proposal.

Resumo Introdução Nos últimos anos, o ácido peracético tem sido utilizado na Odontologia para desinfecção de moldes de hidrocoloide irreversível. Objetivo Avaliar a eficácia antimicrobiana do ácido peracético nas técnicas de nebulização e pulverização, em moldes de hidrocoloide irreversível. Material e método Oitenta moldes de hemiarcos de voluntários foram distribuídos aleatoriamente em quatro grupos experimentais (n=20), com respectivos controles. Os moldes foram submetidos à desinfecção por dez minutos com ácido peracético 0,2% e hipoclorito de sódio 1%, pelos métodos de nebulização, com atmosfera de 100% de umidade relativa, e pulverização. Após desinfecção, cada molde foi imerso em solução salina e submetido à vibração ultrassônica para dispersão de possíveis microrganismos. Para análise microbiológica desta solução, foi realizada contagem de colônias que cresceram em meio de cultura estéril BHI-ágar após 24 h em estufa incubadora a 37°C. Resultado Em todos os grupos, foi significante a diferença no número médio de colônias decorrentes da análise estatística do controle e do grupo experimental correspondente (p<0,05). Comparando-se o ácido peracético (0,2%) nos dois métodos, não houve diferença significativa (p=0,420); no entanto, comparando-se o hipoclorito de sódio (1%) nos dois métodos, a diferença foi estatisticamente significante (p=0,010). No mesmo método e com soluções diferentes, a nebulização com ácido peracético 0,2% foi mais eficaz que o hipoclorito de sódio 1% (p=0,030). Conclusão Ácido peracético 0,2% pode ser usado para desinfecção de moldes de hidrocoloide irreversível nos métodos de pulverização e nebulização. Hipoclorito de sódio 1% mostrou ser mais eficaz quando se usou o método de pulverização.

Abstract Introduction In recent years, peracetic acid has been used in dentistry for disinfection of irreversible hydrocolloid. Objective To evaluate the antimicrobial effectiveness of peracetic acid using nebulization and spray techniques on irreversible hydrocolloid impressions. Material and method 80 impressions of the hemi-arches of volunteers were randomly divided into four experimental groups (n = 20), with respective controls. The impressions were disinfected for 10 minutes with 0.2% peracetic acid and 1% sodium hypochlorite using the methods of nebulization in a 100% relative humidity atmosphere, and spraying. After disinfection, each impression was immersed in saline solution and subjected to ultrasonic vibration to disperse possible microorganisms. For the microbiological analysis of the solution, bacterial colonies, grown in sterile BHI-agar culture after 24h in an oven incubator at 37 ° C, were counted. Result There was a statistically significant difference between the mean number of colonies of the control and each experimental group (p <0.05). There was no statistically significant difference between the two methods when using 0.2% peracetic acid (p = 0.420). However, there was a statistically significant difference between the two methods when using 1% sodium hypochlorite (p = 0.010). Nebulization with 0.2% peracetic acid was more effective than 1% sodium hypochlorite (p=0.030). Conclusion 0.2% peracetic acid can be used for disinfection of irreversible hydrocolloid impressions using the methods of spraying or nebulization. Sodium hypochlorite (1%) proved to be more effective using the spraying method.