Abstract The incorporation of antimicrobials in the composites as an attempt to reduce bacterial adhesion without jeopardizing mechanical properties is a challenge for Dentistry. Objective: To evaluate the bacterial adhesion and physical properties of a composite containing the methacrylate triclosan- derivative monomer (TM). Methodology: TM was synthesized and added to an experimental composite. Samples were divided into two groups: Control and TM (13.4 wt%). Antibacterial Activity: Three specimens of each material were prepared and placed on bacterial suspensions of Streptococcus mutans for 1, 5 and 10 days. After these periods the counting of the colonies (log10) was performed. Assays was performed in triplicate. Physical Properties: Three-body Abrasion (TBA): Ten specimens of each material were prepared and stored at 37°C/24 h. The surface roughness (Ra) and hardness (KHN) were analyzed. Next, the specimens were submitted to abrasive wear (30,000 cycles) and re-evaluated for Ra and KHN; Sorption/solubility (SS): cylindrical specimens (n=10) were prepared and weighted. The specimens were immersed in deionized water for 7 days at 37°C and then their weight was verified again. SS were calculated using accepted formulas; Diametral tensile strength (DTS): specimens (n=10) underwent test performed in an Instron universal testing machine at a crosshead speed of 1 mm/min. Data were submitted to appropriate statistical tests according to data distribution and assay (p<0.05). Results: Bacterial Adhesion: TM showed a significant reduction on biofilm accumulation in the evaluated periods: 1 day (1.537±0.146); 5 days (2.183±0.138) and 10 days (4.469±0.155) when compared with Control: 1 day (4.954±0.249); 5 days (5.498±0.257) and 10 days (6.306±0.287). Physical Properties: For TBA, SS and DTS no significant difference was found between groups Control and TM. The incorporation of methacrylate triclosan-based monomer in the experimental composite reduce bacterial adhesion of S. mutans and did not affect important polymer properties.

Resumo Este trabalho teve por objetivo avaliar a influência do tratamento químico da borra de café em relação as propriedades mecânicas e térmicas, morfologia e suscetibilidade à biodegradação quando utilizada na preparação de compósitos com Poli(ε-caprolactona) comparando-o com o polímero puro. A borra de café foi submetida ao tratamento álcali com hidróxido de sódio, seguida da acetilação. Os compósitos foram preparados utilizando diferentes porcentagens de borra de café. Com tratamento químico houve um aumento na estabilidade térmica da borra de café. Houve um aumento significativo no módulo elástico para o compósito com 10% de borra de café acetilada. As imagens obtidas por MEV mostraram uma parcial interação fibra/matriz para compósitos com borra acetilada. As análises térmicas mostraram que a adição de borra de café deslocou positivamente 10º C o pico máximo de degradação térmica em relação ao polímero puro. As amostras mais suscetíveis à biodegradação foram as que continham borra de café acetilada.

Abstract This study aimed to evaluate the influence of chemical treatments of coffee grounds in relation to mechanical, thermal and morphological properties, and its susceptibility to biodegradation when used in the preparation of composites with poly (ε-caprolactone) as compared to pure polymer. The coffee grounds were submitted to alkali treatment with sodium hydroxide followed by acetylation. The composites were prepared using different percentages of coffee grounds. There was an increase in the thermal stability of coffee grounds using chemical treatment, and a significant increase of the elastic modulus for the composite with 10% acetylated coffee grounds. The images obtained by SEM showed a partial interaction between fiber/matrix for composites and acetylated coffee grounds. The Thermal analysis showed that the addition of coffee grounds positively shifted 10°C, the maximum peak of thermal degradation, as compared to pure polymer. The most susceptible samples to biodegradation were those that contained acetylated coffee grounds.

Este artigo apresenta uma revisão sobre o tema degradação térmica e estabilização do PVC. Os principais mecanismos de degradação desta resina são apresentados e correlacionados com os defeitos estruturais presentes no polímero, bem como os princípios de estabilização.

This paper presents a review of PVC thermal degradation and stabilization. The main degradation mechanisms for this resin are shown and correlated to structural defects present in the polymer, as well the stabilization principles