Correspondence to: Lincoln I. Nojima Universidade do Brasil UFRJ Faculdade de Odontologia Programa de Pós-graduação em Odontologia Av. Professor Rodolpho Paulo Rocco, 325 Ilha do Fundão Rio de Janeiro RJ Brasil CEP: 21941-617 Phone: 2590-2727 / Fax: 21-2590-9771 E-mail: [email protected] Abstract Aim: To assess the flexural strength of orthodontic acrylic resins from two different manufacturer...

Polyphenolic resol resins were obtained from an ethanolic extraction of green plantain peels (Musa paradisiaca) grown in Colombia. A synthesis was then performed by polycondensation in an alkaline pH solution in order to perform research on phenolic resin production with high mechanical performance. The polymers were characterized by DSC and TGA analyses and the resins showed a melting point of...

Phenol formaldehyde (PF) resins are widely used as wood adhesives in the industrial production of exterior-grade plywood panels, oriented strand board panels and particleboards due to their superior performance including high bonding strength, heat resistance, excellent water resistance and chemical stability1. However, phenol, one raw material for the synthesis of PF resins, is a petroleum-bas...

For the development of a cost-effective melamine-modified urea formaldehyde resin (MUF), the study evaluated the effects of reaction pH and melamine content on resin properties and bond performance of the MUF resin adhesive systems. Eight resins, each with three replicates, were prepared in a factorial experiment that included two formulation variables: two reaction pHs (i.e., 4.5 and 8.0) and ...

The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymeriz...

Objective This study investigated the wear resistance of injection-molded thermoplastic denture base resins using nanoindentation instrument. Materials and methods Six injection-molded thermoplastic denture base resins (two polyamides, two polyesters, one polycarbonate, one polymethylmethacrylate [PMMA]) and a PMMA conventional heat-polymerized denture-based polymer control were tested. Elastic...

Six thermoplastic resins and conventional acrylic resin were examined to characterize their mechanical and physical properties, water sorption, solubility, flexural strength, modulus of elasticity, tensile strength and color stability. Thermoplastic resins for non-metal clasp dentures exhibiting low water sorption and solubility offer hygienic advantages. Since they have a low modulus of elasti...

The previous study on low mole ratio urea-formaldehyde (UF) and ureamelamine–formaldehyde (UMF) resins synthesized in the typical way as particleboard binders was repeated with the inclusion of a strong acidic reaction step at a mole ratio of 2.7 in the beginning of the resin synthesis procedure. The resulting UF and UMF resins showed longer storageand pot-lives, longer gel times, and the parti...

A new group of synthetic resins (the ethoxyline or epoxide resins) has been widely accepted in industry during the last few years. These resins, thanks to their novel properties as adhesives and casting resins, are used in the modern manufacture of various kinds of apparatus, of electrical equipment, of automobiles, and of aircraft. They are usually supplied in the form of two reactive componen...