The mechanical properties of an ultrathin film made from a thermoplastic differ the bulk due to presence free surface. Here, molecular dynamics simulations are used explore thickness dependence uniaxial and equi-biaxial tensile responses polymethyl methacrylate (PMMA) films. sensitivity deformation response temperature, weight degree side-branching is determined. We find that failure strain dec...

Background and objectives: Essential oils (EOs) of medicinal herbs are prone to degradation by oxidation, heating, or light. Encapsulation of EOs can protect these fragile volatile natural products from degradation. Thymus vulgaris (thyme) is a well-known herb which has been used as food additive as well as medicine since ancient times. Electrospraying is a novel techn...

In this work, an efficient procedure for the functionalization of multiwalled carbon nanotube (MWCNTs) based on nitric acid oxidation was presented. The morphologies of MWCNTs oxidized under various conditions were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The FTIR provided clear evidence for the presence of carboxylic groups (–COOH)...

Background and aims. Polymethyl methacrylate, PMMA, is widely used in prosthodontics for fabrication of removable prostheses. This study was undertaken to investigate the effect of adding silver nanoparticles (AgNPs) to PMMA at 2% and 0.2% concentrations on compressive and tensile strengths of PMMA. Materials and methods. The silver nanoparticles were mixed with heat-cured acrylic resin in an a...

Porous ceramics of Y2O3-stabilized ZrO2 (YSZ) were prepared by tape-casting methods using both pyrolyzable pore formers and NiO followed by acid leaching. The porosity of YSZ wafers increased in a regular manner with the mass of graphite or polymethyl methacrylate (PMMA) to between 60% and 75% porosity. SEM indicated that the shape of the pores in the final ceramic was related to the shape of t...

STATEMENT OF PROBLEM Poor wettability of denture relining materials may lead to retention problems and patient discomfort. PURPOSE Purpose of this study is to compare and evaluate wettability of nine denture relining materials using contact angle measurements under air and water storage over time. MATERIAL AND METHODS Nine denture relining materials were investigated in this study. Two heat...

Wetting of polymer-grafted nanoparticles (NPs) in a polymer nanocomposite (PNC) film is driven by difference surface energy between components as well bulk thermodynamics, namely, the value interaction parameter, χ. The interplay these contributions investigated PNC containing 25 wt % polymethyl methacrylate (PMMA)-grafted silica NPs (PMMA-NPs) poly(styrene-ran-acrylonitrile) (SAN) upon anneali...

OBJECTIVES The aim of this study was to assess and compare the water sorption and flexural strength of thermoplastic and conventional acrylic resins. MATERIALS AND METHODS Water sorption and flexural strength were compared between a thermoplastic modified polymethyl methacrylate (PMMA) denture base resin (group A) and a heat-polymerized PMMA acrylic resin (group B) as the control group (n=10)...

This article compares resonant ultrasound spectroscopy ~RUS! and other resonant methods for the determination of viscoelastic properties such as damping. RUS scans from 50 to 500 kHz were conducted on cubical specimens of several materials including brass, aluminum alloys, and polymethyl ~methacrylate! ~PMMA!, a glassy polymer. Comparison of damping over the frequency ranges for broadband visco...