STATEMENT OF PROBLEM Dynamic mechanical properties of hard, direct reline resins are important factors in the clinical success of dentures. However, little information is available on the nature of these properties. PURPOSE This study evaluated the dynamic mechanical properties of a variety of hard, direct reline resins: (1) visible light-polymerized, powder-liquid type, (2) visible light-pol...

A petroleum fluid can be di®ided into three types of species: asphaltenes, resins, and oils. Asphaltenes and resins are polar, while the rest of the so-called oils are either nonpolar or mildly polar. The interaction among these species strongly affect asphaltene precipitation from petroleum fluids. Different measuring methods for asphaltenes in a petroleum fluid gi®e similar results, but diffe...

Background and Purpose: In people wearing dentures, the growth of various Candida species under the prosthesis leads to the formation of biofilm, which can play the role of a reservoir for Candida and other kinds of microbes. Since nano-chitosan particles can cause lasting antimicrobial activity, a more recent approach that utilizes acrylic resins with nano-chitosan particles is proposed. Th...

to evaluate the ultimate compressive strength of five composite resins after 1 hour, 24 hours, 7 days and 1 month. twenty four cylindrical 4 mm×8mm specimens of each commonly used composite resins in posterior region (nulite-f , z250 , p60, biscore, tetric ceram hb) were prepared. each group of composite resins were divided into four time groups of 1 h, 24 h, 7 days and 1 month. all of specimen...

The marginal fracture toughness of several types of composite resins was determined by means of the rattler test. Microparticle-filled resins showed significantly higher marginal fracture toughness than conventional composites. Posterior restorative composites were intermediate between MFRs and conventional composites. Amalgams were inferior to restorative resins. These data correspond with the...

Strong base anion-exchange resins represent an important option for water utilities and homeowners to address growing concerns with nitrate, arsenate, and perchlorate contamination of source waters. Most commercially available anion-exchange resins employ quaternary amine functional groups. Previous research has provided contradictory evidence regarding whether these resins serve as sources of ...

BACKGROUND Chemicals that have estrogenic activity (EA) can potentially cause adverse health effects in mammals including humans, sometimes at low doses in fetal through juvenile stages with effects detected in adults. Polycarbonate (PC) thermoplastic resins made from bisphenol A (BPA), a chemical that has EA, are now often avoided in products used by babies. Other BPA-free thermoplastic resins...

A new, easy and cost-effective synthetic procedure for the preparation of thermosetting melamine-based epoxy resins is reported. By this innovative synthetic method, different kinds of resins can be obtained just by mixing the reagents in the presence of a catalyst without solvent and with mild curing conditions. Two types of resins were synthesized using melamine and a glycidyl derivative (res...

Thin-layer chromatography/flame ionization detection (TLC/FID) allows for the fractionation of bitumen into four fractions, namely, the saturates, the aromatics, the resins A and the resins B (SARAB). The technique is rapid and economical, but it lack reproducibility. The effect of chromarod aging on reproducibility was investigated along with that of the time between bitumen dissolution and it...