The fluoride ion has a well-established beneficial role in dentistry in protecting the teeth from assault by caries. It is known to contribute to the dynamic mineralisation process of the natural tooth mineral, and also to become incorporated with the mineral phase, forming a thin layer of fluorapatite. This is more resistant to acid attack than the native hydroxyapatite, hence protects the too...

Water-soluble perfluorocyclobutyl (PFCB) aryl ether ionomers bearing sulfonic acid groups in the main chain and phosphonic acid end groups were prepared and used to modify the surfaces of mesoporous carbon materials containing dispersed zirconia nanoparticles. Ionomer surface grafting occurred via phosphonate bonding onto the zirconia particle surfaces.

OBJECTIVE The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. MATERIAL AND METHODS Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional com...

OBJECTIVES This study evaluated the mortality experience of workers from the styrene-butadiene rubber industry. Concerns about a possible association of 1,3-butadiene and styrene with lymphohaematopoietic, gastrointestinal, and lung cancers prompted the investigation. METHODS A retrospective follow up study was conducted of 15,649 men employed for at least one year at any of eight North Ameri...

In this work, the influence of three types of styrene maleic anhydride (SMA) oligomers on the adhesion of polystyrene wood plastic composites (WPC) was investigated. The composites were processed on a twin-screw co-rotating extruder below 200°C using 20 wt% of wood flour. The styrene maleic anhydride with different content of maleic anhydride groups, 30%, 25% and 20% (w/w) and levels of 1, 2 an...

A physically based diffusion model is used to evaluate the sink effect of diffusion-controlled indoor materials and to predict the transient contaminant concentration in indoor air in response to several time-varying contaminant sources. For simplicity, it is assumed the predominant indoor material is a homogeneous slab, initially free of contaminant, and the air within the room is well mixed. ...

INTRODUCTION With the development of living cationic polymerization of isobutylene (IB)1 and styrenic monomers,2–5 the synthesis of ABA triblock copolymer thermoplastic elastomers (TPEs) with polyisobutylene (PIB) as rubbery middle segments and styrenic polymers as plastic outer segments became possible. TPEs with PIB rubbery segments inherently exhibit superior oxidative, chemical and thermal ...

4-chloromethyl styrene homopolymer and its copolymers with styrene were prepared from their corresponding 4-chloromethyl styrene and styrene monomers at 1:0, 1:1, 1:3 and 1:5 mole ratios. these homo- and copolymerswere synthesized by radical polymerization in presence of aibn as initiator and dry toluene as solvent. then, chloromethyl groups were converted into azidomethyl groups on the homo- a...

Fuel cells used for transport applications hold polymer membranes as a key element. Their efficiency can be significantly increased if structured ion channels are implemented at the molecular level into proton-conducting membrane. New functional molecules with selective affinity ionomers needed to obtain such membrane design. This study presents method screen peptide binders perfluorinated sulf...

Six male subjects were exposed for two hours during light physical exercise to 2.81 mmol/m3 (293 mg/m3) of styrene on one occasion and to a mixture of 2.89 mmol/m3 (301 mg/m3) of styrene and 21.3 mmol/m3 (1240 mg/m3) of acetone on another (combination study). About 68% of the dose (somewhat more than 4 mmol) of styrene was taken up. The arterial blood concentration of styrene reached a relative...