ABSTRACT:Copolymer particles consisting of acrylamide (AM) and acryloyloxyethyl dimethylbenzyl ammonium chloride (AODBAC) were prepared by dispersion polymerization in an aqueous solution of ammonium sulfate and in the presence of poly(acryloyloxyethyl trimethyl ammonium chloride) (PAOTAC) as the stabilizer. The average particle size ranged from 4 to 7 m, and M w and M n were 2-6 ϫ10 6 g/mol and 1-3 ϫ 10 6 g/mol, respectively. The effects of the AM/AODBAC ratio, monomer, initiator, salt, and stabilizer concentration on the particle size and molecular weight were studied. Increase of the AODBAC/AM ratio resulted in a decrease in the molecular weight and an increase in particle size. With the increase of the AODABA/AM ratio, the dispersion became less stable during long storage. Due to the presence of the salt, ionization of the quaternary ammonium groups in the dispersed particles is considered significantly suppressed.

No abstract

Natural polymers and their derivatives are attracting increasing interest as promising biodegradable materials that can meet the environmental and recycling demands from society. This study prepared biodegradable composites of cellulose diacetate and starch, and examined their physical and thermal properties. In addition, the morphology of the composites was examined by scanning electron microscopy. For melt processing, epoxidized soybean oil, as a lubricant, and triacetine, as a plasticizer, were added to the composites. The optimal conditions for the preparation of the biodegradable composites were determined. Increasing the amount of starch in the composites resulted in further enhancement of the processability of cellulose diacetate. The tensile strength and Young's modulus decreased, and the amount of elongation and Tg value increased with increasing amount of starch.

A new material, called synthetic rubber in this paper, is proposed as a material for artificial muscle actuator based on dielectric elastomer. The presented material displays enhanced electrical as well as mechanical characteristics in terms of higher dielectric constant, elastic strength and lower stress relaxation. Several experiments are performed to evaluate actuation performance of the material. Also, its advantages are proved by conducting comparative studies with the other existing materials.

Polymer gel electrolytes were prepared by thermal crosslinking reaction of a series of acrylic endcapped poly(ethylene glycol) and poly(propylene glycol) [P(EG-co-PG)] having various geometries and molecular weights. Acrylic end-capped prepolymers were prepared by the esterification of low molecular weight (M n : 1900 -5000) P(EG-co-PG) with acrylic acid. The linear increase in the ionic conductivity of polymer gel electrolyte films was observed with increasing temperature. The increase in the conductivity was also monitored by increasing the molecular weight of precursor polymer. Nanocomposite electrolytes were prepared by the addition of 5 wt % of organically modified layered silicate (montmorillonite) into the gel polymer electrolytes. The enhancement of the ionic conductivity as well as mechanical properties was observed in the nanocomposite systems.