For improving the adhesion property of ethylene-co-n-butyl acrylate copolymer (EBA) at ambient temperature, binary blends of EBA with 27 wt% n-butyl acrylate and different amounts (20–62 wt%) of low molecular weight hydrogenated glycerol rosin ester (ECH) resin have been prepared. The addition of glycerol rosin ester resin decreased the crystallinity and size of the ethylene domains of the EBA copolymer. The addition of up to 50 wt% (100 phr) ECH resin improved the compatibility with the EBA copolymer, whereas when more than 50 wt% (100 phr) ECH resin was added, the compatibility of the blends did not change but the viscoelastic properties were noticeably decreased. Furthermore, the compatibility was noticeably improved by adding only 20 wt% ECH resin although the best compromise between compatibility and viscoelasticity corresponded to the binary blend made with 43 wt% ECH resin. The EBA copolymer + ECH resin blends showed high tack (initial adhesion) at 25 °C and some of them even at 5 °C, and they have adequate 180° peel strength both to polar (polyethylene terephthalate-PET) and nonpolar (polypropylene-PP) substrate. Furthermore, all EBA copolymer + ECH resin blends showed high shear strength at 25 °C. Finally, the blend with 43 wt% ECH resin showed excellent pressure sensitive adhesive property exhibiting excellent creep, high tack, high 180° peel strength, and high single lap-shear strength.
Three different conducting polymers, polythiophene (PT), polypirrol (PPY) and polyaniline (PANI) have been synthesized via oxidative chemical polymerization in aqueous media, in such a way that the synthesis protocol did not involve any toxic solvents. They have been tested in the abatement of nitrates from an aqueous solution without the need of any metal catalyst. The N-containing polymers (PANI and PPy) were able to remove nitrates to a level that accomplishes the European legislation requirements; however, the nature of each polymer greatly influenced the process mechanism. Whereas ion exchange between Cl and SO counter-ions in the polymer and NO from water is the main responsible for the effective nitrate removal in PANI, as assessed by FTIR and XPS analyses, the nitrate removal mechanism on PPy is based in an electron transfer from the polymer to nitrate through N sites located in the pyrrolic ring. On the other hand, PT was not able to exchange nitrate unless it was synthesized with FeCl as oxidant/dopant and an anionic surfactant (sodium dodecyl sulfate -SDS-) is used. In that case, the electrostatic attraction between sulfate (OSO) groups from the surfactant and Fe ions from FeCl produced the anchoring of Cl to the oxidized PT growing chain, this favoring ion exchange with nitrate in the aqueous solution, followed by a redox process.
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