Preparation and characterization of polystyrene-b-poly(2-vinylpyridine) coordinated to metal or metal ion nanoparticles

Abstract

a b s t r a c tIn this study, Co, Cr or Au 3+ functional polystyrene-block-poly(2-vinylpyridine), PS-b-P2VP complexes were prepared and characterized. Coordination of metal atom or ion to nitrogen atom of pyridine rings was confirmed by FTIR analyses. The strength and efficiency of coordination of P2VP blocks to Co, Cr or Au 3+ mainly depends on charge and stability of the complex formed that is mainly related to the energy of d orbitals. The results reveal that the thermal stability of the polymer composite formed increases with the increase in strength of the coordination. Changes in thermal decomposition mechanism and product distribution were recorded. Degradation of P2VP units coordinated to Cr, Co or Au 3+ was started by loss of pyridine units leaving an unsaturated and/or crosslinked polymer backbone that degraded at relatively high temperatures.

Preparation and thermal characterization of poly(2‐vinylpyridine) copolymers coordinated to Cr nanoparticles

“…Actually, a careful analyses of pyrolysis mass data indicated, although weak, evolution of new products that can be associated with fragments involving unsaturation, such as fragments 281 and 355 Da that can be associated with C 21 H 29 and C 27 H 31. These species showed three maxima in their evolution profiles at 405, 484 and 547°C. It may be thought that a degradation mechanism involving loss of side chains in the first step became preferential compared to the depolymerization mechanism as a result of the increase in the mass of the side chains generating conjugated double bonds and/or cross‐linked segments along the main chain as shown in Scheme .…”

“… These species showed three maxima in their evolution profiles at 405, 484 and 547°C. It may be thought that a degradation mechanism involving loss of side chains in the first step became preferential compared to the depolymerization mechanism as a result of the increase in the mass of the side chains generating conjugated double bonds and/or cross‐linked segments along the main chain as shown in Scheme . Elimination of fragments involving unsaturation at slightly higher temperatures supported this proposal.…”

“…In order to investigate the effects of metal coordination on thermal characteristics, the thermal degradation behavior of the copolymers has to be known. Recently, we reported the thermal degradation characteristics of three common diblock copolymers polystyrene‐b‐poly(2‐vinylpyridine) (PS‐b‐P2VP), polyisoprene‐b‐poly(2‐vinylpyridine) (PI‐b‐P2VP) and poly(2‐vinylpyridine)‐b‐poly(methyl methacrylate) (PMMA‐b‐P2VP) . We have determined that thermal decomposition of each block took place independently without being affected by the presence of the other block in the cases of PS‐b‐P2VP and PI‐b‐P2VP; depolymerization of PS blocks yielding mainly the monomer styrene, cleavages at the β positions of carbon–carbon single bonds of PI blocks accompanied with dehydrogenation and aromatization reactions producing isoprene and dipentene and decomposition of P2VP through a complex degradation mechanism producing mainly monomer, low mass oligomers and their protonated analogues in accordance with literature findings.…”

“…We have also studied the thermal behavior of PS‐b‐P2VP coordinated to Co, Cr and Au 3+ nanoparticles via DP‐MS technique to elucidate the effect of metal coordination on thermal stability and degradation mechanism . It has been determined that the strength and efficiency of coordination of P2VP blocks to Co, Cr or Au 3+ mainly depend on charge and stability of the complex formed that is mainly related to the energy of d orbitals.…”

Characterization of Polystyrene-block-Poly(2-vinyl pyridine) Copolymers and Blends of Their Homopolymers by Liquid Chromatography at Critical Conditions

“…Amphiphilic block copolymers consisting of poly­(2-vinyl pyridine) (P2VP) as a hydrophilic part and polystyrene (PS) as a hydrophobic segment have remarkable applications in advanced technologies such as information storage, biosensors, and photonic crystals owing to strong affinity of amine groups toward ions and polar moieties. , Likewise, the repeated presence of amine groups in the P2VP block favors the interaction of these block copolymers with metals that have been exploited for stabilization of metal nanoparticles. − The presence of a lone pair of electrons on nitrogen of the pyridine repeat unit plays a very important role in the aforementioned applications. Nonetheless, the presence of this lone pair makes them a challenging case for synthesis and characterization of P2VP homo- and copolymers by separation techniques. , …”