New conducting thermoplastic elastomers. I. Synthesis and chemical characterization

Abstract

ABSTRACT:In the last 20 years, much interest has been focused on conducting polymers to find new materials to transfer from research to industry. However, in many cases, as for elastomers for which intrinsically conducting materials are unavailable, it is necessary to use conducting particles that are physically mixed with the polymeric matrix to give loaded rubbers. In this work we report the synthesis and the chemical characterization of an intrinsically conducting material with good mechanical and electrical conduction properties. To achieve such a global goal, we covalently linked, by an amidation reaction, the terminal NH 2 of Emeraldine (EB) and sulfonated Emeraldine (SPAN) to a free carboxylic group belonging to the repetitive unit of a functionalized segmented polyurethane. The reaction was carried out by activating such a carboxylic group with N,NЈ-dicyclohexylcarbodiimide and N-hydroxysuccinimide. The reaction yields and the chemical properties of the polymers were studied by proton and carbon-13 nuclear magnetic resonance, ultraviolet, and Fourier transform infrared spectroscopy. The average numbers of EB or SPAN aromatic rings per polyether urethane acid (PEUA) repetitive unit, which cannot be assumed to be amidation degree because at this moment the molecular weights of the inserted EB and SPAN chains are unavailable, were 6 in case of the polymer obtained from the pristine Emeraldine and 1 for that obtained from the sulfonated Emeraldine. This result could be because SPAN was used in the acidic form, which depresses the nucleophilicity of the NH 2 group because of the presence of the sulfonic protons.

New conductive thermoplastic elastomers. Part II. Physical and chemical‐physical characterization

“…9 Recently we reported 10 a third method, consisting of the synthesis of copolymers prepared by grafting polyaniline (EB) or sulfonated polyaniline (SPAN) chains to the backbone of a carboxylated segmented polyurethane (PEUA) by means of an amidation reaction. From the chemical characterization of the new conducting materials 10 (PEUAPAN and PEUASPAN), the presence of an average number of one SPAN aromatic ring and three EB aromatic rings per PEUA repetitive unit was found, which cannot be assumed as amidation degree being at this moment unavailable the molecular weight of the inserted EB and SPAN chains.…”

“…Because of the high amidation degree the first process in not observable in the PEUAPAN. 10 In the PEUASPAN sample the two processes due to the decarboxylation and to the desulfonation merge in a large weight loss between 200 to 330°C. The temperature of the maximum decomposition rate is located for both the amidated polymers at 380°C, at a slightly lower temperature than that of PEUA.…”

“…Moreover, the electrical properties of these composites strongly depend on the polymer used as matrix, on the polyaniline synthesis, on doping agents, on the sample preparation method and, of course, on the concentration of the conductive filler. From the analysis reported in our previous article, 10 it was possible to estimate that the grafted conducting polymer concentration was about 13 and 5 wt % for PEUAPAN and PEUASPAN, respectively. Elastomeric conductors based on polyaniline blend, with comparable conducting filler content and neat EB conductivity, show a value lower 6,20 or similar 7 to that we have measured in our samples.…”

Inflammation and angiogenesis in osteoarthritis

“…Recently we reported10 a third method, consisting of the synthesis of copolymers prepared by grafting polyaniline (EB) or sulfonated polyaniline (SPAN) chains to the backbone of a carboxylated segmented polyurethane (PEUA) by means of an amidation reaction. From the chemical characterization of the new conducting materials10 (PEUAPAN and PEUASPAN), the presence of an average number of one SPAN aromatic ring and three EB aromatic rings per PEUA repetitive unit was found, which cannot be assumed as amidation degree being at this moment unavailable the molecular weight of the inserted EB and SPAN chains.…”

Synthesis and characterization of epoxidized polybutadiene/polyaniline graft conducting copolymer

“…In previous articles we described the synthesis1 and the physical and chemical physical characterization2 of new elastomeric copolymers obtained by grafting polyaniline (EB) or sulfonated polyaniline (SPAN) to a carboxylated segmented polyurethane (PEUA). However, the overall procedure is a quite time‐consuming process, including (a) synthesizing the noncommercial insulating matrix (typically carried out in two steps),(b) grafting the conducting polymer, and (c) eventually performing the crosslinking reaction (necessary to improve the mechanical properties of the material).…”