FT-IR Study of Blends and Complexes of Poly(mono n-alkyl itaconates) with Poly(N,N-dimethylacryl amide) and Poly(ethyloxazoline) Emilio Meaurio, Issa Katime* Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Departamento de Quı ´mica Fı ´sica, Facultad de Ciencias, Universidad del Paı ´s Vasco, Campus de Leioa, Apartado 644, Bilbao, Espan ˜a E-mail: issa.katime@ehu.es Received: July 1, 2005; Revised: August 31, 2005; Accepted: September 26, 2005; DOI: 10.1002/mame.200500233 Keywords: blends; complexes; FT-IR; hydrogen bonding; polyacids; polybases; poly(ethyloxazoline); poly(mono n-alkyl itaconates); poly(N,N-dimethylacrylamide); specific interactions Introduction When two miscible polymers are mixed, a polymer blend or a polymer complex can be obtained, depending upon the polymer system and the mixing procedure. Regarding the polymer system, complexes can only be obtained when specific interactions are present between the polymer chains. On the other hand, this is not a prerequisite to obtain polymer blends. This kind of materials can be obtained too with polymers of similar nature, [1] dispersive forces being the miscibility driving force, although this is a rare situation. There are two main procedures to obtain polymer- polymer complexes. The first one is matrix polymerization (polymerization of a solution containing one of the mono- mers and the second polymer). The second one is mixing of solutions of the polymers in a common solvent in which polymer-polymer interactions are stronger than polymer- solvent ones. In this case, phase separation is observed and the interpolymer complex precipitates. It is accepted that Summary: This paper reports an FT-IR study of blends and complexes of poly(mono n-alkyl itaconates) with poly (N,N-dimethylacrylamide) (PDMA) and poly(ethyloxazo- line) (PEOX). Strong hydrogen bonding has been found and both polybases have shown similar acceptor strengths. The extent of the interassociation has been estimated by spectral curve fitting of the polybase carbonyl band. The influences of the solvent medium and alkyl side group length of the poly (mono n-alkyl itaconate) on the interassociation extents have been discussed. Blend and complex interassociation behavior has been compared too. Results show that media influences the interassociation degree in systems with PDMA, but has negligible influence in systems with PEOX. Moreover, the interassociation degree in blends with PEOX does not depend on the length of the poly(monoalkyl itaconate) side group, while an interassociating ability loss is observed in blends with PDMA as the side group size of the polyacid increases. This different behavior is attributed to the greater interspac- ing between vicinal carbonyl groups in PEOX. Anyway, this band shows conformational sensitivity and reflects the con- formational changes that are forced to adopt as the steric hindrances present in the medium (due to the bulky side groups of the polyacids) increase. Auto scaled carbonyl stretching region for PMBuI/PEOX complexes. Macromol. Mater. Eng. 2005, 290, 1166–1175 ß 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1166 DOI: 10.1002/mame.200500233 Full Paper