Synthesis and characterization of functional gradient copolymers of glycidyl methacrylate and butyl acrylate Marta Fernández-García a , Pedro Francisco Cañamero b , José Luis de la Fuente b, * a Instituto de Ciencia y Tecnología de Polímeros (CSIC), Juan de la Cierva 3. 28006 Madrid, Spain b Instituto Nacional de Técnica Aeroespacial ‘‘Esteban Terradas”, INTA. Ctra. de Ajalvir, Km 4, Torrejón de Ardoz. 28850 Madrid, Spain article info Article history: Received 22 April 2008 Received in revised form 26 June 2008 Accepted 28 June 2008 Available online 5 July 2008 Keywords: Atom transfer radical polymerization (ATRP) Glycidyl methacrylate n-Butyl acrylate Gradient copolymers Microstructure abstract Epoxy-functional spontaneous gradient copolymers of glycidyl methacrylate (G) and n- butyl acrylate (B) were synthesized via atom transfer radical polymerization (ATRP). The copolymerization reactions were carried out in toluene solution at 70 °C, using methyl 2-bromopropionate (MBrP) as initiator and copper chloride with N,N,N 0 ,N 00 ,N 00 -pentameth- yldiethylenetriamine (PMDETA) as the catalyst system. The kinetic behaviour of the statis- tical copolymerizations was studied in a wide composition interval with molar fractions of G ranging from 0.10 to 0.75. The synthesized copolymers were characterized by size exclu- sion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. 1 H NMR was employed to determine the copolymer composition, demonstrating the gradient char- acter of the copolymers along the main chain in the whole monomer conversion interval. Apart from this, the sequence distribution and stereoregularity were analyzed. These microstructural experimental data agreed well with those calculated from Mayo-Lewis ter- minal model (MLTM) and a Bernoullian statistic with an isotacticity parameter of r G = 0.28 and a coisotacticity parameter of r = 0.30. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction In the recent years, the synthesis of homopolymers and copolymers with functional active groups at lateral substit- uents of the main chain has been an active field of research in polymer science. Copolymerization is the most success- ful method adopted for the preparation of materials with tailor made properties [1]. These kinds of macromolecules possess significant importance from both a fundamental and an applied point of view. One of the copolymeric sys- tems which better reflects these attributes is that based on glycidyl methacrylate (G). Therefore, copolymers of G pres- ent various industrial applications such as leather adhe- sives [2–4], pharmaceutical use for drug delivery [5], pressure sensitive adhesives [6], dental composites [7], super-absorbents [8] and non-linear optical materials [9]. Besides, this monomer enters into a vast number of chem- ical reactions by opening of its oxirane ring (active reactive group) yielding a hydroxy group on the b-carbon atom, thus offering an opportunity for chemical modifications in pendant copolymers. For example, G polymers react with amines, aminopyridines, propanesultone, and phenol. By oxidation with periodic acid, they can be transformer to polymers containing aldehyde groups that easily immobi- lize proteins via a Schiff base linkage [10]. On the other hand, it is well known that in order to achieve adequate properties, and so find widespread new applications it is necessary to use polymerization tech- niques with a precise control in the macromolecular struc- ture. The structural parameters may include molecular weight (MW) and polydispersity, composition and func- tionality as well as chain microstructure. The controlled/ living radical polymerization (CRP) has opened up a whole new dimension in the synthesis of well-defined polymers. The CRP mechanism relies on creating a dynamic equilib- rium between a low concentration of growing radicals and a large amount of dormant species which are unable 1381-5148/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.reactfunctpolym.2008.06.019 * Corresponding author. Fax: +34 91 5206611. E-mail address: fuentegj@inta.es (J. L. d. l. Fuente). Reactive & Functional Polymers 68 (2008) 1384–1391 Contents lists available at ScienceDirect Reactive & Functional Polymers journal homepage: www.elsevier.com/locate/react