Polycinnamates and Block Co-polymers Prepared by Atom Transfer Radical Polymerization and Microwave Irradiation

Abstract

Homo-polymers of 2-cinnamoyloxyethyl methacrylate (PCEMA) and block co-polymers with methylmethacrylate (MMA) synthesized via copper(I)bromide/pentamethyldiethylentriamine-mediated atom transfer polymerization (ATRP) and microwave irradiation, under homo(co)polymerization conditions, are reported. Method 1 led to homo-polymers with relatively low molecular weight (PCEMA-1: 5100; PCEMA-2: 25 000), while the second method offered polymer of 100 000 average molecular weight (PCEMA-3), the polymerization being completed within 60 min. Two di-block co-polymers, poly(2-cinnamoyloxyethyl methacrylate-block-poly(methyl methacrylate)) ((PCEMA-b-PMMA)-1, (PCEMA-b-PMMA)-2) with 0.33 and, respectively, 0.5 molar fraction of photo-cross-linkable PCEMA were also prepared and utilized for this study. Subsequent gel-permeation chromatography (GPC) measurements on block co-polymers have indicated molecular weights of 24 000 and 45 700, respectively. In addition, structural characteristics for all photo-polymers were determined by FT-IR, 1 H-NMR, UV-Vis spectroscopy, AFM and SEM/ESEM measurements. Photochemistry in thin polymeric films suggested that UV irradiation is accompanied by an insolubilization of the film caused by the transformation of cinnamate moieties and the formation of intermolecular cross-links, with important effects on the morphology. As expected, it was found that by electrospinning the above photo-polymers produced electrospun fibers of small diameter.

Electrospinning Multiwalled Carbon Nanotubes–Polyurethane Composite Fibers

“…Increasing the concentration of composite, electrospinning generally produces non-woven matrices with randomly arranged, ultrafine fibers with nanometer diameters (Fig. 6B-D) [26]. Figure 6E shows the SEM image of MWCNTs-PU (Run 3-1) with higher CNTs content as the use of solvent as DMF with the combination of optimal process conditions in this work.…”

Preparing and structuring of block copolymers with cinnamate and adamantane moieties

“…Poly(2-cinnamoyloxyethyl methacrylate)-Br (PCEMABr) prepared as previously reported [35] was used as macroinitiator, the molar ratio of the components 2-cinnamoyloxyethyl methacrylate (CEMA)/(N,N,N′,N′, N″-pentamethyldiethylentriamine) (PMDETA)/ethyl 2-bromoisobutyrate (EBiB) /CuBr being 25:2:1:1. ).…”

“…The second macroinitiator, poly(2-cinnamoyloxyethyl methacrylate-block-poly(methyl methacrylate)-Br was obtained by a method described earlier [35], with the mention that the molar ratio of components used in synthesis was MMA/PMDETA/PCEMA-Br/CuBr = 18:2:1:1. …”

“…Electrospinning was carried out according to our previous report [35], starting from solutions of block copolymers (PCEMA-b-PMAdU and PCEMA-b-PMMAb-PMAdU) in a solvent mixture (DMF/chloroform: 3:1 v/v). The electrospinning apparatus was composed of several components: a high-voltage supplier (Gamma High Voltage Research, E3 30P-5 W), a capillary tube with a stainless steel needle, a syringe pump (Harvard Apparatus), and a stainless steel collecting screen.…”

“…The advantages of this powerful technique to produce polymer nanofibers have provided impetus for novel developments in the above mentioned field. Recently, we have reported the synthesis of poly (2-cinnamoyloxyethyl methacrylate) (PCEMA) by microwave-mediated polymerization and ATRP, together with the corresponding block copolymers with methyl methacrylate, accompanied of a study concerning the formation of electrospun micro/nanofibers [35]. Having this in mind, the present work is focused on a combination of the above presented polymers into an attempt to create several polymeric materials.…”