Characterization of New Amphiphilic Block Copolymers of N‐Vinyl Pyrrolidone and Vinyl Acetate, 1 – Analysis of Copolymer Composition, End Groups, Molar Masses and Molar Mass Distributions

Abstract

New amphiphilic block copolymers consisting of N‐vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4‐dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. 13C NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, 13C NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non‐ideal RAFT mechanism.

Characterization of New Amphiphilic Block Copolymers of N‐Vinylpyrrolidone and Vinyl Acetate, 2 ‐ Chromatographic Separation and Analysis by MALDI‐TOF and FT‐IR Coupling

“…This explanation is supported by the results of the investigation of sample 4, which has a significantly higher molecular mass than the other three samples. [1] Thus, the peak at 10 mL became very intense, as shown in the chromatogram (Figure 5d). …”

“…Typical RAFT end groups (propionic acid/butyronitrile) could be detected. [1] In addition, the formation of dioxane end groups was univocally proved by means of MALDI-TOF MS as well.…”

“…A characterization of formed copolymers with regard to molecular masses, mass distributions and copolymer composition was performed using NMR, gel permeation chromatography (GPC) and multi-angle laser light scattering (MALLS) and is described in detail in ref. [1] Liquid Chromatography An Agilent 1100/1200 series chromatograph (Agilent; USA) combined with an evaporative light scattering detector (ELSD; PL-ELS 1000; Polymer Laboratories; GB) was used. Acetonitrile (AcN), methanol (MeOH) (HPLC quality; Roth; Germany), N,Ndimethylacetamide (DMAc) (HPLC quality; Fluka; Germany) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) (>99.5%; Acros Organics; Belgium) were used as solvent.…”

Preparation of a Mini-Library of Thermo-Responsive Star (NVCL/NVP-VAc) Polymers with Tailored Properties Using a Hexafunctional Xanthate RAFT Agent

“…Characteristics of the star ((PNVCL-co-PNVP)-b-PVAc) 6 copolymers. , where X and Y are the respective molar ratios of PNVCL and PNVCL block in the star copolymer; the dn/dc value for PNVCL is 0.109 mL/g [35] and 0.1194 mL/g [72] for PNVP. c Determined by DLS (1 mg/mL) in water at room temperature.…”

Synthesis of Water‐Soluble Copolymers Carrying Long‐Chain (C12 to C30) Aliphatic Moieties

“…Due to the low AIC x content in the studied copolymers, the dn/dc used in all cases was that of polyvinylpyrrolidone (0.1194 mL g À1 ). [19] Reactivity ratios (r 1 and r 2 ) were calculated using the Terminal Model program, kindly offered by Mao and Huglin. [17] For solubility testing, aqueous solutions were prepared by dispersing %0.01 g L À1 of the copolymers in water and by adding drops of ammonia solutions up to neutral pH.…”