Interactions in a blend of two polymers greatly differing in glass transition temperature

Abstract

Blends of poly(N‐methyldodecano‐12‐lactam) PMDL with poly(4‐vinyphenol) PVPh have been studied by the DSC and ATR FTIR methods. The difference in glass transition temperature Tg between the components is 206 °C. A single composition‐dependent Tg suggests miscibility of the system, that is, homogeneity on the scale of about 10 nm. Fitting of the equation of Brostow et al. to the Tg data indicates relatively strong specific interactions and high complexity of the system. The Schneider's equation applied separately to low‐ and high‐PVPh regions provides good agreement with experiment; the calculated curves cross at the point of PVPh weight fraction 0.27. In the low‐PVPh region, the analysis indicates weak interactions with predominance of segment homocontacts and strong involvement of conformational entropy. In the high‐PVPh region, strong specific interactions predominate and entropic effects are suppressed. Composition dependences of the heat capacity difference at Tg and the width of glass transition indicate strong interactions in the system and existence of certain heterogeneities on segmental level, respectively. According to ATR FTIR, hydrogen bonds between PVPh as proton donor and PMDL as proton acceptor induce miscibility in blends of higher PVPh content (above about 0.28 weight fraction). In low‐PVPh blends, it is conformational entropy that enables intimate intermolecular mixing. Hydrogen bonds adopt several (distorted) geometries and are on average stronger than average hydrogen bonds formed in self‐associating PVPh. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011

Fractional complexation in a miscible polymer blend. Calorimetry and size exclusion chromatography

“…3), which is indirect evidence of the miscibility of the PMDL + PVPh system as discussed in our previous publication concerning the LM polymer pair. 24 Similar single-T g behaviour is also seen in Fig. 4 for the complex samples.…”

“…In the PMDL + PVPh + THF systems studied in our previous work 24 and here, all factors, except molar mass of the polymers, are the same. Thus, higher molar mass of the polymers is the key factor in the formation of the interpolymer complex in the studied system containing the HM polymer pair.…”

“…Hydrogen bonding between these two functional groups is the driving force of miscibility of the two polymers. 24 THF is a moderately strong proton-accepting solvent that participates, together with PMDL and PVPh, in establishing equilibrium of interaction forces: intermolecular hydrogen bonds between OH groups of PVPh and CO groups of PMDL; intramolecular hydrogen bonds of self-associating PVPh; and hydrogen bonds between ether oxygen of THF and OH groups of PVPh.…”

“…24 The feed composition covered the whole range from 0.1 to 0.9 molar fraction of PVPh (m PVPh ) in increments of 0.1. In addition, a sample of 0.66 molar fraction (i.e.…”

Blends of Poly(vinyl Pyridine)s and Dihydric Phenols: Thermal and Infrared Spectroscopic Studies. Part V

“…A cross-cutting goal in these works is to improve the properties of the obtained products. In the case of polymer-polymer blends, the obtaining of materials with enhanced properties is supported by the fundamental characterization of the intermolecular interactions involving a series of different functional groups, namely: methacrylic acid and ether groups [12], 4-vinylphenol and 2-ethoxyethyl methacrylate [13], itaconamic acids and 2-vinylpyridine [14], aryl esters [15], lactam group [16], lactide and styrene [17], vinyl methyl ether and methyl methacrylate [18], ethylene oxide and vinyl alcohol [19], aniline and amide groups [20] and alkylstyrenes and isoprene [21], among others. In this way it has been possible to find many applications involving polymer-polymer blends [22][23][24][25] and re-using preexisting polymeric materials [6,25,[26][27][28].…”