Glass transition relations in ionomeric “comb” polymers

Abstract

The glass transition temperatures (Tg) and dynamic mechanical properties of random copolymers of styrene‐4‐vinylpyridine quaternized with iodoalkanes are presented for vinylpyridine contents up to ten percent and pendant alkyl chains up to ten carbons in length. Two linear relationships, between ion content and glass transition temperature and between pendant alkyl chain length and the Tg, are observed. An equation is presented that can be used to predict the Tg for such copolymers based on their ion contents and alkyl chain lengths.

Mixtures of an Acid-Functionalized Mesogen with Poly(4-vinylpyridine)

“…In comparing the P4VP/LC-4,6A and the P4VP/Zn laurate systems at a particular point in the linear region of T g depression, 8 mol %, it is noted that the decrease per axial atom (counting three axial atoms for each phenyl moiety) of the small molecule is roughly 3 °C in both systems. This is comparable to 2.5 °C/carbon atom observed for stoichiometric blends of linear alkyl amines with polystyrene sulfonated to 8 mol %, where proton transfer from the amine to sulfonic acid takes place leading to ion−ion interactions, and to 2.4 °C/carbon atom observed for copolymers of styrene and 7 mol % 4-vinylpyridine quaternized with iodoalkanes (thus, with the side chains covalently attached to the polymer backbone) . It is also noteworthy that the maximum decrease in T g and the solubility limit of the small molecules in P4VP appears to be somewhat greater in the P4VP/Zn laurate system (about 70 °C, 30−35 mol % Zn laurate) than in the P4VP/LC-4,6A system (75−80 °C, about 20 mol % LC-4,6A), even though the Zn laurate molecule is shorter in axial length than the LC-4,6A molecule.…”

“…This is comparable to 2.5 °C/carbon atom observed for stoichiometric blends of linear alkyl amines with polystyrene sulfonated to 8 mol %, where proton transfer from the amine to sulfonic acid takes place leading to ion-ion interactions, 28 and to 2.4 °C/carbon atom observed for copolymers of styrene and 7 mol % 4-vinylpyridine quaternized with iodoalkanes (thus, with the side chains covalently attached to the polymer backbone). 29 It is also noteworthy that the maximum decrease in T g and the solubility limit of the small molecules in P4VP appears to be somewhat greater in the P4VP/Zn laurate system (about 70 °C, 30-35 mol % Zn laurate) than in the P4VP/LC-4,6A system (75-80 °C, about 20 mol % LC-4,6A), even though the Zn laurate molecule is shorter in axial length than the LC-4,6A molecule. This may be related to the type of interactions involved (coordination vs H-bonding), to the greater propensity (thermodynamic driving force) for crystallization of the biphenyl-containing alkyl chain compared to the linear alkyl chain, and/or to the greater rigidity of the biphenyl segment in LC-4,6A.…”

Viscoelastic properties of telechelic ionomers. 2. Quaternized α,ι-bis(dimethylamino)polyisoprene

“…A similar behavior has already been reported (i) whenever carboxylic or sulfonic acid end groups have been neutralized by n-alkylamines36•41 and (ii) for ionomers containing vinylpyridine units quaternized with n-alkyl halides. 37 The less bulky ammonium ion pairs are responsible for an increase in Tg as a result of their mutual dipolar interactions which are a restriction to the chain mobility. Whenever the length of the alkyl radical of these ion pairs increases, some steric effect is expected to occur at the expense of the interaction and association of the ammonium end groups.…”

Thermal stability of modified telechelic polystyrenes

“…Dequaternization, unlike quaternization, can be achieved more easily if the corresponding amine is less basic, on the one hand, and sterically hindered, on the other hand.I4 Since the pK,'s of N,N-dimethyl n -butylamine and pyridine are, respectively, equal to 10 and 5,15 the quaternized dimethylamino end groups of the polystyrene under investigation are, therefore, expected to be more stable than the pyridinium functions of the quaternized poly (styreneco-vinylpyridine ) studied by Eisenberg et al 7,8 Before assessing the thermal stability of the telechelic polymer, we have studied a model molecule, N,N-dimethyldodecylamine ( CI4HS1N), quaternized with MeI. Its structure is similar to that of the quaternized PS terminal functions:…”