Fractionation of Polymers

Relaxation behavior of poly(ethylene terephthalate)/poly(ethylene naphthalene 2,6‐dicarboxylate) blends prepared by cryogenic blending

“…The blending of PET and PEN by extrusion with subsequent granulation and compression molding of specimens obviously has major industrial applications 4, 8, 10, 11. The other is the dissolution of the polymers in a common solvent followed by solution precipitation by an excess of a nonsolvent, producing a powder that can be compression‐molded 6, 12–14. The first method requires extrusion temperatures of 270–300 °C and mixing times of 5–20 min 4.…”

Synthesis and Thermal Properties of Comb‐Like Maleimide Copolymers Containing Polymethylene and Poly(Ethylene Oxide) Side Chains as the N‐Substituents

“…A diffraction due to the crystallized domains was detected at the angle of 2 θ = 22° in addition to the broad diffraction at the region of 10-25° in the XRD profi les of poly(HDMI-alt -IB) and poly(ODMI-alt -IB), whereas no sharp diffraction due to the crystalline domain was observed in the profi le of poly(TDMI-alt -IB). The broad diffraction was commonly observed for the all poly(RMI-alt -IB)s. The side-chain crystallization of the homopoly(RMI)s was previously reported by Barrales-Rienda et al [ 30,31 ] and Matsumoto et al [ 29 ] They reported that the side-chain crystallization occurred for the poly(RMI)s when the carbon number was larger than 10, indicates the 8-9 carbons of the N-alkyl groups close to the polymer main chains cannot participate in a crystallization process. The results obtained in this study suggest the more restricted motion of the side alkyl groups of the poly(RMI-alt -IB)s and at least the 14 carbons of the N-alkyl groups in an amorphous state.…”

“…increase in the T g values of the obtained copolymers, but simultaneously it induced another problem of the brittleness of the copolymers. Previously, Barrales-Rienda and co-workers [ 27,28 ] and Matsumoto et al [ 29 ] reported that the T g values decreased according to an increase in the carbon number of the N-n -alkyl groups of the poly(RMI)s. Furthermore, it was pointed out that the semifl exible mainchain suppressed side-group crystallization due to their restricted mobility of the segments, [29][30][31][32] while the side alkyl chains introduced into common comb-like polymers with a fl exible main-chain readily crystallized accompanying the reconstruction of main-chain conformation. [33][34][35] In this study, we synthesized maleimide copolymers with a low-T g value by the introduction of fl exible and linear substituents into the side groups and characterized the thermal and viscoelastic properties of the copolymers consisting of a rigid main-chain and fl exible side chains.…”

Inverse gas chromatography. Relationship between mass activity coefficient and flory-huggins interaction parameter in the examination of petroleum pitches

“…where: M 1, p~, B n, V~'l, P2, and ~ are the molecular weight, saturated vapour pressure, second virial coefficient, molar volume, density and specific retention volume of the solute, respectively; P2 and ~ are the density and molar volume of the stationary phase; T is column temperature and R is the gas constant [7][8][9][10]. The importance of this parameter has been discussed elsewhere [1,11].…”