Journal•ISSN: 0323-7648
Acta Polymerica
Wiley
About: Acta Polymerica is an academic journal. The journal publishes majorly in the area(s): Polymerization & Polymer. It has an ISSN identifier of 0323-7648. Over the lifetime, 2404 publications have been published receiving 26379 citations.
Topics: Polymerization, Polymer, Copolymer, Radical polymerization, Monomer
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1,168 citations
TL;DR: In this article, a general expression for the degree of branching in hyperbranched polymers based on AB 2, AB 3 and AB m (m ≥ 2) type monomers is derived.
Abstract: Topological considerations concerning the ratio of linear, imperfectly branched, dendritic and terminal units in hyperbranched polymers based on AB 2 , AB 3 and AB m (m ≥ 2) type monomers are summarized. The reaction of AB 2 monomers with a core molecule of the structure B f is also treated. For larger hyperbranched polymers based on AB 2 monomers the fraction of terminal units has to be equal to the number of dendritic units. A general expression for the degree ofbranching (DB) is derived for AB 2 systems, which is based on the number of dendritic and linear units. The expression is valid for low molecular weight as well as high molecular weight hyperbranched polymers in contrast to the commonly used expression based on dendritic, linear and terminal units. DB may not exceed 0.5 in hyperbranched polymers based on AB 2 systems (0.44 in AB 3 systems). Furthermore, a general expression for DB in hyperbranched polymers based on AB m monomers is derived. Consequences for signal ratios in NMR-spectra of hyperbranched polymers are discussed. The expressions presented allow verification of NMR-integration ratios obtained experimentally on the basis of model compounds.
729 citations
535 citations
TL;DR: In this paper, a systematic procedure to coarse grain atomistic polymer models into a mesoscopic model, which then allows an effective and fast simulation of melts, is introduced, which provides information on both static and dynamic properties, is tested for three different modifications of polycarbonate.
Abstract: The paper introduces a systematic procedure to coarse grain atomistic polymer models into a mesoscopic model, which then allows an effective and fast simulation of melts. The method, which provides information on both static and dynamic properties, is tested for three different modifications of polycarbonate. The models successfully describe the variation in the Vogel -Fulcher temperature as well as the total chain extension. The effective speedup compared to the corresponding atomistic simulation is significantly above 10 3 .
430 citations
TL;DR: In this paper, an extended series of monodisperse oligomers of the dialkoxy-substituted phenyleneethenylenes was used to determine the limiting values of the energies Ei and the wavelengths λi of the UV/vis absorption.
Abstract: On the basis of an extended series of monodisperse oligomers of the dialkoxy-substituted phenyleneethenylenes 1a–i the Eqs. (3) and (4) were conceived in order to determine the limiting values of the energies Ei and the wavelengths λi of the UV/vis absorption. The convergence of the Ei, and λi values with a growing number n of repeating units permits a precise prediction of the Ei,∞ and λi,∞ values of the corresponding polymer 1j as well as a statement about the overall effect of conjugation ΔEi and the effective conjugation length ECL. A great variety of different conjugated oligomers 2–14 can be evaluated by the same algorithm.
414 citations