XNBR/LDH nanocomposites: Effect of vulcanization and organic modifier on nanofiller dispersion and strain‐induced crystallization

In elastomer/organo clay nanocomposites, the morphological characteristics, and hence the mechanical properties, of the vulcanizates are strongly influenced by the organic modifier and the vulcanization process. When the elastomer itself undergoes strain‐induced crystallization, both the organic modifier and the dispersed filler particles could significantly influence the crystallization process. These phenomena are very common in case of natural rubber‐based vulcanizates. In this study, the similar effects have been demonstrated with carboxylated nitrile rubber (XNBR) and organically modified layered double hydroxide (O‐LDH)‐based nanocomposites. The effect of size of the organic modifier was obviously visible on the interlayer distance of O‐LDH and also on the morphological reorganization of the dispersed O‐LDH particles during vulcanization process. The strain‐induced crystallization of the XNBR was found to be strongly dependent on the morphological change that occurs during vulcanization process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

Transnormale Isotopien und transnormale Kurven

For transnormal manifolds which admit a nontrivial decktransformation leaving the transnormal frames invariant there is a natural construction of parallel transnormal manifolds. Generalizing a result of M. C. IRWIN [3] this construction is applied to show that every transnormal embedding of a 1-sphere is isotopic through transnormal embeddings to a spherical embedding. Moreover we show that the transnormal frame of a transnormal curve has only a finite number of points.

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Die vorliegende Arbeit stellt den Inhalt der letzten beiden Kapitel der von der Fakultät für Allgemeine Ingenieurwissenschaften der TU Berlin genehmigten Dissertation [10] dar.     

Ein globales Ergebnis für Bifurkationsaufgaben mit schwach differenzierbaren Operatoren

In this paper we are dealing with positive linear functionals on W-algebras. We introduce the notion of a positive linear functional with ∑-property (see Definition 1.1). It is shown that each positive linear functional on a W-algebra possesses the ∑-property. This fact allows to give a short proof of UHLMANN's conjecture on unitary mixing in the state space of a W-algebra. In proving our main theorem (see Theorem 1.2.) we obtain some results on positive linear functionals and orthoprojections which are useful in other context, too.     

High resolution 13C NMR in undoped cis- and trans-polyacetylene

We have applied ¹³C cross-polarization (CP) powder- and MAS-NMR to cis- and trans-polyacetylene. All three elements of the chemical shift tensor (σ₁₁, σ₂₂, σ₃₃) were determined in p.p.m. with respect to TMS as: (a) Cis; σ₁₁ = ?228, σ₂₂ = ?139, σ₃₃ = ?17; (b) Trans; σ₁₁ = ?234, σ₂₂ = ?146, σ₃₃ = ?34.