Summary: A comparative study of the performances of (bpzmp)ZrBz3 ( 1 ) and (hppzm)ZrBz3 ( 2 ) activated with B(C6F5)3 or [Ph3C][B(C6F5)4] in ethylene polymerisation pointed out that the steric properties of the metal complex and the boron activator affect the productivity of the catalyst and, more remarkably, the microstructure of the polyethylenes produced. A polymerisation mechanism accounting for these results has been proposed.
Structure of two heteroscorpionate zirconium complexes (bpzmp)ZrBz3 ( 1 ) and (hppzm)ZrBz3 ( 2 ). 相似文献
Summary: The nanoindentation test is a fundamental tool to assess the link between morphology and mechanical properties. The preliminary results of a more exhaustive study about the applicability to polymers of the most used procedure to determine elastic modulus by indentation are reported in this short communication. A departure of the experimental conditions from the theoretical assumptions and results that give rise to the Oliver and Pharr analysis is shown to occur under a wide range of experimental conditions, with applied loads and penetration depths covering several orders of magnitude and using different indenter geometries. Unloading curves with exponents significantly larger than 2 are observed in disagreement with the contact mechanics approach used by Oliver and Pharr.
An AFM image obtained in non contact mode of an indentation induced by a sharp AFM tip with a maximum applied load of ca 1.2 µN on amorphous PET. 相似文献
In this paper, we consider a bankruptcy problem with the additional constraint that the estate has to be assigned in integer unities; differently from the approaches by other authors, we allow for non-integer claims. This situation poses new questions on the existence and the uniqueness of the solution. We propose a new solution method that leads to the “box solution”, for which uniqueness may be guaranteed introducing a ranking on the claimants. Some examples complete the paper. 相似文献
