ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Relaxation time spectra of star polymers (2000)
    Springer
    Rheologica acta 39 (2000), S. 38-43 
    Details
    ISSN: 1435-1528
    Keywords: Key words Relaxation time spectra ; Linear viscoelasticity ; Star polymers ; Parsimonius model ; BSW spectrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract  The linear viscoelastic data for model star polymer melts with varying functionality and arm molecular weight were represented by means of a modified Baumgaertel-Schausberger-Winter (BSW) relaxation time spectrum, based on data analysis with the parsimonius model of Baumgaertel et al., reported in 1990. In the case of high arm functionality, the second slow terminal relaxation observed by Vlassopoulos et al. in 1997, was captured with a straightforward extension of the BSW model using broad cut-off functions. This study represents a potentially promising attempt to extend the applicability of this representation of viscoelastic data to more complex architectures, beyond simple linear chains which are characterized by self-similarity. The casting of linear viscoelastic data into spectra allows the exploration of star polymer behavior. It is a necessary step in preparation for large scale complex flow calculations in conjunction with constitutive models and for material databases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003970050005
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The effect of boron nitride on the rheology and processing of polyolefins (2000)
    Springer
    Rheologica acta 39 (2000), S. 583-594 
    Details
    ISSN: 1435-1528
    Keywords: Key words Boron nitride ; Processing aids ; Polyolefins ; Gross melt fracture ; Crosshead die
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The influence of a new processing additive (fine particles of boron nitride) on the rheology and processability of polyolefins is studied. The equipment used includes an Instron capillary rheometer equipped with capillary and special annular dies (Nokia Maillefer wire coating crosshead) and two rheometers, namely a parallel-plate and a sliding-plate rheometer. Several types of boron nitride powders, varying in average particle size and distribution and in morphology are tested at various concentration levels. The additive with the smallest average particle size and free of agglomeration was found to have the greatest influence on the processability (melt fracture performance) of the polyolefins tested. Specifically, it was found that boron nitride not only eliminates surface melt fracture but also postpones the critical shear rate for the onset of gross melt fracture to significantly higher values, depending on the additive concentration, surface energy, and morphology. A flow visualization technique was used to visualize the polymer flow at the entrance of a transparent capillary die in order to determine the mechanism by which boron nitride eliminates gross melt fracture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003970000113
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...