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
    Effect of mold temperature on the morphology and properties of polypropylene: I. A propylene-ethylene copolymer (1975)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 15 (1975), S. 79-83 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanical properties of a propylene-ethylene copolymer resin depend strongly on the mold temperature employed during injection molding. Average spherulite size correlates well with most physical properties; good impact properties are related to small average size, and high heat distortion temperatures to large average size. Tensile specimens have three distinct regions when viewed through crossed polars. The outer region (Region 1) does not contain spherulites, but Regions 2 and 3 do. The largest spherulites are found in Region 3, the center of the specimen. Region 1 has a molecular weight higher than that of the other two regions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760150205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Studies on the β-crystalline form of isotactic polypropylene (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 461-491 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A study has been made of the mechanical, thermal, and morpholigical characteristics of melt-crystallized isotactic polypropylene containing high levels of the β or pseudohexagonal crystalline form. Different levels of β-form crystallinity were produced in the polymer by blending in low levels of quinacridone dye nucleating agent. Microscopical studies of the crystallization process revealed that both α-form (monoclinic), and β-form spherulites nucleated on the dye particles, with α-spherulite growth commencing at a higher temperature. These observations were able to qualitatively explain the dependence of β-form level on both the nucleant concentration and its state of dispersion in the polymer. Improving the dispersion of the nucleant was found to reduce the level of β-form crystallinity if the nucleant concentration exceeded an optimum level. A new procedure for quantifying the volume fraction of β spherulites in a sample was developed which utilized the technique of selective solvent extraction. From volume-fraction, x-ray, and density data, the pure α and β crystal densities were obtained. Dynamic mechanical measurements-obtained on unoriented specimens containing varying levels of β-form crystallinity showed an increase in the magnitude of the damping in the post-Tg region with increasing β content. High levels of the β form lead to lower values of the modulus and yield stress, and higher values of the elongation at break and impact strength.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1986.090240301
    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...