Advantage of Preserving Bi-orientation Structure of Isotactic Polypropylene through Die Drawing
نویسندگان
چکیده
منابع مشابه
Structure and molecular mobility of nascent isotactic polypropylene powders
The detailed structure and molecular mobility of nascent isotactic polypropylene (iPP) powder was investigated using differential scanning calorimetry, transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR). The crystallinity of the nascent iPP powder is approximately 33%, which is much lower than that of melt-quenched or isothermally crystallized iPP. Peaks from the variab...
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A filament stretching extensional rheometer with a custom-built oven was used to investigate the effect of uniaxial flow on the crystallization of polypropylene. Prior to stretching, samples were heated to a temperature well above the melt temperature to erase their thermal and mechanical histories and the Janeschitz-Kriegl protocol was applied. The samples were stretched at extension rates in ...
متن کاملHigh-pressure crystallization of isotactic polypropylene droplets
Dispersions of isotactic polypropylene (PP) particles in polystyrene (PS) were produced by interfacially driven breakup of nanolayers in multilayered systems that were fabricated by means of layer-multiplying coextrusion. The droplet size was controlled by the individual PP layer thickness ranging from 12 to 200 nm. In addition, PP was melt blended with PS to produce PP droplets larger than tho...
متن کاملA first principles investigation of isotactic polypropylene
Bulk isotactic polypropylene in the a form was studied using density functional theory-based computations. The computed physical structure of this system is in excellent agreement with available experimental data. The electronic band structure, ionization potential, and electron affinity were also determined. The impact of various types of chemical imperfections (including double bond, hydroxyl...
متن کاملCrystal structure of the trigonal form of isotactic polypropylene as an example of density-driven polymer structure.
Propene-hexene copolymers crystallize in a new polymorphic form of isotactic polypropylene when the concentration of hexene is higher than nearly 10-15 mol %. The hexene units are included in the crystals, inducing an increase of density that allows crystallization of 3-fold helical chains in a trigonal unit cell according to the space group R3c or Rc, where the helical symmetry of the chains i...
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ژورنال
عنوان ژورنال: Chinese Journal of Polymer Science
سال: 2020
ISSN: 0256-7679,1439-6203
DOI: 10.1007/s10118-020-2465-z