A NOVEL APPROACH TO RHEOLOGICAL CHARACTERIZATION FOR THE GELATION IN POLYMER CRYSTALLIZATION
Papers|Updated:2021-06-21
|
A NOVEL APPROACH TO RHEOLOGICAL CHARACTERIZATION FOR THE GELATION IN POLYMER CRYSTALLIZATION
Vol. 23, Issue 4, Pages: 423-434(2005)
Affiliations:
Author bio:
Funds:
DOI:
CLC:
Published:20 July 2005
Accepted:
Scan QR Code
Qing Chen, Yu-run Fan, Qiang Zheng. A NOVEL APPROACH TO RHEOLOGICAL CHARACTERIZATION FOR THE GELATION IN POLYMER CRYSTALLIZATION[J]. 2005, 23(4): 423-434.
DOI:
Qing Chen, Yu-run Fan, Qiang Zheng. A NOVEL APPROACH TO RHEOLOGICAL CHARACTERIZATION FOR THE GELATION IN POLYMER CRYSTALLIZATION[J]. 2005, 23(4): 423-434.DOI:
A NOVEL APPROACH TO RHEOLOGICAL CHARACTERIZATION FOR THE GELATION IN POLYMER CRYSTALLIZATION
The isothermal crystallizations of three kinds of commercial isotactic polypropylene have been studied by DSC and rheometric experiments
in a range of temperatures where the rate of crystallization is moderate. As the crystallization proceeds
volume contraction induces tensile force upon the parallel plates. The tensile force relaxed quickly in liquid states
but after a critical amount of the relative crystallinity
it starts to accumulate in the static test
that is
with the motionless parallel plates. A new method to determine the liquid-solid transition by the static tensile force is proposed and compared with two dynamic methods of detecting liquid-solid transition
that is
the power-law modulus theory and the yield modulus model. The tensile force method predicted considerably earlier transition than the dynamic methods
and the corresponding DSC data indicate relative crystallinity of larger than 0.2 at the transition times. The limitation of dynamic methods and other possible errors have been analyzed. While the dynamic methods are suitable for slow crystallization
the tensile force method is more appropriate for the crystallization of moderate rates. Moreover
it has the advantage of almost not disturbing the crystallizing materials before the transition.
Abstract
The isothermal crystallizations of three kinds of commercial isotactic polypropylene have been studied by DSC and rheometric experiments
in a range of temperatures where the rate of crystallization is moderate. As the crystallization proceeds
volume contraction induces tensile force upon the parallel plates. The tensile force relaxed quickly in liquid states
but after a critical amount of the relative crystallinity
it starts to accumulate in the static test
that is
with the motionless parallel plates. A new method to determine the liquid-solid transition by the static tensile force is proposed and compared with two dynamic methods of detecting liquid-solid transition
that is
the power-law modulus theory and the yield modulus model. The tensile force method predicted considerably earlier transition than the dynamic methods
and the corresponding DSC data indicate relative crystallinity of larger than 0.2 at the transition times. The limitation of dynamic methods and other possible errors have been analyzed. While the dynamic methods are suitable for slow crystallization
the tensile force method is more appropriate for the crystallization of moderate rates. Moreover
it has the advantage of almost not disturbing the crystallizing materials before the transition.
关键词
Keywords
references
The trial reading is over, you can activate your VIP account to continue reading.