PMID- 30965871
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20231006
IS  - 2073-4360 (Electronic)
IS  - 2073-4360 (Linking)
VI  - 9
IP  - 11
DP  - 2017 Nov 2
TI  - New Insight into Time-Temperature Correlation for Polymer Relaxations Ranging 
      from Secondary Relaxation to Terminal Flow: Application of a Universal and 
      Developed WLF Equation.
LID - 10.3390/polym9110567 [doi]
LID - 567
AB  - The three equations involved in the time-temperature superposition (TTS) of a 
      polymer, i.e., Williams(-)Landel(-)Ferry (WLF), Vogel(-)Fulcher(-)Tammann(-)Hesse (VFTH) 
      and the Arrhenius equation, were re-examined, and the mathematical equivalence of 
      the WLF form to the Arrhenius form was revealed. As a result, a developed WLF 
      (DWLF) equation was established to describe the temperature dependence of 
      relaxation property for the polymer ranging from secondary relaxation to terminal 
      flow, and its necessary criteria for universal application were proposed. TTS 
      results of viscoelastic behavior for different polymers including isotactic 
      polypropylene (iPP), high density polyethylene (HDPE), low density polyethylene 
      (LDPE) and ethylene-propylene rubber (EPR) were well achieved by the DWLF 
      equation at high temperatures. Through investigating the phase-separation 
      behavior of poly(methyl methacrylate)/poly(styrene-co-maleic anhydride) 
      (PMMA/SMA) and iPP/EPR blends, it was found that the DWLF equation can describe 
      the phase separation behavior of the amorphous/amorphous blend well, while the 
      nucleation process leads to a smaller shift factor for the crystalline/amorphous 
      blend in the melting temperature region. Either the TTS of polystyrene (PS) and 
      PMMA or the secondary relaxations of PMMA and polyvinyl chloride (PVC) confirmed 
      that the Arrhenius equation can be valid only in the high temperature region and 
      invalid in the vicinity of glass transition due to the strong dependence of 
      apparent activation energy on temperature; while the DWLF equation can be 
      employed in the whole temperature region including secondary relaxation and from 
      glass transition to terminal relaxation. The theoretical explanation for the 
      universal application of the DWLF equation was also revealed through discussing 
      the influences of free volume and chemical structure on the activation energy of 
      polymer relaxations.
FAU - Shangguan, Yonggang
AU  - Shangguan Y
AUID- ORCID: 0000-0003-4628-5868
AD  - MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department 
      of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China. 
      shangguan@zju.edu.cn.
FAU - Chen, Feng
AU  - Chen F
AD  - MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department 
      of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China. 
      juhuatai@zju.edu.cn.
FAU - Jia, Erwen
AU  - Jia E
AD  - MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department 
      of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China. 
      jiaerwen@zju.edu.cn.
FAU - Lin, Yu
AU  - Lin Y
AUID- ORCID: 0000-0002-5379-5359
AD  - MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department 
      of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China. 
      linyu@ecust.edu.cn.
FAU - Hu, Jun
AU  - Hu J
AD  - The Affiliated Stomatology Hospital, College of Medicine, Zhejiang University, 
      Hangzhou 310006, China. arzthujun@zju.edu.cn.
FAU - Zheng, Qiang
AU  - Zheng Q
AD  - MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department 
      of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China. 
      zhengqiang@zju.edu.cn.
LA  - eng
PT  - Journal Article
DEP - 20171102
PL  - Switzerland
TA  - Polymers (Basel)
JT  - Polymers
JID - 101545357
PMC - PMC6418538
OTO - NOTNLM
OT  - developed WLF equation
OT  - flow
OT  - relaxation
OT  - time-temperature superposition
COIS- The authors declare no conflict of interest.
EDAT- 2017/11/02 00:00
MHDA- 2017/11/02 00:01
PMCR- 2017/11/02
CRDT- 2019/04/11 06:00
PHST- 2017/10/15 00:00 [received]
PHST- 2017/10/28 00:00 [revised]
PHST- 2017/10/30 00:00 [accepted]
PHST- 2019/04/11 06:00 [entrez]
PHST- 2017/11/02 00:00 [pubmed]
PHST- 2017/11/02 00:01 [medline]
PHST- 2017/11/02 00:00 [pmc-release]
AID - polym9110567 [pii]
AID - polymers-09-00567 [pii]
AID - 10.3390/polym9110567 [doi]
PST - epublish
SO  - Polymers (Basel). 2017 Nov 2;9(11):567. doi: 10.3390/polym9110567.