Orientation Induced Nucleation in Polymer Crystallization

1967 ◽  
Vol 40 (3) ◽  
pp. 786-787
Author(s):  
F. L. Binsbergen
Keyword(s):  
Crystallization Kinetics ◽  
Polymer Crystallization ◽  
Morphological Description ◽  
Half Time ◽  
Suitable Temperature ◽  
History Of ◽  
Kinetics Of

Abstract Crystallization kinetics of polymers crystallizing from the melt are influenced by the mechanical history of the sample. Strain free samples show a larger crystallization half time than samples in which the strain has not been completely removed by relaxation at a suitable temperature. A larger number of nuclei has been assumed to be present in strained samples than in strain free ones. This has been called “orientation induced” or “stress induced” nucleation. This communication presents a morphological description of the phenomenon and of the underlying type of nucleation. My observations were made with a microscope (Reichert ‘Zetopan-Pol’) equipped with a hot stage and 24-mm camera, and mainly with the polarizers crossed. For most of my experiments I used polypropylene, but similar phenomena were also observed with several other polymers.

scholarly journals Fast-Scanning Chip-Calorimetry Measurement of Crystallization Kinetics of Poly(Glycolic Acid)

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 891
Author(s):  
Yongxuan Chen ◽  
Kefeng Xie ◽  
Yucheng He ◽  
Wenbing Hu
Keyword(s):  
Crystallization Kinetics ◽  
Temperature Region ◽  
Glycolic Acid ◽  
Crystal Nucleation ◽  
Side Group ◽  
Half Time ◽  
Temperature Range ◽  
Chip Calorimetry ◽  
Kinetics Of ◽  
Fast Scanning Chip Calorimetry

We report fast-scanning chip-calorimetry measurement of isothermal crystallization kinetics of poly(glycolic acid) (PGA) in a broad temperature range. We observed that PGA crystallization could be suppressed by cooling rates beyond -100 K s−1 and, after fast cooling, by heating rates beyond 50 K s-1. In addition, the parabolic curve of crystallization half-time versus crystallization temperature shows that PGA crystallizes the fastest at 130 °C with the minimum crystallization half-time of 4.28 s. We compared our results to those of poly(L-lactic acid) (PLLA) with nearby molecular weights previously reported by Androsch et al. We found that PGA crystallizes generally more quickly than PLLA. In comparison to PLLA, PGA has a much smaller hydrogen side group than the methyl side group in PLLA; therefore, crystal nucleation is favored by the higher molecular mobility of PGA in the low temperature region as well as by the denser molecular packing of PGA in the high temperature region, and the two factors together decide the higher crystallization rates of PGA in the whole temperature range.

Synthesis and Crystallization Kinetics of Y 2CaA1 4SiO 12 Garnet-Type Glass-Ceramic

2020 ◽  
Author(s):  
Liyuan Wang ◽  
Jiaxi Liu ◽  
Nan Lu ◽  
Zengchao Yang ◽  
Gang He ◽  
...  
Keyword(s):  
Crystallization Kinetics ◽  
Glass Ceramic ◽  
Kinetics Of

Reordering and Crystallization of Silicon Carbide Amorphized by Neutron Irradiation

2000 ◽  
Vol 650 ◽  
Author(s):  
Lance L. Snead ◽  
Martin Balden
Keyword(s):  
Thin Film ◽  
Silicon Carbide ◽  
Crystallization Kinetics ◽  
Neutron Irradiation ◽  
Onset Temperature ◽  
Kinetics Of Crystallization ◽  
Crystallization Onset Temperature ◽  
Crystallization Onset ◽  
Kinetics Of

ABSTRACTDensification and crystallization kinetics of bulk SiC amorphized by neutron irradiation is studied. The temperature of crystallization onset of this highly pure, fully amorphous bulk SiC was found to be between 875-885°C and crystallization is nearly complete by 950°C. In-situ TEM imaging confirms the onset of crystallization, though thin-film effects apparently alter the kinetics of crystallization above this temperature. It requires >1125°C for complete crystallization of the TEM foil. Annealing at temperatures between the irradiation and crystallization onset temperature is seen to cause significant densification attributed to a relaxation, or reordering, of the as-amorphized structure.

Crystallization kinetics of compatibilized blends of polypropylene and polyethylenimine

2021 ◽  
Author(s):  
Pratim Kumar Patra ◽  
Aanchal Jaisingh ◽  
Vishal Goel ◽  
Gurpreet Singh Kapur ◽  
Leena Nebhani
Keyword(s):  
Crystallization Kinetics ◽  
Kinetics Of ◽  
Compatibilized Blends

Crystallization kinetics of amorphous acetonitrile nanoscale films

2021 ◽  
Vol 154 (14) ◽  
pp. 144703
Author(s):  
R. Scott Smith ◽  
M. Tylinski ◽  
Greg A. Kimmel ◽  
Bruce D. Kay
Keyword(s):  
Crystallization Kinetics ◽  
Nanoscale Films ◽  
Kinetics Of

Experimental and theoretical studies of glass and crystallization kinetics of semiconducting As40Se40Ag20 chalcogenide glass

2021 ◽  
Vol 608 ◽  
pp. 412745
Author(s):  
Mohamed N. Abd-el Salam ◽  
E.R. Shaaban ◽  
F. Benabdallah ◽  
Abdelwahab M.A. Hussein ◽  
Mansour Mohamed
Keyword(s):  
Chalcogenide Glass ◽  
Crystallization Kinetics ◽  
Theoretical Studies ◽  
Kinetics Of ◽  
Experimental And Theoretical Studies

scholarly journals Approach to nonisothermal crystallization kinetics of poly( 4‐methyl‐1‐pentene ) melt: Effect of gamma‐ray

SPE Polymers ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 50-61
Author(s):  
Yuan‐Hsiang Chang ◽  
Yulin Zhang ◽  
Donyau Chiang ◽  
Fuqian Yang ◽  
Sanboh Lee
Keyword(s):  
Crystallization Kinetics ◽  
Gamma Ray ◽  
Nonisothermal Crystallization ◽  
Nonisothermal Crystallization Kinetics ◽  
Kinetics Of
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