Crystallization, recrystallization, and melting of polymer crystals on heating and cooling examined with fast scanning calorimetry

Self Cite

The crystallization behavior during cooling from a melt was investigated for polypropylene (PP), poly(4‐methyl‐1‐pentene) (PMP), and their blends (PP 70 wt%). PMP did not affect the crystallization temperature of the α‐form of PP under the nonisothermal condition and vice versa. On the other hand, the existence of PMP tends to prevent the formation of the conformational disordered phase of PP at a cooling rate of 50‐100 K s–1. Regarding the crystallinity of PP, there were no differences in the heat of fusion between PP and PP/PMP blends that were prepared with the same cooling rate from the melt. The existence of PMP does not affect the total crystallinity of PP that was prepared by continuous cooling from the melt. Comparing the crystallization rate during cooling, PMP is at least 100 times faster than PP.

Section: Resultssupporting

confidence: 76%

“…On the basis of Ozawa's model, the cooling rate ( β ) dependence on the heat of fusion (Δ H total ) of many semicrystalline polymers can be described as follows:

Δ H_{total} = C - B \exp ([], - {(\frac{β_{normalc}}{β})}^{n}) - A ({}, \log \frac{β}{β_{2 nd}}) \times \frac{1}{2} ((), 1 - \frac{β - β_{2 nd}}{|β - β_{2 nd}|}),

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of poly(4‐methyl‐1‐pentene) on the nonisothermal crystallization kinetics of polypropylene

Furushima

Masuda

Kuroda

et al. 2019

Self Cite

“…Therefore, understanding the molecular behavior and influencing factors in the force‐induced melting is of fundamental importance to design high‐performance polymer materials . The introduction of novel techniques, such as in situ atomic force microscopy (AFM), modulated and high speed calorimetry, microbeam X‐ray scattering, solid‐state nuclear magnetic resonance (NMR), and the combination of related techniques have especially expanded the knowledge of chain behaviors in force‐induced melting . Nevertheless, the corresponding mechanism is still not completely understood due to the relatively complex deformation behaviors in bulk materials .…”

Section: Introductionmentioning

confidence: 99%

Force‐induced melting of a single polyethylene oxide chain from single crystal: Molecular behavior and influencing factors

Song

Yang

Jiang

et al. 2019

Force‐induced melting plays a key role in defining the mechanical strength and toughness of semicrystalline polymer materials. To understand its molecular mechanism, the direct measurement and monitoring of force‐induced melting process at the single‐molecule level are necessary. Here, the force‐induced melting of a single polyethylene oxide (PEO) chain from the single crystal has been investigated by using atomic force microscopy‐based single‐molecule force spectroscopy. Both the constant‐speed and constant‐force experiments show that PEO folds are unfolded predominantly one by one during the force‐induced melting process. The mechanical stability of PEO fold is confirmed to increase significantly with the increasing interfacial tension of polymer solvent and the thickness of crystal. The results obtained here provide new concepts in tuning the nanomechanical properties of crystalline polymer materials.

“…Most of the research activities in the field of polymer crystallization have been focused on three systems: bulk, solution, or thin films. In bulk, recent progress includes new perspectives on crystallization behavior and newly discovered crystal structures/phases . Flow‐induced crystallization has also attracted intense attention and most of the studied systems are bulk although polymer solution has also been investigated .…”

Section: Introductionmentioning

confidence: 99%

Polymer crystallization at liquid‐liquid interface

Staub

2018

Most of the research activities in the field of polymer crystallization have been focused on bulk, solution, or thin films. Liquid/liquid (L/L) interface provides another insightful platform to manipulate the crystallization of long chain polymers. This review will discuss polymer crystallization influenced by or confined near/at L/L interfaces. Polymer blends and solution will be first discussed as the underlying liquid‐liquid‐phase separation (LLPS) generates L/L interface which strongly couples with crystallization. This will continue into a discussion of utilizing flat air/water interface where the fast dynamics offers a unique opportunity to tune crystal structure and crystallization. The focus will then be shifted to polymer crystallization confined at curved L/L interface where the crystallization process is simultaneously influenced by the interface chemistry and dynamics, LLPS within the droplet, and the confinement in such a curved environment. Manipulating this diverse parameter space has allowed the attainment of numerous novel crystalline and hybrid nanostructures.