Crystallization and fusion of self-seeded polymers

Kovacs, A. J.; Gonthier, A.

doi:10.1007/978-3-642-47049-3_3

Cited by 5 publications

(15 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, when a crystalline polymer is melted between the nominal melting point ( T m ) and equilibrium melting point ( T 0 m ), the surviving ordered structures in the melt will significantly influence its following crystallization. This phenomenon is often referred to as a self-nucleation or melt memory effect [ 27 , 28 , 29 , 30 , 31 , 32 ] and the surviving structure was often called the precursor. For its fundamental scientific and industrial possibilities, the melt memory effect has received a great deal of attention since it was first revealed in the 1960s [ 33 ].…”

Section: Introductionmentioning

confidence: 99%

RETRACTED: Investigation of the Ordered Structure in Partially Melted Isotactic Polypropylene

Shen

Zhu

et al. 2021

Polymers

View full text Add to dashboard Cite

The ordered structure of partially melted isotactic polypropylene (iPP) was investigated using polarized optical microscopy (POM) and small-/wide-angle X-ray scattering (SAXS/WAXS) measurements. The crystalline morphology was first examined by means of pulling a glass fiber through the iPP melt, which was generated by partially melting a preformed spherulite. The results from the POM experiments indicated that, even at a minimal pulling rate, the surviving ordered structure could also relocate along the direction of fiber pulling and grow into cylindrites eventually. In addition, during the quiescent crystallization from the partially melted sample, which had the same thermal history of fiber-pulling experiments, the obvious memory effect of melt was also observed from the results of X-ray experiments. Moreover, the SAXS profile derived from the partially melted iPP at 170 °C was fitted by the theory of scattering amplitude with the cylindrical form factor. The fit result implied that the surviving ordered structure is of cylindrical nanocrystals with a diameter D ≈ 30 ± 3 nm and height h ≈ 45 ± 3 nm, which can significantly influence the crystallization morphology and kinetics during the subsequent crystallization process.

show abstract

Section: Introductionmentioning

confidence: 99%

RETRACTED: Investigation of the Ordered Structure in Partially Melted Isotactic Polypropylene

Shen

Zhu

et al. 2021

Polymers

View full text Add to dashboard Cite

show abstract

“…The square shape of the platelets reflects the symmetry of the crystal unit cell of PEO and was observed previously for single crystals of PEO and PS- b -PEO [ 14 , 17 , 18 , 21 , 36 , 45 ]. From the optical micrographs, we deduced

, the number of the platelet-like crystals per unit area, and assumed that each crystal resulted from a single nucleation site provided by a seed surviving at

.…”

Section: Resultssupporting

confidence: 65%

“…Kovacs and Gonthier investigated the decoration of crystals via self-seeding in thin ( ca. 1 µm) films of polyethylene oxide (PEO) [ 21 ]. There, the polymer film was first completely melted at 80 °C, i.e., well above the equilibrium melting temperature (

) and then quenched to a low crystallization temperature to ensure fast growth and a high nucleation density [ 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

“…1 µm) films of polyethylene oxide (PEO) [ 21 ]. There, the polymer film was first completely melted at 80 °C, i.e., well above the equilibrium melting temperature (

) and then quenched to a low crystallization temperature to ensure fast growth and a high nucleation density [ 21 , 22 ]. These crystalline PEO films were heated to

, slightly lower than

, yielding a controlled number of remaining crystalline seeds.…”

Section: Introductionmentioning

confidence: 99%

“…These crystalline PEO films were heated to

, slightly lower than

, yielding a controlled number of remaining crystalline seeds. Furthermore, using a sequential crystallization procedure, these crystals were decorated with many smaller ones [ 21 ]. Interestingly, the properties of the initial crystals from which the seeds originated allowed controlling characteristic features of the resulting seeded crystals such as their orientation [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Self-Seeding Procedure for Obtaining Stacked Block Copolymer Lamellar Crystals in Solution

2021

View full text Add to dashboard Cite

We examined the formation of self-seeded platelet-like crystals from polystyrene-block-polyethylene oxide (PS-b-PEO) diblock copolymers in toluene as a function of polymer concentration (c), crystallization temperature (TC), and self-seeding temperature (TSS). We showed that the number (N) of platelet-like crystals and their mean lateral size (L) can be controlled through a self-seeding procedure. As (homogeneous) nucleation was circumvented by the self-seeding procedure, N did not depend on TC. N increased linearly with c and decayed exponentially with TSS but was not affected significantly by the time the sample was kept at TSS. The solubility limit of PS-b-PEO in toluene (c*), which was derived from the linear extrapolation of Nc→ 0 and from the total deposited mass of the platelets per area (MCc→0), depended on TC. We have also demonstrated that at low N, stacks consisting of a (large) number (η) of uniquely oriented lamellae can be achieved. At a given TC, L was controlled by N and η as well as by ∆c=c−c∗. Thus, besides being able to predict size and number of platelet-like crystals, the self-seeding procedure also allowed control of the number of stacked lamellae in these crystals.

show abstract

Controlling the Growth of Stacks of Correlated Lamellar Crystals of a Block Copolymer

Majumder

Reiter

et al. 2019

Macromolecules

View full text Add to dashboard Cite

In the crystallization of polymers, besides monolamellar polymer crystals, stacks of correlated lamellae with a unique orientation and signatures of single crystals have often been observed. However, we still lack a generic criterion for such stacking, that is, vertical growth of polymer crystals. Here, by employing self-induced nucleation on the fold surface of a basal lamella for generating appropriate seeds, we identify experimental conditions allowing for a controlled formation of stacks of crystalline lamellae of a block copolymer. Adopting a two-step crystallization procedure, we decoupled nucleation and growth conditions of stacked lamellae and thereby favored vertical growth of polymer crystals in thin films. A sufficient reservoir of molten polymers in combination with slow lateral growth of the basal lamella is required for observing the formation of stacks of correlated lamellae. Taking this path, we were able to form stacks reaching heights of about 10 times the initial film thickness.

show abstract

Crystallization and fusion of self-seeded polymers

Cited by 5 publications

References 9 publications

RETRACTED: Investigation of the Ordered Structure in Partially Melted Isotactic Polypropylene

RETRACTED: Investigation of the Ordered Structure in Partially Melted Isotactic Polypropylene

Self-Seeding Procedure for Obtaining Stacked Block Copolymer Lamellar Crystals in Solution

Controlling the Growth of Stacks of Correlated Lamellar Crystals of a Block Copolymer

Contact Info

Product

Resources

About