Experimental evidence for immiscibility of enantiomeric polymers: Phase separation of high-molecular-weight poly(ʟ-lactide)/poly(ᴅ-lactide) blends and its impact on hindering stereocomplex crystallization

Chen, Yujing; Lan, Qiaofeng

doi:10.1016/j.ijbiomac.2024.129459

Cited by 2 publications

(2 citation statements)

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“…In the molten state, many polymers are thermodynamically immiscible due to unfavorable interactions between their components and the minimal gain in entropy resulting from the mixing of high-molecular-weight species [31]. As a result, polymer blends typically exhibit a heterogeneous morphology defined by the size, form, and dispersion of the domains that comprise the dispersed phase.…”

Section: Fragmentation Of Dropletsmentioning

confidence: 99%

“…This mechanism for the fragmentation of fluid clusters proposes that not only the shear flow can lead to the dispersion of droplets, but that the elongational flow can stretch the droplets into a state of elongated fibers, which is conducive to the dispersion and mixing of fluids [35]. Researchers has already noted that the critical capillary number for threads is generally smaller than that for drops [31]. This suggests that achieving a finer dispersion by the temporary mechanism of thread breakage during extension is preferable than repeatedly drop breakup at C .…”

Section: Fragmentation Of Dropletsmentioning

confidence: 99%

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A comprehensive review on flow field properties in polymer mixing processes: a focus on applications in energetic materials

Wang,

Xie,

Liu

2024

Mater. Res. Express

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The mixing process is a critical step in the production of energetic materials and has a profound impact on product performance. As modern formulations for energetic materials continue to advance, the needs placed on the mixing process have become increasingly complex. Understanding and mastering the properties of the mixing flow field are essential for achieving optimal mixing function, ensuring process safety, and optimizing the parameters of both the mixing process and equipment specifically for energetic materials. In this comprehensive review, we analyze the influence of flow field properties on the mixing process of energetic materials by examining the mixing mechanism of two types of flow within the flow field. Additionally, we provide evidence to support the advantages of elongational flow in achieving effective mixing. We also discuss the application of mixing flow field properties in the processing of energetic materials, including advancements in mixing equipment and methods designed to optimize flow fields. Finally, we address the current shortcomings in energetic material mixing and offer an outlook for future developments in this field.

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Section: Fragmentation Of Dropletsmentioning

confidence: 99%

Section: Fragmentation Of Dropletsmentioning

confidence: 99%

A comprehensive review on flow field properties in polymer mixing processes: a focus on applications in energetic materials

Wang,

Xie,

Liu

2024

Mater. Res. Express

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Polymer Chirality Modulates Phase Transitions at Liquid–Liquid Interfaces

Chen,

Shi

2024

Macromolecules

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In the poly(lactic acid) family, poly(l-lactic acid) (PLLA), poly(d-lactic acid) (PDLA), and mesomeric poly(d,l-lactic acid) (mPLA) have the same chemical constituents but distinct configurations. It is well-known that PLLA and PDLA could crystallize to homocrystals individually (HC L and HC D ) or form stereocomplex crystals (SC) together. But it remains a debated question whether poly(lactic acid) mixtures with different chiralities can phase separate in melt or in solutions. Here, we study the phase transitions of PLLA/mPLA and PLLA/PDLA in dichloromethane (DCM) solutions at double emulsion interfaces. We find that crystallization is dominant in the low-molecular-weight (M W) mixtures, while liquid–liquid phase separation indeed occurs ahead of crystallization in the high-M W mixtures. The PLLA/mPLA double emulsion droplets transform into a spindle-like shape when the homocrystallization of PLLA is dominant in the low-M W region, while eyeball-like microcapsules form when phase separation is dominant in the high-M W region. The PLLA/PDLA double emulsion droplets are solidified to spherical microcapsules with dense stereocomplex crystallites at low M Ws, while the multiphase patchy microcapsules form by sequential liquid–liquid phase separation, stereocomplex crystallization, and homocrystallizations at high M Ws. We quantify a very weak repulsive energy of 0.0050kT (kT is the thermal energy at room temperature) between the l- and d-segments and depict the complete phase diagrams to provide insight into the multiple phase transitions. This study quantifies the interaction of poly(lactic acid) mixtures and provides a design principle for taking advantage of chiral polymers to modulate the microcapsule structures and properties via phase transitions at the liquid–liquid interface.

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Experimental evidence for immiscibility of enantiomeric polymers: Phase separation of high-molecular-weight poly(ʟ-lactide)/poly(ᴅ-lactide) blends and its impact on hindering stereocomplex crystallization

Cited by 2 publications

References 71 publications

A comprehensive review on flow field properties in polymer mixing processes: a focus on applications in energetic materials

A comprehensive review on flow field properties in polymer mixing processes: a focus on applications in energetic materials

Polymer Chirality Modulates Phase Transitions at Liquid–Liquid Interfaces

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