Journal ArticleDOI
Shear-Induced Nucleation and Morphological Evolution for Bimodal Long Chain Branched Polylactide
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TLDR
In this article, the effects of long chain branching on the nucleation density enhancements and morphological evolution for polylactide (PLA) materials during shear-induced isothermal crystallization process were thoroughly investigated by using rotational rheometer and polarized optical microscopy (POM).Abstract:
The effects of long chain branching on the nucleation density enhancements and morphological evolution for polylactide (PLA) materials during shear-induced isothermal crystallization process were thoroughly investigated by using rotational rheometer and polarized optical microscopy (POM). Shear-induced nucleation density enhancements for the long chain branched PLA (LCB PLA) were studied on the basis of the determination of the critical shear rate, for which the stretch of the longest chains of the linear component is expected. The results of shear-induced isothermal crystallization kinetics show that the crystallization process under shear is greatly enhanced compared to the quiescent conditions and the crystallization kinetics is accelerated with the increases in shear rate and/or shear time. LCB PLA crystallizes much faster than linear PLA under the same shear condition. A saturation effect of shear time on crystallization kinetics is observed for both linear PLA and LCB PLA. In-situ POM observations d...read more
Citations
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Journal ArticleDOI
Tailoring Crystallization: Towards High‐Performance Poly(lactic acid)
TL;DR: Methods for manipulating crystallization towards high-performance PLA materials are introduced, and the relationship between crystalline structure and properties of PLA are summarized.
Journal ArticleDOI
Use of stereocomplex crystallites for fully-biobased microcellular low-density poly(lactic acid) foams for green packaging
TL;DR: In this article, a series of asymmetric biodegradable poly( l -lactide) (PLLA) and poly( d -lactic acid) (PDLA) blends with small amounts of PDLA were used to obtain large-scale PLLA/PDLA blends using a continuous melt compounding technique.
Journal ArticleDOI
Star-shaped and branched polylactides: Synthesis, characterization, and properties
TL;DR: A review of star-shaped polymers with arms composed of homo- or copolymers of polylactide (PLA) can be found in this article, where a large number of various structures of star shape polymers are precisely described.
Journal ArticleDOI
Super-Robust Polylactide Barrier Films by Building Densely Oriented Lamellae Incorporated with Ductile in Situ Nanofibrils of Poly(butylene adipate-co-terephthalate)
Shengyang Zhou,Hua-Dong Huang,Xu Ji,Ding-Xiang Yan,Gan-Ji Zhong,Benjamin S. Hsiao,Zhong-Ming Li +6 more
TL;DR: The methodology proposed in this work presents an industrially scalable processing method to fabricate super-robust PLA barrier films that would indeed push the usability of biopolymers forward, and certainly prompt wider application of biodegradable polymers in the fields of environmental protection such as food packaging, medical packaging, and biodesgradable mulch.
Journal ArticleDOI
Enhanced Heat Deflection Resistance via Shear Flow-Induced Stereocomplex Crystallization of Polylactide Systems
Zheng-Chi Zhang,Zi-Hong Sang,Yan-Fei Huang,Jia-Feng Ru,Gan-Ji Zhong,Xu Ji,Ruyin Wang,Zhong-Ming Li +7 more
TL;DR: In this paper, an upgraded injection molding method was employed to impose intense shear flow on poly(l)-lactide (PLLA)/poly(d-lactides) (PDLA) samples, which resulted in a high Vicat softening temperature (close to 200 °C) and superb heat deflection resistance in boiling water.
References
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Journal ArticleDOI
Poly(lactic acid) crystallization
TL;DR: An overview of the current understanding on the fundamentals of PLA crystallization in quiescent conditions and on the practical means to enhance its rate can be found in this paper, where the most promising efforts in enhancing PLA crystallisation kinetics through plasticization or heterogeneous nucleation are reviewed.
Journal ArticleDOI
Tube theory of entangled polymer dynamics
TL;DR: In this paper, the authors review the progress in the last 30 years in the light of specially-synthesized model materials, an increasing palette of experimental techniques, simulation and both linear and nonlinear rheological response.
Journal ArticleDOI
Structure Development during Shear Flow-Induced Crystallization of i-PP: In-Situ Small-Angle X-ray Scattering Study
Rajesh H. Somani,Benjamin S. Hsiao,Aurora Nogales,Srivatsan Srinivas,Andy H. Tsou,Igors Sics,F. J. Baltá-Calleja,Tiberio A. Ezquerra +7 more
TL;DR: In this paper, small-angle X-ray scattering (SAXS) was used to follow orientation-induced crystallization of isotactic polypropylene (i-PP) in the subcooled melt at 140 °C after step shear under isothermal conditions.
Journal ArticleDOI
Shear-Mediated Crystallization of Isotactic Polypropylene: The Role of Long Chain−Long Chain Overlap
TL;DR: In this article, the role of long chains in shear-induced oriented crystallization was studied by in situ rheo-optical measurements and ex situ microscopic observations, and it was shown that long chain overlap is enhanced by long chain−long chain overlap.
Journal ArticleDOI
Influence of Shear on Crystallization Behavior of the β Phase in Isotactic Polypropylene with β-Nucleating Agent
TL;DR: In this paper, wide-angle X-ray diffraction (WAXD) was used to investigate the effects of shear on the crystallization behavior of polypropylene (PP) with β-nucleating agent.
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