New opportunities for sustainable bioplastic development: Tailorable polymorphic and three-phase crystallization of stereocomplex polylactide by layered double hydroxide

Chen, Qi; Auras, Rafael; Corredig, Milena; Kirkensgaard, Jacob J. K.; Mamakhel, Aref; Ünalan, İlke Uysal

doi:10.1016/j.ijbiomac.2022.09.205

Cited by 12 publications

(5 citation statements)

References 60 publications

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“…Introducing LDH had little effect on the RAF of T 225 and T 200 samples but led to a gradual increase of RAF for T 140 and T 80 samples. In our previous work, it was found that LDH below 1 wt % loading does not introduce the filler-induced RAF but the local nucleation-induced ordering effect could cause an increase of overall RAF quantity, as evidenced in T 140 and T 80 . The independence of RAF from LDH loading at T 225 and T 200 indicates that the nucleation-induced RAF may not develop at such high temperatures with high chain mobility.…”

Section: Resultsmentioning

confidence: 92%

“…27 Like in the discussion above, T 225 and T 200 generated exclusive SC content. Due to the selective SC nucleation effect by LDH, 28 increasing LDH content to ≥0.5 wt % resulted in a higher SC crystallinity compared to lower LDH content. For T 140 and T 80 samples, 0.5 and 1 wt % LDH loading (0.5LDH and 1LDH) altered the polymorphism toward higher SC-crystal content, whereas less LDH content yielded HC-dominated polymorphism.…”

Section: Resultsmentioning

confidence: 99%

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Modulating Barrier Properties of Stereocomplex Polylactide: The Polymorphism Mechanism and Its Relationship with Rigid Amorphous Fraction

Chen,

Auras,

Kirkensgaard

et al. 2023

ACS Appl. Mater. Interfaces

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The barrier properties of semicrystalline polymers are crucial for their performance and their use as packaging materials. This work uncovers the mechanism of polymorphism modification (α, α′ and stereocomplex-crystals) and its combined effect on the oxygen and water vapor barrier properties of semicrystalline stereocomplex polylactide (SCPLA). A polymorphic selective filler-type nucleator was employed to eliminate the temperature effect on the development of polymorphism and rigid amorphous fraction (RAF), allowing correlations of barrier properties with different crystal forms and RAF combinations under the same amorphous composition (SCPLA). The oxygen and water vapor barrier performances strongly correlated with crystallinity and crystal form but were not monotonically related to the RAF quantity. The study proposes that the chain conformation of intermediate phases between the crystalline and amorphous phases differs with the associated crystal forms, thereby leading to different RAF “qualities” and contributing to different gas diffusion and solubility coefficients of the amorphous regions. RAF’s per unit excess free volume may be varied with crystal forms, for instance: α′ ≫ SC > α. Therefore, SCPLA with α′ crystals exhibited high oxygen and water vapor permeabilities. Those with high SC and α crystals showed similar barrier behaviors governed by Henry’s law dissolution and followed a linear “two-phase” relationship with total crystallinity.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Modulating Barrier Properties of Stereocomplex Polylactide: The Polymorphism Mechanism and Its Relationship with Rigid Amorphous Fraction

Chen,

Auras,

Kirkensgaard

et al. 2023

ACS Appl. Mater. Interfaces

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“…In other words, the use of a special mesh structure of star-shaped molecules with a large free volume could be one strategy for the absorption of supercritical gases during the physical foaming process. In our former work, one hyperbranched epoxy resin [31] was introduced to the thermosetting epoxy and the system presented enhanced foamability due to the special hyperbranched epoxy structure and consequential gas diffusion ability. The above-mentioned star-shaped topological design and PLA stereocomplexation method could be combined for our target.…”

Section: Introductionmentioning

confidence: 99%

High-Expansion Open-Cell Polylactide Foams Prepared by Microcellular Foaming Based on Stereocomplexation Mechanism with Outstanding Oil–Water Separation

Zhang

Zhao

et al. 2023

Polymers

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Biodegradable polylactic acid (PLA) foams with open-cell structures are good candidates for oil–water separation. However, the foaming of PLA with high-expansion and uniform cell morphology by the traditional supercritical carbon dioxide microcellular foaming method remains a big challenge due to its low melting strength. Herein, a green facile strategy for the fabrication of open-cell fully biodegradable PLA-based foams is proposed by introducing the unique stereocomplexation mechanism between PLLA and synthesized star-shaped PDLA for the first time. A series of star-shaped PDLA with eight arms (8-s-PDLA) was synthesized with different molecular weights and added into the PLLA as modifiers. PLLA/8-s-PDLA foams with open-cells structure and high expansion ratios were fabricated by microcellular foaming with green supercritical carbon dioxide. In detail, the influences of induced 8-s-PDLA on the crystallization behavior, rheological properties, cell morphology and consequential oil–water separation performance of PLA-based foam were investigated systemically. The addition of 8-s-PDLA induced the formation of SC-PLA, enhancing crystallization by acting as nucleation sites and improving the melting strength through acting as physical cross-linking points. The further microcellular foaming of PLLA/8-s-PDLA resulted in open-cell foams of high porosity and high expansion ratios. With an optimized foaming condition, the PLLA/8-s-PDLA-13K foam exhibited an average cell size of about 61.7 μm and expansion ratio of 24. Furthermore, due to the high porosity of the interconnected open cells, the high-absorption performance of the carbon tetrachloride was up to 37 g/g. This work provides a facile green fabrication strategy for the development of environmentally friendly PLA foams with stable open-cell structures and high expansion ratios for oil–water separation.

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“…8 Still, SC and homochiral crystals can be generated during the crystallization of the PLLA/PDLA blends. 9 Various modification methods have been proposed to enhance SC crystallization, including copolymerization, 10 blending, 11 nucleating agents, 12 plasticizers, 13 and compatibilizers. 14 Adding nucleating agents can improve the nucleation of PLLA by giving heterogeneous nucleation sites to enhance heat resistance performance.…”

Section: ■ Introductionmentioning

confidence: 99%

“…These stereocomplexed PLLA (SC-PLA) has a remarkably high melting temperature, high mechanical performances, superior thermal stability, and resistance to hydrolysis . Still, SC and homochiral crystals can be generated during the crystallization of the PLLA/PDLA blends . Various modification methods have been proposed to enhance SC crystallization, including copolymerization, blending, nucleating agents, plasticizers, and compatibilizers .…”

Section: Introductionmentioning

confidence: 99%

Various-Sized Nanocelluloses Induced Stereocomplexes Crystallization Formation and Its Mechanism of Stereoisomers Poly(lactide acid) Blend

Xie

Abdalkarim

et al. 2023

ACS Sustainable Chem. Eng.

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This work provides evidence to explore the relationship between hydrogen bonding interactions and stereocomplex crystallization (SC) formation of nanocomposite-based nanocelluloses (NCs). Here, we evaluated the synergistic effect of various aspect ratios of NCs as nucleating agents on the properties of a poly(l-lactic acid)/poly(d-lactic acid) (l/d) stereocomplexable matrix using the casting method. Furthermore, NCs enhanced the interfacial adhesion interaction of the l/d matrix, improving crystallization ability, heat resistance, and barrier properties against the water vapor of nanocomposites. As expected, the nanocomposite with cellulose nanofibers (CNF3) had the highest SC crystallinity of 33.9% and a maximum SC melting temperature of 220.6 °C. The tensile strength of the l/d/CNF3 nanocomposite increased to 53.0 MPa due to the highest aspect ratio and rigidity of CNF, which improved interfacial hydrogen bonding interactions between CNF3 and the l/d matrix. Compared with different samples, nanocomposite with cellulose nanospheres (CNS3) had the smallest spherulite size. While nanocomposite with cellulose nanocrystals (CNC3) exhibited more efficient heterogeneous nucleation than that of CNS3 or CNF3. We demonstrated the relationship between the hydrogen-bonding interactions of l/d nanocomposites and crystallization kinetic/mechanism. This work offers a suitable strategy for selecting appropriate types of NCs as nucleating agents for designing high-performance materials for food packaging industries to solve the plastic melt processing problem.

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New opportunities for sustainable bioplastic development: Tailorable polymorphic and three-phase crystallization of stereocomplex polylactide by layered double hydroxide

Cited by 12 publications

References 60 publications

Modulating Barrier Properties of Stereocomplex Polylactide: The Polymorphism Mechanism and Its Relationship with Rigid Amorphous Fraction

Modulating Barrier Properties of Stereocomplex Polylactide: The Polymorphism Mechanism and Its Relationship with Rigid Amorphous Fraction

High-Expansion Open-Cell Polylactide Foams Prepared by Microcellular Foaming Based on Stereocomplexation Mechanism with Outstanding Oil–Water Separation

Various-Sized Nanocelluloses Induced Stereocomplexes Crystallization Formation and Its Mechanism of Stereoisomers Poly(lactide acid) Blend

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