Stereocomplex Poly(lactic acid) Alloys with Superb Heat Resistance and Toughness

Oyama, Hideko T.; Abe, Saki

doi:10.1021/acssuschemeng.5b00832

Cited by 58 publications

(36 citation statements)

References 40 publications

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“…Among them, two critical issues needed to be solved are its relatively low T g and the very slow crystallization rate which can affect its application as a promising polymer. Expanding its scope of application and the deduction of structure‐properties relationships are now the targets of scientific research for PLA …”

Section: Introductionmentioning

confidence: 99%

Evaluation of Relationship Between Crystallization Structure and Thermal‐Mechanical Performance of PLA with MCC Addition

Wen

Wang

et al. 2019

ChemistrySelect

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Poly(lactic acid) (PLA) biocomposite with 1 wt % microcrystalline cellulose (MCC) addition were prepared by melt-mixed method using torque rheometer and annealed under different isothermal conditions. The morphology, crystallization behaviors, thermal and dynamic-mechanical properties were evaluated by techniques of polarized optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and dynamic mechanical analysis (DMA). Nucleus density, crystallization rate and crystallinity (X c ) of PLA matrix were significantly increased by addition of MCC. It was found that MCC could improve the activity of PLA segments at low crystallization temperature (T c ), and the stability of segments in crystal lattice was also enhanced at high T c . DSC and XRD analysis supported that MCC contributed to the transformation of α' form into α form in PLA during annealing. The temperature range in which α crystal form appeared for pure PLA was 125 to 135°C and it was enlarged from 105 to 145°C for PLA with MCC addition. The Avrami exponent (n) and crystallization rate constant (k) for MCC/PLA decreased and increased respectively, supporting that the time dimension in nucleation mode was inhibited and crystallization kinetics was improved. MCC/PLA showed an increased stiffness and the highest value of storage modulus (E') was 52 GPa at T c of 125°C, which is basically consistent with the condition of maximum X c . DMA analysis supported that at high T c , the addition of MCC greatly increased the crystallization ability of PLA and the elasticity and toughness were also improved.[a] Dr.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Relationship Between Crystallization Structure and Thermal‐Mechanical Performance of PLA with MCC Addition

Wen

Wang

et al. 2019

ChemistrySelect

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“…This increase in the stereocomplexation suppresses the intensity of tan δ peak for sPLA-2.5% n-HAP compared to sPLA, as discussed in the previous section that the stereocomplex crystallites are more tightly packed than the homocrystals, which induces chain rigidity. 57 This analysis suggests that the prepared biocomposite was thermally more stable than pristine sPLA at elevated temperature.…”

Section: Resultsmentioning

confidence: 89%

Multifunctional Nanohydroxyapatite-Promoted Toughened High-Molecular-Weight Stereocomplex Poly(lactic acid)-Based Bionanocomposite for Both 3D-Printed Orthopedic Implants and High-Temperature Engineering Applications

et al. 2017

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The current work focuses on the fabrication of high-molecular-weight stereocomplex poly(lactic acid)/nanohydroxyapatite (sPLA/n-HAP)-based bionanocomposite for three-dimensional (3D)-printed orthopedic implants and high-temperature engineering applications. To achieve the same, n-HAP is grafted with poly(d-lactic acid) (PDLA) via in situ ring-opening polymerization of d-lactide, followed by blending with poly(l-lactic acid) (PLLA), which yields sPLA/n-HAP biocomposite with improved storage modulus even at temperatures higher than 140 °C. X-ray diffraction and calorimetric analysis ensure the presence of 100% stereocomplex crystallites of biocomposite along with significant improvement in the melting temperature (∼227 °C). Noteworthy improvements in the mechanical and gas-barrier properties of the developed biocomposites are achieved due to the uniform dispersion of n-HAP (∼60 nm) confirmed by morphological studies. An unusual improvement in elongation at break (∼130% at 1 wt % HAP loading) makes this composite a toughened material. However, the tensile strength is improved by ∼16%, whereas oxygen permeability and water vapor transmission rate are found to reduce by ∼48 and ∼34%, respectively. Interestingly, the developed material is processed as monofilament, followed to 3D printing to yield a middle phalanx bone as a representative example of orthopedic implants. In vitro studies reveal that cell adhesion and proliferation on the surface of the developed biocomposite support its biocompatible nature. This signifies the possible future aspects of the material in commercial biomedical and high-temperature engineering applications.

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“…The specific structure offers SC many unique properties such as high melting temperature, efficient nucleation ability to homocrystallization. SC is a promising strategy to improve the crystallization rate of PLA . When the asymmetric blend of PLLA and PDLA is subjected to heat over 185°C, all the homocrystals are in the molten state, while the SC crytallites stay unmelted because of its high melting temperature.…”

Section: Introductionmentioning

confidence: 99%

The role of cold crystallization of homochiral crystallites in the superb heat resistant poly(lactic acid)

Zhao

Fan

et al. 2020

Polymers for Advanced Techs

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The superb heat resistance poly(lactic acid) (PLA) were prepared by blending PLA and poly(D-lactic acid) (PDLA) with various molecular weight (M n ). Formation of the stereocomplex in the blends was confirmed by differential scanning calorimetry and wide-angle X-ray diffraction. The results of the heat resistance implied it is possible that elevating the Vicat penetration temperature of PLA up to 150 C by blending with PDLA. The cold crystallization of homochiral crystallites is proven to be the critical factor affecting the heat resistance of PLA. While the PLA or PLA/PDLA blends were heated to cold crystallization temperature of samples, both the crystal content and the rigid amorphous region content are increased due to the cold crystallization and tethering effect, and the stiffness and heat resistance of the sample are improved. The cold crystallization homochiral crystallites kinetics of PLA and PLA/PDLA blends was also studied. The results showed the activation energy (ΔE) of cold crystallization increased from 120.30 kJ/mol to 144.66 kJ/mol with the increasing of PDLA content from 2% to 10%. K E Y W O R D Scold crystallization, poly(lactic acid), superb heat resistance

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Stereocomplex Poly(lactic acid) Alloys with Superb Heat Resistance and Toughness

Cited by 58 publications

References 40 publications

Evaluation of Relationship Between Crystallization Structure and Thermal‐Mechanical Performance of PLA with MCC Addition

Evaluation of Relationship Between Crystallization Structure and Thermal‐Mechanical Performance of PLA with MCC Addition

Multifunctional Nanohydroxyapatite-Promoted Toughened High-Molecular-Weight Stereocomplex Poly(lactic acid)-Based Bionanocomposite for Both 3D-Printed Orthopedic Implants and High-Temperature Engineering Applications

The role of cold crystallization of homochiral crystallites in the superb heat resistant poly(lactic acid)

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