Improvement of toughness by stereocomplex crystal formation in optically pure polylactides of high molecular weight

López-Rodríguez, N.; Arenaza, Inger Martínez de; Meaurio, Emilio; Sarasua, Jose‐Ramon

doi:10.1016/j.jmbbm.2014.05.022

Cited by 35 publications

(28 citation statements)

References 24 publications

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“…Mixture models, most commonly used in fitting data, are the functions known as the Scheffé canonical [37] polynomials (Equation (4)) and given by:…”

Section: Experimental Section 21 Materials and Methodsmentioning

confidence: 99%

“…In the field of nucleating agents the commercial product LAK (an aromatic sulfonate) is reported to provide a high crystallinity, high heat-stability of PLA mould parts and allows the onset of cold crystallization beginning at higher temperature [34]. PDLA was also found to behave as a nucleating agent for decreasing the half-time of crystallization [35] of PLA, with the advantage of the excellent compatibility because of the much similar structure and also thanks to the formation of stereocomplexes [36,37]. More recently Shi et al [38] evidenced again the synergistic effect of nucleating agents and plasticizer by plasticizing PLA with PEG and adding also different nucleating agents such as PDLA, LAK and talc.…”

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confidence: 99%

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Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid): A Mixture Design study

Fehri¹,

Mugoni²,

Cinelli³

et al. 2016

Express Polym. Lett.

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“…Mixture models, most commonly used in fitting data, are the functions known as the Scheffé canonical [37] polynomials (Equation (4)) and given by:…”

Section: Experimental Section 21 Materials and Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid): A Mixture Design study

Fehri¹,

Mugoni²,

Cinelli³

et al. 2016

Express Polym. Lett.

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“…[16] Therefore, the high T m,sc and X sc of sc-PLA(1,1) were attributed to the more perfect stereocomplex crystallite formed in sc-PLA. Keeping PLLA-1 constant, the sc-PLA(1,1) showed higher T m,sc and X sc than sc-PLA(1,2) (prepared from PLLA-1 and PDLA-2) and sc-PLA(1,3) (prepared from PLLA-1 and PDLA-3).…”

Section: Dsc Analysismentioning

confidence: 98%

“…[16] However, when the melt blending method is employed, the mechanical properties of sc-PLA become unsatisfactory due to high processing temperature. sc-PLA prepared by solution cast method exhibited better mechanical properties than PLLA due to the presence of a high density of intercrystalline connections through mobile amorphous phase in the former, i.e., tie chains in the stereocomplexed supramolecular spherulitic entities provide the enhanced strength.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Evaluation of thermal resistance and mechanical properties of injected molded stereocomplex of poly(l‐lactic acid) and poly(d‐lactic acid) with various molecular weights

Yu-zeng

Yang

et al. 2017

Adv Polym Technol

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Poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) with various molecular weights (MW) were melt blended in equivalent proportions, and then followed by injection molding to form polylactide stereocomplex (sc-PLA). The crystalline structures, thermal resistance, and mechanical properties of the formed sc-PLA were then investigated in detail. The results showed stereocomplex crystallites (sc) were formed predominantly in all the sc-PLA regardless of the MW of the PLLA or PDLA pellets, and a small amount of homocrystallites (hc) also coexisted in sc-PLA. The MW of PLLA and PDLA pellets displayed significant effects on the crystallinity, thermal resistance, and mechanical properties of sc-PLA. PLLA and PDLA with low and similar MW facilitated the formation of sc, and also improved the onset degradation temperature and Vicat softening temperature of sc-PLA. For a similar degree of crystallinity, high MW was found to be more favorable in improving the thermal performance of sc-PLA. Although sc-PLA prepared from PLLA and PDLA with low MW showed decreased mechanical properties, the mechanical properties of sc-PLA increased with an increase in the MW of the PLLA or PDLA pellet. When PLLA and PDLA pellets with high and similar MW were used, the mechanical properties of sc-PLA could even exceed those of pure PLLA. K E Y W O R D Sbiodegradable, blending, mechanical properties, thermal properties

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“…However, for most of the PLLA composites, such far research works reveal that the improvements of heat resistance temperature (HRT) and mechanical properties are at the compensation of sacrificing the toughening of the materials. For the PLLA/PDLA binary blends, although the HRT is highly improved due to the higher melting temperature and fast crystallization rate, the elongation at break of these blends hardly varies or becomes even worse …”

Section: Introductionmentioning

confidence: 99%

The toughening behavior of PLLA and its asymmetric PLLA/PDLA blends with lower optical purity

Guo

Shao

Hou

2017

J of Applied Polymer Sci

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Linear poly(d‐lactide) (PDLA) with various molecular weights is synthesized and incorporated into commercial poly(l‐lactide) (PLLA) with different optical purities. And then, the crystallization, mechanical and thermal properties of the PLLA and PLLA/PDLA cast films are investigated. In the PLLA and PDLA/PLLA specimens with lower optical purity, few homochiral crystallites (HC) form in all the specimens and only a small amount of PLA stereocomplex crystallites (SC) are observed in the blends. The elongation at break of all the specimens is extraordinary high, >300%. Dynamic mechanical analyses indicate that the destruction temperature increases at first, and then depresses as enlarging the molecular weight of PDLA in these blends. For the PLLA and PLLA/PDLA with higher optical purity, more content of HC develops in neat PLLA, and both SC and HC produce in the PLLA/PDLA specimens. However, the strains of neat specimens and binary blends are much lower than that of specimens with lower optical purity. The specimens with higher optical purity exhibit higher destruction temperatures and lower loss factors. The high content of crystals (SC and HC) would act as the physical cross‐linking points and provide a key factor to impede the deformation of neat PLLA and binary blends during stretching, which should result in the fragile behavior of the PLLA and PLLA/PDLA blends with higher optical purity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44730.

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Improvement of toughness by stereocomplex crystal formation in optically pure polylactides of high molecular weight

Cited by 35 publications

References 24 publications

Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid): A Mixture Design study

Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid): A Mixture Design study

Evaluation of thermal resistance and mechanical properties of injected molded stereocomplex of poly(l‐lactic acid) and poly(d‐lactic acid) with various molecular weights

The toughening behavior of PLLA and its asymmetric PLLA/PDLA blends with lower optical purity

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