Non-isothermal crystal nucleation of poly (l-lactic acid)

Androsch, René; Iqbal, Humaira; Schick, Christoph

doi:10.1016/j.polymer.2015.11.006

Cited by 106 publications

(72 citation statements)

References 38 publications

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“…This strongly suggested that crystallization during cooling was effectively bypassed when the cooling rate was beyond 50 K min −1 . And this value of the critical cooling rate is similar to previously reported results, determined by either conventional DSC or flash DSC . Finally, the cooling rate was selected as 150 K min −1 in the work reported here.…”

Section: Resultssupporting

confidence: 78%

The difference of equilibrium melting point between poly(l‐lactic acid) and poly(l‐lactic acid)/poly(d‐lactic acid) blends: cases with three molecular weights

Guo

Shao

et al. 2018

Polymer International

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In order to explore the origin of the higher melting point of poly(lactic acid) (PLA) stereocomplex crystal (SC) than that of homo‐crystal (HC), the equilibrium melting point (Tm0) differential between SC and HC was determined using the Hoffman–Weeks method. The results showed that, for PLA samples with Mn around 16, 20 and 65 kg mol−1, the Tm0 differential between SC and HC is around 36, 42 and 55 °C, respectively. Thus, the higher melting point of SC compared to HC does not stem from Tm0 differential only. For PLA samples with lower Mn, the supercooling differential between poly(l‐lactic acid) (PLLA)/poly(d‐lactic acid) (PDLA) blends and PLLA is smaller than that with higher Mn, which means chain diffusion behavior is crucial for SC formation in PLLA/PDLA blends. The fact that the SC adopts the intermolecular parallel arrangement rather than the adjacent chain folding is verified by the greater slope of the melting point of SC versus crystallization temperature fitting curve when Mn is relative higher. © 2018 Society of Chemical Industry

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Section: Resultssupporting

confidence: 78%

The difference of equilibrium melting point between poly(l‐lactic acid) and poly(l‐lactic acid)/poly(d‐lactic acid) blends: cases with three molecular weights

Guo

Shao

et al. 2018

Polymer International

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“…The maximum nucleation rate of PLA is 120 C [37], a temperature which needs to be passed in the annealing procedure at 85 C from the melt. The quenching following the melting of PLA in the thermal press to the annealing temperature in the oven was not apparently fast enough to stop the nucleation and crystallization at temperatures higher than 85 C. Androsch et al [38,39] showed recently, using fast scanning chip calorimetry, that a cooling rate of 30 K min À1 is sufficient to prevent melt crystallization while a cooling rate of 500 K min À1 is required to inhibit the formation of nuclei in PLA containing 4% D-units. This is hardly compatible with processing of large samples, required for the present study.…”

Section: Pla Crystallization Kineticsmentioning

confidence: 99%

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Nassar

Guinault

Delpouve

et al. 2017

Polymer

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scale analysis of the impact of polylactide morphology on gas barrier properties. Polymer, Elsevier, 2017, 108, pp.163-172. 10.1016/j.polymer.2016 Multi-scale analysis of the impact of polylactide morphology on gas barrier properties Samira Fernandes Nassar t r a c tSemicrystalline polylactide (PLA) films with controlled morphology were produced by thermal crystallization to optimize the oxygen barrier properties. The crystalline morphology of PLA at the scales of the lamella and the spherulite was investigated and the mobile amorphous phase dynamics were studied. The crystalline morphology had a negligible impact on the oxygen diffusion coefficient. The occurrence of a rigid amorphous fraction (RAF) in the amorphous phase due to its insufficient decoupling from the crystalline phase provided an accelerated pathway for diffusion, though. As a conclusion, for reaching optimal barrier properties, semicrystalline PLA should be pre-nucleated and rapidly crystallized from the glass in the a-polymorph in the aim to reach a high crystallinity degree and decoupling of the amorphous and the crystalline phase. These recommendations can benefit to industry for the optimization of PLA annealing treatments.

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“…. As known, [44] Numerical values of the ΔH parameters were normalized with respect to the 91.9 (*), 89.8 (**) weight % of the PLA content in the IM formulations. Instead, the thermal response of formulations #1, #2, and #3 was studied in both injection (IM #1, IM #2, IM #3) and compression molded (CM #1, CM #2, CM #3) samples.…”

Section: Characterization Of Molded Pla/ Talc Compositesmentioning

confidence: 99%

Improvements in mechanical strength and thermal stability of injection and compression molded components based on Poly Lactic Acids

et al. 2017

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Degradable polymers are limited by their often-insufficient mechanical and thermal properties, which limit their usage to single-use packaging items at room temperature and in dry conditions. In this respect, the present work deals with the manufacture of custom-built Poly Lactic Acids (PLAs), which are designed to be compostable, suitable for food contact and are characterized by a good compromise between mechanical properties and thermal stability. A commercial grade PLA was, therefore, compounded in a twin-screw co-rotating extruder by the use of specific additives: maleated and glycidyl methacrylate PLAs as compatibilizers/chain extenders and microlamellar talc as mineral filler/nucleation promoter. After pelletizing, the resulting compounds were melt-processed by injection and compression molding.Differential scanning calorimetry, flexural tests in static machine and top-hat cylindrical flat indentations were performed to evaluate the thermal and mechanical response of the molded components. The experimental findings show that crystallization of the PLA can be controlled by fine-tuning the compound formulation as well as by properly setting the processing parameters. In addition, achievement of the appropriate crystallization degree in the polymer can lead to molded components, which exhibit improved mechanical strength and high thermal stability. K E Y W O R D Scompostable polymer, mechanical response, melt processing, molding, thermal stability

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Non-isothermal crystal nucleation of poly (l-lactic acid)

Cited by 106 publications

References 38 publications

The difference of equilibrium melting point between poly(l‐lactic acid) and poly(l‐lactic acid)/poly(d‐lactic acid) blends: cases with three molecular weights

The difference of equilibrium melting point between poly(l‐lactic acid) and poly(l‐lactic acid)/poly(d‐lactic acid) blends: cases with three molecular weights

Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

Improvements in mechanical strength and thermal stability of injection and compression molded components based on Poly Lactic Acids

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