Toward all stereocomplex-type polylactide with outstanding melt stability and crystallizability via solid-state transesterification between enantiomeric poly(l-lactide) and poly(d-lactide)

Li, Xiangli; Yang, Dongsheng; Zhao, Youbo; Diao, Xingyuan; Bai, Hongwei; Zhang, Qin; Fu, Qiang

doi:10.1016/j.polymer.2020.122850

Cited by 26 publications

(14 citation statements)

References 64 publications

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“…Hence, they could be available for a large number of manufacturers and processors. Nevertheless, special attention should be paid on the polymerization process, since it is affected by the diffusion of the reactive end groups inside the polymer, and by the diffusivity of the byproducts from the polymer particles [ 45 , 46 , 47 , 48 , 49 ].…”

Section: Resultsmentioning

confidence: 99%

Evaluation of the Technical Viability of Distributed Mechanical Recycling of PLA 3D Printing Wastes

et al. 2021

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3D printing PLA wastes were recovered from a well-known reference grade and from different sources. The recovered wastes were subjected to an energic washing step and then reprocessed into films by melt-extrusion, followed by compression molding to simulate the industrial processing conditions. The obtained materials were characterized and the optical, structural, thermal and crystallization behavior are reported. The mechanical recycling process leads to an increase of the crystallinity and a decrease of the intrinsic viscosity of the formulations, particularly in the sample based on blends of different 3D-PLA wastes. Moreover, the obtained films were disintegrated under composting conditions in less than one month and it was observed that recycled materials degrade somewhat faster than the starting 3D-PLA filament, as a consequence of the presence of shorter polymer chains. Finally, to increase the molecular weight of the recycled materials, the 3D-PLA wastes were submitted to a solid-state polymerization process at 110, 120, and 130 °C, observing that the recycled 3D-wastes materials based on a well-known reference grade experiences an improvement of the intrinsic viscosity, while that coming from different sources showed no significant changes. Thus, the results show that 3D printing PLA products provides an ideal environment for the implementation of distributed recycling program, in which wastes coming from well-known PLA grades can successfully be processed in films with good overall performance.

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Section: Resultsmentioning

confidence: 99%

Evaluation of the Technical Viability of Distributed Mechanical Recycling of PLA 3D Printing Wastes

et al. 2021

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“…Apparently, with the increase of the Sc crystallinity, the cold crystallization peak of PLA became sharper and shifted to a lower temperature in the heating scanning. Li et al also reported a similar phenomenon and its mechanism . The existing Sc crystals acted as a crystallization nucleation agent to promote the formation of cold crystallization.…”

Section: Resultsmentioning

confidence: 75%

Flexibly Controlling the Polycrystallinity and Improving the Foaming Behavior of Polylactic Acid via Three Strategies

Liu

et al. 2022

ACS Omega

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Controlling foamability plays the central role in preparing PLA foams with high performances. To achieve this, chain extension was often used to improve the rheological property of PLA resins; however, despite the availability of this approach, it often deteriorates the biodegradability of PLA and greatly increases the processing cost and complexity. Hence, we reported a special crystallization induction method to design PLA foams with a tunable cellular structure and a high expansion ratio. A novel crystallization-promoting agent combination (D-sorbitol, CO2, and phenylphosphonic acid zinc salt) was used to induce PLA to enhance the chain interaction force and chain mobility and to provide crystallization templets. A series of PLAs with tunable stereocomplex (Sc)/α crystallinity and rapid non-isothermal crystallization ability were obtained. The effect of various crystallization properties on the foaming behavior of PLA was studied. The results demonstrated that proper crystallization conditions (a small spherulite size, a crystallinity of 6%, and rapid crystallization ability) could virtually contribute to the optimized cellular structure with the highest cell density of 4.36 × 106 cell/cm3. When the Sc crystallinity was above 10%, PLA had a superior foamability, which thereby resulted in a high foaming expansion ratio of 16.2. A variety of cellular morphologies of PLA foams could be obtained by changing the foaming temperature and the crystallization property. The proposed crystallization-induced approach provided a useful method for controlling the cellular structure and the performances of the PLA foams.

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“…This phenomenon implies that the addition of TEAP can suppress the combustion of PLA and lower the pHRR and THR. Flame retardancy index (FRI) is a simple criterion for quantifying the ame retardancy of polymeric composites, which is calculated by eqn (1). The FRI values of PLA/TEAP 1.0 and PLA/TEAP 3.0 are 1.1 and 1.3, respectively, indicating PLA composites have good ame retardancy.…”

Section: Combustion Behavior Of Pla and Pla/teapmentioning

confidence: 99%

“…Owing to the excellent biocompatibility, easy processibility, high melting temperature and mechanical properties, [1][2][3][4] poly(lactic acid) (PLA) is considered to be one of the most promising biodegradable polymers for decreasing environmental pollution caused by the indiscriminate use of non-degradable fossilbased plastics. [5][6][7] However, in many new elds such as electronic appliances, automotive and rail transit materials, its low crystallization rate and ammability restrict its further development.…”

Section: Introductionmentioning

confidence: 99%

Simultaneously enhancing the crystallization rate and fire retardancy of poly(lactic acid) by using a novel bifunctional additive trimethylamine phenylphosphonate

Jin

Tian

et al. 2021

RSC Adv.

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Toward all stereocomplex-type polylactide with outstanding melt stability and crystallizability via solid-state transesterification between enantiomeric poly(l-lactide) and poly(d-lactide)

Cited by 26 publications

References 64 publications

Evaluation of the Technical Viability of Distributed Mechanical Recycling of PLA 3D Printing Wastes

Evaluation of the Technical Viability of Distributed Mechanical Recycling of PLA 3D Printing Wastes

Flexibly Controlling the Polycrystallinity and Improving the Foaming Behavior of Polylactic Acid via Three Strategies

Simultaneously enhancing the crystallization rate and fire retardancy of poly(lactic acid) by using a novel bifunctional additive trimethylamine phenylphosphonate

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