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

Yu-zeng, LI; Li, Qiao; Yang, Gesheng; Ming, Ruihao; Yu, Minghui; Zhang, Huihui; Shao, Huili

doi:10.1002/adv.21824

Cited by 19 publications

(7 citation statements)

References 23 publications

(68 reference statements)

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“…Studies have confirmed that stereoselective association between D-and L-polymers occurred preferably when PDLA and PLLA were blended in equivalent proportions (1:1) Ikada 1993, 1999). However, homo-crystallites (hc) and stereocomplex crystallites (sc) were reported to coexist, although sc crystallites predominated, in sc-PLA manufactured by melt blending equivalent proportions of PLLA/PDLA, followed by conventional compression or injection molding (Li et al 2018;Srithep et al 2015). The obtained sc-PLA showed inferior mechanical properties to those of PLLA or PDLA, likely due to degree of polymerization (DP) loss caused by the high temperature during the melting process (Xu et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Structure and properties of flax vs. lyocell fiber-reinforced polylactide stereocomplex composites

et al. 2021

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A commonly used natural cellulose fiber (flax) and a regenerated cellulose fiber (Lyocell) were used at 20 wt% to reinforce polylactide stereocomplex (sc-PLA) composites. Composites were prepared by melt compounding cellulose fibers and an equivalent proportion of PLLA/PDLA, followed by injection molding. The structures and properties of these two kinds of cellulose fiber/sc-PLA composites were compared and evaluated. The results showed that the total crystallinity and stereocomplex crystallite content of composites could be increased by reinforcing with cellulose fibers, and Lyocell fibers were more effective in accelerating crystallinity and the formation of stereocomplex crystallites than flax fibers. Mechanical properties of Lyocell fibers were much poorer than those of flax fibers, and the interfacial adhesion values of Lyocell/sc-PLA composites were inferior to those of flax/sc-PLA composites. Lyocell/ sc-PLA composites showed higher impact strength and similar tensile strength vs. flax/sc-PLA composites, but the Young's modulus values of Lyocell/sc-PLA composites were lower than those of flax/sc-PLA composites. The Vicat softening temperatures of both flax/sc-PLA and Lyocell/sc-PLA composites were increased to nearly 100°C higher than that of PLLA. Lyocell/sc-PLA composites showed the highest Vicat softening temperature of * 170°C.

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Section: Introductionmentioning

confidence: 99%

Structure and properties of flax vs. lyocell fiber-reinforced polylactide stereocomplex composites

et al. 2021

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“…Poly(lactic acid) (PLA) can replace traditional plastic in food packaging [ 1 , 2 , 3 , 4 , 5 , 6 ], bioengineering materials [ 7 , 8 , 9 ], composites [ 10 , 11 , 12 ] and other fields due to its good biodegradability, biocompatibility, and processability. However, PLA still has many inherent defects, such as the long degradation period and poor hydrophilicity, as well as low heat resistance which may increase PLA processing difficulty [ 13 , 14 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Poly(l-lactic acid) through Stereocomplexation with Enantiomeric Poly(d-lactic acid) and Its Copolymer

Zhu

Chang

et al. 2021

Polymers

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Poly(l–lactic acid) with high molecular weight was used to prepare PLLA films by means of the solvent casting technique. Poly(d–lactic acid) (PDLA) and poly(d–lactic acid–co–glucose) copolymer (PDLAG) with a low molecular weight were synthesized from d–lactic acid and glucose through melt polycondensation. PLLA films were immersed in PDLA or PDLAG solution to prepare surface-modified PLLA films. The modified PLLA film presented stereocomplex crystal (SC) on its surface and homogeneous crystals (HC) in its bulk. The HC structure and surface morphology of modified PLLA films were obviously damaged by PDLA or PDLAG solution. With increasing immersion time, the PLLA films modified by PDLA decreased both the HC and SC structure, while the PLLA films modified by PDLAG increased the SC structure and decreased the HC structure. Hydrophilic glucose residues of PDLAG on the surface would improve the hydrophilicity of surface-modified PLLA films. Moreover, the hydrophilicity of glucose residues and the interaction of glucose residues with lactic acid units could retard HC destruction and SC crystallization, so that PLLA films modified by PDLAG possessed lower melting temperatures of HC and SC, the crystallinity of SC and the water contact angle, compared with PDLAG–modified PLLA films. The SC structure could improve the heat resistance of modified PLLA film, but glucose residues could block crystallization to promote the thermal degradation of PLA materials. The surface modification of PLLA films will improve the thermal stability, hydrophilicity and crystallization properties of PLA materials, which is essential in order to obtain PLA-based biomaterials.

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“…Herein, this review focuses on discussing recent progress in the development of methodologies for preparing PLA-SC ( Figure 1 ), which not only includes scientific mechanisms for the origin of PLA-SC formation enhancement from each method but also highlights their processing-structure-property relationship for different applications including engineering plastics, biomedicine, and bioelectronics. We want to note, as a mini-review, there is no attempt to be comprehensive, and interested readers can find many excellent reviews on relevant topics of PLA-based materials including material synthesis, processing, macroscopic property, and applications that provide a more in-depth discussion (Pan et al, 2017 , 2018 ; Li et al, 2018 ). Our goal is rather to provide a succinct summary about progress to date on technology development for enhancing PLA-SC formation in order to compel new or interdisciplinary researchers to enter the fray and inspire more progress in the field.…”

Section: Introductionmentioning

confidence: 99%

Recent Progress in Enhancing Poly(Lactic Acid) Stereocomplex Formation for Material Property Improvement

et al. 2020

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The production and utilization of polymers have been widely implemented into diverse applications that benefit modern human society, but one of the most valuable properties of polymers, durability, has posed a long-standing environmental challenge from its inception since plastic waste can lead to significant contamination and remains in landfills and oceans for at least hundreds of years. Poly(lactic acid) (PLA) derived from renewable resources provides a sustainable alternative to traditional polymers due to its advantages of comparable mechanical properties with common plastics and biodegradability. However, the poor thermal and hydrolytic stability of PLA-based materials limit their potential for durable applications. Stereocomplex crystallization of enantiomeric poly (l-lactide) (PLLA) and poly (d-lactide) (PDLA) provides a robust approach to significantly enhance material properties such as stability and biocompatibility through strong intermolecular interactions between L-lactyl and D-lactyl units, which has been the key strategy to further PLA applications. This review focuses on discussing recent progress in the development of processing strategies for enhancing the formation of stereocomplexes within PLA materials, including thermal processing, additive manufacturing, and solution casting. The mechanism for enhancing SC formation and resulting material property improvement enabled by each method are also discussed. Finally, we also provide the perspectives on current challenges and opportunities for improving the understanding of processing-structure-property relationship in PLA materials that could be beneficial to their wide practical applications for a sustainable society.

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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

Cited by 19 publications

References 23 publications

Structure and properties of flax vs. lyocell fiber-reinforced polylactide stereocomplex composites

Structure and properties of flax vs. lyocell fiber-reinforced polylactide stereocomplex composites

Surface Modification of Poly(l-lactic acid) through Stereocomplexation with Enantiomeric Poly(d-lactic acid) and Its Copolymer

Recent Progress in Enhancing Poly(Lactic Acid) Stereocomplex Formation for Material Property Improvement

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