Influence of liquid media on the craze initiation in amorphous polylactide

Трофимчук, Е. С.; Никонорова, Н. И.; Москвина, М. А.; Efimov, Alexander; Khavpachev, Mukhamed A.; Volynskiĭ, A. L.

doi:10.1016/j.polymer.2018.03.023

Cited by 15 publications

(7 citation statements)

References 20 publications

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“…Figure shows σ 1cz vs average diameter of the dispersed PEO-PBO particles in PLA. The σ 1cz for neat PLA is 50 MPa, which is within the typical stress range seen in the literature, , while σ 1cz decreased by ∼50% to 26 MPa upon blending 3 wt % PEO-PBO with PLA. As a crack approaches a particle, a larger sample volume can initiate a craze due to the decreased σ 1cz . , As the material begins to deform and dissipate energy at lower stresses, additional strain is required to reach the craze fibril breakdown stress (fibril failure), leading to greater toughness.…”

Section: Resultssupporting

confidence: 85%

“…Figure 9 shows σ 1cz vs average diameter of the dispersed PEO-PBO particles in PLA. The σ 1cz for neat PLA is 50 MPa, which is within the typical stress range seen in the literature, 71,72 while σ 1cz decreased by ∼50% to 26 MPa upon blending 3 wt % PEO-PBO with PLA. As a crack approaches a particle, a larger sample volume can initiate a craze due to the decreased σ 1cz .…”

Section: Influence Of Peo-pbo Loading Onsupporting

confidence: 84%

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Crazing Mechanism and Physical Aging of Poly(lactide) Toughened with Poly(ethylene oxide)-block-poly(butylene oxide) Diblock Copolymers

et al. 2020

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Sustainable polymers are important alternatives to plastics and elastomers derived from petroleum resources. Poly(lactide) (PLA), a commercially available sustainable plastic, is a well-known success story. However, PLA lacks ductility and toughness, limiting the number of potential uses. In this study, small amounts of a liquid poly(ethylene oxide)-block-poly(butylene oxide) (PEO-PBO) diblock copolymer additive were blended with PLA to enhance its toughness and ductility. The incorporated PEO-PBO diblock copolymers generated a macrophase-separated morphology with particle diameters of 0.2–0.9 μm, and nearly matched refractive indices of PLA and PEO-PBO led to retention of optical transparency. Addition of just 1.8 wt % PEO-PBO into PLA led to a 20-fold increase in toughness, measured as the area under the stress–strain data in tension without affecting the bulk elastic modulus of the plastic. The micromechanical deformation process of the PEO-PBO/PLA blend was investigated via in situ small angle X-ray scattering during tensile testing. The total volume of the crazed material was proportional to the total surface area of the dispersed PEO-PBO particles, and both quantities increased with increasing PEO-PBO loading. Increasing the PEO-PBO loading also resulted in (A) an increase in particle size, causing a decrease in the craze initiation stress, and (B) an increase in fibril spacing, indicating a lower craze propagation stress. Furthermore, craze development was found to be independent of aging time. As a result, the PEO-PBO/PLA blend was able to remain ductile and tough for up to 114 days, exhibiting a 10-fold increase in elongation at break and toughness compared to neat PLA, which becomes brittle in less than 2 days. These results demonstrate that designing additives that promote deformation by crazing is an effective way to overcome the aging-induced embrittlement of glassy polymers.

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Section: Resultssupporting

confidence: 85%

Section: Influence Of Peo-pbo Loading Onsupporting

confidence: 84%

Crazing Mechanism and Physical Aging of Poly(lactide) Toughened with Poly(ethylene oxide)-block-poly(butylene oxide) Diblock Copolymers

et al. 2020

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“…The corresponding pore size distributions are narrow and unimodal with a wellpronounced maximum, which agrees with the average pore diameter estimated by the PDLP method. 27,47,48 Immediately after the EIC, the unloaded samples experience spontaneous strain recovery at room temperature and nearly restore their initial dimensions (up to ∼96%) (Figure 1E). As a result of the SSR, the porosity of the samples decreases down to zero.…”

Section: Resultsmentioning

confidence: 98%

Mechanoresponsive Hard Elastic Materials Based on Semicrystalline Polymers: From Preparation to Applied Properties

Аржакова

Долгова

Yarysheva

et al. 2020

ACS Appl. Polym. Mater.

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This work offers an alternative strategy for the preparation of hard elastic (HE) materials via environmental intercrystallite crazing and subsequent spontaneous strain recovery. Structure and properties of HE materials are characterized: secondary loading in air is accompanied by the development of porosity (up to 40%) with pores below 20 nm; upon unloading, the as-opened porous structure is closed in the elastic manner (strain recovery up to 90%). Upon loading/unloading cycles, the HE samples behave as "living" mechanoresponsive materials with openable and closable mesopores. This strategy has proved to be universal for diverse semicrystalline polymers [high-density polyethylene, polypropylene, poly(tetrafluoroethylene)]. The phenomenon of the forced impregnation of polymer matrixes with target cargo upon cyclic loading offers benefits for the incorporation of diverse additives when the overall uptake can be increased by 500%. The mechanism behind this phenomenon is discussed. Practical benefits of HE polymers and related nanocomposites as applied materials (including antibacterial and photoactive materials) are highlighted.

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“…Trofimchuk et al have carried out a lot of investigations in the field of exploration of PLA crazing [ 130 , 131 , 132 , 133 ]. In particular, the effect of different media (air and adsorption-active liquids) during uniaxial stretching on the formation of crazes in PLA was studied in [ 131 ]. The crazing mechanism was investigated in hydrocarbons, organosilicon liquids, aliphatic alcohols, and water-alcohol solutions.…”

Section: Structural Rearrangement Of Pla Chainsmentioning

confidence: 99%

Recent Approaches to the Plasticization of Poly(lactic Acid) (PLA) (A Review)

Mastalygina,

Aleksanyan

2023

Polymers

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Poly(lactic acid) (PLA) is a polyester attracting growing interest every year in different application fields, such as packaging, cosmetics, food, medicine, etc. Despite its significant advantages, it has low elasticity that may hinder further development and a corresponding rise in volume of consumption. This review opens a discussion of basic approaches to PLA plasticization. These considerations include copolymerization and blending with flexible polymers, introducing oligomers and low-molecular additives, as well as structural modification. It was demonstrated that each approach has its advantages, such as simplicity and low cost, but with disadvantages, including complex processing and the need for additional reagents. According to the analysis of different approaches, it was concluded that the optimal option is the application of copolymers as the additives obtained via reactive mixing to PLA and its blends with other polymers.

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Influence of liquid media on the craze initiation in amorphous polylactide

Cited by 15 publications

References 20 publications

Crazing Mechanism and Physical Aging of Poly(lactide) Toughened with Poly(ethylene oxide)-block-poly(butylene oxide) Diblock Copolymers

Crazing Mechanism and Physical Aging of Poly(lactide) Toughened with Poly(ethylene oxide)-block-poly(butylene oxide) Diblock Copolymers

Mechanoresponsive Hard Elastic Materials Based on Semicrystalline Polymers: From Preparation to Applied Properties

Recent Approaches to the Plasticization of Poly(lactic Acid) (PLA) (A Review)

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