Cooperativity length scale in nanocomposites: Interfacial and confinement effects

Saiter, Allisson; Prevosto, D.; Passaglia, Elisa; Couderc, H.; Delbreilh, Laurent; Saiter, Jean‐Marc

doi:10.1103/physreve.88.042605

Cited by 35 publications

(24 citation statements)

References 58 publications

(72 reference statements)

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“…and given in Table . The volume of a CRR ( ξ 3 ) varies in the same range than those calculated for other glass‐formers . It decreases of about 60% as the percentage of TA or ATBC reached 10 %wt.…”

Section: Resultsmentioning

confidence: 60%

Molecular mobility and physical ageing of plasticized poly(lactide)

Dobircau

Delpouve

Herbinet

et al. 2014

Polymer Engineering & Sci

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Molecular mobility and physical ageing of amorphous plasticized polylactide (PLA) with two different contents of mesolactide are studied with the help of thermal analysis. Used plasticizers are acetyl tributyl citrate (ATBC) and triacetin (TA), two molecules with established miscibility and plasticizing efficiency. Lower plasticizer permanence of TA compared with ATBC is found. The plasticizer molecules decreased the size of the cooperativity domains at the glass transition temperature Tg and likely in the glassy state by decreasing intermacromolecular interactions and notwithstanding the mesolactide content of PLA and the chemical identity of the plasticizer. The recovery function is given and shows a significant effect of the plasticizer on the physical ageing. The supplementary free volume brought by the plasticizer enhances molecular mobility in the glassy state and increases structural relaxation at one order of magnitude. The comparison between different plasticizers reveals that the structural relaxation is however independent from the type of plasticizer and the percentage of mesolactide in PLA. POLYM. ENG. SCI., 55:858–865, 2015. © 2014 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 60%

Molecular mobility and physical ageing of plasticized poly(lactide)

Dobircau

Delpouve

Herbinet

et al. 2014

Polymer Engineering & Sci

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“…It is also interesting to notice that the increase of cooperativity in an initially bulk amorphous material is often related to the same cause, i.e. the creation of nano-domains playing the role of anchoring points between the macromolecules [10,51]. In our case, we can reasonably assume that the highly cohesive mesophase plays this role by increasing the level of inter-molecular interactions, thus leading to the global increase of the cooperativity length.…”

Section: Tablementioning

confidence: 64%

“…In the second case, the approach of Donth has widely been used to investigate the decrease of cooperativity for two kinds of structural hindrances namely external and internal hindrances. External hindrances are related to geometrical restrictions like the confinement between nanolayers [7,8] or the addition of additives such as fillers [9,10] or plasticizer [11]. On the other hand, internal hindrances are related to the materials itself, in other words its microstructural modifications such as spherulitic crystallization [12,13] or orientation/crystallization of the amorphous phase induced by drawing [5,14].…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics in electrospun amorphous plasticized polylactide fibers

Monnier

Delpouve

Basson

et al. 2015

Polymer

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. The molecular dynamics in the amorphous phase of electrospun fibers of polylactide (PLA) has been investigated using the cooperative rearranging region concept. An unusual and significant increase of the cooperativity length at the glass transition induced by the electrospinning has been observed. This behavior is attributed to the singularity of the amorphous phase organization. Electrospun PLA fibers rearrange in a pre-ordered metastable state which is characterized by highly oriented but non-crystalline polymer chains, and the presence of highly cohesive mesophase which plays the role of an anchoring point in the amorphous phase. The successful processing of electrospun fibers of plasticized polylactide is also demonstrated. It is shown that the plasticizer remains in the polymer matrix of the nanofiber after electrospinning. When PLA is plasticized, the loosening of the macromolecules prevails over the preferential orientation of the chains; therefore no mesophase is formed during the electrospinning and the cooperativity length remains the same. When the content of plasticizer increases, the inter-chain characteristic distances estimated from wide angle X-ray scattering (WAXS) are redistributed, suggesting a change in the level of interactions between macromolecules. It is assumed that the resulting decrease of the cooperativity length is driven by the progressive reduction of the number of inter-chain weak bonds. It is shown that in a non-confined environment, the number of structural entities involved in the alpha relaxation is strongly dependent on the level of physical interactions in the amorphous phase.

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“…Besides, the cooperativity length may change when the relaxation is hindered by structural constraints. The decrease of the CRR size under confinement has been reported for nanoparticles, nanolayers, intercalated nanocomposites, and semicrystalline polymers . Any modification of the intermolecular bonds may also impact the cooperativity, as observed in plasticized polylactide, when electro‐donor and electro‐acceptor side groups are associated in statistical methacrylate copolymers, or when π‐stacking is hindered in polycarbonate .…”

Section: Introductionmentioning

confidence: 89%

A structural interpretation of the two components governing the kinetic fragility from the example of interpenetrated polymer networks

Araujo

Batteux

et al. 2018

J Polym Sci B Polym Phys

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Kinetic fragility and cooperativity length, two major characteristics of the relaxation dynamics at the glass transition, are, respectively, investigated by dynamic mechanical analysis and modulated temperature differential scanning calorimetry in a series of interpenetrated polymer networks based on acrylate and epoxy systems. The relaxation dynamics are impacted by two variables: the rigidity of the network, and the structural heterogeneity resulting from blending. However, the fragility and the cooperativity do not vary similarly. The glass transition progressively broadens as the mass fractions of acrylate and epoxy become equivalent, leading to a strong decrease in cooperativity. On the other hand, under the same conditions, the fragility transitions between the lower value of pure acrylate and theAdditional Supporting Information may be found in the online version of this article.

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Cooperativity length scale in nanocomposites: Interfacial and confinement effects

Cited by 35 publications

References 58 publications

Molecular mobility and physical ageing of plasticized poly(lactide)

Molecular mobility and physical ageing of plasticized poly(lactide)

Molecular dynamics in electrospun amorphous plasticized polylactide fibers

A structural interpretation of the two components governing the kinetic fragility from the example of interpenetrated polymer networks

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