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

Araujo, Steven; Batteux, Florian; Li, Wenlong; Butterfield, Lena; Delpouve, Nicolas; Esposito, Antonella; Tan, Li; Saiter, Jean Marc; Negahban, Mehrdad

doi:10.1002/polb.24722

Cited by 23 publications

(19 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, 41 we proposed a structural interpretation of the two components governing the liquid fragility in polymers. In this representation, ( m – m V ) depends on the interchain interactions, whereas m V characterizes the stiffness of the backbone.…”

Section: Results and Discussionmentioning

confidence: 99%

Reducing the Gap between the Activation Energy Measured in the Liquid and the Glassy States by Adding a Plasticizer to Polylactide

et al. 2018

Self Cite

View full text Add to dashboard Cite

The kinetic fragility of a glass-forming liquid is an important parameter to describe its molecular mobility. In most polymers, the kinetic fragility index obtained from the glassy state by thermally stimulated depolarization current is lower than the one determined in the liquid-like state by dielectric relaxation spectroscopy, as shown in this work for neat polylactide (PLA). When PLA is plasticized to different extents, the fragility calculated in the liquid-like state progressively decreases, until approaching the value of fragility calculated from the glass, which on the other hand remains constant with plasticization. Using the cooperative rearranging region (CRR) concept, it is shown that the decrease of the fragility in the liquid-like state is concomitant with a decrease of the cooperativity length. By splitting the fragility calculated in the liquid, in two contributions: volume and energetic, respectively, dependent and independent on cooperativity, we observed that the slope of the fragility plot in the glass is equivalent to the energetic contribution of the fragility in the liquid. It is then deduced that the difference between the slopes of the relaxation time dependence calculated in both glass and liquid is an indicator of the cooperative character of the segmental relaxation when transiting from liquid to glass. As the main structural consequence of plasticization lies in the decrease of interchain weak bonds, it is assumed that these bonds drive the size of the CRR. In contrast, the dynamics in the glass are independent on plasticization structural effects.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Reducing the Gap between the Activation Energy Measured in the Liquid and the Glassy States by Adding a Plasticizer to Polylactide

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…To estimate the combined influence of crystallization and plasticization on MAF dynamics, the CRR concept has been applied to scÀ PLAs. The temperature fluctuation approach has been recently used to describe the behavior of blends [77,78], providing information regarding the structural heterogeneity. The calculation procedure is presented in Fig.…”

Section: Free Volume and Glass Transition Cooperative Dynamicsmentioning

confidence: 99%

Amorphous rigidification and cooperativity drop in semi−crystalline plasticized polylactide

Varol

Delpouve

Araujo

et al. 2020

Polymer

View full text Add to dashboard Cite

Plasticization of amorphous polylactide shifts the glass transition and extends its temperature range of crystallization to lower temperatures. In this work, we focus on how lowÀ temperature crystallization impacts the mobility of the amorphous phase. Plasticizer accumulates in the amorphous phase because it is excluded from the growing crystal. The formation of rigid amorphous fraction is favored by the low crystallization temperature. It reaches values up to 50% in plasticized polylactide. The increase in the content of rigid amorphous fraction coincides with both the increase of free volume quantified by positron annihilation lifetime spectroscopy, and the decrease in the cooperativity length obtained from the temperature fluctuation approach. The drop of cooperativity is interpreted in terms of mobility gradient due to the amorphous rigidification.

show abstract

“…Structural Interpretation of the Two Fragility Components. In a recent study on the interpenetrated polymer networks, 36 we proposed a structural interpretation of the two components governing the liquid fragility in polymers. In this representation, (m − m V ) depends on the interchain interactions, whereas the stiffness of the backbone mainly influences m V .…”

Section: ■ Introductionmentioning

confidence: 99%

Cooperativity Scaling and Free Volume in Plasticized Polylactide

et al. 2019

Self Cite

View full text Add to dashboard Cite

The experimental evidence of the increase of activation energy associated with the super Arrhenius behavior governing amorphous polylactide by free volume variations has been obtained through a combination of calorimetric, dielectric, and positron annihilation lifetime measurements. The amount of free volume in polylactide was controlled by the amount of acetyltributylcitrate plasticizer in the composition. Plasticization is shown to decrease both the fragility index and the scale of cooperative motions at the glass transition. The calculations of volume and energetic components of kinetic fragility reveal that the fragility drop is governed by the change in the size of cooperative rearranging region. As a result, direct correlation has been established between cooperativity and activation energy for the entire plasticized polylactide series. It is also shown that cooperativity variations with both temperature and plasticizer content can be simplified as a master curve with free volume.

show abstract

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

Cited by 23 publications

References 78 publications

Reducing the Gap between the Activation Energy Measured in the Liquid and the Glassy States by Adding a Plasticizer to Polylactide

Reducing the Gap between the Activation Energy Measured in the Liquid and the Glassy States by Adding a Plasticizer to Polylactide

Amorphous rigidification and cooperativity drop in semi−crystalline plasticized polylactide

Cooperativity Scaling and Free Volume in Plasticized Polylactide

Contact Info

Product

Resources

About