Complex deformation histories and modeling mechanical behavior of glassy polymers

Song, Hosup; Medvedev, Grigori A.; Caruthers, James M.; Jo, Jun Young; Kim, Jae-Woo

doi:10.1016/j.polymer.2023.125707

Cited by 3 publications

(3 citation statements)

References 19 publications

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“…The procedure for synthesizing poly(BMA-co-MMA) (PBMA/MMA) copolymer is described elsewhere. 22 Polymerization was carried out between a pair of glass plates with a 1 mm thick silicone rubber sheet as a spacer under an inert atmosphere. Cure was performed in two steps: at 25 C for 24 h and then at 70 C for 48 h. The PBMA/MMA sheet was cut into dog-bone specimens (Type I) according to ASTM D638 using a 4.5 W CO 2 laser cutting machine (ILS 12.150D, Universal Laser Systems).…”

Section: Methodsmentioning

confidence: 99%

“…The system is 50:50 random co‐polymer of butyl methacrylate and methyl methacrylate lightly crosslinked with ethylene glycol dimethacrylate (EGDMA). The procedure for synthesizing poly(BMA‐ co ‐MMA) (PBMA/MMA) copolymer is described elsewhere 22 . Polymerization was carried out between a pair of glass plates with a 1 mm thick silicone rubber sheet as a spacer under an inert atmosphere.…”

Section: Methodsmentioning

confidence: 99%

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Effect of anisotropic deformation on the differential scanning calorimetry response of polymer glasses

Song,

Medvedev,

Caruthers

2023

Journal of Polymer Science

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Large anisotropic deformation affects the physical state of a polymer glass, where the changes in the state of material are revealed by performing a differential scanning calorimetry (DSC) experiment. Previously, the deformation was applied to polymers well below their glass transition temperatures, and it was found that uniaxial compressive loading–unloading resulted in a broad exothermic peak on the DSC trace. Here we report on the effect on the subsequent DSC response of a deformation experiment performed in uniaxial extension on a ductile 50:50 co‐polymer poly(BMA‐co‐MMA) (PBMA/MMA). The deformation of up to 80% strain was applied at Tg − 30°C and Tg − 40°C, that is, closer to Tg than in the previous work. Unlike in the well below Tg deformation case, the DSC trace contains an endothermic peak followed by an exothermic peak. The magnitude of the endothermic peak as well as the asymptotic glassy heat capacity increase with the amount of mechanical work performed during the deformation cycle.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effect of anisotropic deformation on the differential scanning calorimetry response of polymer glasses

Song,

Medvedev,

Caruthers

2023

Journal of Polymer Science

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“…Relaxation (dielectric, − mechanical, − specific volume, − or enthalpy − ) experiments and simulations − are important tools in understanding the behavior of glassy and near-glassy polymers. ,, Unlike conventional liquids, glassy materials exhibit relaxations that substantially deviate from the standard Debye single-exponential decay. In some cases, the material property of interest changes slowly over many decades in time (“stretched relaxation”), while in others, it exhibits no change until a sudden avalanche-like event takes place (“compressed relaxation”).…”

Section: Introductionmentioning

confidence: 99%

Unifying Physical Framework for Stretched-Exponential, Compressed-Exponential, and Logarithmic Relaxation Phenomena in Glassy Polymers

Ginzburg,

Gendelman,

Zaccone

2024

Macromolecules

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We develop a simple yet comprehensive nonlinear model to describe relaxation phenomena in amorphous glass-formers near the glass transition temperature. The model is based on the two-state, two-(time)scale (TS2) framework and describes the isothermal relaxation of specific volume, enthalpy, or shear stress via a simple first-order nonlinear differential equation (the Trachenko-Zaccone [TZ] equation) for local cooperative events. These nonlinear dynamics of cooperatively rearranging regions naturally arise from the TS2 framework. We demonstrate that the solutions of the TZ equation comprehensively encompass the Debye exponential relaxation, the Kohlrausch–Williams–Watts stretched and compressed relaxations, and the Guiu–Pratt logarithmic relaxation. Furthermore, for the case of stress relaxation modeling, our model recovers, as one of its limits, the Eyring law for plastic flow, where the Eyring activation volume is related to thermodynamic parameters of the material. Using the example of polystyrene, we demonstrate how our model successfully describes the Kovacs’ “asymmetry of approach” specific volume and enthalpy experiments, as well as the stress relaxation. Other potential applications of the model, including the dielectric relaxation, are also discussed. The presented approach disentangles the physical origins of different relaxation laws within a single general framework based on the underlying physics.

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Models for the decrease in ultimate elongation and embrittlement of organic coatings during degradation

Croll

2024

Progress in Organic Coatings

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Complex deformation histories and modeling mechanical behavior of glassy polymers

Cited by 3 publications

References 19 publications

Effect of anisotropic deformation on the differential scanning calorimetry response of polymer glasses

Effect of anisotropic deformation on the differential scanning calorimetry response of polymer glasses

Unifying Physical Framework for Stretched-Exponential, Compressed-Exponential, and Logarithmic Relaxation Phenomena in Glassy Polymers

Models for the decrease in ultimate elongation and embrittlement of organic coatings during degradation

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