Study and Modeling of Polymer Degradation in Bulk

Тихомиров, С. Г.; Podvalny, S. L.; Хвостов, А. А.; Карманова, О. В.; Bityukov, V. K.

doi:10.1134/s0040579518010189

Cited by 8 publications

(3 citation statements)

References 4 publications

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“…Currently, the demand for polymeric materials is on the rise, leading to extensive research on the aging mechanisms of these materials. The research focuses on understanding the complex aging processes and their effects on the physical and chemical properties of polymeric materials, as well as the influence of processing on said aging phenomena [ 5 , 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Modification of Polycaprolactone with Plant Extracts to Improve the Aging Resistance

et al. 2023

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Natural extracts of plant origin are used as anti-aging compounds of biodegradable polymers. Coffee, cocoa, or cinnamon extracts in amounts from 0.5 to 10 wt.% were added to the polycaprolactone matrix. The manufactured materials were aged at elevated temperatures with increased relative humidity and continuous exposure to UV radiation for 720, 1440, or 2160 h. The performance of the proposed extracts was compared with the retail anti-aging compound, butylated hydroxytoluene. Visual assessment, FTIR analysis, melt flow rate, tensile strength, impact tensile strength, thermogravimetry, and differential scanning calorimetry tests were conducted. Results showed that the use of lower contents of the tested extracts is particularly advantageous. When the content of the extract did not exceed 1 wt.%, no unfavorable influence on the properties of the materials was observed. The stabilizing performance during accelerated aging was mostly similar to or greater than that of the reference compound used.

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Section: Introductionmentioning

confidence: 99%

Modification of Polycaprolactone with Plant Extracts to Improve the Aging Resistance

et al. 2023

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“…The degradation of poly(esters), poly(ester urea), poly(amides), and poly(anhydrides) commonly used for biomedical devices occurs primarily through hydrolysis (see for review). After being exposed to water, these polymers lose their mechanical properties through the decrease in molecular mass resulting in dissolution of small polymer fragments. ,− This process, known as erosion, is initiated at the surface of the sample (heterogeneous or surface erosion) and in many cases propagates throughout the entire sample (homogeneous or bulk erosion). The dominance of one erosion mechanism over another is a result of the fine interplay between the diffusion of water and the rate of the bond cleavage reaction.…”

Section: Introductionmentioning

confidence: 99%

“…Modeling of the erosion and degradation is usually carried out by numerically solving diffusion-reaction equations that are based on the macroscopic diffusion coefficient and reaction rates. ,− ,− While this approach allows modeling of the surface and bulk erosion on the macroscopic level, it lacks molecular details and is missing specifics of coupling between water diffusion and degradation kinetics. This coupling becomes even more critical when one attempts to model degradation of microphase-separated copolymers.…”

Section: Introductionmentioning

confidence: 99%

Degradation of Films of Block Copolymers: Molecular Dynamics Simulations

et al. 2020

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Coarse-grained molecular dynamics simulations are used to study the degradation of films of copolymers in a selective solvent for one of the blocks. Simulations were designed to mimic the hydrolytic degradation of glycine, valine, and phenylalanine-based poly(ester urea)s. The analysis of the simulation results shows that the rate of copolymer degradation is a result of the interplay between chain-breaking kinetics, solvent diffusion, and swelling of the solvophilic domains. The evolution of the film structure during the degradation process was monitored by calculating the scattering function S(q) of the copolymer film. In the initial stages of the polymer degradation and swelling, the scattering function has a characteristic peak corresponding to a domain spacing of solvophilic and solvophobic domains. The solvent diffusion into the films results in a monotonic shift of the peak position to smaller q. This shift is accompanied by the increase in the scattering intensity at q ≪ 1 in such a way that the peak completely disappears at the later stages of film degradation with the function S(q) having two characteristic scaling regimes: S(q) ∼ 1/q 2 and S(q) ∼ 1/q 4 . At this stage of film degradation, the film is composed of the interconnected network of solvophobic domains. The number and weight average degree of polymerizations (DPs) of the copolymer fragments monotonically decrease with time. However, the dispersity (Đ) shows a nonmonotonic dependence. The copolymer degradation kinetics allows for universal description of the time dependence of the copolymer DP and the dispersity in terms of the fraction of the broken bonds.

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