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Wang Y, Ma R, Li H, Hu S, Gao Y, Liu L, Zhao X, Zhang L. Effect of the content and strength of hard segment on the viscoelasticity of the polyurethane elastomer: insights from molecular dynamics simulation. SOFT MATTER 2022; 18:4090-4101. [PMID: 35575258 DOI: 10.1039/d2sm00463a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Due to the wide application, it is very crucial to understand the viscoelasticity of the polyurethane elastomer (PU, denoted by soft-hard block copolymer), which contains the soft segments (SS) and hard segments (HS). Thus, in this work, the effect of the content and strength of HS on the viscoelasticity of PU is explored in detail by adopting a coarse-grained model. First, the phase morphology of PU is characterized where both the single continuous phase and the bicontinuous phase are observed by varying the content of HS. Then, the viscoelasticity of PU is calculated by analyzing the storage modulus, the loss modulus, and the loss factor, which depends on the content and strength of HS. To further elucidate the mechanism for the storage modulus, the normalized interaction energy, the order parameter, and the formation probability of the HS or SS phase are characterized with the shear strain amplitude, which reflects the deformation of the phase structure. Then, the energy dissipation is quantified, which can rationalize the loss modulus well. A parameter is introduced, which considers the relative slippage and the content of HS or SS. It can explain the change in the loss factor with the content and strength of HS. In summary, this work can help to further understand how the content and strength of hard segments affect the viscoelasticity of the soft-hard block PU and structure evolution at the molecular level.
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Affiliation(s)
- Yimin Wang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Ruibin Ma
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Haoxiang Li
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Shikai Hu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Yangyang Gao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Li Liu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Xiuying Zhao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
| | - Liqun Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029 Beijing, P. R. China.
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
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Nematollahi M, Jalali-Arani A, Golzar K, Modarress H. Investigation of nanoparticle-polymer interaction in bio-based nanosilica-filled PLA/NR nanocomposites: molecular dynamics simulation. J Mol Model 2020; 26:230. [PMID: 32785857 DOI: 10.1007/s00894-020-04431-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/27/2020] [Indexed: 01/13/2023]
Abstract
Molecular dynamics (MD) simulation, by employing the COMPASS force field, was utilized to investigate structural and thermal characteristics as well as interfacial interactions between components of nanocomposite consisting of poly(lactic acid) (PLA)/natural rubber (NR)/nanosilica, abbreviated as PSxN, where 1 ≤ x ≤ 7 and it represents the parts of SiO2 nanoparticles added to the PLA/NR (PN) blend. Analysis of the obtained results including density (ρ), fractional free volume (FFV), glass transition temperature (Tg), interaction energy (Einteraction), and radial distribution function (RDF) of these nanocomposites was performed. Comparing Einteraction of nanocomposites with that of the PN blend showed that the interactions between the chains of the two polymers are highly dependent on the added amounts of silica nanoparticles, so that by adding silica to the PN blend to obtain PS1N and PS3N nanocomposites, the amount of Einteraction was reduced to a smaller positive value, which indicates the tendency of the nanocomposite's components to interact with each other. By further addition of silica nanoparticles to have PS5N and PS7N nanocomposites and then by analysis of the RDF results, it was found that the nanoparticles were not well dispersed in these two nanocomposites and they were accumulated in the NR rubbery phase. Therefore, the percolation threshold for silica loading on the PN blend is at most 3 parts (x = 3). These results as well as the other obtained simulation results were compared with the available experimental data, and the agreement observed between them approved the simulation procedure and validated the obtained results.
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Affiliation(s)
- Mahsa Nematollahi
- Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, No. 424, Hafez St., Tehran, Iran
| | - Azam Jalali-Arani
- Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, No. 424, Hafez St., Tehran, Iran
| | - Karim Golzar
- Department of Chemical Engineering, Amirkabir University of Technology, No. 424, Hafez St., Tehran, Iran
| | - Hamid Modarress
- Department of Chemical Engineering, Amirkabir University of Technology, No. 424, Hafez St., Tehran, Iran.
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