scholarly journals Formation Mechanism of Residual Stresses in Micro-Injection Molding of PMMA: A Molecular Dynamics Simulation

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1368
Author(s):  
Can Weng ◽  
Tao Ding ◽  
Mingyong Zhou ◽  
Jiezhen Liu ◽  
Hao Wang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Aspect Ratio ◽  
Injection Molding ◽  
Residual Stresses ◽  
Formation Mechanism ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Injection Molding Process ◽  
Aspect Ratios

Injection molding is an economical and effective method for manufacturing polymer parts with nanostructures and residual stress in the parts is an important factor affecting the quality of molding. In this paper, taking the injection molding of polymethyl methacrylate (PMMA) polymer in a nano-cavity with an aspect ratio of 2.0 as an example, the formation mechanism of residual stresses in the injection molding process was studied, using a molecular dynamics simulation. The changes in dynamic stress in the process were compared and analyzed, and the morphological and structural evolution of molecular chains in the process of flow were observed and explained. The effects of different aspect ratios of nano-cavities on the stress distribution and deformation in the nanostructures were studied. The potential energy, radius of gyration and elastic recovery percentage of the polymer was calculated. The results showed that the essence of stress formation was that the molecular chains compressed and entangled under the flow pressure and the restriction of the cavity wall. In addition, the orientation of molecular chains changed from isotropic to anisotropic, resulting in the stress concentration. At the same time, with the increase in aspect ratio, the overall stress and deformation of the nanostructures after demolding also increased.

scholarly journals Formation mechanism of bound rubber in elastomer nanocomposites: a molecular dynamics simulation study

RSC Advances ◽  
2018 ◽  
Vol 8 (23) ◽  
pp. 13008-13017 ◽  
Author(s):  
Jun Liu ◽  
Haixiao Wan ◽  
Huanhuan Zhou ◽  
Yancong Feng ◽  
Liqun Zhang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Molecular Dynamics Simulations ◽  
Formation Mechanism ◽  
Simulation Study ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Bound Rubber ◽  
Dynamics Simulations ◽  
Coarse Grained Molecular Dynamics

The formation mechanism of the bound rubber in elastomer nanocomposites using the coarse-grained molecular-dynamics simulations.

scholarly journals Molecular Dynamics Simulation on the Influences of Nanostructure Shape, Interfacial Adhesion Energy, and Mold Insert Material on the Demolding Process of Micro-Injection Molding

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1573 ◽  
Author(s):  
Jin Yang ◽  
Can Weng ◽  
Jun Lai ◽  
Tao Ding ◽  
Hao Wang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Injection Molding ◽  
Interfacial Adhesion ◽  
Mold Insert ◽  
Adhesion Energy ◽  
Dynamics Simulation ◽  
Micro Injection Molding ◽  
Interfacial Adhesion Energy

In micro-injection molding, the interaction between the polymer and the mold insert has an important effect on demolding quality of nanostructure. An all-atom molecular dynamics simulation method was performed to study the effect of nanostructure shape, interfacial adhesion energy, and mold insert material on demolding quality of nanostructures. The deformation behaviors of nanostructures were analyzed by calculating the non-bonded interaction energies, the density distributions, the radii of gyration, the potential energies, and the snapshots of the demolding stage. The nanostructure shape had a direct impact on demolding quality. When the contact areas were the same, the nanostructure shape did not affect the non-bonded interaction energy at PP-Ni interface. During the demolding process, the radii of gyration of molecular chains were greatly increased, and the overall density was decreased significantly. After assuming that the mold insert surface was coated with an anti-stick coating, the surface burrs, the necking, and the stretching of nanostructures were significantly reduced after demolding. The deformation of nanostructures in the Ni and Cu mold inserts were more serious than that of the Al2O3 and Si mold inserts. In general, this study would provide theoretical guidance for the design of nanostructure shape and the selection of mold insert material.

Insight into the formation and permeability of ionic liquid unilamellar vesicles by molecular dynamics simulation

Soft Matter ◽  
2020 ◽  
Vol 16 (10) ◽  
pp. 2605-2610 ◽  
Author(s):  
Kun Jiang ◽  
Xiaomin Liu ◽  
Hongyan He ◽  
Jianji Wang ◽  
Suojiang Zhang
Keyword(s):  
Molecular Dynamics ◽  
Ionic Liquid ◽  
Molecular Dynamics Simulation ◽  
Formation Mechanism ◽  
Dynamics Simulation ◽  
Unilamellar Vesicles ◽  
Insight Into

The formation mechanism and permeability properties of [C12mim][Sal] vesicles are investigated by molecular dynamics simulation.

Binding of biguanides to β-lactoglobulin: molecular-docking and molecular dynamics simulation studies

2014 ◽  
Vol 68 (11) ◽  
Author(s):  
Mehdi Sahihi ◽  
Yousef Ghayeb
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Molecular Dynamics Simulation ◽  
Hydrophobic Interactions ◽  
Mean Value ◽  
Transport Protein ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Accessible Surface ◽  
Β Lactoglobulin

AbstractBiguanides are a class of drugs derived from biguanide and they are the most widely used drugs for diabetes mellitus or pre-diabetes treatment. An investigation of their interaction and a transport protein such as β-lactoglobulin (BLG) at atomic level could be a valuable factor in controlling their transport to biological sites. Molecular-docking and molecular dynamics simulation methods were used to study the interaction of metformin, phenformin and buformin as biguanides and BLG as transport protein. The molecular-docking results revealed that these biguanides bind to BLG and that the BLG affinity for binding the biguanides decreases in the following order: phenformin — buformin — metformin. The docking results also show the hydrophobic interactions to have a significant role in the BLG-biguanides complex stability. Analysis of molecular dynamic simulation trajectories shows that the root mean square deviation of various systems attained equilibrium and fluctuated around the mean value at various times. The time evolution of the radius of gyration and the total solvent-accessible surface of the protein showed that BLG and BLG-biguanide complexes became stable at approximately 2500 ps and that there was not any conformational change in the BLG-biguanide complexes. In addition, the profiles of atomic fluctuations show the rigidity of the ligand-binding site during the simulation.

scholarly journals Phytochemicals from Leucas zeylanica Targeting Main Protease of SARS-CoV-2: Chemical Profiles, Molecular Docking, and Molecular Dynamics Simulations

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 789
Author(s):  
Mycal Dutta ◽  
Abu Montakim Tareq ◽  
Ahmed Rakib ◽  
Shafi Mahmud ◽  
Saad Ahmed Sami ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Molecular Dynamics Simulation ◽  
Surface Area ◽  
Dynamics Simulation ◽  
Solvent Accessible Surface Area ◽  
Gas Chromatography Mass Spectrometry ◽  
Radius Of Gyration ◽  
Hydrogen Bond Formation ◽  
Main Protease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a contemporary coronavirus, has impacted global economic activity and has a high transmission rate. As a result of the virus’s severe medical effects, developing effective vaccinations is vital. Plant-derived metabolites have been discovered as potential SARS-CoV-2 inhibitors. The SARS-CoV-2 main protease (Mpro) is a target for therapeutic research because of its highly conserved protein sequence. Gas chromatography–mass spectrometry (GC-MS) and molecular docking were used to screen 34 compounds identified from Leucas zeylanica for potential inhibitory activity against the SARS-CoV-2 Mpro. In addition, prime molecular mechanics–generalized Born surface area (MM-GBSA) was used to screen the compound dataset using a molecular dynamics simulation. From molecular docking analysis, 26 compounds were capable of interaction with the SARS-CoV-2 Mpro, while three compounds, namely 11-oxa-dispiro[4.0.4.1]undecan-1-ol (−5.755 kcal/mol), azetidin-2-one 3,3-dimethyl-4-(1-aminoethyl) (−5.39 kcal/mol), and lorazepam, 2TMS derivative (−5.246 kcal/mol), exhibited the highest docking scores. These three ligands were assessed by MM-GBSA, which revealed that they bind with the necessary Mpro amino acids in the catalytic groove to cause protein inhibition, including Ser144, Cys145, and His41. The molecular dynamics simulation confirmed the complex rigidity and stability of the docked ligand–Mpro complexes based on the analysis of mean radical variations, root-mean-square fluctuations, solvent-accessible surface area, radius of gyration, and hydrogen bond formation. The study of the postmolecular dynamics confirmation also confirmed that lorazepam, 11-oxa-dispiro[4.0.4.1]undecan-1-ol, and azetidin-2-one-3, 3-dimethyl-4-(1-aminoethyl) interact with similar Mpro binding pockets. The results of our computerized drug design approach may assist in the fight against SARS-CoV-2.

scholarly journals In silico identification of novel chemical compounds with anti-TB potential for the inhibition of InhA and EthR from Mycobacterium tuberculosis

2020 ◽  
Author(s):  
Sajal Kumar Halder ◽  
Fatiha Elma
Keyword(s):  
Molecular Dynamics ◽  
Mycobacterium Tuberculosis ◽  
Molecular Docking ◽  
Molecular Dynamics Simulation ◽  
Chemical Compounds ◽  
Dynamics Simulation ◽  
Health Concern ◽  
Radius Of Gyration

ABSTRACTTuberculosis (TB) continuously pose a major public health concern around the globe, with a mounting death toll of approximately 1.4 million in 2019. The reduced bioavailability, increased toxicity and resistance of several first-line and second-line anti-TB drugs such as isoniazid, ethionamide have necessitated the search for new medications. In this research, we have identified several novel chemical compounds with anti-TB properties using various computational tools like molecular docking analysis, drug-likeness evaluation, ADMET profiling, P450 site of metabolism prediction and molecular dynamics simulation study. This study involves fifty drug-like compounds with antibacterial activity that inhibit InhA and EthR involved in the synthesis of one of the major lipid components, mycolic acid, which is crucial for the viability of Mycobacterium tuberculosis. Among these fifty compounds, 3-[3-(4-Fluorophenyl)-1,2,4-oxadiazol-5-yl]-N-(2-methylphenyl) piperidine-1-carboxamide (C22) and 5-(4-Ethyl-phenyl)-2-(1H-tetrazol-5-ylmethyl)-2H-tetrazole (C29) were found to pass the two-step molecular docking, P450 site of metabolism prediction and pharmacokinetics filtering analysis successfully. Their binding stability for target proteins have been evaluated through RMSD, RMSF, Radius of gyration analysis from 10 ns Molecular Dynamics Simulation (MDS) run. Our identified drugs could be a capable therapeutic for Tuberculosis drug discovery, having said that more in vitro and in vivo testing is required to justify their potential as novel drug and mode of action.

scholarly journals Solvent Effects on Catechol Crystal Habits and Aspect Ratios: A Combination of Experiments and Molecular Dynamics Simulation Study

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 316 ◽  
Author(s):  
Dan Zhu ◽  
Shihao Zhang ◽  
Pingping Cui ◽  
Chang Wang ◽  
Jiayu Dai ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Hydrogen Bonds ◽  
Solvent Effects ◽  
Dynamics Simulation ◽  
Crystal Habit ◽  
Aspect Ratios ◽  
Solvent Environment ◽  
Solvent Adsorption ◽  
Attachment Energy

This work could help to better understand the solvent effects on crystal habits and aspect ratio changes at the molecular level, which provide some guidance for solvent selection in industrial crystallization processes. With the catechol crystal habits acquired using both experimental and simulation methods in isopropanol, methyl acetate and ethyl acetate, solvent effects on crystal morphology were explored based on the modified attachment energy model. Firstly, morphologically dominant crystal faces were obtained with the predicted crystal habit in vacuum. Then, modified attachment energies were calculated by the molecular dynamics simulation to modify the crystal shapes in a real solvent environment, and the simulation results were in agreement with the experimental ones. Meanwhile, the surface properties such as roughness and the diffusion coefficient were introduced to analyze the solvent adsorption behaviors and the radial distribution function curves were generated to distinguish diverse types of interactions like hydrogen bonds and van der Waals forces. Results show that the catechol crystal habits were affected by the combination of the attachment energy, surface structures and molecular interaction types. Moreover, the changing aspect ratios of catechol crystals are closely related to the existence of hydrogen bonds which contribute to growth inhibition on specific faces.

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