Size Effects on Miscibility and Glass Transition Temperature of PS/TMPC Blend Films: a Simulation and Thermodynamic Approach

2007 ◽  
Vol 334-335 ◽  
pp. 105-108 ◽  
Author(s):  
Zhi Min Ao ◽  
Qing Jiang
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Size Effects ◽  
Md Simulation ◽  
Weight Fraction ◽  
Blend Films ◽  
Size Dependent ◽  
Binary Polymer ◽  
Interaction Parameter Χ

The size dependent miscibility of binary polymer blend films of polystyrene (PS) and tetramethylbisphenol-A polycarbonate (TMPC) is studied by the molecular dynamics (MD) simulation in the way of computing Flory-Huggins interaction parameter, χ, of the blend films, which determines the blend films compatibility. It is found that the miscibility of the two polymers decreases as the film thickness D decreases. After that, the size dependent glass transition temperature Tg(w,D) of the two polymers blend films in miscible ranges are determined by computer simulation and the Fox equation where w is the weight fraction of the second component.

scholarly journals Ag–NYLON NANOCOMPOSITES BY DYNAMIC EMULSION POLYCONDENSATION

MRS Advances ◽  
2016 ◽  
Vol 1 (36) ◽  
pp. 2519-2524 ◽  
Author(s):  
Linqi Zhang ◽  
Sriharsha Karumuri ◽  
A. Kaan Kalkan
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Weight Fraction ◽  
Thermoplastic Polymer ◽  
Nylon 66 ◽  
Novel Technique ◽  
Nucleation Effect ◽  
Ag Nanowires ◽  
Ag Nanowire

ABSTRACTThe present work demonstrates a novel technique for dispersing nanofillers in a thermoplastic polymer, where polymerization and dispersion of the nanofillers occur simultaneously via dynamic emulsion polycondensation at ambient temperature. The composite is manufactured in the form of a uniform powder, which can then be molded into desired shape by melting or sintering. The technique is demonstrated for Ag nanowire / Nylon 66 composites. In this demonstration, Ag nanowires are synthesized by the polyol process. Polyvinylprrolidone (PVP) is used to functionalize the Ag nanowires. Nanocomposites with varying Ag content are prepared and investigated. The nanowires are found to be monodispersed and hydrogen-bonded to the Nylon 66 matrix through PVP. Glass transition temperature of the composites decreases from 61 to 48 °C with Ag weight fraction increasing from 0 to 6.47%. The depression of the glass transition temperature is owed to the plasticizer effect as well as heterogeneous nucleation effect of the nanowires for polymerization leading to shorter chain length.

scholarly journals Molecular Dynamics Simulation-Based Study on Enhancing Thermal Properties of Graphene-Reinforced Thermoplastic Polyurethane Nanocomposite for Heat Exchanger Materials

2020 ◽  
Author(s):  
Animesh Talapatra ◽  
Debasis Datta
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Md Simulation ◽  
Thermoplastic Polyurethane ◽  
Simulation Based ◽  
Simulation Results

Molecular dynamics (MD) simulation-based development of heat resistance nanocomposite materials for nanoheat transfer devices (like nanoheat exchanger) and applications have been studied. In this study, MD software (Materials Studio) has been used to know the heat transport behaviors of the graphene-reinforced thermoplastic polyurethane (Gr/TPU) nanocomposite. The effect of graphene weight percentage (wt%) on thermal properties (e.g., glass transition temperature, coefficient of thermal expansion, heat capacity, thermal conductivity, and interface thermal conductance) of Gr/TPU nanocomposites has been studied. Condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field which is incorporated in both amorphous and forcite plus atomistic simulation modules within the software are used for this present study. Layer models have been developed to characterize thermal properties of the Gr/TPU nanocomposites. It is seen from the simulation results that glass transition temperature (Tg) of the Gr/TPU nanocomposites is higher than that of pure TPU. MD simulation results indicate that addition of graphene into TPU matrix enhances thermal conductivity. The present study provides effective guidance and understanding of the thermal mechanism of graphene/TPU nanocomposites for improving their thermal properties. Finally, the revealed enhanced thermal properties of nanocomposites, the interfacial interaction energy, and the free volume of polymer nanocomposites are examined and discussed.

Molecular Dynamics Simulation on Compatibility and the Glass Transition Temperature of HTPB/Plasticizer Blends

2013 ◽  
Vol 718-720 ◽  
pp. 136-140 ◽  
Author(s):  
Lu Xia Yang ◽  
Lin Yu Mei ◽  
Yan Hua Lan ◽  
Li Qiong Liao ◽  
Yi Zheng Fu
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Specific Volume ◽  
Md Simulation ◽  
Dibutyl Phthalate ◽  
Dioctyl Phthalate ◽  
Dynamics Simulation ◽  
Solubility Parameters

By means of full atomistic molecular dynamics (MD) simulation, the solubility parameters for hydroxyl-terminated polybutadiene (HTPB), dioctyl sebacate (DOS), dioctyl adipate (DOA), dibutyl phthalate (DBP), dioctyl phthalate (DOP), nitrated esters nitroglycerine (NG) and diethylene glycol dinitrate (DEGDN) are calculated and the results are in agreement with the literature values. Furthermore, in order to reveal the HTPB/plasticizer blend property, the specific volume vs. temperature curves of the blend systems are simulated by employing MD simulation to obtain the glass transition temperature (Tg). From the specific volume vs. temperature curve, the Tg of HTPB, HTPB/DOS, HTPB/DOA, HTPB/DBP, HTPB/DOP, HTPB/NG and HTPB/DEGDN are 197.54, 176.30, 183.11, 189.27,187.40, 200.03 and 205.31 K, respectively. It should be pointed out that as for HTPB and DOS, DOA, DBP, DOP, the solubility parameters are similar and there is only one glass transition of the blend system, these indicate that these studied blend systems are miscible, but HTPB/NG and HTPB/DEGDN are not miscible.

Effect of Chain Morphology and Carbon-Nanotube Additives on the Glass Transition Temperature of Polyethylene

2013 ◽  
Vol 23 ◽  
pp. 16-23 ◽  
Author(s):  
S. Herasati ◽  
H.H. Ruan ◽  
Liang Chi Zhang
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Md Simulation ◽  
Md Simulations ◽  
Crystalline Polymers ◽  
Good Agreement

Glass transition temperature Tg is the most important parameter affecting the mechanical properties of amorphous and semi-crystalline polymers. However, the atomistic origin of glass transition is not yet well understood. Using Polyethylene (PE) as an example, this paper investigates the glass transition temperature Tg of PE with the aid of molecular dynamics (MD) simulation. The effects of PE chain branches, crystallinity and carbon-nanotube (CNT) additives on the glass transition temperature are analyzed. The MD simulations render a good agreement with the relevant experimental data of semi-crystalline PE and show the significant effects of crystallinity and addition of CNTs on Tg.

scholarly journals Systematic Modification of the Glass Transition Temperature of Ion-Pair Comonomer Based Polyelectrolytes and Ionomers by Copolymerization with a Chemically Similar Cationic Monomer

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 45
Author(s):  
Guodong Deng ◽  
Timothy D. Schoch ◽  
Kevin A. Cavicchi
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Functional Groups ◽  
Repeat Unit ◽  
Ion Pairs ◽  
Weight Fraction ◽  
Ion Pair ◽  
Cationic Monomer ◽  
Vinyl Benzyl

Ion-pair comonomers (IPCs) where both the anion and cation contain polymerizable functional groups offer a route to prepare polyampholyte, ion-containing polymers. Polymerizing vinyl functional groups by free-radical polymerization produces bridging ion-pairs that act as non-covalent crosslinks between backbone segments. In particular the homopolymerization of the IPC vinyl benzyl tri-n-octylphosphonium styrene sulfonate produces a stiff, glassy polymer with a glass transition temperature (Tg) of 191 °C, while copolymerization with a non-ionic acrylate produces microphase separates ionomers with ion-rich and ion-poor domains. This work investigates the tuning of the Tg of the polyelectrolyte or ion-rich domains of the ionomers by copolymerizing with vinyl benzyl tri-n-octylphosphonium p-toluene sulfonic acid. This chemically similar repeat unit with pendant rather than bridging ion-pairs lowers the Tg compared to the polyelectrolyte or ionomer containing only the IPC segments. Rheological measurements were used to characterize the thermomechanical behavior and Tg of different copolymers. The Tg variation in the polyelectrolyte vs. weight fraction IPC could be fit with either the Gordon–Taylor or Couchman–Karasz equation. Copolymerization of IPC with a chemically similar cationic monomer offers a viable route to systematically vary the Tg of the resulting polymers useful for tailoring the material properties in applications such as elastomers or shape memory polymers.

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