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.

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 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.

A Novel Poly(Ionic Liquid) as the Thermal Insulating Material

2020 ◽  
Vol 13 (3) ◽  
pp. 241-247
Author(s):  
Wenxin Wei ◽  
Guifeng Ma ◽  
Hongtao Wang ◽  
Jun Li
Keyword(s):  
Thermal Conductivity ◽  
Ionic Liquid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Flame Resistance ◽  
Insulating Material ◽  
Low Thermal Conductivity ◽  
Thermal Insulating ◽  
Poly Ionic Liquid

Objective: A new poly(ionic liquid)(PIL), poly(p-vinylbenzyltriphenylphosphine hexafluorophosphate) (P[VBTPP][PF6]), was synthesized by quaternization, anion exchange reaction, and free radical polymerization. Then a series of the PIL were synthesized at different conditions. Methods: The specific heat capacity, glass-transition temperature and melting temperature of the synthesized PILs were measured by differential scanning calorimeter. The thermal conductivities of the PILs were measured by the laser flash analysis method. Results: Results showed that, under optimized synthesis conditions, P[VBTPP][PF6] as the thermal insulator had a high glass-transition temperature of 210.1°C, high melting point of 421.6°C, and a low thermal conductivity of 0.0920 W m-1 K-1 at 40.0°C (it was 0.105 W m-1 K-1 even at 180.0°C). The foamed sample exhibited much low thermal conductivity λ=0.0340 W m-1 K-1 at room temperature, which was comparable to a commercial polyurethane thermal insulating material although the latter had a much lower density. Conclusion: In addition, mixing the P[VBTPP][PF6] sample into polypropylene could obviously increase the Oxygen Index, revealing its efficient flame resistance. Therefore, P[VBTPP][PF6] is a potential thermal insulating material.

Sign in / Sign up

Export Citation Format

Share Document