Characterization of crystalline structure and free volume of polyamide 6/nitrile rubber elastomer thermoplastic vulcanizates: Effect of the processing additives

2017 ◽  
Vol 134 (48) ◽  
pp. 45576 ◽  
Author(s):  
Ana Catarina de O. Gomes ◽  
Bluma G. Soares ◽  
Marcia G. Oliveira ◽  
José C. Machado ◽  
Dario Windmöller ◽  
...  
Keyword(s):  
Free Volume ◽  
Crystalline Structure ◽  
Polyamide 6 ◽  
Nitrile Rubber ◽  
Thermoplastic Vulcanizates

scholarly journals Thermal and Quasi-Static Mechanical Characterization of Polyamide 6-Graphene Nanoplatelets Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1454
Author(s):  
Pietro Russo ◽  
Francesca Cimino ◽  
Antonio Tufano ◽  
Francesco Fabbrocino
Keyword(s):  
Chemical Resistance ◽  
Experimental Tests ◽  
Polyamide 6 ◽  
Graphene Nanoplatelets ◽  
Strength Parameter ◽  
Melt Compounding ◽  
Static Mechanical ◽  
Thermal And Electrical Properties ◽  
Multifunctional Products

The growing demand for lightweight and multifunctional products in numerous industrial fields has recently fuelled a growing interest in the development of materials based on polymer matrices including graphene-like particles, intrinsically characterized by outstanding mechanical, thermal, and electrical properties. Specifically, with regard to one of the main mass sectors, which is the automotive, there has been a significant increase in the use of reinforced polyamides for underhood applications and fuel systems thanks to their thermal and chemical resistance. In this frame, polyamide 6 (PA6) composites filled with graphene nanoplatelets (GNPs) were obtained by melt-compounding and compared in terms of thermal and mechanical properties with the neat matrix processed under the same condition. The results of the experimental tests have shown that the formulations studied so far offer slight improvements in terms of thermal stability but much more appreciable benefits regarding both tensile and flexural parameters with respect to the reference material. Among these effects, the influence of the filler content on the strength parameter is noteworthy. However, the predictable worsening of the graphene sheet dispersion for GNPs contents greater than 3%, as witnessed by scanning electron images of the tensile fractured sections of specimens, affected the ultimate performance of the more concentrated formulation.

scholarly journals Free-volume Characterization of Polysilanes Using Positron Annihilation Spectroscopy.

1999 ◽  
Vol 12 (5) ◽  
pp. 739-742
Author(s):  
Mutsumi Tashiro ◽  
Shu Seki ◽  
Pradeep K. Pujari ◽  
Yoshihide Honda ◽  
Seiichi Tagawa
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Annihilation Spectroscopy

scholarly journals Comparison characterization of copper selenide thin layers prepared on polyamide 6 films by sorption-diffusion method

2013 ◽  
Vol 11 (4) ◽  
pp. 636-643 ◽  
Author(s):  
Remigijus Ivanauskas ◽  
Vitalijus Janickis ◽  
Vitalija Jasulaitienė
Keyword(s):  
Phase Composition ◽  
Polyamide 6 ◽  
Copper Selenide ◽  
Thin Layers ◽  
Diffusion Method ◽  
Two Phases ◽  
Xrd Patterns ◽  
Sem Studies

AbstractSome earlier synthesized copper selenide (Cux Se) layers formed on the surface of polyamide 6 by sorption-diffusion method using potassium selenotrithionate (K2SeS2O6) as precursor of selenium were characterized by the XRD, XPS and SEM methods. According to the results of the SEM studies, the most uniform Cux Se layers form at the 2.5 h polyamide seleniumized duration at the temperature of 60°C. The thickness of layers, which dependeds on the duration of seleniumization, changed in the range of 0.8–3.2 µm. The XRD patterns of not previously studied Cux Se layers showed their phase composition of six copper selenides: Cu2Se, two phases of CuSe2, Cu3Se2, berzellianite, Cu2-x Se, and bellidoite Cu2Se. Analysis of the XRD and XPS data shows that the macrostructure and composition of the CuxSe layers depend on the conditions of formation of these layers.

Diffusivity of solvents in semi-crystalline polyethylene using the Vrentas-Duda free-volume theory

2018 ◽  
Vol 38 (10) ◽  
pp. 925-931 ◽  
Author(s):  
Derek R. Sturm ◽  
Kevin J. Caputo ◽  
Siyang Liu ◽  
Ronald P. Danner
Keyword(s):  
Free Volume ◽  
Weight Fraction ◽  
Amorphous Region ◽  
Model Parameters ◽  
Crystalline Region ◽  
Free Volume Theory ◽  
Melt Temperature ◽  
Tortuosity Factor ◽  
Crystalline Polyethylene

Abstract Diffusion of penetrants in polyethylene below the melt temperature is heavily dependent on the crystallinity of the polyethylene, the temperature of the experiment, and the concentration of solvent in the polymer. As the crystallinity of the polyethylene increases, there is an increase in the path that the solvent must travel as the solvent cannot penetrate the tightly packed chains in the crystalline domain. This effect is typically accounted for by a tortuosity factor. In this work, a simple and effective characterization of the tortuosity factor based simply on the crystal weight fraction has been developed. Data have been collected for six polyethylenes having densities ranging from 0.912 to 0.961 g/cm3 and for three solvents – isopentane, cyclohexane, and 1-hexene. Diffusivity predictions have been obtained using the free-volume theory of Vrentas and Duda in conjunction with the new tortuosity factor. The polyethylenes had crystallinities varying from 40% to 82% effecting an approximately 60% change in the diffusivity. The decrease resulting from ignoring the crystallinity altogether was in some cases essentially a factor of 5. The error in the predicted diffusivities over all the systems was 25%. For cyclohexane, it is shown that the same model parameters characterize data below the melt temperature (in the semi-crystalline region) as well as above the melt temperature (in the amorphous region).

scholarly journals Molecule Dynamics Simulation of the Effect of Oxidative Aging on Properties of Nitrile Rubber

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 226
Author(s):  
Jinsong Yang ◽  
Weitao Lou
Keyword(s):  
Free Volume ◽  
Dynamic Properties ◽  
Compressive Strain ◽  
Mean Square Displacement ◽  
Nitrile Rubber ◽  
Dynamics Simulation ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Fractional Free Volume ◽  
Oxidative Aging

The effects of oxidative aging on the static and dynamic properties of nitrile rubber at the molecular scale were investigated by molecular dynamics simulation. The aged nitrile rubber models were constructed by introducing hydroxyl groups and carbonyl groups into rubber molecular chains to mimic oxidative aging. The static and dynamic properties of the unaged and aged nitrile rubber under different conditions were evaluated by mean square displacement, self-diffusion coefficients, hydrogen bond, fractional free volume, radial distribution function, cohesive energy density and solubility parameter. The results show that the elevated temperature intensified significantly the mobility of rubber molecular chains and fractional free volume, while the compressive strain displayed the opposite effect resulting in packing and rearrangement of rubber chains. The introduction of hydroxyl groups and carbonyl groups enhanced the polarity, intermolecular interactions, the volume and rigidity of molecular chains, implying weaker mobility of molecular chains as compared to unaged models. The compressive strain and oxidative aging both decreased the fractional free volume, which inhibited gaseous and liquid diffusion into the rubber materials, and slowed down the oxidative aging rate. This study provides insights to better understand the effect of molecular changes due to oxidative aging on the structural and dynamic properties of rubber materials at the molecular level.

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