PHYSICAL PRINCIPLES OF CATALYSIS OF THE CURING OF EPOXY POLYMERS IN THE PRESENCE OF CARBON NANOTUBES

2016 ◽  
Vol 57 (1) ◽  
2015 ◽  
Vol 44 (19) ◽  
pp. 6916-6953 ◽  
Author(s):  
Federica De Leo ◽  
Alessandra Magistrato ◽  
Davide Bonifazi

Thiscritical reviewpresents a detailed overview of the chemico-physical principles ruling the non-covalent association between proteins and fullerene, carbon nanotubes and graphene towards the creation of fascinating and innovative hybrid materials for biotechnological applications.


2014 ◽  
Vol 56 (3) ◽  
pp. 330-336 ◽  
Author(s):  
S. V. Kondrashov ◽  
V. P. Grachev ◽  
R. V. Akatenkov ◽  
V. N. Aleksashin ◽  
I. S. Deev ◽  
...  

Author(s):  
Luiza B. Atlukhanova ◽  
Georgii V. Kozlov ◽  
Evgenii V. Rumyantsev ◽  
Igor V. Dolbin

The structural (fractal) model, describing the dependence of catalytic ability of carbon nanotubes in process of epoxy polymers curing, was proposed. Enhancement of epoxy polymers curing temperature leads to growth of constant of reaction rate for both initial epoxy polymers and systems epoxy polymer/carbon nanotubes, but for the last this effect is expressed much stronger. This means existence of catalytic effect of carbon nanotubes, which intensifies at temperature enhancement at their constant concentration. It has been found that constant of catalysis rate of second order is proportional to the difference of constants of curing reactions rate for system epoxy polymer/carbon nanotubes and initial epoxy polymer. This circumstance assumes that catalytic ability of carbon nanotubes in curing process is connected with their structure and specifically – with surface structure of this nanofiller aggregates. Reduction of this surface fractal dimension leads to increasing of catalytic ability of carbon nanotubes. The indicated ability is also a function of structure of reaction product – microgel, i.e. cross-linked macromolecular coil of epoxy polymer. Enhancement of microgel fractal dimension defines increasing of constant of catalysis rate. This means that efficiency of catalysis of epoxy polymers curing by carbon nanotubes is controlled by difference of fractal dimensions of microgels for the considered systems. The limiting temperature of curing exists, at which catalyzing action of carbon nanotubes ceases. Hence, two structural factors are defined catalytic ability of carbon nanotubes: by structure of catalyst (carbon nanotubes) surface and structure of forming in curing process microgel of epoxy polymer.


2018 ◽  
Vol 63 (1) ◽  
pp. 32-40 ◽  
Author(s):  
A. E. Tarasov ◽  
E. R. Badamshina ◽  
D. V. Anokhin ◽  
S. V. Razorenov ◽  
G. S. Vakorina

2013 ◽  
Vol 129 (5) ◽  
pp. 2754-2764 ◽  
Author(s):  
Ignatios Fotiou ◽  
Athanasios Baltopoulos ◽  
Antonios Vavouliotis ◽  
Vassilis Kostopoulos

Author(s):  
V.V. Korskanov ◽  
O.M. Fesenko ◽  
V.B. Dolgoshey

The aim of this work was to find the optimal conditions for the formation of nanocomposites, study their structure and properties and conditions for the formation of multicomponent materials based on epoxy polymers and carbon nanotubes with predetermined performance properties. The basis for the formation of epoxy polymers was an epoxydian oligomer (EDO) based on bisphenol A. Polypox H354 was used as a hardener for EDO. Carbon nanotubes (CNT) were used as a nanofiller for the preparation of nanocomposites. The research methods were a diffractometer for measuring the intensity of X-ray scattering in the region of small angles and a differential scanning calorimeter for obtaining heating thermograms. The electrical conductivity of the samples at a temperature of 293 K was measured at direct current according to the two-electrode scheme. In this work the structure, thermophysical properties and electrical conductivity of nanocomposites based epoxy polymers and carbon  nanotubes have been studied. It was found that at low CNT content the formation of nanocomposites occurs by the mechanism of epoxy network growth, which is accompanied by the displacement of CNT particles to the periphery of the epoxy matrix. This process is accompanied by an increase in the scattering intensity of the SAXS, a rapid increase in the glass transition temperature and the degree of crosslinking of the epoxy polymer. When the critical concentration is reached, CNT particles form a continuous cluster, which leads to occurrence percolation threshold, reducing the glass transition temperature, expanding the glass transition range, occurrence of pores and reducing the degree of completion of the crosslinking reaction in nanocomposites relative to the epoxy polymer. It is established that the improvement of nanocomposite properties and the occurrence of the percolation threshold is due to the maximum specific energy of ER-CNT interaction and is achieved at a critical mass concentration of nanofiller from 0,1% to 0,4%.


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