TY  - JOUR
AU  - Tomić, Miloš
AU  - Dunjić, Branko
AU  - Nikolić, Marija S.
AU  - Trifković, Kata
AU  - Stanković, Nadežda
AU  - Pavlović, Vladimir B.
AU  - Bajat, Jelena B.
AU  - Đonlagić, Jasna A.
PY  - 2019
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0300944018312487
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8076
AB  - In the present study the commercial multifunctional fatty acid polyamidoamine (PAA) was for the first time simultaneously applied as a curing agent and clay modifier for epoxy/clay nanocomposites (NC) based on diglycidyl ether of bisphenol A. The montmorillonite (Cloisite®Na + ) was modified with different quantities of partially and fully protonated polyamidoamine. The NCs with 0.5 wt% novel organoclay were prepared by solution intercalation method. The major aims of this paper are investigations of the effects of the composition of PAA modified clays on structure, mechanical, barrier properties and corrosion stability on steel substrates of NCs were studied. The thermogravimetric, flame photometry and X-ray diffraction analyses confirmed the efficient modification of clay surface with polyamidoamine, predominantly located within layers. The NCs exhibited an intercalated/exfoliated morphology and the presence of free amino groups and increased content of modifier facilitated dispersion of clay particles within the polymer matrix, as shown by electron microscopy techniques (SEM, TEM). Under an optimized loading of PAA (molar quantity of total amino groups per clay cation exchange capacity of 1.75), the layers in stacks were separated by 5.0 nm and high number of individual layers was present in NC. Clay modified by PAA with free amino groups showed increased storage modulus in the rubbery state, glass transition temperature of NCs, while dumping factor was decreased. The tensile test confirmed that introduction of flexible modifier on the epoxy/clay interface lead to increase in the ultimate tensile strenght and elongation at break by 31% and toughness up to 83%. The electrochemical impedance spectroscopy and permeability tests proved the pronounced barrier effect of clay particles against corrosive species and water vapor when high dispersion degree of clay in NC was achieved. © 2019 Elsevier B.V.
T2  - Progress in Organic Coatings
T1  - Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites
VL  - 131
SP  - 311
EP  - 321
DO  - 10.1016/j.porgcoat.2019.02.037
ER  - 

@article{
author = "Tomić, Miloš and Dunjić, Branko and Nikolić, Marija S. and Trifković, Kata and Stanković, Nadežda and Pavlović, Vladimir B. and Bajat, Jelena B. and Đonlagić, Jasna A.",
year = "2019",
abstract = "In the present study the commercial multifunctional fatty acid polyamidoamine (PAA) was for the first time simultaneously applied as a curing agent and clay modifier for epoxy/clay nanocomposites (NC) based on diglycidyl ether of bisphenol A. The montmorillonite (Cloisite®Na + ) was modified with different quantities of partially and fully protonated polyamidoamine. The NCs with 0.5 wt% novel organoclay were prepared by solution intercalation method. The major aims of this paper are investigations of the effects of the composition of PAA modified clays on structure, mechanical, barrier properties and corrosion stability on steel substrates of NCs were studied. The thermogravimetric, flame photometry and X-ray diffraction analyses confirmed the efficient modification of clay surface with polyamidoamine, predominantly located within layers. The NCs exhibited an intercalated/exfoliated morphology and the presence of free amino groups and increased content of modifier facilitated dispersion of clay particles within the polymer matrix, as shown by electron microscopy techniques (SEM, TEM). Under an optimized loading of PAA (molar quantity of total amino groups per clay cation exchange capacity of 1.75), the layers in stacks were separated by 5.0 nm and high number of individual layers was present in NC. Clay modified by PAA with free amino groups showed increased storage modulus in the rubbery state, glass transition temperature of NCs, while dumping factor was decreased. The tensile test confirmed that introduction of flexible modifier on the epoxy/clay interface lead to increase in the ultimate tensile strenght and elongation at break by 31% and toughness up to 83%. The electrochemical impedance spectroscopy and permeability tests proved the pronounced barrier effect of clay particles against corrosive species and water vapor when high dispersion degree of clay in NC was achieved. © 2019 Elsevier B.V.",
journal = "Progress in Organic Coatings",
title = "Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites",
volume = "131",
pages = "311-321",
doi = "10.1016/j.porgcoat.2019.02.037"
}

Tomić, M., Dunjić, B., Nikolić, M. S., Trifković, K., Stanković, N., Pavlović, V. B., Bajat, J. B.,& Đonlagić, J. A.. (2019). Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites. in Progress in Organic Coatings, 131, 311-321.
https://doi.org/10.1016/j.porgcoat.2019.02.037

Tomić M, Dunjić B, Nikolić MS, Trifković K, Stanković N, Pavlović VB, Bajat JB, Đonlagić JA. Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites. in Progress in Organic Coatings. 2019;131:311-321.
doi:10.1016/j.porgcoat.2019.02.037 .

Tomić, Miloš, Dunjić, Branko, Nikolić, Marija S., Trifković, Kata, Stanković, Nadežda, Pavlović, Vladimir B., Bajat, Jelena B., Đonlagić, Jasna A., "Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites" in Progress in Organic Coatings, 131 (2019):311-321,
https://doi.org/10.1016/j.porgcoat.2019.02.037 . .

TY  - JOUR
AU  - Tomić, Miloš
AU  - Dunjić, Branko
AU  - Nikolić, Marija S.
AU  - Maletaškić, Jelena
AU  - Pavlović, Vladimir B.
AU  - Bajat, Jelena B.
AU  - Đonlagić, Jasna A.
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1951
AB  - The major aims of this paper are the investigation of the effects of the mixing procedure and the montmorillonite (Mt) surface modification on the structure (optical microscopy, XRD, TEM, SEM), rheological, mechanical properties (DMA, tensile test) and corrosion stability (electrochemical impedance spectroscopy) of clay mineral/epoxy nanocomposite (CPN). Two series of CPN samples were prepared based on diglycidyl ether of bisphenol A (DGEBA) and polyamidoamine curing agent with three organophilic Mt and sodium-montmorillonite (1 wt%). Mt were mixed with DGEBA solution in the powder (direct mixing) and in the form of dispersions, preswollen in a commercial coating thinner (solution intercalation). The commercial Mt (Cloisite 30B) modified by quaternary alkylammonium ions bearing hydroxyl groups and especially Mt functionalized by primary (HDA(+)-Mt) alkylammonium ions, at loadings close to cation exchange capacity (CRC), were significantly swollen by thinner and further uniformly dispersed into CPN. Meanwhile, low gel volumes in thinner were found for more hydrophobic Mt (Cloisite 15A). The compatibility of Mt with solvents was well described by solubility and Flory-Huggins interaction parameters. In contrast to the direct incorporation of Mt powders in CPN, swelling enhanced intercalation of epoxy matrix into Mt, and for HDA(+)-Mt based CPN interlayer spacing reached 4.4 nm. The usage of HDA(+)-Mt organoclay and solution intercalation procedure provided the highest enhancement in rheological parameters (G, G, of Mt/epoxy dispersions and glassy storage modulus, Youngs modulus and barrier properties of cured CPN.
T2  - Applied Clay Science
T1  - Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods
VL  - 154
SP  - 52
EP  - 63
DO  - 10.1016/j.clay.2017.12.047
ER  - 

@article{
author = "Tomić, Miloš and Dunjić, Branko and Nikolić, Marija S. and Maletaškić, Jelena and Pavlović, Vladimir B. and Bajat, Jelena B. and Đonlagić, Jasna A.",
year = "2018",
abstract = "The major aims of this paper are the investigation of the effects of the mixing procedure and the montmorillonite (Mt) surface modification on the structure (optical microscopy, XRD, TEM, SEM), rheological, mechanical properties (DMA, tensile test) and corrosion stability (electrochemical impedance spectroscopy) of clay mineral/epoxy nanocomposite (CPN). Two series of CPN samples were prepared based on diglycidyl ether of bisphenol A (DGEBA) and polyamidoamine curing agent with three organophilic Mt and sodium-montmorillonite (1 wt%). Mt were mixed with DGEBA solution in the powder (direct mixing) and in the form of dispersions, preswollen in a commercial coating thinner (solution intercalation). The commercial Mt (Cloisite 30B) modified by quaternary alkylammonium ions bearing hydroxyl groups and especially Mt functionalized by primary (HDA(+)-Mt) alkylammonium ions, at loadings close to cation exchange capacity (CRC), were significantly swollen by thinner and further uniformly dispersed into CPN. Meanwhile, low gel volumes in thinner were found for more hydrophobic Mt (Cloisite 15A). The compatibility of Mt with solvents was well described by solubility and Flory-Huggins interaction parameters. In contrast to the direct incorporation of Mt powders in CPN, swelling enhanced intercalation of epoxy matrix into Mt, and for HDA(+)-Mt based CPN interlayer spacing reached 4.4 nm. The usage of HDA(+)-Mt organoclay and solution intercalation procedure provided the highest enhancement in rheological parameters (G, G, of Mt/epoxy dispersions and glassy storage modulus, Youngs modulus and barrier properties of cured CPN.",
journal = "Applied Clay Science",
title = "Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods",
volume = "154",
pages = "52-63",
doi = "10.1016/j.clay.2017.12.047"
}

Tomić, M., Dunjić, B., Nikolić, M. S., Maletaškić, J., Pavlović, V. B., Bajat, J. B.,& Đonlagić, J. A.. (2018). Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods. in Applied Clay Science, 154, 52-63.
https://doi.org/10.1016/j.clay.2017.12.047

Tomić M, Dunjić B, Nikolić MS, Maletaškić J, Pavlović VB, Bajat JB, Đonlagić JA. Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods. in Applied Clay Science. 2018;154:52-63.
doi:10.1016/j.clay.2017.12.047 .

Tomić, Miloš, Dunjić, Branko, Nikolić, Marija S., Maletaškić, Jelena, Pavlović, Vladimir B., Bajat, Jelena B., Đonlagić, Jasna A., "Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods" in Applied Clay Science, 154 (2018):52-63,
https://doi.org/10.1016/j.clay.2017.12.047 . .

TY  - JOUR
AU  - Nikolić, Marija S.
AU  - Petrović, Rada
AU  - Veljović, Đorđe N.
AU  - Ćosović, Vladan
AU  - Stanković, Nadežda
AU  - Đonlagić, Jasna A.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1899
AB  - Poly(epsilon-caprolactone) (PCL) based nanocomposites with unmodified and organomodified sepiolites were prepared by solution casting method. The sepiolites were modified with short (3-mercaptopropyl)trimethoxysilane (SEP-SI) by using covalent grafting or with long hexadecylamine (SEP-HDA) by using ionic exchange. In order to reveal the influence of the organomodification on the nanoclay dispersion and the properties of the nano composites XRD, DSC, TG, SEM, TEM, optical microscopy, melt rheology and dynamic-mechanical analyses were performed. A better dispersion was achieved when organomodified sepiolites instead of native ones were used as fillers. As deduced from the melt rheology data, by analysis of the Cole-Cole plots, the best dispersion was obtained for SEP-SI nanoclay. The thermal stability was not improved, however in the initial stages of the thereto-oxidative degradation a delay in the weight loss was observed for nanocomposites with organomodified sepiolites. The mechanical properties of the nanocomposites were improved in comparison to PCL, particularly for those with modified sepiolites. In terms of mechanical properties the use of sepiolite modified with HDA gave the best results, as a consequence of better interaction between longer alkyl hydrophobic part of the organic modificator and the hydrophobic PCL matrix.
T2  - European Polymer Journal
T1  - Effect of sepiolite organomodification on the performance of PCL/sepiolite nanocomposites
VL  - 97
SP  - 198
EP  - 209
DO  - 10.1016/j.eurpolymj.2017.10.010
ER  - 

@article{
author = "Nikolić, Marija S. and Petrović, Rada and Veljović, Đorđe N. and Ćosović, Vladan and Stanković, Nadežda and Đonlagić, Jasna A.",
year = "2017",
abstract = "Poly(epsilon-caprolactone) (PCL) based nanocomposites with unmodified and organomodified sepiolites were prepared by solution casting method. The sepiolites were modified with short (3-mercaptopropyl)trimethoxysilane (SEP-SI) by using covalent grafting or with long hexadecylamine (SEP-HDA) by using ionic exchange. In order to reveal the influence of the organomodification on the nanoclay dispersion and the properties of the nano composites XRD, DSC, TG, SEM, TEM, optical microscopy, melt rheology and dynamic-mechanical analyses were performed. A better dispersion was achieved when organomodified sepiolites instead of native ones were used as fillers. As deduced from the melt rheology data, by analysis of the Cole-Cole plots, the best dispersion was obtained for SEP-SI nanoclay. The thermal stability was not improved, however in the initial stages of the thereto-oxidative degradation a delay in the weight loss was observed for nanocomposites with organomodified sepiolites. The mechanical properties of the nanocomposites were improved in comparison to PCL, particularly for those with modified sepiolites. In terms of mechanical properties the use of sepiolite modified with HDA gave the best results, as a consequence of better interaction between longer alkyl hydrophobic part of the organic modificator and the hydrophobic PCL matrix.",
journal = "European Polymer Journal",
title = "Effect of sepiolite organomodification on the performance of PCL/sepiolite nanocomposites",
volume = "97",
pages = "198-209",
doi = "10.1016/j.eurpolymj.2017.10.010"
}

Nikolić, M. S., Petrović, R., Veljović, Đ. N., Ćosović, V., Stanković, N.,& Đonlagić, J. A.. (2017). Effect of sepiolite organomodification on the performance of PCL/sepiolite nanocomposites. in European Polymer Journal, 97, 198-209.
https://doi.org/10.1016/j.eurpolymj.2017.10.010

Nikolić MS, Petrović R, Veljović ĐN, Ćosović V, Stanković N, Đonlagić JA. Effect of sepiolite organomodification on the performance of PCL/sepiolite nanocomposites. in European Polymer Journal. 2017;97:198-209.
doi:10.1016/j.eurpolymj.2017.10.010 .

Nikolić, Marija S., Petrović, Rada, Veljović, Đorđe N., Ćosović, Vladan, Stanković, Nadežda, Đonlagić, Jasna A., "Effect of sepiolite organomodification on the performance of PCL/sepiolite nanocomposites" in European Polymer Journal, 97 (2017):198-209,
https://doi.org/10.1016/j.eurpolymj.2017.10.010 . .

TY  - JOUR
AU  - Nikolić, Marija S.
AU  - Mitrić, Miodrag
AU  - Dapčević, Aleksandra
AU  - Đonlagić, Jasna A.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/790
AB  - Viscoelastic properties in solid and in melt state of poly(epsilon-caprolactone), PCL, nanocomposites with organomodified clays (Cloisite30B and Cloisite15A) are thoroughly investigated. Although WAXD is insensitive to the difference in the nanocomposites structure, the melt rheology reveals pronounced differences between the two series. Melt yield stress values, obtained from fittings by the Carreau-Yasuda model, are used as a measure of partial exfoliation of the clay. Temperature dependence of the shift factors, used for time-temperature superposition of the modulus curves, yields similar values of the flow activation energies for all the samples. Temperature dependences of the dynamic modulus and loss factor of solid nanocomposites were correlated to the structural differences deduced from the melt rheology. The increase in the storage modulus is compared to the theoretical predictions from the Hal-pin-Tsai model. The effective aspect ratio obtained from this comparison agrees reasonably with the value estimated from the melt rheology. (C) 2015 Wiley Periodicals, Inc.
T2  - Journal of Applied Polymer Science
T1  - Viscoelastic properties of poly(e-caprolactone)/clay nanocomposites in solid and in melt state
VL  - 133
IS  - 3
DO  - 10.1002/app.42896
ER  - 

@article{
author = "Nikolić, Marija S. and Mitrić, Miodrag and Dapčević, Aleksandra and Đonlagić, Jasna A.",
year = "2016",
abstract = "Viscoelastic properties in solid and in melt state of poly(epsilon-caprolactone), PCL, nanocomposites with organomodified clays (Cloisite30B and Cloisite15A) are thoroughly investigated. Although WAXD is insensitive to the difference in the nanocomposites structure, the melt rheology reveals pronounced differences between the two series. Melt yield stress values, obtained from fittings by the Carreau-Yasuda model, are used as a measure of partial exfoliation of the clay. Temperature dependence of the shift factors, used for time-temperature superposition of the modulus curves, yields similar values of the flow activation energies for all the samples. Temperature dependences of the dynamic modulus and loss factor of solid nanocomposites were correlated to the structural differences deduced from the melt rheology. The increase in the storage modulus is compared to the theoretical predictions from the Hal-pin-Tsai model. The effective aspect ratio obtained from this comparison agrees reasonably with the value estimated from the melt rheology. (C) 2015 Wiley Periodicals, Inc.",
journal = "Journal of Applied Polymer Science",
title = "Viscoelastic properties of poly(e-caprolactone)/clay nanocomposites in solid and in melt state",
volume = "133",
number = "3",
doi = "10.1002/app.42896"
}

Nikolić, M. S., Mitrić, M., Dapčević, A.,& Đonlagić, J. A.. (2016). Viscoelastic properties of poly(e-caprolactone)/clay nanocomposites in solid and in melt state. in Journal of Applied Polymer Science, 133(3).
https://doi.org/10.1002/app.42896

Nikolić MS, Mitrić M, Dapčević A, Đonlagić JA. Viscoelastic properties of poly(e-caprolactone)/clay nanocomposites in solid and in melt state. in Journal of Applied Polymer Science. 2016;133(3).
doi:10.1002/app.42896 .

Nikolić, Marija S., Mitrić, Miodrag, Dapčević, Aleksandra, Đonlagić, Jasna A., "Viscoelastic properties of poly(e-caprolactone)/clay nanocomposites in solid and in melt state" in Journal of Applied Polymer Science, 133, no. 3 (2016),
https://doi.org/10.1002/app.42896 . .