Fluorescent labels to study thermal transitions in epoxy/silica composites

Abstract

The analysis of the fluorescen response from the dansyl moiety as a function of temperature has been used to estimate the thermal transi-tions in silica particle/epoxy-based composite materials. Silica particles were surface-coated with 3-aminopropyltriethoxysilane (APTES) and 3-aminopropylmethyldiethoxysilane (APDES). 5-Dimethylamino-1-naphtalenesulfonyl chloride (DNS) and 5-dimethylaminonaphthalene-1-(2-aminoehyl)) sulfonamide (DNS-EDA) were selectively attached to the silanized silica particles and to the epoxy matrix respectively. The fluoresce ce results, interpreted in terms of the model of interpenetrating polymer networks, suggest that (i) independent of the silane coating, the interfacial region is slightly more rigid and heterogeneous than the epoxy bulk and (ii) the interface generated with APTES seems to be more flexibl than that obtained with APDES.

Molecular probe technique for determining local thermal transitions: The glass transition at Silica/PMMA nanocomposite interfaces

“…<n> has been used both to observe in situ polymerization of epoxies [34e37], and the thermal transitions in epoxy/silica composites [38,39]. This parameter offers an easy method and gives a direct measure of the excited state average relaxation of the fluorophores.…”

A Near‐Infrared Spectroscopy Study on Thermal Transitions of PMMA and PMMA/SiO2 Nanocomposites

“…[1][2][3] Some attempts have been done from the use of fluorescent probes and labels which allows to obtain information about the dynamics of polymers exactly from the sites in where the fluorophores are localized. [4][5][6][7] In principle, the fluorescent response or the emission bands of those labels are used to locally extract information since, on average, they reflect physico-chemical properties of their surroundings. However, it would be even more instructive if the information is taken exactly from the polymer chains and, if possible, from different positions.…”

Fluorescence response from anthracene labeled polystyrene to study its thermal transitions

“…The use of fluorescence to detect thermal transitions is taking a great interest due to the possibility of locating fluorescent molecules at specific sites and being able to get information from there [19][20][21].…”

“…In other works, the variation of the energy of the fluorescence emission with the temperature was used to determine thermal transitions as the T g [20,23,29,30].…”

“…Albalá et al [20] used the fluorescence response from dansyl moiety chemically attached to the surface of silica particles to obtain the thermal transitions associated to the interphase formed between silica fillers and an epoxy matrix in a composite. In this work [20], a new parameter, based on the first moment of the fluorescence band, hni, was used for this kind of determination…”