Study on intercalation and exfoliation behavior of organoclays in epoxy resin

Sustainable Production of Syngas from Biomass‐Derived Glycerol by Steam Reforming over Highly Stable Ni/SiC

“…As per Lu et al, if the exothermal curing heat of the intragallery resin exceeds the endothermal heat required to overcome the attractive forces between the silicate layers, then only the clay will be exfoliated during the curing process and exfoliation can occur only before the gel point of the resin is reached 16. Lu et al also suggested that there is a curing competition between the intragallery and extragallery region of an epoxy resin.…”

Sustainable Production of Syngas from Biomass‐Derived Glycerol by Steam Reforming over Highly Stable Ni/SiC

“…As per Lu et al, if the exothermal curing heat of the intragallery resin exceeds the endothermal heat required to overcome the attractive forces between the silicate layers, then only the clay will be exfoliated during the curing process and exfoliation can occur only before the gel point of the resin is reached 16. Lu et al also suggested that there is a curing competition between the intragallery and extragallery region of an epoxy resin.…”

Isothermal and nonisothermal cure kinetics of an epoxy/poly(oxypropylene)diamine/octadecylammonium modified montmorillonite system

“…For composite system the sum of H I and H R determined experimentally is lower than H I + H R calculated from the neat epoxy–curing agent data (see the last column in Table II). The possible explanation for this findings is that a part of the reaction heat released is consumed in endothermic exfoliation of nanofiller 7. Another reason could be the change of the heat capacity of the system due to the addition of the filler.…”

Layered Silicate Nanocomposites Based on Various High-Functionality Epoxy Resins: The Influence of Cure Temperature on Morphology, Mechanical Properties, and Free Volume

“…While this was not the case for a 4,4‘-diaminodiphenyl sulfone (DDS)-cured TGDDM nanocomposite, similar results have recently been reported for various DGEBA-based systems. , In fact, very recent in-situ small-angle XRD studies by Tolle and Anderson 14 have shown for a m -phenylenediamine-cured DGEBA nanocomposite system using the same commercially available organoclay as in this work, the higher cure temperatures resulted in both earlier initiation of exfoliation and greater silicate spacing. The mechanism of organoclay exfoliation in epoxy-layered silicate nanocomposites has been the focus of various studies, ,,, and it was pointed out that control of intra- and extragallery reaction is the key to overcoming the attractive forces between the silicate layers and achieving exfoliation. The improved organoclay delamination at increased temperatures may be related to a number of aspects, one being that the lower viscosity or enhanced molecular mobility improves mass transfer into the clay galleries.…”

“…7,8 Decreasing polarity during reaction of the resin in the galleries displaces the equilibrium, causing more monomers to diffuse into, and react within, the silicate galleries. Depending on the layered silicate charge density, 7,8 the nature of the interlayer exchanged ion, [9][10][11] the cure conditions, [12][13][14] the curing agent, 12,15 and the resin (as is reported in this work), the resultant epoxy nanocomposite will show either an intercalated or exfoliated morphology. Recently, Chin et al 16 have shown for a m-phenylenediamine (MPDA)/DGEBA/ octadecylamine-layered silicate system that the resin/ curing agent ratio can also influence the exfoliation process.…”

“…The mechanism proposed for the formation of such epoxy nanocomposites is that the penetrating monomers swell the silicate layers until a thermodynamic equilibrium is reached between the polar resin, curing agent blend, and the high surface energy of the silicate layers. , Decreasing polarity during reaction of the resin in the galleries displaces the equilibrium, causing more monomers to diffuse into, and react within, the silicate galleries. Depending on the layered silicate charge density, , the nature of the interlayer exchanged ion, − the cure conditions, − the curing agent, , and the resin (as is reported in this work), the resultant epoxy nanocomposite will show either an intercalated or exfoliated morphology. Recently, Chin et al have shown for a m -phenylenediamine (MPDA)/DGEBA/octadecylamine-layered silicate system that the resin/curing agent ratio can also influence the exfoliation process.…”

Sustainable Production of Syngas from Biomass‐Derived Glycerol by Steam Reforming over Highly Stable Ni/SiC

“…As per Lu et al, if the exothermal curing heat of the intragallery resin exceeds the endothermal heat required to overcome the attractive forces between the silicate layers, then only the clay will be exfoliated during the curing process and exfoliation can occur only before the gel point of the resin is reached 16. Lu et al also suggested that there is a curing competition between the intragallery and extragallery region of an epoxy resin.…”

Isothermal and nonisothermal cure kinetics of an epoxy/poly(oxypropylene)diamine/octadecylammonium modified montmorillonite system

“…For composite system the sum of H I and H R determined experimentally is lower than H I + H R calculated from the neat epoxy–curing agent data (see the last column in Table II). The possible explanation for this findings is that a part of the reaction heat released is consumed in endothermic exfoliation of nanofiller 7. Another reason could be the change of the heat capacity of the system due to the addition of the filler.…”

Layered Silicate Nanocomposites Based on Various High-Functionality Epoxy Resins: The Influence of Cure Temperature on Morphology, Mechanical Properties, and Free Volume

“…While this was not the case for a 4,4‘-diaminodiphenyl sulfone (DDS)-cured TGDDM nanocomposite, similar results have recently been reported for various DGEBA-based systems. , In fact, very recent in-situ small-angle XRD studies by Tolle and Anderson 14 have shown for a m -phenylenediamine-cured DGEBA nanocomposite system using the same commercially available organoclay as in this work, the higher cure temperatures resulted in both earlier initiation of exfoliation and greater silicate spacing. The mechanism of organoclay exfoliation in epoxy-layered silicate nanocomposites has been the focus of various studies, ,,, and it was pointed out that control of intra- and extragallery reaction is the key to overcoming the attractive forces between the silicate layers and achieving exfoliation. The improved organoclay delamination at increased temperatures may be related to a number of aspects, one being that the lower viscosity or enhanced molecular mobility improves mass transfer into the clay galleries.…”

“…7,8 Decreasing polarity during reaction of the resin in the galleries displaces the equilibrium, causing more monomers to diffuse into, and react within, the silicate galleries. Depending on the layered silicate charge density, 7,8 the nature of the interlayer exchanged ion, [9][10][11] the cure conditions, [12][13][14] the curing agent, 12,15 and the resin (as is reported in this work), the resultant epoxy nanocomposite will show either an intercalated or exfoliated morphology. Recently, Chin et al 16 have shown for a m-phenylenediamine (MPDA)/DGEBA/ octadecylamine-layered silicate system that the resin/ curing agent ratio can also influence the exfoliation process.…”

“…The mechanism proposed for the formation of such epoxy nanocomposites is that the penetrating monomers swell the silicate layers until a thermodynamic equilibrium is reached between the polar resin, curing agent blend, and the high surface energy of the silicate layers. , Decreasing polarity during reaction of the resin in the galleries displaces the equilibrium, causing more monomers to diffuse into, and react within, the silicate galleries. Depending on the layered silicate charge density, , the nature of the interlayer exchanged ion, − the cure conditions, − the curing agent, , and the resin (as is reported in this work), the resultant epoxy nanocomposite will show either an intercalated or exfoliated morphology. Recently, Chin et al have shown for a m -phenylenediamine (MPDA)/DGEBA/octadecylamine-layered silicate system that the resin/curing agent ratio can also influence the exfoliation process.…”

Sustainable Production of Syngas from Biomass‐Derived Glycerol by Steam Reforming over Highly Stable Ni/SiC

“…As per Lu et al, if the exothermal curing heat of the intragallery resin exceeds the endothermal heat required to overcome the attractive forces between the silicate layers, then only the clay will be exfoliated during the curing process and exfoliation can occur only before the gel point of the resin is reached 16. Lu et al also suggested that there is a curing competition between the intragallery and extragallery region of an epoxy resin.…”

Isothermal and nonisothermal cure kinetics of an epoxy/poly(oxypropylene)diamine/octadecylammonium modified montmorillonite system

“…For composite system the sum of H I and H R determined experimentally is lower than H I + H R calculated from the neat epoxy–curing agent data (see the last column in Table II). The possible explanation for this findings is that a part of the reaction heat released is consumed in endothermic exfoliation of nanofiller 7. Another reason could be the change of the heat capacity of the system due to the addition of the filler.…”

Layered Silicate Nanocomposites Based on Various High-Functionality Epoxy Resins: The Influence of Cure Temperature on Morphology, Mechanical Properties, and Free Volume

“…While this was not the case for a 4,4‘-diaminodiphenyl sulfone (DDS)-cured TGDDM nanocomposite, similar results have recently been reported for various DGEBA-based systems. , In fact, very recent in-situ small-angle XRD studies by Tolle and Anderson 14 have shown for a m -phenylenediamine-cured DGEBA nanocomposite system using the same commercially available organoclay as in this work, the higher cure temperatures resulted in both earlier initiation of exfoliation and greater silicate spacing. The mechanism of organoclay exfoliation in epoxy-layered silicate nanocomposites has been the focus of various studies, ,,, and it was pointed out that control of intra- and extragallery reaction is the key to overcoming the attractive forces between the silicate layers and achieving exfoliation. The improved organoclay delamination at increased temperatures may be related to a number of aspects, one being that the lower viscosity or enhanced molecular mobility improves mass transfer into the clay galleries.…”

“…7,8 Decreasing polarity during reaction of the resin in the galleries displaces the equilibrium, causing more monomers to diffuse into, and react within, the silicate galleries. Depending on the layered silicate charge density, 7,8 the nature of the interlayer exchanged ion, [9][10][11] the cure conditions, [12][13][14] the curing agent, 12,15 and the resin (as is reported in this work), the resultant epoxy nanocomposite will show either an intercalated or exfoliated morphology. Recently, Chin et al 16 have shown for a m-phenylenediamine (MPDA)/DGEBA/ octadecylamine-layered silicate system that the resin/ curing agent ratio can also influence the exfoliation process.…”

“…The mechanism proposed for the formation of such epoxy nanocomposites is that the penetrating monomers swell the silicate layers until a thermodynamic equilibrium is reached between the polar resin, curing agent blend, and the high surface energy of the silicate layers. , Decreasing polarity during reaction of the resin in the galleries displaces the equilibrium, causing more monomers to diffuse into, and react within, the silicate galleries. Depending on the layered silicate charge density, , the nature of the interlayer exchanged ion, − the cure conditions, − the curing agent, , and the resin (as is reported in this work), the resultant epoxy nanocomposite will show either an intercalated or exfoliated morphology. Recently, Chin et al have shown for a m -phenylenediamine (MPDA)/DGEBA/octadecylamine-layered silicate system that the resin/curing agent ratio can also influence the exfoliation process.…”