Surfactant-free dimer fatty acid polyamide/montmorillonite bio-nanocomposites

Abstract

Polyamide bio-nanocomposites were successfully prepared using a surfactant-free approach. The clay morphology was fixed by dispersing the ammonium ion-exchanged clay in acetic acid. This was mixed wi th an aceti c aci d sol uti on of the polyamide and the composite was recovered by precipitation with water. The composites featured a mixed morphology containing some exfoliated clay sheets together with nano-sized clay tactoids.Bio-nanocomposites containing as much as 27.5 wt.% clay were obtained. At this filler level, and depending on the temperature, the modulus was up to nine times higher than that of the parent polymer. Addition of clay also increased the glass transition temperature by as much as 5°C. This indicates that the high interfacial surface area, presented by the clay platelets dispersed in the matrix, significantly impaired the polymer chain mobility.

Thermal decomposition studies of bio-resourced polyamides by thermogravimetry and evolved gas analysis

“…Natural oils, replacing petroleum-based ones, are good alternative feedstock in the 'green chemistry' approach and have received an increasing attention in the last decade [1][2][3][4][5]. Bio-polyamides from renewable resources link typical long-chain polyamide properties, such as low moisture absorption, with high melting point and high crystallization rate [6][7][8]. However, their thermal stability which is crucial for processing purposes and may limit novel applications, has not been investigated in detail so far.…”

Polyhedral oligomeric silsesquioxane/polyamide bio-nanocomposite membranes: structure-gas transport properties

“…Their useful applications in therapeutic aids, medicines, heat-seal coatings printing inks, varnishes, food products and packaging materials have been realized. [26][27][28] Although a large number of bio-nanocomposites have been reported in the literature for various applications, 7,26,27,38,39,[40][41] to the best of our knowledge, POSS 5 incorporated Euramelt dimer fatty acid polyamide based bio-nanocomposite as membranes for gas transport applications have not yet been reported.…”

Stiffening mechanisms in vermiculite–amorphous polyamide bio-nanocomposites

“…When these polyamides are dissolved in acidic solvents, the amine functional groups at the ends of some chains become protonated. Thus, it is possible for these cationic polymer end groups to displace the exchangeable cations present in clays to facilitate exfoliation of the clay sheets [11]. The technique also allows organo-modification of the external surfaces of nano-sized clay sheets suspended in an acidic solution.…”

“…The ammonium exchanged vermiculite (A-VMT) was prepared as previously described [11]. A typical procedure was as follows: Vermiculite (100 g) was suspended in 500 mL of a polymer bio-nanocomposite.…”

“…Unfortunately the use of cationic surfactants introduces problems including limitations with respect to thermal stability. Hence surfactant-free organo-modifications are of interest [11]. In polyamides it is possible for the polymer chains themselves to provide the required organo-modification when amine functional groups are present, e.g.…”