Hyperbranched polyurethane/triethanolamine functionalized multi‐walled carbon nanotube nanocomposites as remote induced smart materials

Abstract

Triethanolamine functionalized multi-walled carbon nanotubes (TEA-f-MWCNTs)/hyperbranched polyurethane nanocomposites were prepared by the in situ polymerization technique. The functionalization of the MWCNTs was confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy studies. The homogeneous distribution and the strong interfacial interaction of TEA-f-MWCNTs with the polyurethane chains were confirmed by transmission electron microscopy and Fourier transform infrared spectroscopy studies, respectively. Significant enhancements of tensile strength (6.5 − 28.5 MPa) and scratch resistance (3-7 kg) with content of TEA-f-MWCNTs (0-2 wt%) were observed. Thermogravimetric analysis showed an increase in thermal stability from 240 to 287• C by the formation of nanocomposites. X-ray diffraction and differential scanning calorimetry studies confirmed an increment in the degree of crystallinity of the nanocomposites with increase in TEA-f-MWCNT content. The extent of shape recovery as well as recovery speed were enhanced with increase in the output power of the microwave. Thus the studied nanocomposites could be utilized as non-contact microwave energy tunable shape memory materials.

Bio‐Based Hyperbranched Polyurethane Nanocomposites

“…A TGA thermogram is obtained by recording the change in weight of the polymer either against temperature or time. In most of the cases, the thermograms clearly indicate higher thermal stability of the pristine bio-based hyperbranched polyurethane matrix after incorporation of different nanomaterials (43)(44)(45)(46)(57)(58)(59)(60)(61)(62). The study also confirmed that nanomaterials are thermal insulators and mass transport barriers to the volatile products produced during decomposition.…”

“…of such nanocomposites are essential for their various applications. Most of the studies showed significant improvement in such mechanical properties of bio-based hyperbranched polyurethanes even at very low loading of suitable nanomaterials (43)(44)(45)(46)(57)(58)(59)(60)(61)(62). The extent of improvement depends on the actual interfacial interactions between nanomaterial and bio-based hyperbranched polyurethane (Fig.…”

“…However, this technique is not a well-accepted approach for mass production of such nanocomposites due to the requirement of a large volume of solvent and phase separation of the prepared product except for waterborne such polyurethanes (56,63). In this regard, author and his co-workers reported a few bio-based hyperbranched polyurethane nanocomposites using preformed different polyurethanes with organically modified nanoclay, silver, and iron oxide nanoparticles, acidfunctionalized MWCNT, iron oxide decorated MWCNT,[57][58][59][60][61][62]. The use of ultrasonication in the preparation of such nanocomposites has strong influence to obtain partially exfoliated nanostructure.…”

“…The unique structural geometry, presence of large number of freely exposed functionality of hyperbranched polyurethane, combination of hydrophobic (long hydrocarbon chain) and hydrophilic (ester/ether/hydroxyl linkage) moieties in bio-based component, and functional groups of nanomaterial support strong interfacial interactions between the polymer matrix and nanomaterial (Fig. 7), and thereby forming uniform and stable nanocomposites in most of the cases (43)(44)(45)(46)(57)(58)(59)(60)(61)(62). The preparative techniques generally used to obtain biobased such nanocomposites are in situ polymerization and solution techniques, and hence these techniques are described briefly here.…”

“…8). Furthermore, epoxy-cured Mesua ferrea oil-based hyperbranched polyurethane/triethanolamine functionalized MWCNT thermosetting nanocomposites exhibited enhanced tensile strength and scratch hardness (77).The average values of a few mechanical properties of bio-based thermoplastic hyperbranched polyurethane, its modified thermoset, and their nanocomposites are given in Table 2 (51,57,62,68,77,78,83,84). The adhesive strength of such nanocomposites, especially for epoxy-modified thermosetting ones is found to be very high for different substrates particularly for joint of wood-wood substrates, and this strength is much higher than the pristine polyurethanes.…”