Bio‐Based Hyperbranched Polyurethane Nanocomposites

Abstract

BIO-BASED HYPERBRANCHED POLYURETHANE NANOCOMPOSITESadjusting the ratio of isocyanate (-NCO) to hydroxyl (-OH) functionality and the chemical composition in the final structure of the polyurethane, different types of polymeric products like thermosetting resin and elastomer as well as thermoplastic and fiber can be obtained (3). In all such polyurethanes, the main linkage, urethane (-NH-C(=O) -O-) is a unique combination of rigid amide (-NH-C=O), which has a tendency to donate proton, and a flexible ester (-O-C=O) group, which has a tendency to accept proton. Further flexibility arises from the flexible soft segment and long hydrocarbon part of fatty acid chains of the vegetable oil component present in the bio-based segmented polyurethanes. Moreover, they are biodegradable and biocompatible. All these unique features of bio-based polyurethanes widen their applications in the domains of coating, paint, adhesive, sealant, composite, biomaterial, smart material, and so on.Again, incorporation of branching in the polymer structure greatly influences the processing and properties of the branched polymer. Thus hyperbranched polymers are treated as macromolecules for 21st century. These hyperbranched polymers are one type of dendritic polymers ( Fig. 1), where the other type is a perfectly regular structure with a three-dimensional architecture, known as a dendrimer (4). However, hyperbranched polymers are preferred in most of the industrial applications over multistep laborious synthesized dendrimers because of easier and simpler one-step synthetic protocol of the former as they can accommodate some defects in their structures. Thus mass-scale industrial production at relatively low cost is possible for hyperbranched polymers like conventional linear polymers. However, hyperbranched polymers enjoy many advantages over linear polymers (Fig. 1). These include a unique three-dimensional structural architecture with dendritic, linear, and terminal units, the presence of a large number of freely exposed surface groups, low polydispersity index, low viscosity, high solubility, high compatibility with other materials, etc. Therefore, bio-based hyperbranched polyurethanes are preferred as superior materials over their conventional analogs for different advanced applications.However, "virginity is not a virtue" in case of polymer, whatsoever the structural architecture is! Thus bio-based hyperbranched polyurethanes also require to be adulterated by incorporation of appropriate additives or ingredients. It is pertinent to mention here that most of the vegetable oil-based hyperbranched polyurethanes do not have required mechanical strength and toughness, although they possess very good flexibility. In this vein, conventional filled and composite systems are widely used, although both the approaches suffer from serious drawbacks, as a huge amount of additive(s) is necessary to be incorporated to achieve the desired level of performance of the stated polyurethanes. Most importantly, the resultant products lost most of the central a...

Biobased Multifunctional Macroglycol Containing Smart Thermoplastic Hyperbranched Polyurethane Elastomer with Intrinsic Self-Healing Attribute

“…In this milieu, among different self-healing polymers (SHPs), polyurethanes (PURs) have attracted significant interest to the research enthusiasts due to their inborn versatility and tunable properties with manipulation of structure and composition of the components. Again, three-dimensional globular, nonentanglement architectural hyperbranched PURs (HBPURs) demand special attention because of their high solubility, compatibility, surface groups, and low viscosity over the analogous linear PURs . Thus, efforts can be made to develop renewable resource based smart HBPUR with self-healing abilities.…”

“…Again, it is noticed that no researcher uses biobased multifunctional macroglycol in such PURs, although biobased chain extenders are often used. , …”

“…Again, three-dimensional globular, nonentanglement architectural hyperbranched PURs (HBPURs) demand special attention because of their high solubility, compatibility, surface groups, and low viscosity over the analogous linear PURs. 6 Thus, efforts can be made to develop renewable resource based smart HBPUR with selfhealing abilities. Literature advocates a few attempts.…”

“…Again, it is noticed that no researcher uses biobased multifunctional macroglycol in such PURs, although biobased chain extenders are often used. 5,6 The authors, therefore, wish to report the synthesis of thermoplastic HBPUR elastomers from biobased macroglycol as the branch generating moiety with varying compositions. The structural characterizations of the synthesized HBPURs were performed by using different instrumental tools.…”

Morphological studies on renewable castor oil-based nanocomposites with modified clay and MWCNTs as fillers

“…Therefore, the occurrence of such interactions as confirmed using FTIR spectroscopy revealed the complete formation of the nanocomposites. 22 -25…”