Propiolated Castor Oil: A Novel and Highly Versatile Bio-Based Platform for Extremely Fast, Catalyst-, and Solvent-Free Amino-yne Click Reactions

Abstract

The quest for sustainable monomers and “green” synthetic pathways for the design, fabrication, and modification of various polymers is of great importance and attracts a great deal of attention. Here, a highly versatile and novel bio-based platform was developed by reacting castor oil with propiolic acid for performing amino-yne click reactions. Owing to the electron-deficient nature of the propiolic acid esters, amino-yne click reactions were conducted with ease at room temperature, in the absence of any catalyst and solvent (as long as the amines were low-viscosity liquids at room temperature), and within 5 min. Several primary and secondary amines were shown to react readily with the developed platform. Furthermore, thermosets were prepared by using the propiolated castor oil and multifunctional amines. The prepared thermosets displayed improved thermal properties and elastomer-like mechanical properties.

New Horizon in Phospha-Michael Reaction: Ultrafast Double Addition of P–H Bond-Bearing Nucleophiles to Electron-Deficient Triple Bonds and Its Use for Functional Monomer Synthesis and Polymer Modification

“…The prepared films were characterized by FTIR spectroscopy and by measuring their gel content values. The FTIR spectrum of the base formulation (FR0) can be seen in our previous publication . The FTIR spectra of the photocured compositions are given in Figure S35.…”

“…Within the scope of this work, we preferred TBD as the catalyst due to its outstanding performance in Michael reactions. [33][34][35][36][37]51,52 Finally, for simplicity, the parametric studies were conducted by using DMAD, and the results obtained from these studies are collected in Table 2.…”

“…In recent years, electron-deficient alkyne-containing monomers/polymers have gained much interest to prepare new polymeric materials due to the excellent reactivity of such alkynes toward sulfur-, nitrogen-, and oxygen-based nucleophiles. Indeed, reactions between such nucleophiles and electron-deficient alkynes have proven to proceed rapidly under mild conditions, with high efficiency and without the need to use metal catalysts. − In this regard, our group has demonstrated the feasibility of the synthesis and modification of these monomers/polymers for various applications such as phase change materials, flame-retardant thermosets, hydrophobic coatings, and composites. − We have previously shown that the acetylenedicarboxylic acid-based polyesters can be easily modified via aza-Michael, thio-Michael, and azide-alkyne click cycloaddition reactions in the absence of a metal catalyst. Thiol compounds, organic azides, and primary and secondary amines were easily attached to these polyester backbones in a matter of seconds. − Furthermore, we prepared acetylenedicarboxylic acid diallyl ester (ACDAE) and functionalized this monomer via the aforementioned click reactions with either perfluorinated chains or phosphorus- or amine-containing groups .…”

Fully Biobased Self-Healing and Recyclable Covalent Adaptable Networks Prepared via a Catalyst-Free Aza-Michael Reaction

“…Besides, three new peaks appeared at around 166.2 ppm (assigned as c), 131.3 ppm (assigned as e), and 128.5 ppm (assigned as d), which are merely attributed to the carbonyl carbons of the acrylic ester groups and the carbon atoms of the acrylated double bonds, respectively. 21 The formation of ACO was further confirmed by FTIR analysis, as shown in Figure 1b, and the data were compared with those of CO. The FTIR spectrum of CO showed the characteristic stretching vibration bands associated with the ester carbonyl bonds (C�O) at 1740 cm −1 , a stretching vibration band of C−O ester groups at 1175 and 1276 cm −1 , and a broad band at 3471 cm −1 for the stretching −OH groups.…”

“…21−23 In recent years, the robust and economically viable aza-Michael reaction has been further implemented to construct CANs that could bring a revolution for the existing conventional polymeric systems and/or thermoset materials. 7,19,21 Following the above background and aiming to create sustainable materials for a better future, herein, we present the development of fully biobased CANs as free-standing thin films using a catalyst-free aza-Michael reaction, where disulfide linkages have been introduced into the chemical structure of CANs to make them recyclable in nature. The CANs were prepared using the acrylated castor oil (a renewable resourcebased derivative) as a Michael acceptor and cystamine (biobased; aliphatic diamine disulfide obtained from an amino acid) as a Michael donor.…”