Synthesis of a novel glycerol based B₃-type monomer and its application in hyperbranched polyester urethane–urea coatings

Abstract

Glycerol (GLY) based hyperbranched polyester polyols (HBP) were synthesized by the reaction of GLY and Succinic anhydride (SA) as a B 3 -type monomer with GLY as the core moiety without using any solvent. Acid terminated B 3 monomer and HBP were characterized by techniques such as 1 H, and 13 C nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Degree of branching present in the HBP was calculated by NMR spectroscopy. The HBP was further reacted with different ratios of isophorone diisocyanate (IPDI) to get isocyanate-terminated polyurethane prepolymer that was cured under atmospheric moisture to get the desired coating films. Thermomechanical, viscoelastic and contact angle properties of these films were also evaluated. Glass transition temperatures (T g ) of the cross-linked networks were found to be in the range of 95−125 o C, and the water contact angles were in the range of 78 o −82 o . The T g and hydrophobic character of the coating films found to increase with an increasing NCO:OH ratio. This work provides an effective and promising way to prepare glycerol based HBPs for high-performance coatings.under double monomer methodology (DMM) then followed by development of HBP through this process. [15][16][17][18] As there are many limitations like commercial unavailability of monomers, gelation, solubility and uncontrollable molecular weight, a new synthetic method was established namely couple monomer methodology (CMM). This methodology developed by Yan and Gao 19-21 , which involves strategies like A 2 +BB 2 * , A 2 +CB 2 , AB+CD n , A * +B n and AA * B 2 . The A 3 +B 3 type approach adopted in the synthesis of HBP is somewhat less explored, which gives complete symmetry to the monomers and provides better chances of maximized formation of HBP without gelation. In the present work, we wish to establish the potential for using glycerol as renewable resources, to replace petroleum based monomers (high price monomers). To this achievement, an acid terminated monomer (B 3 ) was synthesized by nucleophilic ring-opening addition reaction of GLY and SA, which was further reacted with GLY (A 3 ) monomer in a solvent-free one pot reaction to form HBP. Herein, we described the synthesis as well as thermal and mechanical properties, contact angle, and morphological properties of PU films based on HBP (Scheme 1).To develop a high-performance moisture curable coating composition, we successfully studied the effect of the NCO/OH ratio on HBP and also its effect on thermo-mechanical properties in moisture curable systems. Synthesized HBP was further reacted with isophorone diisocyanate (IPDI) at different NCO/OH equivalent ratios to get NCO-terminated prepolymers. The physical and thermal properties were studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and XRD measurements. Our resea...

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“…The application of 13 C NMR to determine whether the glycerol units lead to branched structures by reaction of their secondary alcohol moiety has been previously described by Somisetti et al 42 In their work, the authors related the middle carbon in glycerol units to a 13 C NMR peak around 69 ppm for branched glycerol units and a peak around 65 ppm for linear or terminal ones. In our case, we observe peaks in both regions, suggesting the coexistence of terminal, linear and branched glycerol units in the synthesized polyester.…”

Design and development of low cost polyurethane biopolymer based on castor oil and glycerol for biomedical applications

“…[30] Figure 2B shows an asymmetrical shape of the band around 1725 cm 21 , indicating that a free C@O stretch is overlapping with a hydrogen bonded C@O. [31] Free C@O from urethane and urea groups are centered at 1725-1740 cm 21 and at 1710-1725 cm 21 , respectively. Hydrogen bonded C@O linkages are centered approximately at 1670-1685 cm 21 and at 1644-1655 cm 21 .…”

“…[31] Free C@O from urethane and urea groups are centered at 1725-1740 cm 21 and at 1710-1725 cm 21 , respectively. Hydrogen bonded C@O linkages are centered approximately at 1670-1685 cm 21 and at 1644-1655 cm 21 . All PU compositions showed a low intensity band corresponding to NAH stretching at 3332 cm 21 .…”

“…Hydrogen bonded C@O linkages are centered approximately at 1670-1685 cm 21 and at 1644-1655 cm 21 . All PU compositions showed a low intensity band corresponding to NAH stretching at 3332 cm 21 . This confirms the presence of hydrogen bonding interactions, [32] Figure 2A.…”

“…This is the case with glycerol. [ ] Recently, the synthesis of biodegradable elastomers with tolylene‐2, 4‐diisocyanate‐terminated poly (ethylene adipate) (PEA‐TDI) with a mixture of castor oil (CO) and glycerol (GO) has also been reported …”