Synthesis and characterization of hyperbranched polyesters and polyurethane coatings

Abstract

Polyurethane (PU) coatings are widely used for variety of high-performance applications in today's coating technology. The emerging hyperbranched polymers having three-dimensional morphology have opened a new avenue to tailor the architecture of PU coatings. The methodology followed here is based on preparation of PU coatings from hyperbranched polyester. Initially, different hyperbranched polyester polyols (HPs) were synthesized by varying the hydroxyl-terminated precursors that is, pentaerythritol, trimethylol propane or glycerol and keeping the diacid that is, adipic acid quantity constant at various mole ratios of 1:0.6, 1:0.8, 1:0.9, and 1:1, respectively. The obtained HPs were characterized by nuclear magnetic resonance (NMR) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-mass spectrometry, and Fourier transform-infrared (FTIR) spectroscopy. The degree of branching and the quantity of different structural units present in the various HPs were calculated by integrating the quaternary carbon and carbonyl zone in 13 C NMR spectroscopy. The extent of condensation in different HPs was also calculated from 1 H NMR spectra. Later on, NCO-terminated PU prepolymers (NCO-PU) were synthesized by reacting HPs with isophorone diisocyanate (IPDI) at NCO/OH ratio of 1.6:1. In the third step, the excess NCO content in the NCO-capped PU prepolymers were reacted with atmospheric moisture and hyperbranched polyurethane (HPU) coatings were formed. The coating films were analyzed by FTIR and dynamic mechanical thermal analysis instruments.

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

“…[1][2][3] Owing to the use of glycerol, making polymers from it would be an efficient utilization for coating industry because glycerol is the principle coproduct in the transesterification process by which biodiesel is produced. Our research group has explored the direct utilization of glycerol to produce HBPs.…”

UV-curing of hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion and TGA/FTIR study of cured films

“…The maximum value of conversion ratio of C=C of HBPUA oligomer is 81% which is the highest among the above three samples. This result is due to the lower viscosity of spherical structure of Scheme 2 Sol-gel reaction HBPUA [12]. The radiation time of HBPUA is 83 s, which is faster than HBPUA-PUDA dispersion, on account of the slower movement of longer chain in PUDA.…”

Synthesis and characterization of polyhydroxylated polybutadiene binding 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) with isophorone diisocyanate

“…FT-IR spectra were recorded by a Tensor 27 spectrometer (Bruker, Germany). The measurements were carried out in the range of 4000-400 cm 21 . The number of scans per spectrum was 16, and the spectral resolution was 4 cm 21 .…”

“…It was often used as a linkage to prepare functional polymer by a two-step nucleophilic addition reaction. [17][18][19][20][21][22][23] In our previous work, a macromolecular antioxidant, hydroxyl-terminated polybutadiene-bound 2,2 0 -thiobis(4methyl-6-tert-butylphenol) (HTPB-IPDI-TPH), was prepared via a two-step nucleophilic addition reaction with IPDI. 24 When the content of hindered phenol structure units in the HTPB-IPDI-TPH were almost equal to that of TPH, the HTPB-IPDI-TPH in natural rubber exhibited better thermo-oxidative aging resistance than TPH by accelerated thermal aging test and oxidation induction time (OIT), and it had excellent extraction resistance and thermal stability.…”