Influence of diisocyanate, glycidol and polyol molar ratios on the mechanical and thermal properties of glycidyl-terminated biobased polyurethanes

Abstract

A series of epoxy-terminated polyurethanes (EPUs) were synthesized from castor oil, 4,4 ′ -methylenebis(cyclohexyl isocyanate) (H 12 MDI) and 2,3-epoxy-1-propanol (glycidol) by changing the molar ratio of H 12 MDI to glycidol to polyol. Fourier transform infrared, 1 H NMR and solid-state CP/MAS 13 C NMR spectroscopic analyses revealed the presence of epoxy linkages within the polyurethane backbone. Thermogravimetric analysis showed that EPU4 with a polyol:diisocyanate:glycidol molar ratio of 1:6:6 exhibited an initial decomposition temperature of 128 ∘ C, which was 26 ∘ C higher than that of EPU1 (1:3:3 molar ratio). Differential scanning calorimetry showed an upward shift in the glass transition temperature with increasing molar ratio. Mechanical analysis demonstrated that the tensile modulus of EPU4 was 7.8 times greater than that of EPU1. The crosslinking densities of EPUs were determined using swelling studies which revealed a gradual increase in crosslinking density with increasing epoxy content within the polyurethane. The morphologies of cryo-fractured surfaces of EPUs were determined through scanning electron microscopy to analyse the phase dispersion of epoxy and polyurethane.

The use of lignin as cross-linker for polyurethane foam for potential application in adsorbing materials

“…where mp and ms represent the masses of the polyurethane and solvent (g), respectively, ρp and ρs are the densities of the polyurethane and solvent (g/cm 3 ), respectively, R and T are the gas constant (8.314 J/K·mol) and absolute temperature (K), respectively, and δs is the solubility parameter of the solvent (J/cm 3 ). The variable δp (J/cm 3 ) was determined by fitting the curves of the swelling coefficients (Q) versus the solubility parameter (δ) (Mathew et al 2017). The corresponding abscissa value at the top of the curve was determined as δp in Fig.…”

“…3 (a). The corresponding abscissa values at the top of the curves were fitted by Gauss and were determined as the solubility parameter (Valero et al 2009;Mathew et al 2017). It was found that the abscissa corresponding to the maximum value of the ordinate was 18.7 (J/cm 3 ) 1/2 (Zhu et al 2011).…”

Frost-Resistant Epoxy-Urethane Binders Containing Diglycidyl Urethane

“…Analysis of FTIR spectra in the area of carbonyl valence vibrations (wave number interval ν = 1600-1760 cm -1 ) revealed important features of structural organization of studied objects (Figure 2). The results of spectral studies of some similar polymers with urethane groups were used to classify the corresponding absorption bands [26,27].…”

Preparation and characterization of siloxane modified: Epoxy terminated polyurethane‐silver nanocomposites

“…The SNPs (0.3 wt %) are dispersed in dehydrated castor oil via ultrasonication method and is added into the heated H 12 MDI kept in a three necked round bottom flask. The detailed procedure for the synthesis of PU and PE are described in the previous works . Further, 10 wt% of HTPDMS was added into the viscous PE solution containing SNPs, followed by the addition of γ‐APS (0.01%) coupling agent and DBTDL.…”