DOI: 10.5061/dryad.h70rxwdh8
title: Effect of urea concentration on properties of peanut protein isolate, arachin and conarachin-based adhesives during urea-epichlorohydrin modification

description: Data of RSOS-202227. Wet shear
 strength, Apparent viscosity, Solid content，SEM, FTIR and TGA
 results of  the PPI, arachin and conarachin-based
 adhesives. To lay theoretical basis for the preparation of peanut
 protein-based adhesives and promote the sustainable development of
 adhesive industry, properties of peanut protein isolate (PPI), arachin and
 conarachin-based adhesives modified by urea and epichlorohydrin (ECH) were
 investigated under different urea concentrations. When the urea
 concentration was 2 mol/L, the wet shear strength of the PPI-based
 adhesive was 1.24 MPa with the best water resistance. With the increase of
 urea concentration from 0 to 4 mol/L, the apparent viscosity of the
 PPI-based adhesive increased from 3.87 Pa·s to 136.80 Pa·s and the solid
 content increased from 18.11% to 31.11%. Compared with conarachin-based
 adhesive, the properties of arachin-based adhesive were improved more
 obviously during the combined modification. Scanning electron microscopy
 images illustrated that when the urea concentration was 2 mol/L, the
 surface of the PPI-based adhesive was more compact and smoother, which was
 beneficial to the improvement of water resistance and related to the
 structure changes of arachin and conarachin components. Fourier-transform
 infrared spectroscopy results indicated that different urea concentrations
 caused the change of ester and ether bonds in the PPI-based adhesive,
 which was mainly related to arachin component. Thermogravimetry results
 suggested that when the urea concentration was 2 mol/L, the decomposition
 temperature of protein skeleton in the PPI-based adhesive reached a
 maximum of 314 °C exhibiting the highest thermal stability. The
 improvement of the thermal stability of conarachin was greater than that
 of arachin during the combined modification.
description: I0-I4: 20 g PPI and 100 mL
 urea solution (0, 1, 2, 3, 4 mol/L) were added into the reaction vessel
 (condensation tube, thermometer, magnetic rotor) respectively, and stirred
 at 50 °C for 1 h. Then, 6 wt% ECH (according to the total adhesive mass)
 was introduced and the resulting slurry was stirred at 50 °C for 1 h.
 After cooling, the modified PPI-based adhesive I0, I1, I2, I3 and I4 were
 prepared respectively. A0-A4: 20 g arachin and 100 mL
 urea solution (0, 1, 2, 3, 4 mol/L) were added into the reaction vessel
 (condensation tube, thermometer, magnetic rotor) respectively, and stirred
 at 50 °C for 1 h. Then, 6 wt% ECH (according to the total adhesive mass)
 was introduced and the resulting slurry was stirred at 50 °C for 1 h.
 After cooling, the modified arachin-based adhesives A0, A1, A2, A3 and A4
 were prepared. C0-C4: 20 g conarachin and 100 mL
 urea solution (0, 1, 2, 3, 4 mol/L) were added into the reaction vessel
 (condensation tube, thermometer, magnetic rotor) respectively, and stirred
 at 50 °C for 1 h. Then, 6 wt% ECH (according to the total adhesive mass)
 was introduced and the resulting slurry was stirred at 50 °C for 1 h.
 After cooling, the modified conarachin-based adhesives C0, C1, C2, C3 and
 C4 were prepared respectively.