Preparation optimization by response surface and performance characterization of PEG-urea-dialdehyde starch adhesive

In this study, a new kind of green, pollution-free, renewable and formaldehyde-free starch adhesive was prepared by using corn starch as raw material, which was oxidized into dialdehyde starch by sodium periodate, and then grafted and cross-linked with polyethylene glycol (PEG) and urea. The PEG-urea-dialdehyde starch adhesive has good dry shear strength and certain hydrophobicity. The preparation parameters of PEG-urea-dialdehyde starch adhesive were optimized by response surface methodology and it characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscope (SEM) and X-ray spectroscopy (EDAX). The results showed that when the dosage of PEG was 54% (w/w, dry starch basis), the dosage of urea was 70% (w/w, dry starch basis), the reaction time was 2.4 h, and the reaction temperature was 40 degrees C, the comprehensive properties of the adhesive were better. The dry shear strength of the PEG-urea-dialdehyde starch adhesive can reach 3.01 MPa, and the water contact angle was 61.76 degrees. When the adhesive was used to bond paper-based materials, the tensile strength, burst strength and ring crush strength of the paper were increased by 17.0%, 16.0% and 42.0%, respectively. This paper provided a new idea for the preparation of the high quality starch-based adhesive, which has a wide application prospect in paper adhesive.