Date of Award
Spring 5-14-2022
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
Dr. Ram Gupta
Second Advisor
Dr. Charles Neef
Third Advisor
Dr. Timothy Dawsey
Fourth Advisor
Dr. Anuradha Ghosh
Keywords
Bio-based, renewable, adhesive, wood application, wood science
Abstract
Introducing bio-based materials as an alternative to petroleum-based products has been the greatest challenge for the industry which may reduce environmental problems. Currently, most of the wood adhesive is prepared using formaldehyde which is a non-renewable source as well as toxic. In this research, soybean meal was used as a renewable bio-based source for wood adhesive which has a potential to replace formaldehyde-based adhesives. In this study, soymeal was chemically modified, characterized, and evaluated for its adhesion performance, flow behavior, service life, and thermal stability.
In the first, soymeal was modified using acid (HCl), alkali (NaOH), and salt (CaCl2) to study the combined effect of these chemicals on the resultant products. The synthesized product was analyzed by Fourier transformed infrared (FTIR) spectroscopy. The synthesized adhesive was characterized for its viscosity and thermal stability using Brookfield viscometer and thermogravimetric analyzer (TGA), respectively. Further, the dry shear strength of the adhesive was determined by manual clamping and hot pressing for oak and maple wood specimens. The FTIR spectra supported the chemical modification of soymeal as new functional groups appeared after the chemical modification. The dry shear strength of the unmodified soymeal-based adhesive for oak and maple wood samples was 0.92 MPa and 1.4 MPa, respectively and on chemical modification it increased to 2.7 MPa and 3.1 MPa, respectively. The effect of soymeal particle size (63 - >250 micron) on the bonding strength was studied where higher size soymeal particles showed higher dry shear strength compared to smaller particles.
Secondly, the effect of additives (silica nanoparticles, SiO2) and crosslinkers on the adhesion properties of soymeal-based adhesive was investigated. The incorporation of the low amount of SiO2 improved the dry shear strength of both the wood samples (5.79 MPa for maple and 4.62 MPa for oak). Epoxy, tetra ethylene glycol diacrylate, and 1,2,3,4-butane tetracarboxylic acid (BTCA) were used as crosslinkers. The addition of only 6 wt.% epoxy and tetra ethylene glycol diacrylate showed drastic improvement in the dry shear strength, while 15 wt.% of BTCA was required to improve the dry shear strength. The results indicate that improvement in the service life of soymeal-based adhesives has great potential to replace the commercially available petroleum-based adhesives. Further, the use of bio-based products will lead to sustainable development.
Recommended Citation
Kote, Prashant, "Soymeal based bio-based adhesive for wood application" (2022). Electronic Theses & Dissertations. 639.
https://digitalcommons.pittstate.edu/etd/639
