Abstract
Predominantly non-furanic commercial humins were used to prepare humin-based non-isocyanate polyurethane (NIPU) resins for wood panel adhesives. Pure humin-based NIPU resins and tannin–humin NIPU resins were prepared, the latter to upgrade the humins’ performance. Species in the raw humins and species formed in the NIPU resins were identified by Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI ToF) spectrometry and Fourier Transform Infrared (FTIR). Humins, fulvic acid and derivatives, humic acid and its fragments, some lignans present and furanic oligomers present formed NIPU linkages. Thermomechanical analysis (TMA) showed that as with other biomaterials-based NIPU resins, all these resins also showed two temperature peaks of curing, the first around 130 °C and the second around 220 °C. A decrease in the Modulus of Elasticity (MOE) between the two indicated that the first curing period corresponded to linear growth of the oligomers forming a physical entanglement network. This then disentangled, and the second corresponded to the formation of a chemical cross-linked network. This second peak was more evident for the tannin–humin NIPU resins. All the laboratory particleboard made and tested either bonded with pure humins or with tannin–humin NIPU adhesives satisfied well the internal bond strength requirements of the relevant standard for interior grade panels. The tannin–humin adhesives performed clearly better than the pure humins one.
Highlights
Furanic humins derived from the acid treatment of pure fructose have been the focus of attention for the preparation of various foams and resins [1,2,3,4,5,6,7,8,9,10]
The results indicate that all four types of nonisocyanate polyurethane (NIPU) resins satisfied the requirement of the relevant European norm [36] for interior grade particleboard panels
It can be noted that the pure humins NIPU resin presented the lowest internal bond (IB) strength value, this was still well above the requirements of the standards
Summary
Furanic humins derived from the acid treatment of pure fructose have been the focus of attention for the preparation of various foams and resins [1,2,3,4,5,6,7,8,9,10]. This interest was prompted by a Netherlands company having developed a novel process of industrialization to render commercially available this type of interesting material [11]. The organic components of soil can be subdivided into fractions that are soluble, largely humic acids, and insoluble, the humins
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
