Production of carbohydrate-based binders for wood products
The main task of Wood K plus in the SUSBIND project is the development of carbohydrate-based resins and other wood adhesive systems and characterization of the resins will be performed on laboratory scale. The most promising bio-based binders will then be up-scaled to pilot production and used for manufacturing P2 particleboards and medium density fiber boards (MDF).
The project partner Cargill did the selection of suitable carbohydrate feedstock. More information on the selection process can be found in a previous blog post. The selected carbohydrates are the monomers fructose and glucose as well as the oligomer maltodextrin. The investigation of conversion reactions is based on the selected feedstock.
Investigation of conversion reactions of carbohydrates
With regard to the final application in the wood board industry, the bio-based binder system must have a reduced carbon footprint and lower human health impact than the current fossil-based binder systems. Hence, special focus is put on the reaction conditions and materials used in the carbohydrate conversion reaction. The obtained reactive intermediates will be applied directly in the bio-based binder system and should meet the environmental and regulatory requirements.
The following criteria need to be assessed when investigating carbohydrate conversion reactions:
- Reactivity of products
- Utilization of suitable solvents and catalysts
- Applicability for an in-situ process
- Technical applicability in terms of large-scale production
- Economic considerations
- Efficient material and energy use
The conversion reaction must avoid using or generating substances that are harmful to humans and/or the environment. In addition, the chemical products of the conversion reaction have to perform in the desired way but be as non-toxic and non-hazardous as possible. In terms of reactivity, the produced intermediates must be able to crosslink in the subsequent polymerization reaction. Furthermore, the time needed for full curing of the bio-based resin should be comparable to commercial fossil-based binders with similar strength values.
In terms of the utilization of solvents, special focus is put on the utilization of the solvent in the follow-up resin production step. Water was identified as an ideal solvent that can be used in the carbohydrate conversion and the resin production.
The amount of conversion product that ends up in the final product must be maximized in order to have an economic and efficient process.
Selecting the most promising crosslinking systems
The literature was screened for the selection process of the most promising crosslinking systems based on the previously defined criteria. The carbohydrate conversion reactions will be tested in laboratory-scale to determine the practicability of the production method as well as to define the optimal parameters. The final selection of a potential precursor will be based on these results. The results of the literature screening will be topic of a follow-up blog post later this year.
Author: DI Catherine Thoma, BSc.
Junior Researcher, Area Wood Materials Technologies