Grantee Research Project Results
Final Report: Soy-Capped Polycarbonate Dendrimers for Tough, Sustainable Water-Based Wood Coatings
EPA Contract Number: EPD15010Title: Soy-Capped Polycarbonate Dendrimers for Tough, Sustainable Water-Based Wood Coatings
Investigators: Cameron, Randy E.
Small Business: Instrumental Polymer Technologies, LLC
EPA Contact: Richards, April
Phase: II
Project Period: November 1, 2014 through October 31, 2016 (Extended to October 31, 2017)
Project Amount: $300,000
RFA: Small Business Innovation Research (SBIR) - Phase II (2014) Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Innovation in Manufacturing
Description:
The purpose of this research was to develop low cost and sustainable polycarbonate nanotechnology that could replace environmentally toxic oil-based alkyd resins currently used in the large wood and architectural coatings markets. Ironically, alkyd resins, though initially derived from natural oils, contain an unsustainable polyester backbone and are dissolved in a large amount of solvent. Even worse, the clean-up of these coatings requires a large amount of volatile organics. This project was directed towards developing an oil-based resin technology that has the performance of oil based alkyd paints but requires little or no solvent and can be cleaned with water.
To achieve the goals of this project we used the proprietary method of Instrumental Polymer Technologies, (IPTECH) to produce high molecular weight dendrimers with a tough polycarbonate core and with soyate groups attached to their surface. The spherical nature of these "dendryds" would give them much lower viscosity than current alkyd paint, therefore requiring less solvent. An inherent feature of spheres is that as they grow larger their volume increases at a faster rate than their surface area. Consequently larger dendrimers were expected to provide a coating with a much larger polycarbonate content, and therefore a tougher coating, than smaller dendrimers, though their viscosity would increase minimally.
Amino acid groups were to be incorporated into the core to make the dendrimers water dispersible so the solution would be cleaned with water, but would still maintain low viscosity. Another advantage of dendrimers is that they can invert, and having the salts in the core of the dendrimer would enable the dendrimer to invert and become water dispersible when mixed with water, but be tucked back in to the core of the dendrimer once the water had evaporated.
Sustainable raw materials, including methyl soyate, the most common form of biodiesel, would result in a cost competitive with current alkyd paint.
Summary/Accomplishments (Outputs/Outcomes):
During this project we were able to demonstrate the first example of an oil-based coating which is low enough in viscosity to be applied directly as a coating, without the use of solvent, but which could be cleaned with water. This demonstrated the uniqueness of dendrimer technology. Specifically we produced polycarbonate dendrimers that are covered with soyate groups and which contain an amino acid for water dispersibility. The resulting dendrimers were very low in viscosity and could be applied as a coating without use of solvent and could be cured into a film.
A significant amount of the project focused on finding the most cost effective way of providing an aliphatic polycarbonate polymer or dendrimer derivitized with soyate groups, without forming undesirable side products like cyclic ethers. Such groups would create monomer species that lower the performance properties of the final coating. We were able to achieve the best results by a stepwise process in which we first formed the ester bond at elevated temperatures, but performed the polycarbonate synthesis in a second step.
Conclusions:
In general we did find that larger dendrimers did form tougher coatings because of their larger amount of polycarbonate. They were very scratch resistance, but their impact resistance was still lower than desired. We therefore synthesized more linear versions of the polycarbonate alkyd so the polycarbonate functionality could play more of a role in the performance of the coating. This led to tougher coatings though the viscosity was higher. Furthermore, the resulting coatings were more water sensitive, as we had predicted, because the amino acid salt was not ultimately hidden inside the core of the dendrimer. The optimum performance and application characteristics was found with a blend of linear and dendrimeric polymers.
During the Commercialization Option we were able to formulate this technology in to pigmented colors and provide physical data which our customers can use to quickly formulate products.
SBIR Phase I:
Soy-Capped Polycarbonate Dendrimers for Tough, Sustainable Water Based Wood Coatings | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.