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Synthetic method for developing plant oil-based monomers (POBMs) using direct transesterification reaction of oil triglycerides with N-(Hydroxyethyl) acrylamide was created and widely used by our group. Resulted acrylic monomers undergo free-radical polymerization, including in emulsion process, to yield latex polymers, suitable for application as adhesives. 

Synthetic method for developing plant oil-based monomers (POBMs) using direct transesterification reaction of oil triglycerides with N-(Hydroxyethyl) acrylamide was created and widely used by our group. Resulted acrylic monomers undergo free-radical polymerization, including in emulsion process, to yield latex polymers, suitable for application as adhesives. 

Sustainability of the adhesives prepared from fossil-based materials has become a growing concern. Thus, replacement of petroleum-based materials by ones derived from renewable resources is pursued as a sustainable strategy for reducing their carbon footprint. Biobased latexes can be widely used as waterborne adhesives if their performance and properties are competitive to those currently available in the market. This work aims to evaluate the performance of latex adhesives with higher biobased content recently developed in our group. For this purpose, plant oil-based vinyl monomers HOSBM and CMM (derived from high oleic soybean oil and camelina oil, respectively) in combination with methyl methacrylate (MMA) and butyl acrylate (BA) were copolymerized using miniemulsion to yield latexes to be tested as adhesives. The MMA (“rigid” fragment) content was kept at 55 wt%, while BA (within remaining 45 wt% of the “soft” fragments) has been gradually replaced by either CMM or HOSBM. The effect of partial substitution of the BA by CMM or HOSBM on adhesive properties was assessed using peel testing (ASTM D 1876-08) on the multiple substrates. Presence of plant oil-based fragments in latex copolymers improves adhesives peel strength on most substrates. Plant oil-based latexes with the maximum content of CMM or HOSBM (up to 45wt %) and their optimal adhesive performance were determined on various carpet and paperboard substrates. Additionally, Life Cycle Assessment (LCA) method was used as a tool to evaluate the environmental performance of the synthesized latex adhesives as well as identify the hotspots in the synthesis of these plant-derived adhesives in their early design stages. LCA of plant oil-based monomers can explain to which extent the sustainability of the biobased latex adhesives can be improved. The authors thank the NSF Industry and University Cooperative Research Center for Bioplastic and Biocomposites for financial support. Thanks to NSF CB2 (1916564) 

High functionality of new adhesives based on vinyl monomers from plant oils (POBMs) can be controlled by physico-chemical properties of latexes synthesized from POBMs. This research aims to improve the performance and sustainability of POBM-based latex adhesives. Elaborating on this concept, camelina (CMM) and high oleic soybean oil-based (HOSBM) monomers were incorporated into latex copolymers to evaluate adhesives performance on multiple substrates. Life Cycle Assessment (LCA) method was used as a tool to evaluate the environmental performance of the synthesized biobased latex adhesives. Latex adhesives were synthesized from combination of methyl methacrylate (MMA), butyl acrylate (BA) and POBMs at various monomer ratios. The MMA content in monomer mixture was kept at 55 wt%, while BA (within remaining 45 wt% of the feed) has been gradually replaced by POBM in monomer feed, yielding feasible latex adhesive formulations. Latex adhesives performance was evaluated using peel testing (ASTM D 1876-08) on the multiple substrates. Presence of HOSBM and CMM fragments in latex copolymers improves adhesives peel strength on most substrates. It was found that performance of POBM-based adhesives can be improved by varying adhesive consumption. It was shown that the incorporation of POBMs into latex copolymers enhances hardness of the latex films upon formation of latex networks. LCA results demonstrated a positive environmental impact when BA was replaced with POBM leading to a lower toxicity for latex adhesives overall. To address the hotspots pinpointed by conducting the initial LCA a number of strategies were implemented. The environmental performance of the biobased adhesive was improved by synthesizing POBM using 2-Methyl-tetrahydrofuran – an environmentally friendly alternative of widely used solvent tetrahydrofuran. Additionally, monomer washing step was improved by replacing dichloromethane with hexane, a solvent with a relatively lower environmental impact. Finally, comparison of the several monomers used for synthesis of the adhesive showed that POBM had the lowest negative impact on the environment as well as human health in various categories. In summary, the obtained experimental data demonstrate plant-oil based latexes environmental benefits and potential as adhesives as well as their utility for usage on multiple substrates.