In the quest to enhance the performance of starch-based adhesives, a team of researchers led by Mengyu Zhang from Wuhan Polytechnic University has uncovered intriguing insights into the interaction between starch and emulsifiers. Their study, recently published in *Industrial Crops and Products*, explores how varying the alkyl chain lengths of sodium sulfonate emulsifiers can significantly alter the structural and bonding properties of starch-based adhesives.
Starch-based adhesives are widely used in the agriculture sector for applications ranging from paper coating to wood bonding. However, their performance is often limited by the interaction between starch molecules and emulsifiers, which can affect the adhesive’s strength and durability. Zhang and her team investigated how different emulsifiers—sodium dodecyl sulfate (SDS), sodium hexane sulfonate (SHS), and sodium octadecyl sulfonate (SOS)—interact with starch to influence the adhesive’s performance.
The researchers found that the type of emulsifier used can dramatically change the adhesive’s properties. SHS, for instance, exhibited a low migration propensity and was preferentially embedded within starch molecules via hydrogen bonding. This embedding accelerated the fusion process and enhanced the molecular network strength, ultimately improving the adhesive’s strength. “SHS’s ability to integrate seamlessly with starch molecules creates a more robust internal structure, which is crucial for high-performance adhesives,” Zhang explained.
In contrast, SDS formed a V-type complex with starch, promoting uniform latex dispersion through interfacial adsorption. While this reduced the interfacial layer thickness and slowed fusion, it also facilitated molecular migration to air-water interfaces, weakening the internal strength of the adhesive. SOS, on the other hand, moderately increased interparticle repulsion via hydrogen bonding and inclusion complexation. However, its strengthened hydrophobic interactions promoted micelle formation, enhancing latex particle interactions and increasing the interfacial fusion layer thickness and strength.
These findings offer valuable insights for designing high-performance starch-based adhesives. By understanding the mechanistic effects of different emulsifiers, researchers and manufacturers can tailor the properties of adhesives to better suit specific applications. “This research provides a roadmap for optimizing starch-based adhesives, which can have significant commercial impacts for the agriculture sector,” Zhang noted.
The study’s implications extend beyond immediate applications. As the demand for sustainable and eco-friendly materials grows, starch-based adhesives are poised to play a pivotal role in various industries. The insights gained from this research could pave the way for innovative formulations that enhance performance while reducing environmental impact.
Mengyu Zhang is affiliated with the Key Laboratory for Deep Processing of Major Grain and Oil, Ministry of Education, Hubei Key Laboratory for Processing and Transformation of Agricultural Products, Wuhan Polytechnic University, Wuhan 430023, PR China, and the School of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, PR China.