Click Cross-Linking-Improved Waterborne Polymers for Environment-Friendly Coatings and Adhesives.
Waterborne polymers, including waterborne polyurethanes (WPU), polyester dispersions (PED), and polyacrylate emulsions (PAE), are employed as environmentally friendly water-based coatings and adhesives. An efficient, fast, stable, and safe cross-linking strategy is always desirable to impart waterborne polymers with improved mechanical properties and water/solvent/thermal and abrasion resistance. For the first time, click chemistry was introduced into waterborne polymer systems as a cross-linking strategy. Click cross-linking rendered waterborne polymer films with significantly improved tensile strength, hardness, adhesion strength, and water/solvent resistance compared to traditional waterborne polymer films. For example, click cross-linked WPU (WPU-click) has dramatically improved the mechanical strength (tensile strength increased from 0.43 to 6.47 MPa, and Young's modulus increased from 3 to 40 MPa), hardness (increased from 59 to 73.1 MPa), and water resistance (water absorption percentage dropped from 200% to less than 20%); click cross-linked PED (PED-click) film also possessed more than 3 times higher tensile strength (∼28 MPa) than that of normal PED (∼8 MPa). The adhesion strength of click cross-linked PAE (PAE-click) to polypropylene (PP) was also improved (from 3 to 5.5 MPa). In addition, extra click groups can be preserved after click cross-linking for further functionalization of the waterborne polymeric coatings/adhesives. In this work, we have demonstrated that click modification could serve as a convenient and powerful approach to significantly improve the performance of a variety of traditional coatings and adhesives.
School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, China.
Jianqing
J
Hu
School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, China.
Kaimei
K
Peng
Jinshan
J
Guo
Dingying
D
Shan
Gloria B
GB
Kim
Qiyao
Q
Li
Ethan
E
Gerhard
Liang
L
Zhu
School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, China.
Weiping
W
Tu
College of Chemistry and Environmental Engineering, Shenzhen University , Shenzhen 518060, China.
Weizhong
W
Lv
Michael A
MA
Hickner
Jian
J
Yang
click chemistry; coating; polyacrylate emulsions; polyurethanes; waterborne polymers