The crosslinking directing dynamic behavior of polymer latex under the investigation toward waterborne damping coatings

Latex polymers with precisely designed dynamic mechanical behavior are the key for waterborne damping coatings, which are widely desired in noise and vibration reduction with additional environmental benefits. In this work, we synthesized series of polymer latexes with various crosslinking agents (CA) and network distributions through the control on emulsion polymerization processes. We have revealed that the variation on crosslinking can significantly direct the latex behavior under dynamic conditions as well as its films. The variables involve the CA composition, the functionality, the crosslinking manner, the hydrophilic-hydrophobic feature as well as the feeding method. Although all the latex films showed the damping peaks locating in the range from ?10 to 70°C, their damping behaviors were quite different. Suggested by the empirical parameters of LA and TA, the product from sequential monomer feeding method tended to give good extensional damping performance. Especially when the crosslinking of diacetone acrylamide (DAAM)/adipic dihydrazide was applied, there was a linear increase on LA with the increasing dosage of DAAM from 0 to 10 mmol in the final monomer addition batch. Meanwhile, good constrained layer damping is expected on the products from the power monomer feeding method with the maximum CA dosage shown below 7.5 mmol. The best TA was achieved when the CA of divinylbenzene was used in the dosage of 5 mmol. These results would be valuable to be referenced in the engineering on organic damping materials toward modern industrial and vehicles applications.