Role of cellulose-based composite materials in synergistic reinforcement of environmentally friendly waterborne polyurethane

In this study, a graft modified Octa(aminopropyl) polyhedral oligomeric silsesquioxane (OPOSS)/ TEMPO-oxidized cellulose microfibrils (TOCMF) nanocomposite material (named PC) was prepared by a simple peptide-forming reaction to overcome the disadvantages of nanocellulose materials which have limited their application in environmentally friendly waterborne polyurethanes. The modified vegetable oil-based waterborne polyurethane (WPU) was prepared by reacting the excess amino group on the POSS with the -NCO group on the polyurethane matrix in the in-situ polymerization, in which the POSS particles function as a button-like bond between the oxidized cellulose and the polyurethane matrix. And the similar filamentous structure of TOCMF to the linear polyurethane matrix structure could greatly weaken the negative impact of the rigid structure of POSS particles on processability (Elongation at break). The performance test results showed that the mechanical properties, thermal stability and water resistance of the modified WPU composite film are greatly improved by the synergistic effect of the two nano materials. The initial decomposition temperature and water contact angle of the WPU composite film with a PC content of 0.7 wt.% were increased by 41.9 °C and 10°, respectively. Especially, the tensile strength of WPU/PC-0.7 wt.% was twice that of pure WPU.