Probing Rubber Cross-Linking Generation of Industrial Polymer Networks at Nanometer Scale
2016
Gabrielle, Brice | Gomez, Emmanuel | Korb, Jean-Pierre
We present improved analyses of rheometric torque measurements as well as ¹H double-quantum (DQ) nuclear magnetic resonance (NMR) buildup data on polymer networks of industrial compounds. This latter DQ NMR analysis allows finding the distribution of an orientation order parameter (Dᵣₑₛ) resulting from the noncomplete averaging of proton dipole–dipole couplings within the cross-linked polymer chains. We investigate the influence of the formulation (filler and vulcanization systems) as well as the process (curing temperature) ending to the final polymer network. We show that DQ NMR follows the generation of the polymer network during the vulcanization process from a heterogeneous network to a very homogeneous one. The time variations of microscopic Dᵣₑₛ and macroscopic rheometric torques present power-law behaviors above a threshold time scale with characteristic exponents of the percolation theory. We observe also a very good linear correlation between the kinetics of Dᵣₑₛ and rheometric data routinely performed in industry. All these observations confirm the description of the polymer network generation as a critical phenomenon. On the basis of all these results, we believe that DQ NMR could become a valuable tool for investigating in situ the cross-linking of industrial polymer networks at the nanometer scale.
显示更多 [+] 显示较少 [-]