The Interfacial Design And Properties Of Rubber/Clay Nanocomposites Via Dopamine Modification

Dopamine surface modification is inspired by mussel adhesion proteins (MAPs). Besides, polydopamine (PDA) is labeled as one category of synthetic melanin by mimicking the intriguing radical-scavenging behaviors of its nature counterpart. In this study, PDA modified montmorillonite (PDA-MMT) is utilized as a reinforcer for rubber matrix to fabricate efficient rubber/clay nanocomposites.Firstly, even-dispersed PDA-MMT is prepared by aqueous dip-coating based on the spontaneous alkaline auto-oxidative polymerization of dopamine hydrochloride in air atmosphere (TEM & XPS). The formation and micro-structure of PDA is similar to that of natural melanin, which displays distinctive radical property due to its semi-quinone radicals. PDA poses as electron trap to scavenge detrimental radicals which exerts excellent radical-inhibition effect (DPPH assay).Then, PDA-MMT was associated with nature or styrene butadiene rubber via aqueous latex compounding. Modified clay interacts with rubber molecules via robust hydrogen bonding, which contributes to the uniform-dispersion morphology (XRD & TEM). The vicinity of PDA-MMT leads to the reorientation of rubber molecules that averages external loading, which in turn improves the mechanical properties of nanocomposites. Furthermore, this radical-scavenging ability of PDA-MMT was attested by in-situ thermo-oxidative ageing test (ESR). The kinetics calculations of apparent activation energy (Flynn-Wall-Ozawa assay) combined with infrared analyses of degradation product (TG-IR) is employed to assess the overall thermo-oxidative stability of rubber/clay nanocompounds.Above all, the incorporation of PDA-MMT is in accordance with the interfacial tailoring principles for NR/clay compounds. The high dispersion of clay, strong interfacial interplay and cross-link network regularity of SBR/ PDA-MMT systems give rise to impressive reinforcing effects. PDA coating plays an excellent role of radical-scavenger and the uniform-dispersed PDA-MMT significantly functions as physical barrier, which collaborate to decline degradation of rubber matrix.