Tannic acid-assisted green fabrication of functionalized graphene towards its enhanced compatibility in NR nanocomposite

Abstract

A green and efficient method has been developed to prepare functionalized graphene (NTGE) by liquid exfoliated graphene (TGE), using tannic acid (TA) as stabilizer, followed by further derivatization through the mild Mannich reaction between the phenolic hydroxyl groups on TA and octadecylamine (OC). Then the functionalized graphene (NTGE) was well compatible with organic polymer. The qualitative and quantitative analysis for NTGE was characterized by FTIR, UV–vis and TGA. The residual weight substantiated by TGA implies that the grafted OC content onto graphene is about 30%. The morphology of NTGE can be identified from the TEM micrographs and AFM which indicate TGE functionalized with OC increase interlayer spacing and decrease π-π interaction between TGE sheets. TGE sheets as fine as 1.8 nm and NTGE sheets with thickness of 2.1 nm were observed by AFM. A noticeable enhancement was achieved for NTGE compounded with NR systems. With the addition of 1 phr NTGE, tensile strength and tear strength of NTGE1@NR respectively increase 11.1% and 5.1% compared with TGE1@NR composite due to tight rubber-filler interactions. Nevertheless, the significant tensile strength and tear strength increase of 33% and 20% respectively for NTGE1@NR is obtained compared with Neat NR. This new preparation and functionalization route provides a choice for the large-scale application of functionalized graphene.