Influence of carbon nanofiber functionalization and compatibilizer on the physical properties of carbon nanofiber reinforced polypropylene nanocomposites

The effect of acrylic acid (AA) and amine alcohol (DMAE) functionalization via plasma of carbon nanofibers (CNF) on physical and mechanical properties of polypropylene-CNF nanocomposites prepared by melt mixing was studied. The behavior of these functionalized CNF via plasma was compared with a CNF functionalized by oxidation with a mixture of sulphuric acid (H2SO4) and nitric acid (HNO3). Two different types of compatibilizers were used: an amine alcohol modified PP (PPgDMAE) and a maleic anhydride grafted PP (PPgMA). The CNF functionalization was evidenced by Raman spectroscopy, comparing the ratio of peaks at 1371 and at 1590 cm(-1). Dispersion of the CNF was assessed using scanning microscopy, and the effect of the type of CNF functionalization on the dispersion was evidenced. A noticeable increase in thermal stability, mechanical and electrical properties and crystallization rate were observed. For example, the storage modulus when using PPgDMAE and AA functionalized CNF increased up to 48% over the control. The mechanical properties of flexural and impact strength showed an effective load transfer when using this CNF and compatibilizer system, which was attributed to the better functionalized CNF dispersion and the strong interactions between this CNF and the polymer matrix. POLYM. COMPOS., 39:3575-3585, 2018. (c) 2017 Society of Plastics Engineers