Induction of the β-phase in isotactic polypropylene with pimelic acid modified graphene nanoplatelets

• Published in: FlatChem 2023-03, Vol.38, p.100472, Article 100472
• Main Authors: Villarreal-Martínez, Diego, Eduardo Gutiérrez-Páramo, Héctor, Laura Martínez-Hernández, Ana, Velasco-Santos, Carlos, Almendarez-Camarillo, Armando
• Format: Article
• Language: English
• Subjects: Graphene nanoplatelets; Mechanical properties; Polymer-matrix composite
• ISSN: 2452-2627; 2452-2627
• DOI: 10.1016/j.flatc.2023.100472

[Display omitted] •An easy functionalization way to modify oxidized graphene nanoplatelets (oGnPs) with pimelic acid.•A new nucleating agent to promote high percentages of β-polypropylene.•The modified oGnPs showed good interface adhesion with the polymer matrix.•A significant increase in the thermomechanical properties was observed by adding the new nano reinforced. In this work, graphene nanoplatelets (GnPs) were oxidized to functionalize them with molecules of pimelic acid (PA). This fact was confirmed by the presence of two characteristic bands assigned to CH bonds of the aliphatic chains of the pimelic acid (2939 cm−1 and 2860 cm−1). Furthermore, the IR spectra show two vibration bands about 1575–1570 cm−1 and 1413–1410 cm−1, which could be attributed to an ionic bridging linkage between the oxygenated sites of the oGnPs and the organic molecules. The chemical modification was followed by XRD and RAMAN, where an increase in the D/G ratio would suggest a major disorder in the structure because of the attaching in the first instance of oxygen and the pimelic acid during the functionalization. The modified ones were added at different percentages of 0.05, 0.5, and 1 wt% into an iPP matrix to demonstrate the β nucleating ability of our nanofiller. The relative percentages of the β-crystal for all samples were determined by DSC and WAXD, 72% and 75% for the oGnP and 0.05%-PA, respectively. DMA measurements were carried out to follow the influence of the reinforcements on the visco- elastic properties of the iPP matrix. The results showed an increase in the storage modulus of 161.2% at −40 °C and an improvement in the loss modulus of 54.2% for the composite with 1 wt% of the modified ones. The impact strength for this nanocomposite was 39% higher than the raw iPP.