Modelling of mechanical properties of Pa6 based reinforced graphite and graphite nano platelets composites using different aspect ratio

Purpose This study aims to fabricate and study the effect of five cumulative graphite (G) and graphite nanoplatelets (GNP) filler loading composites by polymerising PA6 precursor; monomer epsilon caprolactam with the two carbons in situ while taking cognisance of the mixing effects (simultaneous stirring and sonication at varying amplitudes and duration). Different aspect ratios will be used to model the two streams of polymerisations. Design/methodology/approach High viscosity extrusion grade PA6 and synthetic G of less than 2 µm particle size were used as fillers. GNP and G are dried for 6 h in vacuum oven at 90°C. Prior to in situ polymerisation, probe sonication was applied to disperse fillers in molten ɛ-caprolactam, the PA6 monomer. Five carbon loadings were made, that is 5–25 Wt.% for G and 0.5–2.5 Wt.% for GNP composites. Two different sonification regimes were applied 20% sonication amplitude for 20 min (20/20) and 40% sonication amplitude for 10 min (40/10). Findings Better tensile properties were achieved using the 20/20 processing streams for both G and GNP. The G- and the GNP-based composites systems of the 20/20 processing stream had tensile modulus and yield strength retained or improved above the unfilled PA6 value. The highest modulus obtained in the 20/20 streams are 1,878 and 1,201 MPa, respectively, for GNP and G at the highest loading levels, while the 40/10 processing streams had 963 and 1,247 MPa, respectively, for the GNP and G. Originality/value To the best of the authors’ knowledge, nobody has ever used sonification amplitude to compare mechanical properties.

Correction: Vinylboronic acid pinacol ester as a vinyl alcohol-precursor monomer in radical copolymerization with styrene

Correction for ‘Vinylboronic acid pinacol ester as a vinyl alcohol-precursor monomer in radical copolymerization with styrene’ by Hiroshi Makino et al., Chem. Commun., 2021, DOI: 10.1039/D1CC02603H.

Vinylboronic acid pinacol ester as a vinyl alcohol-precursor monomer in radical copolymerizations with styrene

The use of vinylboronic acid pinacol ester (VBpin) as a comonomer and post-polymerization oxidation afforded vinyl alcohol (VA)-styrene copolymers that was difficult to synthesize using a typical VA precursor monomer,...