Properties and Crystallization of Maleated Polypropylene/Graphite Flake Nanocomposites

Abstract

ABSTRACT:Polypropylene (PP)/graphite (G) hybrid nanocomposites have been prepared by melt mixing using maleated PP (PP-g-MA) and graphite oxide (GO) as compatibilizing agents. Melt mixing was achieved using a Gelimat, a high-speed thermo-kinetic mixer. The PP-g-MA and GO used as compatibilizers helped the dispersion of the graphite on a nano-scale and improved flexural properties but more significantly the impact strength of the material. TEM micrographs showed a partial exfoliation of the graphite in the PP/PP-g-MA/GO/G hybrid nanocomposites. SEM micrographs of etched nanocomposite samples showed a fine grain micron-sized structure, while pure PP was characterized by larger 3-dimensional spherulites. Non-isothermal crystallization kinetics of PP and PP/PP-g-MA/ GO/G nanocomposites were investigated by differential scanning calorimetry (DSC). The crystallinity and crystallization temperature of the nanocomposites were higher than for neat PP. Using the Kissinger model, the activation energy of crystallization of the nanocomposites was determined to be lower than PP. Models by Ozawa and Liu et al. were used to analyze and describe the non-isothermal crystallization kinetics. Overall, results indicate that the type of nucleation, growth and geometry of PP crystals markedly change in the presence of nano-sized graphite particles.

Crystallization and Thermal Properties of Biofiber-Polypropylene Composites

“…It can be seen from Table 4 that the addition of biofiber markedly reduced the activation energy for crystallization in pure PP. The low activation energy for crystallization obtained for the composites is consistent with their high crystallinity reported in Table 3, which could be attributed to the fact that biofibers, being high energy sites, lowered the activation energy for nucleation as similarly reported by Page & Gopakumar (2006). A close inspection of the data in Table 4 for the composites shows that at each level of fiber content, the application of MAPP increased their activation energy.…”

The role of SEBS in tailoring the interface between the polymer matrix and exfoliated graphene nanoplatelets in hybrid composites

“…Gopakumar and Page [26,27] studied the effect of coupling agent (PP-g-MA) in PP/graphite nanocomposites and found that the addition of PP-g-MA in PP/graphite composites resulted an improvement in flexural properties and impact strength. In a recent study, Miquelard-Garnier and co-workers [28] used forced assembly through multilayer co-extrusion method to develop PMMA/PSgraphene and PMMA/PMMA-graphene systems and reported that the amount of reinforcement was greater than normally reported for graphene nanocomposites, due to the orientation of graphene in the direction of extrusion.…”

A comparative study on the electrical and mechanical behaviour of multi‐walled carbon nanotube composites prepared by diluting a masterbatch with various types of polypropylenes

“…Modification with maleic anhydride is commonly used for polyolefins to introduce hydrophilic groups into the originally hydrophobic matrix with the aim to improve the compatibility with hydrophilic fillers. 24 Obviously, maleic anhydride does not react covalently with graphene sheets of CNT, however, maleated polyolefins have much higher adhesion to the polar substrates than unmodified ones. 25 Therefore, improvements in the nanotube dispersion and adhesion between PP and CNT can be expected.…”