Extrusion foaming behavior of a polypropylene/nanoclay microcellular foam

Abstract

With maleic anhydride grafted polypropylene (PP-g-MAH) as a compatibilizer, composites of block-copolymerized polypropylene (B-PP)/nanoclay were prepared. The effects of the PP-g-MAH and nanoclay content on the crystallization and rheological properties of B-PP were investigated. The microcellular foaming behavior of the B-PP/nanoclay composite material was studied with a single-screw extruder foaming system with supercritical (SC) carbon dioxide (CO 2 ) as the foaming agent. The experimental results show that the addition of nanoclay and PP-g-MAH decreased the melt strength and complex viscosity of B-PP. When 3 wt % SC CO 2 was injected as the foaming agent for the extrusion foaming process, the introduction of nanoclay and PP-g-MAH significantly increased the expansion ratio of the obtained foamed samples as compared with that of the pure B-PP matrix, lowered the die pressure, and increased the cell population density of the foamed samples to some extent. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44094.

Role of chain extension in the rheological properties, crystallization behaviors, and microcellular foaming performances of poly (butylene adipate‐co‐terephthalate)

“…In Figure (a), the η * curve of torqued PBAT sample displayed a Newtonian plateau, but others did not. This transition from a Newtonian plateau to the shear thinning regime indicated the presence of microstructure (branching and/or crosslinking structure) with a long relaxation time . The η * of CE‐PBAT samples increased with the increment of CE content, which should be resulted from the increase of molecular weight and the formation of branching and/or crosslinking structures .…”

“…It possesses moderate crystallinity, good processability, high toughness, and well biocompatibility . Supercritical carbon dioxide (SCCO 2 ) was often used as an environment friendly physical blowing agent to prepare the microcellular polymer foaming materials due to its nontoxic, nonflammability, low global warming potential, and ozone depletion potential, as well as safe in performance …”

Supercritical CO2 Foaming of Radiation Cross-Linked Isotactic Polypropylene in the Presence of TAIC

“…The cell structure was greatly improved, and the cells were more uniform as the absorbed dose increased from 0 to 30 kGy. The cells of the foamed PP materials became more uniform, and more closed cells were present in the foamed PP compared to the cell structure of the foamed blends of PP/nanoclay and PP/nanocrystalline cellulose by supercritical carbon dioxide-foamed PP [21,22]. Moreover, the cells have a relatively stable diameter for doses from 10 kGy to 40 kGy, owing to a larger cross-linked region and higher melt strength of PP, which is beneficial for bearing the pressure of CO 2 .…”

“…However, compared to polyethylene, isotactic polypropylene more easily undergoes degradation upon irradiation, resulting in a poorer resistance to weathering [18,19]. Many studies have been performed on the foaming of PP by scCO2 [20][21][22]. The melt strength and mechanical and heat-resistant properties of polypropylene have been shown to be significantly improved by irradiation in the presence of a cross-linking agent [23].…”

Role of nano-SiO2 on the performance of microporous foamed polystyrene polymer

“…Addition of organoclay containing 5 wt% of polybutadiene powder improved the mechanical properties of the foamed PP relative to adding either filler by itself. Wang et al [21] used maleic anhydride-grafted polypropylene (PP-g-MAH) as a compatibilizer to study the effects of PP-g-MAH and nano-clay content on the crystallization and rheological properties of block-copolymerized polypropylene (B-PP). They found that adding nano-clay and PP-g-MAH decreased the melt strength and complex viscosity of B-PP.…”