Microstructure and fracture behavior of polypropylene/barium sulfate composites

Abstract

ABSTRACT:The microstructure, mechanical properties, and fracture behavior of polypropylene (PP)/barium sulfate (BaSO 4 ) composites were studied. Four composite samples with different PP-BaSO 4 interface were prepared by treating the filler with different modifiers. The fracture behavior of the composites under different strain rates was studied by means of Charpy impact tests and essential work of fracture (EWF) tests. It is shown that a moderate interfacial adhesion is favorable for toughening, which ensures that the particles transfer the stress and stabilizes the cracks at the primary stage of the deformation, and satisfies the stress conditions of plastic deformation for matrix ligaments subsequently via debonding. Very strong interfacial adhesion is not favorable for toughness, especially under high strain rate, because the debonding-cavitation process may be delayed and the plastic deformation of matrix may be restrained.

Investigation on the environmental‐friendly poly(lactic acid) composites based on precipitated barium sulfate: Mechanical, thermal properties, and kinetic study of thermal degradation

“…At low concentration of BaSO 4 , the fine and well‐dispersed inorganic fillers have the ability of deflecting the crazes and generating tortuous ways for craze propagation. On the other hand, the fillers also cause stress concentration, which gives rise to the build‐up of triaxial stress around the rigid particles, and then the interface debonding appears at filler–polymer interfaces to satisfy the stress condition of plastic deformation for PLA matrix ligaments . As a result, abundant energy could be required.…”

“…It is delighted to found that all the composites exhibit the higher values of impact toughness than pristine PLA, indicating that the incorporated inorganic filler takes a great part in enhancing the impact resistance of PLA composites. Such analogous effects of BaSO 4 on thermoplastic polymers have also been approved by other researchers, and the significant improvement on impact toughness should be ascribed to the fine particle size as well as homogeneous dispersity of BaSO 4 in the PLA matrix . Our previous study has demonstrated that samples with added precipitated BaSO 4 are accompanied by the increased average diameter and worsened dispersion of inorganic fillers in the polymer matrix .…”

Phenolic rigid organic filler/isotactic polypropylene composites. II. Tensile properties

“…And almost all of traditional rigid inorganic filler (RIF) particles, such as CaCO 3 [2][3][4][5][6], BaSO 4 [7], SiO 2 [8], glass bead [9][10][11][12], Al(OH) 3 [11], Mg(OH) 2 [13,14], carbon black [15] and chalk [16], have been used to modify PP in the past two decades. In these systems, considerable improvements of the modulus have been generally achieved due to the inherent rigid properties of these fillers.…”

Phenolic rigid organic filler/isotactic polypropylene composites. III. Impact resistance property

“…The absorption process of impact energy consists of four stages: stress concentration around filler particles, debonding between matrix and particles, transition of stress states ahead the crack tip from plane strain to plane stress, and shear yielding of interparticles ligaments between particles [4,18]. However, the stress concentration is positively correlated with filler dimension, while the debonding resistance is inversely correlated with filler dimension, as shown the interfacial interaction analysis in tensile test [23].…”

“…Once crazes take place in PP sample, the crazes will rapidly develop into cracks and then propagate through whole sample with little resistance [3,[18][19][20]. As shown in Figs.…”