Adjustable brittle-ductile transition behavior and rheological behavior of polypropylene random copolymer nanocomposites through well interfacial-loaded nanoparticles

To improve the low-temperature toughness of polypropylene random copolymer (PPR), a series of PPR/ethylene-propylene rubber/silica (PPR/EPR/SiO2) nanocomposites were prepared through toughening strategy based on interfacial-loaded particles and adjustable dispersed phase. The results showed that the brittle-ductile transition behavior for PPR/EPR/SiO2 nanocomposites could be adjusted by silica and rubber contents, and consequently the composites were endowed with excellent low-temperature impact resistance. Furthermore, the nanocomposites never presented the significant deterioration of rigidity compared with pure PPR. The dynamic rheological results showed that viscosity change in PPR matrix and EPR phase could make silica particles preferentially locate at PPR-EPR interface, which strongly reduced the size of EPR domain and consequently led to a stronger shape relaxation of long-time scale. According to dynamic rheological behavior, microstructure and interparticle distance analysis of PPR nanocomposites, the adjustable brittle-ductile transition behavior was ascribed to the reduced rubber interparticle distance coming from the well interfacial-loaded nanoparticles. Polypropylene random copolymer/ethylene-propylene rubber/silica (PPR/EPR/SiO2) nanocomposites with excellent low temperature toughness were prepared. Adjustable brittle-ductile transition behavior is ascribed to the well interfacial loaded nanoparticles induced by the filled rubber phase with high viscosity. [Display omitted] •Based on interfacial loaded particles, polypropylene random copolymer/ethylene-propylene rubber/silica (PPR/EPR/SiO2) nanocomposites with excellent low temperature toughness were prepared.•The brittle-ductile transition behavior for PPR/EPR/SiO2 nanocomposites is ascribed to the interfacial loaded particles induced by the filled rubber phase with high viscosity.•The viscosity changes in PPR matrix and EPR phase make silica particles preferentially locate at PPR-EPR interface, reducing the size of EPR domain and consequently leading to a stronger shape relaxation of long-time scale.