Flow mark defects reduction of injection‐molded polypropylene by dynamically vulcanized polyolefin elastomer

Abstract

Flow mark defects (FMs) worsen surface esthetics and mechanical properties of injection‐molded polypropylene (PP). In this work, experiments and dissipative particle dynamic (DPD) simulations were used to investigate the effect of dynamically vulcanized polyolefin elastomer (POE) on FMs of injection‐molded PP. Significant FMs reduction was achieved by dynamically vulcanized POE. DPD simulations indicated that POE molecules were randomly distributed in the PP, while dynamic vulcanization led to the formation of elastomeric quasi‐clusters, and these quasi‐clusters were able to reduce FMs. Both DPD simulations and scanning electron microscopy results showed that more agglomerates with longer and irregular shapes formed with longer vulcanization time and more initiators. The formation of too many agglomerates resulted in different pock surface defects. Dynamically vulcanized POE produced at optimal reaction conditions did not affect the tensile strength, tensile modulus, flexural strength, and flexural modulus, while breaking elongation and notched Izod impact strength of injection‐molded PP decreased slightly. This work suggests that the addition of dynamically vulcanized POE may be a promising way to reduce FMs of injection‐molded PP.

Sodium Benzenesulfonate-Assisted Preparation of Lignosulfonate-Based Spherical Micelles: Insights from Mesoscopic Simulations

“…According to the coarse-grained models of beads A , B , C , D , D Me , D Et , E , and F , both Flory–Huggins parameters χ ij and interaction parameters a ij between those coarse-grained beads used in the DPD simulations were calculated according to the methods in our previous work, , as listed in Tables S2 and , respectively. Briefly, the structures of various beads were orderly performed energy minimization, geometric optimization, NPT ensemble (298 K and 1.0 bar), and NVT ensemble (298 K) calculations to reach the lowest energy configuration.…”

“…Briefly, the structures of various beads were orderly performed energy minimization, geometric optimization, NPT ensemble (298 K and 1.0 bar), and NVT ensemble (298 K) calculations to reach the lowest energy configuration. The subsequent DPD simulations were also carried out according to our previously published procedures. , To avoid finite-size effects, a cubic simulation box of 30 × 30 × 30 R c 3 with periodic boundary conditions was applied in all directions. In this work, it was found that the sizes and structures of aggregates/micelles had no obvious change when 400 000 simulation steps were carried out.…”

“…The subsequent DPD simulations were also carried out according to our previously published procedures. 22,23 To avoid finite-size effects, a cubic simulation box of 30 × 30 × 30 R c 3 with periodic boundary conditions was applied in all directions. In this work, it was found that the sizes and structures of aggregates/micelles had no obvious change when 400 000 simulation steps were carried out.…”

Synergistic effect of β‐nucleating agent and layered double hydroxide on high toughness of polypropylene composites

“…Polypropylene (PP), one of the general-purpose plastics, is used in large quantities due to its excellent corrosion resistance, processability, and low price. [1] Due to the poor anti-impact performance of PP, especially the toughness at a low temperature, it is limited to the application of engineering plastics, especially in building materials and aerospace materials. [2][3][4] In the current stage of research, physical mixing methods are often used to improve the impact performance of PP.…”