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<p>Dynamic melt modification of polyethylene <i>via</i> the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials. In this study, four linear low-density polyethylenes (LLDPEs) with comparable molecular weights but different short-chain branch (SCB) contents (ranging of 5–66 per 1000 carbon atoms) were modified <i>via</i> dynamic melt mixing using 2 wt% benzoyl peroxide at 145 °C and 50 r/min for 30 min. The influence of SCB content on the processability and structure of the resulting products was systematically investigated. All modified products exhibited good melt processability with melt flow rates (MFR) ranging from 0.46 g/10min to 1.07 g/10min. Products derived from low-SCB LLDPEs showed a lower MFR, higher cross-linking content, a larger number of long-chain branches, and a higher degree of benzoyl grafting. In contrast, those produced from high-SCB LLDPEs exhibited improved processability, reduced cross-linking, fewer long-chain branches, and lower benzoyl grafting levels. A detailed structural investigation of the soluble and insoluble fractions, which were separated using trichlorobenzene fractionation, was conducted to analyze the structural features of various modified products and demonstrate that the SCB content (<i>i.e.</i>, tertiary carbon density) significantly influences radical coupling during dynamic modification. Elevated tertiary carbon density, by introducing greater steric hindrance, suppresses radical coupling during dynamic modification, thereby reducing the efficiency of both crosslinking and peroxide fragment grafting. These findings provide new insights into the structure-reactivity relationships in peroxide-induced polyethylene modification and lay the foundation for tailoring material properties <i>via</i> dynamic processing.</p>

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Processability and Structure of Dynamically Modified Linear Low-density Polyethylene with Different Branching Contents Using a High Peroxide Content

  • 期刊论文

  • 发表日期：

    2025年12月17日

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  • Jun-Jin Duan,
  • Yan-Qin Huang,
  • Fu-Qing Wei,
  • Yan Gao,
  • Fu-Shan Wang,
  • Jia-Chun Feng

摘要

Dynamic melt modification of polyethylene via the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials. In this study, four linear low-density polyethylenes (LLDPEs) with comparable molecular weights but different short-chain branch (SCB) contents (ranging of 5–66 per 1000 carbon atoms) were modified via dynamic melt mixing using 2 wt% benzoyl peroxide at 145 °C and 50 r/min for 30 min. The influence of SCB content on the processability and structure of the resulting products was systematically investigated. All modified products exhibited good melt processability with melt flow rates (MFR) ranging from 0.46 g/10min to 1.07 g/10min. Products derived from low-SCB LLDPEs showed a lower MFR, higher cross-linking content, a larger number of long-chain branches, and a higher degree of benzoyl grafting. In contrast, those produced from high-SCB LLDPEs exhibited improved processability, reduced cross-linking, fewer long-chain branches, and lower benzoyl grafting levels. A detailed structural investigation of the soluble and insoluble fractions, which were separated using trichlorobenzene fractionation, was conducted to analyze the structural features of various modified products and demonstrate that the SCB content (i.e., tertiary carbon density) significantly influences radical coupling during dynamic modification. Elevated tertiary carbon density, by introducing greater steric hindrance, suppresses radical coupling during dynamic modification, thereby reducing the efficiency of both crosslinking and peroxide fragment grafting. These findings provide new insights into the structure-reactivity relationships in peroxide-induced polyethylene modification and lay the foundation for tailoring material properties via dynamic processing.