Abstract A hybrid nanomaterial, low crystallinity graphite-layered double hydroxide, was used as a support for zirconocene catalyst. The hybrid nanomaterial graphite-NiAl layered double hydroxides (G/LDH) were synthesized by the co-precipitation method. The synthesized nanomaterial was used as a support for zirconocene catalyst. The polymerization reactions were carried out for ethylene polymerization. The synthesized polyethylene (PE) was analyzed by using differential scanning calorimetry (DSC), Crystallization analysis & fractionation (CRYSTAF), and thermogravimetric analysis for its thermal and microstructural characteristics. The crystallization kinetics were studied by the Ozawa and combined Ozawa and Avrami models. It was found that the presence of G/LDH from the catalyst support nucleated the PE crystallization and shifted the crystallization onset temperature to a higher value. However, the overall crystallization rate was slowed by the presence of the nanomaterial due to growth impingement. Moreover, the PE synthesized by G/LDH supported catalyst possessed higher thermal stability than PE synthesized by unsupported zirconocene catalyst. The integral isoconversional method was used to evaluate the activation energy of thermal degradation and crystallization kinetics. The degradation mechanism was validated by the application of the integral master plot technique. The degradation mechanism of neat PE resembled phase boundary controlled mechanism second and third-order, i.e. (R2, R3), while PE synthesized by G/LDH supported catalyst had a shift in degradation mechanism from (R2, R3) to a diffusion-limited mechanism at the later stages of degradation.

中文翻译：

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用于乙烯聚合的石墨-LDH 杂化负载的二茂锆：载体对聚乙烯结晶动力学和热稳定性的影响

摘要 一种杂化纳米材料，低结晶度石墨层状双氢氧化物，被用作二茂锆催化剂的载体。通过共沉淀法合成了杂化纳米材料石墨-NiAl层状双氢氧化物（G/LDH）。合成的纳米材料用作二茂锆催化剂的载体。为乙烯聚合进行聚合反应。通过使用差示扫描量热法 (DSC)、结晶分析和分馏 (CRYSTAF) 以及热重分析法分析合成的聚乙烯 (PE) 的热和微观结构特性。结晶动力学由 Ozawa 和组合 Ozawa 和 Avrami 模型研究。发现来自催化剂载体的 G/LDH 的存在使 PE 结晶成核并将结晶开始温度转移到更高的值。然而，由于生长冲击，纳米材料的存在减慢了整体结晶速率。此外，G/LDH负载型催化剂合成的PE比非负载型锆茂催化剂合成的PE具有更高的热稳定性。积分等转化方法用于评估热降解和结晶动力学的活化能。通过应用积分主图技术验证了退化机制。纯聚乙烯的降解机制类似于二阶和三阶相边界控制机制，即 (R2, R3)，