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Particle size effects on silyl-chromate/VOx/silica bimetallic catalyst for UHMWPE/HDPE in-reactor blends
Journal of Applied Polymer Science ( IF 2.7 ) Pub Date : 2024-06-10 , DOI: 10.1002/app.55841 Yu Du 1, 2 , Hang Tao 1, 2 , Yang Yang 1, 2 , Changzhi Su 3 , Junrong Wang 3 , Yongnian Wang 3 , Boping Liu 1, 2 , Yulong Jin 1
Journal of Applied Polymer Science ( IF 2.7 ) Pub Date : 2024-06-10 , DOI: 10.1002/app.55841 Yu Du 1, 2 , Hang Tao 1, 2 , Yang Yang 1, 2 , Changzhi Su 3 , Junrong Wang 3 , Yongnian Wang 3 , Boping Liu 1, 2 , Yulong Jin 1
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In this work, four kinds of silica with similar textural properties but different particle size (PS) from 6 to 60 μm were selected as support to prepare silyl-chromate/VOx/silica bimetallic catalysts for ethylene polymerization, thus making it possible to conduct convincing investigation on the effects of catalyst PS over catalytic behaviors and polymer properties. It is found, owing to mass- and heat-transfer limitations, the catalysts with smaller PS showed higher initial activity, while the deactivation in the later stage was more remarkable. Meanwhile, catalysts with smaller PS synthesized bimodal ultrahigh molecular weight polyethylene/high-density polyethylene in-reactor blends (UHMWPE/HDPE IRBs) with higher molecular weight (MW) and narrower molecular weight distribution (MWD). Four PE sample couples with MW increasing from 5 × 105 to 10 × 105 g mol−1 and PS from 40 to 460 μm were selected for tensile and rheological tests. For each couple with similar MW and MWD, the sample with smaller PS always had larger tensile strength and breaking elongation. The cryogenically fractured surface of the samples made by smaller PE particles showed fewer delamination defects and unfused small particles. The rheological results indicate that higher homogeneity was achieved for the sample with smaller PS, which was reflected by the unexpected higher viscosity and storage modulus.
中文翻译：
粒径对用于 UHMWPE/HDPE 反应器内共混物的硅基铬酸酯/VOx/二氧化硅双金属催化剂的影响
本工作选择了四种结构性质相似但粒径（PS）不同（6~60 μm）的二氧化硅作为载体，制备了铬酸硅烷/VO x /二氧化硅双金属乙烯聚合催化剂，从而可以对催化剂 PS 对催化行为和聚合物性能的影响进行令人信服的研究。研究发现，由于传质和传热的限制，PS较小的催化剂表现出较高的初始活性，而后期的失活则更为显着。同时，具有较小PS的催化剂合成了具有较高分子量（MW）和较窄分子量分布（MWD）的双峰超高分子量聚乙烯/高密度聚乙烯反应器内共混物（UHMWPE/HDPE IRB）。选择分子量从 5 × 10 5 增加到 10 × 10 5 g mol −1 和 PS 从 40 增加到 460 μm 的四个 PE 样品对进行拉伸和拉伸测试。流变测试。对于具有相似 MW 和 MWD 的每对样品，具有较小 PS 的样品总是具有较大的拉伸强度和断裂伸长率。由较小的 PE 颗粒制成的样品的低温断裂表面显示出较少的分层缺陷和未熔合的小颗粒。流变结果表明，PS 较小的样品实现了较高的均匀性，这反映在意想不到的较高粘度和储能模量上。
更新日期：2024-06-10
中文翻译：
粒径对用于 UHMWPE/HDPE 反应器内共混物的硅基铬酸酯/VOx/二氧化硅双金属催化剂的影响
本工作选择了四种结构性质相似但粒径（PS）不同（6~60 μm）的二氧化硅作为载体，制备了铬酸硅烷/VO x /二氧化硅双金属乙烯聚合催化剂，从而可以对催化剂 PS 对催化行为和聚合物性能的影响进行令人信服的研究。研究发现，由于传质和传热的限制，PS较小的催化剂表现出较高的初始活性，而后期的失活则更为显着。同时，具有较小PS的催化剂合成了具有较高分子量（MW）和较窄分子量分布（MWD）的双峰超高分子量聚乙烯/高密度聚乙烯反应器内共混物（UHMWPE/HDPE IRB）。选择分子量从 5 × 10 5 增加到 10 × 10 5 g mol −1 和 PS 从 40 增加到 460 μm 的四个 PE 样品对进行拉伸和拉伸测试。流变测试。对于具有相似 MW 和 MWD 的每对样品，具有较小 PS 的样品总是具有较大的拉伸强度和断裂伸长率。由较小的 PE 颗粒制成的样品的低温断裂表面显示出较少的分层缺陷和未熔合的小颗粒。流变结果表明，PS 较小的样品实现了较高的均匀性，这反映在意想不到的较高粘度和储能模量上。
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