摘要
茂金属聚乙烯性能优越,但它的相对分子质量分布通常较窄会造成后续成型加工困难等一系列问题,限制其大规模应用。以甲基铝氧烷(MAO)改性硅胶为载体,茂金属化合物为活性组分得到负载型茂金属催化剂,并在淤浆体系中催化乙烯聚合得到茂金属聚乙烯。系统探究了制备条件对负载量的影响、聚合条件对活性的影响,同时利用扫描电子显微镜、电感耦合等离子质谱仪、激光粒度仪、高温凝胶渗透色谱仪等对催化剂和聚合产物分析表征。实验结果表明,负载型催化剂活性释放平缓,将其用于乙烯/1-己烯共聚时活性可达1576.5 g·g^(-1)。加入1-己烯后产物的加工性能得到改善,聚合物的熔点、密度、堆积密度和结晶度变低,相对分子质量分布从2.6拓宽至3.2,熔体流动速率从0.0882增加至0.36 g·min^(-1)。
Metallocene polyethylene has superior properties,but its molecular weight distribution is usually narrow,which will bring a series of problems such as difficulties in subsequent molding and processing,and limit its large-scale application.In this study,a supported metallocene catalyst was obtained by using methylaluminoxane(MAO)-modified silica gel as a carrier and metallocene compound as the active component,and metallocene polyethylene was obtained by catalyzing ethylene polymerization in a slurry system.The effects of preparation conditions on loading and polymerization conditions on activity were systematically investigated,and the catalysts and polymerization products were analyzed and characterized by scanning electron microscopy,inductively coupled plasma mass spectrometry,laser particle size analyzer,and high-temperature gel permeation chromatography.The experimental results showed that the activity release of the supported catalyst was moderate,and the activity of the supported catalyst could reach 1576.5 g·g^(-1).After the addition of 1-hexene,the processing properties of the product were improved,the melting point,density,bulk density and crystallinity of the polymer became lower,the molecular weight distribution was broadened from 2.6 to 3.2,and the melt flow rate increased from 0.0882 to 0.36 g·min^(-1).
作者
谷勇耀
王立娟
姜涛
李健
GU Yongyao;WANG Lijuan;JIANG Tao;LI Jian(College of Chemical Engineering and Materials Science,Tianjin University of Science&Technology,Tianjin 300457,China;Daqing Chemical Research Center,Petrochemical Research Institute,China National Petroleum Corporation,Heilongjiang,Daqing 163714,China)
出处
《化学工业与工程》
CSCD
北大核心
2024年第6期42-49,共8页
Chemical Industry and Engineering
基金
中国石油天然气集团公司关键核心项目(2022GJ17)
关键词
茂金属催化剂
硅胶
淤浆聚合
相对分子质量分布
metallocene catalysts
silica gel
slurry polymerization
molecular weight distribution
