支化聚乙烯的合成及结构与性能  

Synthesis of Branched Polyethylene and Characterization of Their Structures and Properties

作　　者：张丹枫[1] 樊帅[1] 伏艳[1] 李森[1] 

机构地区：[1]华东理工大学材料科学与工程学院,上海市先进聚合物材料重点实验室,上海200237

出　　处：《高等学校化学学报》2013年第8期2005-2010,共6页Chemical Journal of Chinese Universities

基　　金：上海市重点学科和重点实验室项目(批准号:B502;08DZ2230500)资助

摘　　要：以[ArN C(An)—C(An)NAr]NiBr2[An=acenaphthyl,Ar=2,6-C6H3(iPr)2]为主催化剂,以改性甲基铝氧烷(MMAO)和常规的甲基铝氧烷(MAO)为助催化剂,研究了压力、温度和时间等条件对乙烯聚合制备支化聚乙烯的影响,采用高温核磁、高温凝胶渗透色谱(GPC)及差示扫描量热仪(DSC)等对所得的聚乙烯结构进行表征.研究发现,以MMAO为助催化剂时,催化活性比以MAO为助催化剂时高约1个数量级,达到107g/(mol Ni.h);所得聚乙烯的支化度为(45～64)/1000C,而以MAO为助催化剂时所得聚乙烯的支化度达(82～88)/1000C.对支化聚乙烯的力学性能进行了分析,并与低密度聚乙烯(LDPE)和二元乙丙橡胶(EPM)进行比较.结果表明,支化聚乙烯拉伸强度达27.90 MPa,比LDPE(14.40 MPa)和EPM(5.44 MPa)高,但支化聚乙烯的弹性模量仅为2.10 MPa,与EPM(2.11 MPa)相近;支化聚乙烯的断裂伸长率为774.6%,略高于LDPE的断裂伸长率(725.6%),比EPM的断裂伸长率(1770.1%)低.The branched polyethylene（br-PE） were synthesized by [ArNC（An）-C（An）NAr]NiBr2[An=acenaphthyl, Ar=2,6-C6H3（emPr）2] in the presence of the modified methylaluminoxane（MMAO） and methylaluminoxane（MAO）. The effects of experimental conditions in which ethylene pressure, temperature and time were varied on ethylene polymerization were investigated. The structures of the obtained polyethylene were characterized by high-temperature NMR, high-temperature GPC and DSC. It was found that the activities from MMAO were higher than that from MAO about 10 times, which reaches 10^7 g/（mol Ni·h）. The branches of polyethylene prepared from MMAO were about （45-64）/1000C, while that from MAO were about （82-88）/1000C. The mechanical properties of the br-PE were analyzed and compared with low density polyethylene（LDPE） and ethylene propylene methylene（EPM）. It was shown that br-PE exhibits high tensile strength（27.90 MPa）, which is much higher than LDPE（14.40 MPa） and EPM（5.44 MPa）. The elastic modulus of br-PE is 2.10 MPa, almost same as EPM（2.11 MPa）. The elongation at break of br-PE is 774.6%, little higher than that of LDPE（725.6%）, but lower than that of EPM（1770.1%）.）

关 键 词：后过渡金属催化剂 α-二亚胺合镍配合物 乙烯聚合 支化聚乙烯 

分 类 号：O631[理学—高分子化学]