Preparation and characterization of polyethylene with low entanglement and ultra-high relative molecular mass
In order to solve the problems of high entanglement and difficult processing of ultra-high relative molecular mass polyethylene(UHMWPE)prepared at the catalysis of traditional Ziegler Natta catalyst(Z-N catalyst),low entanglement UHMWPE was synthesized from slurry polymerization using magnesium dichloride supported Z-N catalyst cat1(or cat2),which was prepared from chemical reaction of MgCl2,TiCl4,isooctanol,tetraethyl orthosilicate(or dihexyl phthalate),as main catalysts and triethylaluminum as co catalyst.The particle size distribution and metal element mass fraction of cat1 and cat2 were analyzed.And the influence of polymerization temperature and time on the catalytic activity of cat1 and cat2 as well as the viscosity-average relative molecular mass(Mv)of UHMWPE were investigated,with the entanglement degree of UHMWPE characterized by rheological analysis and DSC thermodynamic annealing.The results showed that the cat1 and cat2 obtained were consistent with the design.Under the polymerization reaction temperature of 65 and 70℃,and reaction time of 5 h,the catalytic activity of cat1 and cat2 reached 27700 and 37700 g PE/g cat,respectively.The Mv of prepared UHMWPE was 6.01×106 and 5.03×106,and the initial storage modulus was 0.21 and 0.13 MPa,respectively.The entanglement degree was lower than that of commercial UHMWPE.
NETL
NSTL
万方数据
