POLYMERIZATION OF ETHYLENE WITH BIS[N-(3-TERT-BUTYLSALICYLIDENE)CYCLOHEPTYLAMINE] TITANIUM DICHLORO-SUPPORTED ON SILICA

Abstract

One of the most popular catalysts for ethylene polymerization is metallocene catalyst that is used with methylaluminoxane as cocatalyst because it makes high activity. The metallocene catalysts in a homogeneous system presents very high activity, but major disadvantages of this system are fouling in a reactor and lack of ability to control polymer morphology. Silica is extensively used for heterogeneous system in order to overcome these drawbacks. In the present study, various silica supports are used for supported metallocence catalyst. This research is aimed to study the effect of various amounts of methylaluminoxane with SiO2-LP, SiO2-SP, SiO2-MP, SiO2-VSP and SSP supports for ethylene polymerization via in situ, and to study the effect of SiCl4-modified SiO2-MP support compared with unmodified SiO2-MP support. From the experiment, it was found that the SSP support expressed the highest activity at low methylaluminoxane and the SiO2-LP support showed the highest activity at high methylaluminoxane. The small particles of silica exhibit good activity and big particles show poor reaction on silica surface where high homopolymerization occurred. The polyethylene obtained from modified SiO2-MP support was observed that the crystallinity is higher than the polyethylene obtained from unmodified SiO2-MP support and improved catalytic activity with decreased methylaluminoxane used.