Improved adhesion of polyethylene by copolymerisation of ethylene with polar monomers

The inertness of polyethylene restricts its compatibility with other materi als, Thus, the adhesion between polyethylene and various substrates usually requires surface pretreatments on the polyolefin in order to obtain satisf actory results. One different approach is the production of ethylene copoly mers with small amounts of polar comonomers that can act as adhesion promot ers. Using metallocene based catalysts, ethylene copolymers with 10-undecen oic acid (UA) and with 5,7-dimethylocta-1,6-diene (5,7DMO) were synthesised . The adhesion strengths of the copolymers in direct tension were measured. The obtained results show that UA/ethylene and 5,7DMO/ethylene copolymers exhibit higher adhesion strengths with increasing comonomer contents, UA/et hylene copolymers are more effective in improving adhesion properties than 5,7DMO/ethylene copolymers. This difference is easily understandable on the basis of the polarities of both comonomers. (C) 2001 Elsevier Science Ltd. All rights reserved.