THE ADVANTAGES OF METALLOCENE - CATALYSED TECHNOLOGY FOR SILANE GRAFTING AND CROSS LINKING OF POLYETHYLENE [PEX]

# 2010 Vancouver

Silane method is a preferred technique of crosslinking polyethylene to modify its properties. Higher ESCR as well as thermal resistance should no longer be demonstrated. Conventional HDPE, LLDPE or LDPE are known to offer different sensitivity to level of silane, curing time and temperature; rate of crosslinking and gel content may differ as well. Many parameters of the base polymer molecular structure have to be taken into account when developing a PEXb compound like vinyl insaturation, vinylidene groups, tertiary carbons, (short and long chain) branching number and distribution, polydispersity index, molecular weight, antiThe literature shows that HDPE usually exhibits lower silane grafting efficiency vs LLDPE or LDPE less increase in zero shear viscosity longer time of crosslinking These observations are constraints for new applications although products offered today show a broad range of characteristics in terms of density (product stiffness) and Melt Index (processability). Base resins can be mapped the same way although the molecular structure may be altered by the reaction pathways with peroxide and silane. 2nd generation metallocene-catalysed HDPE or MDPE offer an alternative to conventional base resins for PEXb as their unique molecular structure will react a different way during the silane grafting and the crosslinking processes allowing to target never achieved before performance in terms of processing behaviour and mechanical properties. High Melt Index 2nd generation metallocene-catalysed HDPE or MDPE offer indeed a unique alternative to Ziegler-Natta equivalent resins thanks to their more favourable molecular structure.

Please note that the whole article content is available on PPCA website onlySource : 2010 Vancouver


Related papers

PE-RT for Industrial and Oil & Gas Applications: New Opportunities with New Standard

Author(s) : Daniel Libert, Pierre Belloir 2014 Chicago

PE-RT is now well established in the Hot & Cold market with various pipe designs and associated standards. For many years, PE-RT has found a good place in Under Floor Heating applications in many places around the world. The comprehensive testing performed on raw materials led to a better knowledge of high...

From double loop to double loop: PE100-RC, the perfect fit for geothermal probes

Author(s) : Libert Daniel 2012 Barcelona

Heating and/or air conditioning systems based on ground heat pumps are increasingly popular in European countries, their growth fuelled by both private and public investments in sustainable energy sources. These systems typically circulate water inside boreholes, effectively using the ground as a constant temperature...

Members of the Association

BOREALISBOROUGEINEOS O&PIRPCKorea Petrochemical IND. Co., LTDLyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
TOP