Molar Mass and Branching Distributions

Metallocene catalysts provide PE with control of molar mass and a narrower molar mass distribution than other catalysts. These PE will have precise control of 

Extrusion All types Extrusion is the main process for compounding with additives, fillers, pigments, blended polymers, and then forming pellets for subsequent processing. Eurther processing may form various profiles such as pipes, beading, wire, and cable coating 

Cast-film extrusion LLDPE, HDPE Eilm is extmded through a slit-die then passed through chilled rollers to crystallize and smooth the surface orientation by cold drawing 

Laminate-film extrusion LLDPE, LDPE PE can be extmded onto other substrates, paper, and paperboard mainly though other polymer films and metal foils are used 

Coextmsion VLDPE-mPE Two or more polymer films are extmded together for combination properties not available by blending strength and heat-seal layers 

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Amer and van Reenen [39] fractionated isotactic polypropylenes by TREE to get fractions with different molar masses but similar tacticities. The DSC results of the fractions indicated that the crystallization behaviour is strongly affected by the configuration (tacticity) and the molar mass of the PP. Soares et al. [40] proposed a new approach for identifying the number of active catalyst sites and the polymer chain microstructural parameters produced at each active site for ethylene/l-olefin copolymers synthesized with multiple-site catalysts. This method is based on the simultaneous deconvolution of bivariate MMD/CCD, which can be obtained by cross-fractionation techniques like SEC/TREE or TREE/SEC. The proposed approach was validated successfully with model ethylene/1-butene and ethylene/ 1-octene copolymers. Alamo and co-workers [41] studied the effects of molar mass and branching distribution on mechanical properties of ethylene/1-hexene copolymer film grade resins produced by a metallocene catalyst Molar mass fractions were obtained by solvent/non-solvent techniques while P-TREE was used for fractionation according to the 1-hexene content. 

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