Polymer, Vol.46, No.25, 11755-11767, 2005
A new turbidimetric approach to measuring polyethylene short chain branching distributions
A new instrument to analyze the short chain branching distribution of polyethylenes has been described. Turbidity analysis of ethylene/alpha-olefin copolymers by turbidity fractionation analysis can provide short chain branching distribution information that is similar to CRYSTAF and TREF. In these experiments, the turbidity of a polymer solution is monitored while changing its temperature at a controlled rate. The turbidimetric response is to the precipitation or dissolution of the crystallized polymer at a given temperature. With an approach similar to CRYSTAF, the differential of the turbidity profile provides Valuable SCBD information for polymers with broad and narrow compositions such as Ziegler-Natta LLDPE and homogeneous polymers catalyzed by single-site catalysts. (c) 2005 Elsevier Ltd. All rights reserved.