Rheological,thermal and crystallisation properties of ethylene,propylene and a-olefin copolymers.I Rheological properties

摘要

A series of random ethylene,propylene/1-butene,1-pentene,1-hexene,1-heptene,1-octene copolymers,ethylene and propylene homopolymers were prepared and investigated.The rheological properties (steady state and dynamic shear viscosity,creep compliance and plateau modulus),of copolymer samples with different co-unit content and molecular masses were determined and compared with the properties of homopolymers.The effects of the length of co-unit and the comonomer content were investigated.The copolymers exhibited similar rheological properties to the homopolymer but they have a lower shear viscosity,normal viscosity,higher steady state creep compliance and smaller plateau modulus values.The effect of comonomer content was evaluated on the bases of free volume theory.