title: Thermorheological and mechanical properties of copolymers of lactide, isosorbide, and different phthalic acids.
abstract: The thermal, rheological, and mechanical behavior of copolymers of lactide, isosorbide, and three different phthalic acids are studied in a wide range of compositions. A linear behavior in glass transition temperature (Tg) with respect to the mole fraction of isosorbide and phthalate content in the copolymers is observed. This behavior is in quantitative agreement with the well-known Di Marzio-Gibbs equation, which correlates the Tg with the mole fraction of flexible bonds in the monomers. The viscoelastic properties are found to obey the Williams-Landel-Ferry (WLF) behavior. This allows us to compare the zero-shear viscosity η0 of all copolymers with different molecular weights at a reference temperature, thus studying the influence of the different phthalic acids on the viscosity. Again, a linear mixing rule on the basis of mole fractions is established in logarithmic scale of viscosities.
authors.affiliation: Freiburg Materials Research Center (FMF) and Institute of Macromolecular Chemistry, Albert-Ludwigs-University, Stefan-Meier-Straße 21, D-79104, Freiburg, Germany.
authors.forename: Zucong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Hans Rytger
authors.initials: HR
authors.lastname: Kricheldorf
authors.forename: Christian
authors.initials: C
authors.lastname: Friedrich
mesh_terms: D000465:Algorithms; D004146:Dioxanes / Q000737:chemistry*; D004548:Elasticity; D005898:Glass / Q000737:chemistry; D007547:Isosorbide / Q000737:chemistry*; D008422:Materials Testing; D008970:Molecular Weight; D010795:Phthalic Acids / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012212:Rheology; D013696:Temperature; D013718:Tensile Strength; D044366:Transition Temperature; D014783:Viscosity
chemical_list: D004146:Dioxanes; D010795:Phthalic Acids; D011108:Polymers; C032279:phthalic acid; C091880:dilactide; D007547:Isosorbide
keywords: copolymers; glass transition temperature; rheology; viscosity