Premium
Viscoelastic properties of random poly (butylene adipate/isophthalate) copolymers
Author(s) -
Righetti Maria Cristina,
Munari Andrea,
Pezzin Giovanni,
Ottani Stefano
Publication year - 1997
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19970228)63:9<1213::aid-app13>3.0.co;2-#
Subject(s) - adipate , copolymer , viscoelasticity , materials science , polymer science , polymer chemistry , polymer , composite material
The viscoelastic properties of random poly(butylene adipate/isophthalate) copolymers of various molecular weights and compositions were investigated by dynamic testing in the molten state. For all samples the storage and loss components of the dynamic shear modulus, G ′(ω) and G ′(ω), were measured at different temperatures. The zero‐shear viscosity, η 0 , for each composition was correlated to the weight‐average molecular weight, M w , by the equation: η 0 = KM a w and the exponent a was found to increase as the content of isophthalate units was increased. Also, increases in the activation energy for viscous flow were observed as the isophthalate unit content was increased. The dynamic viscoelastic behavior of the copolymers was studied in terms of the complex compliances; curve fitting results on data of J ′(ω) and J ′(ω) vs. ω showed that such curves can be accurately reproduced by the following equation: J * (ω) = J g + (J 0 e − J g )/[1 + (iωτ 2 ) β 2] + i/ωη 0 . It was concluded that, in the investigated frequency and temperature ranges, a single retardation phenomenon in the terminal zone provides a satisfactory description of the viscoelastic behavior of the copolymers. The values of the viscoelastic parameters were found to vary monotonically with composition, as expected in the case of statistical copolymers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1213–1221, 1997