Open AccessPoly(butylene terephthalate‐ co ‐5‐ tert ‐butyl isophthalate) copolyesters: Synthesis, characterization, and properties
Author(s) -
Gómez Francisco,
Quintana Robert,
De Ilarduya Antxon Martñez,
Rudé Elisabet,
MuñozGuerra Sebastián
Publication year - 2004
Publication title -
journal of polymer science part a: polymer chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.768
H-Index - 152
eISSN - 1099-0518
pISSN - 0887-624X
DOI - 10.1002/pola.20477
Subject(s) - materials science , crystallinity , isophthalic acid , polymer chemistry , copolymer , polyester , condensation polymer , glass transition , dimethyl terephthalate , microstructure , enthalpy of fusion , polymer , melting point , composite material , terephthalic acid
A series of poly(butylene terephthalate) copolyesters containing 5‐ tert ‐butyl isophthalate units up to 50 mol %, as well as the homopolyester entirely made of these units, were prepared by polycondensation from a melt. The microstructure of the copolymers was determined by NMR to be random for the whole range of compositions. The effect exerted by the 5‐ tert ‐butyl isophthalate units on thermal, tensile, and gas transport properties was evaluated. Both the melting temperature ( T m ) and crystallinity were found to decrease steadily with copolymerization, whereas the glass‐transition temperature ( T g ) increased and the polyesters became more brittle. Permeability and solubility slightly increased with the content in substituted isophthalic units, whereas the diffusion coefficient remained practically constant. For the homopolyester poly(5‐ tert ‐butyl isophthalate), all these properties were found to deviate significantly from the general trend displayed by copolyesters, suggesting that a different structure in the solid state is likely adopted in this case. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 92–100, 2005