Premium
Synthesis of polyurethane–imide (PU–imide) copolymers with different dianhydrides and their properties
Author(s) -
Lin MingFung,
Shu YaoChi,
Tsen WenChin,
Chuang FuSheng
Publication year - 1999
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199906)48:6<433::aid-pi161>3.0.co;2-1
Subject(s) - imide , thermogravimetric analysis , differential scanning calorimetry , glass transition , copolymer , materials science , polyurethane , polymer chemistry , melting point , thermal stability , composite material , polymer , organic chemistry , chemistry , physics , thermodynamics
This study reports the synthesis of polyurethane–imide (PU–imide) copolymers using 4,4′‐diphenylmethane diisocyanate (MDI) polytetramethylene glycols (PTMGs) and different aromatic dianhydrides. Differential scanning calorimetry (DSC) results indicate that PU–imide copolymers had two phase structures containing four transition temperatures ( T gs , T ms , T gh and T mh ). However, only PU–imide copolymers were formed by soft PTMG(2000) segments possessing a T ms (melting point of soft segment). When different aromatic dianhydrides were introduced into the backbone chain of the polyurethane, although the T gs (glass transition temperature of the soft segment) of some of PU–imide copolymers did not change, the copolymers with long soft segments had low T gs values. The T gh (glass transition temperature of hard segment) values of PU–imide copolymers were higher than that of polyurethane (PU). In addition, the high hard segment content of PU–imide copolymer series also had an obvious T mh (melting point of hard segment). According to thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA), the PU–imide copolymers had at least two stages of degradation. Although the T di (initial temperature of degradation) depended on the hard segment content and the composition of hard segment, the different soft segment lengths did not obviously influence the T di . However, PU–imide copolymers with a longer soft segment had a higher thermal stability in the degradation temperature range of middle weight loss (about T d 5%–50%). However, beyond T d 50% (50% weight loss at temperature of degradation), the temperature of degradation of PU–imide copolymers increased with increasing hard segment content. Mechanical properties revealed that the modulus and tensile strength of PU–imide copolymers surpassed those of PU. Wide angle X‐ray diffraction patterns demonstrated that PU–imide copolymers are crystallizable. © 1999 Society of Chemical Industry