A newly synthetic method has been developed for the preparation of block copoly(urethaneimide) (PUI). The copolymer was yielded from the direct reaction of the prepolyurethane terminated with isocyanate and the prepolyimide terminated with anhydride. The latter is prepared by reacting an excess amou
Synthesis and characterization of copoly(arylene sulfide)s
β Scribed by Lee Soon Park; Tae Hyung Lee; Soo Chang Lee
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 187 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0887-624X
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β¦ Synopsis
Copolymerizations of p-dichlorobenzene (DCB)/4-bromophenyl ether (BPE), DCB/4,4Π-dibromobiphenyl (DBB), and DBB/BPE pairs with sodium sulfide under high temperature (270 -290Β°C) utilizing N-methyl-2-pyrrolidinone (NMP) as solvent were carried out to give C(DCB/BPE), C(DCB/DBB), and C(DBB/BPE) copolymers, respectively. The reactivity of dihaloaromatic monomers toward thiolate anion in the polycondensation reaction followed the order DBB ΟΎ DCB ΟΎ BPE. The reactivity gap between DBB and DCB toward thiolate anion seemed to be smaller than that between BPE and DCB, resulting in both high yield and high molecular weight in the C(DCB/DBB) copolymers compared to C(DCB/BPE) copolymers. The copolymerization of DBB/BPE pair with sodium sulfide, which has larger reactivity gap than the DCB/ DBB or DCB/BPE pair, gave mixtures of PBS and PPSE homopolymers especially in the range of 50 -80 mol % BPE in the feed. The C(DCB/DBB) and C(DCB/BPE) copolymers, however, exhibited random copolymer character in all comonomer ratios in the feed as evidenced by copolymer composition and DSC data.
π SIMILAR VOLUMES
Novel liquid crystalline copoly(ester imide)s were synthesized via polyesterification of triethyleneglycol bis(4-carboxyphenyl) ether ( 1e), diacetoxybiphenyl, and diacids with imide moieties. The effects of composition on the changes of T g , T m , and T i were examined by global TSC and DSC. Therm
equipped with a 150 lines mm Β±1 grating and registered by an optical multichannel analyzer (OMA, Hamamatsu Photonics, PMA50).
Starting from some new 2,5-disubstituted-1,3,4-oxadiazole difluorides, synthesized by cyclocondensation of dihydrazides with 4-fluorobenzoic acid, novel poly(arylene ether)s were prepared by halo displacement polymerizations with bisphenol A in the presence of potassium carbonate. Model reactions de