ISSN:
0959-8103
Schlagwort(e):
phosphorus pentoxide/methanesulphonic acid
;
polynaphthimidazoles
;
2,6-naphthalene dicarboxylic acid
;
dimethyl 2,6-naphthalene dicarboxylate
;
thermal stability
;
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Phosphorus pentoxide/methanesulphonic acid (PPMA) was used as both solvent and condensing agent for the preparation of polynaphthimidazoles (PNIs) through direct polycondensation. The reactions of 2,6-naphthalene dicarboxylic acid and dimethyl 2,6-naphthalene dicarboxylate with tetramine monomer were studied with varying concentration of monomer, reaction temperature and reaction time in order to obtain high-molecular-weight polymer with high conversion. The properties, including solvent resistance, thermal properties and film casting, of synthesized polymers were also investigated. It was found that, using PPMA as both solvent and condensing agent, PNIs can be prepared successfully with high molecular weight by direct polycondensation of 2,6-naphthalene dicarboxylic acid or its derivatives with tetramine. The PNIs had inherent viscosities in the range 0.94-2.38 dl/g (in conc. H2SO4 at 30°C); however, polymers synthesized from isophthalic and terephthalic acids with tetramine had inherent viscosities of only 0.56dl/g and 0.48dl/g, respectively, with low conversions under similar reaction conditions. The glass transition temperature of the PNI 1 was 403°C. Thermal analysis indicates that these PNIs have excellent thermal stability, and the 10 wt% loss temperatures were recorded in the range 588-648°C in nitrogen gas, 533-580°C in air. The chemical stability and mechanical properties of films are also outstanding.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
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