Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1995-01-20
1997-06-10
Acquah, Samuel A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
528125, 528126, 528128, 528171, 528172, 528174, 528210, 528211, 528215, 528220, 528226, 528228, 528373, 528391, 528422, 528423, 526935, C08G 7318, C08G 7308
Patent
active
056376707
ABSTRACT:
Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.
REFERENCES:
patent: 5149755 (1992-09-01), Perry
patent: 5182356 (1993-01-01), Connell et al.
patent: 5270432 (1993-12-01), Hergenrother et al.
patent: 5317078 (1994-05-01), Connell et al.
Connell John W.
Hergenrother Paul M.
Smith, Jr. Joseph G.
Acquah Samuel A.
Hampton Hightower P.
Helfrich George F.
The United States of America as represented by the Administrator
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