Premium
Flame‐Retarding Materials, 3. Tailor‐Made Thermal Stability Epoxy Curing Agents Containing Difunctional Phosphoric Amide Groups
Author(s) -
Kuo PingLin,
Wang JaShung,
Chen PoChuan,
Chen LeoWang
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20010701)202:11<2175::aid-macp2175>3.0.co;2-u
Subject(s) - curing (chemistry) , thermal stability , polymer chemistry , epoxy , amide , chemistry , phosphoric acid , steric effects , polymer , materials science , organic chemistry
Four different phosphoric amides, p‐phenylphosphonic diamide (2‐NH 2 ‐PH), phenylphosphonicbis(N‐butylamide) (2‐BU‐PH), phenylphosphorobis(N‐butylamide) (2‐BU‐PHO) and phenylphosphonicbis(N‐benzylamide) (2‐BZ‐PH), have been successfully synthesized by low temperature condensation and characterized by FT‐IR, 1 H NMR and 31 P NMR. These phosphoric amides have been used to cure commercially available, unmodified, liquid epoxy resins. The curing behaviors and thermal stability of the cured films have been studied. Comparing the curing temperatures (initial ( T i ), peak ( T p ), and final ( T f )) and the degree of curing, it has been observed that using the curing agent containing bulky groups i. e., more sterically hindered structure, results in higher curing temperatures but a lower degree of curing. When comparing 2‐BU‐PHO, which contains a phenoxy group, with 2‐BU‐PH containing a phenyl group in the back bone, it is interesting to note that the phosphorus content in 2‐BU‐PHO is lower (4.81%) than that of 2‐BU‐PH (4.93%), but the residual weight percent at 800°C ( R 800 ) and also the temperature needed to obtain 10% weight loss ( T 0.1 ) is significantly higher for 2‐BU‐PHO cured epoxies. Also the results from 2‐BZ‐PH, which unlike 2‐BU‐PH contains aromatic benzyl groups, indicate that the aromaticity of the curing agent does not affect the thermal stability of the cured polymer film.