Cyclization in the reaction between diglycidylaniline and ... - Springer

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Reactions. Polymer Bulletin. 9 Springer-Verlag 1986. Cyclization in the Reaction Between Diglycidylaniline and Amine. L. Mat~jka*, M. Tkaczyk, S. Pokorny, and ...

Polymer Bulletin 15, 389-396 (1986)

Polymer Bulletin 9 Springer-Verlag 1986

Reactions Cyclization in the Reaction Between Diglycidylaniline and Amine L. Mat~jka*, M. Tkaczyk, S. Pokorny, and K. Du~ek Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, CS-162 06 Prague 6, Czechoslovakia Summary The r e a c t i o n of d i g l y c i d y l a n i l i n e (DGA) and N - m e t h y l a n i line (NMA) w a s i n v e s t i g a t e d by m e a n s of HPLC, and the p r o d u c t s w e r e i d e n t i f i e d by m a s s s p e c t r o m e t r y . A n u m b e r of c y c l i c prod u c t s is formed. An e i g h t - m e m b e r e d r i n g f o r m e d by the i n t r a m o l e c u l a r r e a c t i o n of the s e c o n d a r y a m i n o g r o u p and the e p o x y g r o u p in the D G A - a n i l i n e m o n o a d d u c t is the m a i n c y c l i c p r o d u c t . The m o n o a d d u c t D G A - N M A y i e l d s a s e v e n - m e m b e r e d ring by i n t e r n a l e t h e r i f i c a t i o n o n l y a f t e r the a m i n e has b e e n c o n s u m e d . Introduction C y c l i z a t i o n p l a y s an i m p o r t a n t r o l e in n e t w o r k f o r m a t i o n : it a f f e c t s r h e o l o g i c a l p r o p e r t i e s of the r e a c t i n g system, disp l a c e s the gel p o i n t t o w a r d s h i g h e r c o n v e r s i o n s and d e c r e a s e s the c r o s s l i n k i n g d e n s i t y of the network. In the case of d i e p o x i d e s b a s e d on d i g l y c i d y l e t h e r s of B i s p h e n o l A (DGEBA) c u r e d w i t h amines, the c y c l i z a t i o n is n e g l i g i b l e (I-3), as i n d i c a t e d by the i n d e p e n d e n c e of c r i t i c a l c o n v e r s i o n (critical m o l a r ratio) at g e l a t i o n of d i l u t i o n (1,3) and by the good a g r e e m e n t of p o s t - g e l a t i o n p a r a m e t e r s (sol f r a c t i o n , c o n c e n t r a t i o n of e l a s t i c a l l y a c t i v e chains, etc.) w i t h the a s s u m e d n e g l i g i b l e c y c l i z a t i o n (1,4-7). This is due to the fact that the f o r m a t i o n of the s m a l l e s t p o s s i b l e ring, e.g. by a r e a c t i o n of two e p o x i d e g r o u p s of D G E B A w i t h one p r i m a r y a m i n o group, is v e r y u n l i k e l y w i t h r e s p e c t to the n e c e s s a r y c o n f o r m a t i o n a l r e a r r a n g e m e n t . On the c o n t r a r y , w i t h n i t r o g e n - c o n t a i n i n g p o l y e p o x i d e s b a s e d on N , N - d i g l y c i d y l amines - N , N - d i g l y c i d y l a n i l i n e (DGA) and N,N,N',N'-tetra~lycidyl-4,4"-diaminodiphenylmethane (TGDDM) c y c l i z a t i o n b e c o m e s m u c h m o r e p r o b a b l e due to the s t e r i c c l o s e n e s s of g l y c i d y l groups. A p r o n o u n c e d c y c l i z a t i o n is i n d i c a t e d , e.g., by a s t r o n g d e p e n d e n c e of the c r i t i c a l m o l a r r a t i o at g e l a t i o n on the c o n c e n t r a t i o n of d i l u e n t o b s e r v e d for D G A and T G D D M (3). Also, the o c c u r r e n c e of a p r o d u c t c o n s i s t i n g of one m o l e c u l e of D G A and one m o l e c u l e of amine, but n o t c o n t a i n i n g the e p o x i d e group, d e t e c t e d in t h e r e a c t i o n m i x t u r e of D G A w i t h s e c o n d a r y a m i n e (8), s u g g e s t s an i n t r a m o l e c u l a r r e a c t i o n (morp h o l i n e s t r u c t u r e is a s s u m e d ) . The p r e s e n c e of m o r p h o l i n e r i n g s (II) is a l s o i n f e r r e d f r o m the p o s i t i o n of some s i g n a l s in 1 3 C - N M R (9). For the s y s t e m T G D D M - 4 , 4 - - d i a m i n o d i p h e n y l sulfone (DDS) the f o r m a t i o n of c y c l i c e t h e r s is d e d u c e d from the d i s p l a c e m e n t of the IR a b s o r p t i o n of the e t h e r g r o u p (10). * To whom

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M o r g a n (11,12) a s s u m e s t h a t in the p r o d u c t s of the r e a c t i o n T G D D M + D D S , up to 75% b o n d s f o r m e d are i n v o l v e d in cycles. On s u m m a r i z i n g the f i n d i n g s r e p o r t e d in the l i t e r a t u r e , one m a y e x p e c t f o r m a t i o n of two c y c l i c s t r u c t u r e s w i t h the s m a l l e s t ring, viz., I and II:

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