United  States  Patent  (!9J  D’Alelio  (11]  B  4,118,377  (45]  Oct.  3,  1978  (54]  POLY\IERIZING  BIS-MALEIMIDES  (75]  Inventor:  Gaetano  F.  D’Alelio,  South  Bend,  Ind.  (73]  Assignee:  University  of  Notre  Dame  du  Lac,  Notre  Dame,  Ind.  [21]  Appl.  No.:  497,490  (22]  Filed:  Aug.  14, 1974  [44]  Published  under  second  Trial  Voluntary  Protest  Program  on  Mar.  23,  1976  as  document  No.  B  497,490  (63]  Continuation-in-part  of Ser.  No.  363,799,  May  25,  1973.  Pat.  No.  3,890.272.  (51]  Int.  Cl.2  ..............................................  C08G  73/12  (52]  U.S.  Cl . ....................................  526/236;  526/258;  526/270;  526/89;  526/234;  526/256;  526/262  (58]  Field  of  Search  ..................  526/258;  260/78  UA,  260/47  UA,  47 CZ,  47  CP,  65,  326  R, 326  S,  326  NS,  329  AM,  333,  79.7,  88.5  A, 88.3  A  [56]  References  Cited  Related  U.S.  Application  Data  U.S.  PATENT  DOCUMENTS  OTHER  PUBLICATIONS  [57]  ABSTRACT  15  Claims,  No  Drawings  3,576,691  3,671,490  3,708,459  3,748,310  3,748,311  4/1971  6/1972  1/1973  7/1973  7/1973  Meyers  .................................  156/309  Bargain  ..................................  260/47  Lubowitz  ...............................  260/65  Burns  et al.  .........................  260/78.4  Burns  et al.  .........................  260/78.4  3,748.312  7/1973  Burns  et al.  .......................  260/78  A  3.803.081  4/1974  Lubowitz  ..........................  260/37  N  Lubowitz,  New  Polyimides  Polymers  and  Composites  Conference  on  High  Temperature  Polymers,  Rein› forcements  and  Composites,  University  of  Utah,  Jun.  8  to 13,  1970.  Primary  Examiner-Lester  L.  Lee  Attorney,  Agent,  or  Firm-Michael,  Best  &  Friedrich  Processes  for  increasing  the  molecular  weight  of bis› maleimides  are  provided.  The  bis-maleimides  are  re› acted  with  certain  cyclic  dienes  to  form  reversible  ad› ducts.  These  adducts,  upon  elimination  of the  cyclic  diene,  yield  an  extension  of the  bis-maleimides  to  higher  molecular  weight  polymers,  ultimately  to  thermally  stable,  infusible  polymers.  The  process  can  be  inter› rupted  to  yield  tractable  polymers  which  are  also  con› vertible  to  cross-linked,  infusible  products.  Modifica› tions  of the  process  include  preparing  the  adducts  in  the  presence  of  aprotic  solvents  as  well  as  Bronsted  acid  salt  catalysts,  and  the  isolation  of  intermediate  solid  prod› ucts. 