United States  Patent  r19J  King, III et al.  [1 lJ  Patent Number:  4,675,424  [45]  Date of Patent:  Jun.  23, 1987  [54]  METHOD FOR  MAKING  POLYSII:.AZANES  [75]  Inventors:  Roswell E. King,  III,  Pleasantville;  Bernard Kanner,  West Nyack;  Steven  P. Hopper,  Carmel;  Curtis L.  Schilling, Jr.,  Croton-on-Hudson,  all  ofN.Y.  [73]  Assignee:  Union Carbide Corporation,  Danbury, Conn.  [21]  Appl. No.:  841,545  [22]  Filed:  Mar. 19, 1986  [52]  U.S. CI.  ....................................  556/412;  556/410;  501/97; 501/154;  528/28; 528/38;  423/344  [51]  Int.  Cl. 4  ..............................................  C07F 7/10  [58]  Field of Search  ..................  556/410, 412; 501/97,  501/154; 423/344;  528/28, 38  [56]  References Cited  U.S. PATENT  DOCUMENTS  4,404,153  9/1983 Gaul  ................................  556/410 X  4,482,669 11/1984  Seyforth et  al. ................  556/412  X  4,482,689 11/1984  Haluska ..........................  556/412 X  4,540,803  9/1985  Cannady .............................  556/412  Primary  Examiner-Paul  F.  Shaver  Attorney, Agent,  or Firm-P.  W. Luezzi  [57]  ABSTRACT  A method of preparing  silazane polymers,  with 3 or  more repeating units,  of the general formula  and a (CH3)2NH  byproduct group  where  R  is hydro› gen, an alkyl group’  having 1-6 carbon  atoms or an aryl  group having 6-12  carbon atoms, a=0,  or  I,  b=2-4,  C=0-2, d=0 or  I,  e=0-2, f=0-2,  g=  1-3  and a+c› +e+f+g=4  for the polymer units;  and R’ is hydrogen  or methyl, whereby  the silazane polymer  is  substantially  free of halide impurities,  and wherein this  method com› prises:  transaminating  an  aminosilane  of the general formula  (R)a((CH3)2N)1,HcS;  where  R  is defined as above  and  a+b+c=4 with  an amine of the  general formula  (CHJ)dNHJ-dWhereby  dis defined as above  and the  amine has a molecular  weight lower than  45 all in the  presence of an acid  catalyst or the ammonium  salt of  the acid and thereafter  condensing  to form the poly› mer.  37 Claims, No Drawings 