Macmmol. Rapid Commun. 18,163-167 zyxwv (1997) zyxwv 163 zy Synthesis of polymeric organic-inorganic hybrid materials. Partially deacetylated chitin-silica hybrid Jaime Retuert*, Alicia Nuiiez, Francisco Martinez Departamento de Quimica, Facultad de Ciencias Fisicas y Matemhticas, Universidad de Chile, Casilla 2777, Santiago 1, Chile Mehrdad Yazdani-Pedram Departamento de Quimica Orginica, Facultad de Ciencias Quimicas y FarmacCuticas, Universidad de Chile, Casilla 233, Santiago 1, Chile (Received: February 12, 1996; revised manuscript of November 5, 1996) SUMMARY This work reports the synthesis of a novel polymeric organic-inorganic hybrid. The inorganic component is a silica network obtained by controlled hydrolysis of tetraethyl orthosilicate via sol-gel process and the organic counterpart is partially deacetylated chitin (CHI). The resulting polymer hybrids were homogeneous transparent film forming glassy materials being compatible through a wide composition range. Simultaneous ther- mal analysis of a CHI/silica 1 zyxwvuts : 1 mixture confirms the intermolecular complex formation between organic and inorganic polymers. Introduction Using the sol-gel method, it is possible to obtain novel organic-inorganic poly- meric hybrid materials by incorporating organic molecules or polymers at molecular level into an inorganic oxide matrix, such as silica. This can be done by hydrolyzing tetraethyl orthosilicate (TEOS) in the presence of a suitable organic polymer. Poly- mers containing amide groups such as poly(2-methyl-2-oxazoline)') or poly(viny1- pyrrolidone)') has been found to form molecular hybrids with silica gel through strong hydrogen bonding. One of the principal applications of these hybrid materials is to improve the mechanical properties of ceramic materials, to produce porous ceramic products with complicated shapes and in some cases with controlled poros- ity. In this work partially deacetylated chitin was used as organic polymer for obtain- ing silica-bhsed hybrid compounds. Partially deacetylated chitin is a biopolymer structurally similar to cellulose, but containing predominantly amino groups at C-2 position, being the remainder acetamido moieties. This functionality of this biopoly- mer can be used as hydrogen-bond forming group with silica. Experimental part A solution containing linear polysiloxanes was used as silica source. This was obtained by partial hydrolysis of tetraethyl orthosilicate (TEOS) in ethanol as solvent and HC1 as catalyst with molar ratio of H,O/TEOS/HCl= 2.1/1/0.01. zyxw 0 1997, Hiithig & Wepf Verlag, Zug CCC 1022-1336/97/$02.50