Preparation, Characterization, And Properties Of PVA/MCM-48 Inorganic-Organic Nanonetwork Particles

In the light of the Problems of the poor compatibility of inorganic and organic phases in the preparation of nanocomposites, a novel inorganic-organic nanonetwork particle structure has been put forward as a solution in this paper. With regard to its Ia3d symmetry, narrow pore size distribution, tunable pore character and nano-sized channels and walls, MCM-48 was chosen as the inorganic host. Polymers can be directed into its pore structure, and form inorganic-organic three dimensional nanonetwork particles. The preparation, characterization, and properties of the nanonetwork particles have been studied using the system with PVA as the organic phase and silylated MCM-48 as host.First, trimethylsilyl grafting was carried out with uncalcined MCM-48 and trimethylchlorosilane. The results suggest that CTAB (cetyl trimethyl ammonium bromide) can be extracted from the channels of MCM-48 and trimethylsilyl groups are anchored on the surface of MCM-48, retaining its Ia3d symmetry, long range ordered structure, narrow mesopore-size distribution, high surface area, and large mesopore volume.Second, inorganic-organic nononetwork particles have been prepared with silylated MCM-48 through post-polymerization composite path and a pre-polymerization composite path. The results suggest that post-polymerization composite path is preferable for the filling of PVA into the mesopores of MCM-48; With the increasing organic content in the nanonetwork particles, PVA is filled into the channel of silylated MCM-48 step by step, and a structure of the inorganic-organic nanonetwork particles is prepared when the silylated MCM-48/VA monomer ratio is 1.25 wt%; Trimethylsilyl grafting improves the affinity of PVA and silylated MCM-48, and facilitates the formation of inorganic-organic nanonetwork particle structures. The more complete the grafting reaction the more advantageous for the mutual interaction of inorganic host wall and organic phase in the channel. The particle size of the PVA/silylated MCM-48 nanonetwork particles is between 0.1 -0.2 urn.Finally, taking PVA/silylated MCM-48 as the filler and PVA as the organic matrix, nanonetwork materials with different nanonetwork particle content have been prepared. Studies on their mechanical properties suggest that the Shore hardness of the nanonetwork composite material increases with increasing nanonetwork particle content. The addition of inorganic-organic nanonetwork particles can improve the Fs, Ts, and Tsb properties of the PVA matrix at certain nanonetwork particle contents. The breaking extensibility of the nanonetwork composite material is weakened however with regard to the PVA matrix. The resultant nanonetwork materials are transparent, representing a nano-sized separation of inorganic phase in the organic matrix.