Preparation And Properties Of Polyhedral Oligomeric Silsesquioxane / Natural Polymer Organic-inorganic Hybrid Materials

Polyhedral oligomeric silsesquioxane(POSS) is a special family of organic-inorganic hybrid materials at molecular level. The structure of these materials can be designed easily according to the requirements for its special cage structure and surface organic substituent. In addition, with its good biocompatibility, POSS has attracted considerable interest in the field of materials science in recent years. In this paper, cage-like octakis(carboxyethyl-carbonylaminopropyl)silsesquioxane(OCPS) and cage-like octa(γ-chloroaminopropyl)silsesquioxane(OCAPS) were introduced into the natural polymer such as chitosan(CS)、hydroxypropyl cellulose(HPC) and sodium alginate(SA) via hydrogen bonding interaction and electrostatic interaction, preparing three POSS/natural polymer composite systems, such as OCPS/CS、OCAPS/HPC and OCAPS/SA, and studied the structure and properties of these three systems. The contents and results of this paper are listed as follows:1. OCPS with eight carboxyl groups at the end was synthesized in the presence of acid binding agent-triethylamine by the amidation reaction between succinic anhydride and OCAPS. Through FT-IR、NMR、SEM、EDS、XRD and TG showed that its structure were cage-like with good thermal stability.2. OCPS/CS composite film containing 1%~5% OCPS were prepared via solution blending method. The results showed that the composite film had excellent transmission properties(transmittance was 85%~87%). According to the results of FT-IR and XRD, OCPS and CS produced hydrogen bond interaction and inhibited the crystallization of CS. The results of SEM and EDS showed that OCPS had a good dispersion in CS matrix. As DMA and tension test indicated that the introduced of OCPS enhanced the mechanical properties of membrane materials. The degradation experiment of the composite film found that the degradation rate and degradability increased along with the increase of the content of OCPS because of the introduction of OCPS that weakened interactions between CS and inhibited the crystallization of CS that accelerated the fracture of the glycosidic bond in CS. 3. OCAPS/HPC organic-inorganic hybrids with water solubility containing 20%~80% OCAPS were prepared via solution blending method. The results showed that the composite film has excellent light transmission properties whose transmittance is up to 88%; The IR and XRD showed that OCAPS and HPC produced hydrogen bond interaction and inhibited the crystallization of HPC. The results of SEM and EDS showed that OCAPS had a good dispersion in HPC matrix; compared with pure HPC, tensile strength and elongation at break of the OCAPS/HPC hybrid films increased to some extent along with the increase of the content of OCAPS, among which the tensile strength and elongation at break of 60%OCAPS/HPC、80%OCAPS/HPC increased nearly 1.5 times; The rheology research indicated that the increase of the content of OCAPS produced physical cross-linking showed by the increace in solution viscosity, storage modulus and loss modulus between molecular chains of HPC. In addition, the OCAPS brought up weakened the hydrophilia of of HPC, for which the corresponding gel point temperature decreased from 60?C to 55?C.4. OCAPS/SA and OCAPS/SA/CS complex microcapsules were prepared via electrostatic droplet preparation method. The results for OCAPS/SA suggested that OCAPS was able to form binary complex microcapsules POSS/SA as the coagulating bath in the place of traditional Ca Cl2 solution; when the mass ratio of OCAPS to SA was 1:10, its deforming effect was relatively good and the particle size was about 1.0mm. Besides, though densified wavy folds were at the outside surface, its internal structure was loose hollow appearance. OCAPS/SA/CS ternary complex microcapsules were prepared via one- and two-step methods; when the mass ratio of One-step OCAPS:SA:CS was 10:1:3, the size of complex microcapsule was about 0.6mm, the hollow interior, the densified wavy folds at the outside surface and denser polymer electrolyte membrane formed by complexation; Two-step OCAPS/SA/CS was on the base of OCAPS/SA into CS solution with mass fraction of 0.6%, the size was about 0.8mm, its interior was loose with some empty hole well the outer surface was pore structure, and the aperture was also increasingly from the outside to the inside. The research on the drug loading and release properties via bovine serum albumin as the model drug suggested that the drug loading ratio of OCAPS/SA、One-step OCAPS/SA/CS and Two-step OCAPS/SA/CS were 10.34%、10.63%、10.95%,the embedding rate were 73.84%、60.82%、75.57%,and the cumulative amount of drug release of the three reached about 90%.