Synthesis And Hydrolysis Aggregation Behavior Of Hyperbranched Silatranes

Polysilsesquioxanes are a new type of hybrid network materials with organic and inorganic domains dispersed at the molecular level.This makes polysilsesquioxane materials have both the variability of organic materials and the rigidity of inorganic materials and widely used in many fields.Hyperbranched macromolecules have many excellent properties,such as low viscosity,large number of terminal functional groups and large intramolecular cavity.These properties enable hyperbranched polymers to be used in self-assembly,self-healing,surface modification,hybrid materials and other fields.At present,the precursors used for the synthesis of random polysilsesquioxane hybrid materials are mainly divided into two categories:small alkoxysilane monomers and bridged alkoxysilane monomers,and the synthesis methods are mainly acid-base catalyzed two step sol-gel method and emulsion polymerization method.There appear to be no reports regarding to the preparation of random polysilsesquioxane using hyperbranched monomers as the precursor.In this paper we will fill the research blank mentioned above and design a new method for P1-MPS to prepar polysilsesquioxanes.The morphological control and performance exploration of the prepared hyperbranched polysilsesquioxane materials are performed.In the present work,mercaptopropylmethyldimethoxysilane was used to prepare the organosilicon hyperbranched polymer with many double bonds on the end of the branches(P1)through Grignard reaction and thiol-ene "click" reaction.Furthermore,the newly made mercaptopropylsilatrane(MPS)was grafted onto P1 by one step thiol-ene "click" reaction to synthesis hyperbranched silatrane(P1-MPS)for the first time.The products and intermediates were confirmed by FT-IR and NMR and the thermal properties of them were checked by TGA.The results showed that the macromolecule P1-MPS was synthesized successfully and the thermal stability of P1-MPS is better than that of P1 and MPS.The macromolecule P1-MPS was used as a precursor to prepare polysilsesquioxanes(HPS)microspheres through a one step sol-gel method for the first time.The size and morphology of HPS microspheres were observed by scanning electron microscopy and transmission electron microscopy and the results showed that we can control the diameter of the microspheres or even turn them into hollow spheres only by changing the composition and Ph of the solution.The structure and thermal properties of HPS microspheres were analyzed by FT-IR and TGA,the TGA data showed that the microspheres had excellent thermal properties.Finally,the mechanism model of P1-MPS converted to HPS microspheres in acidic aqueous solution was designed.Some HPS materials with different morphologies were prepared by changing the composition of the solution.For example,HPS macroporous material was synthesized by adding pore forming agent to P1-MPS sol,HPS thin films were formed on the surface of aluminum on the sol stage by changing the polarity of the solvent and its ratio with water.The HPS macroporous materials and the prepared films were characterized by SEM and TGA.The results showed that the HPS macroporous material was a three-dimensional macroporous material with a uniform pore wall and regular pore distribution,and its thermal stability is excellent;the HPS thin films can be very smooth film and star-like thin film which can be applied to metal anticorrosion and material surface modification fields.In conclusion,a novel hyperbranched silatrane was synthesized and used to prepare polysilsesquioxanes for the first time.The HPS materials showed different morphologies and good properties.