High temperature resistant silane/zirconium-oxocluster hybrid copolymers containing "free" thiol/ene functionalities in the polymer matrix

Inorganic-organic hybrid copolymers are promising materials where the size of the inorganic/organic domains, the phase continuity and the interface between the domains play an important role in their behavior. Two types of hybrid copolymers composed of 3-butynoate-substituted zirconium-oxoclusters covalently bonded to a (3-mercaptopropyl)trimethoxysilane or a vinyltrimethoxysilane matrix are investigated in bulk. Their properties are directly correlated with the degree of condensation of the silanes and the alkyne-3-mercaptopropyl or alkyne-vinyl interface. Both copolymers show storage moduli and glass-transition temperatures (T gG″) above 130 MPa and 230°C. However, the more impressive results are achieved with the (3-mercaptopropyl)trimethoxysilane copolymer where a T gG″ of about 300°C holds over six dynamical mechanical spectroscopy analyses. In addition to their excellent thermo-mechanical proprieties, the copolymers show unreacted 3-mercaptopropyl or vinyl groups which could be employed either in direct usage of the materials or for post-functional modifications.