A one step synthetic route of polymeric compositions of a polyolefin and inorganic network consisting of components selected from Si, Zr, Ti, is disclosed. The synthetic route combines parallel reactions of free radical polymerization to form polymer, and hydrolysis of either Si, or Zr, or Ti or both of them precursors. The network consisting of Si, Zr, Ti, is chemically bonded to or within the polymer matrix. The inorganic or organic molecules can then be polymerized under conditions effective to cause the polymerized inorganic or organic molecules into macromolecular networks. The compositions of the polymeric composites can be easily controlled by adjusting the reactant ratio and reaction rate or conditions such as temperature and pressure, wherein the inorganic compositions disperse in nanoscale within polymeric composites when their concentrations fall below moderate levels. A novel synthesis route for making polymer composites and/or polymer nanocomposites of a polyolefin and an inorganic network consisting of components selected from Si, Zr, Ti, is disclosed. The synthesis route comprises hydrolysis of either Si, or Zr, or Ti alkoxides or mixtures of these precursors within a polymer matrix in supercritical fluids.