Abstract
Metallocene catalyzed cycloolefin copolymers (mCOC) are transparent, rigid, high Tg and low water uptake because of the saturated hydrocarbon nature, the rigid cyclic norbornene comonomer and the randomly arranged copolymer chain, which properties are urgly needed by the optoelectronic industry. But other properties such as pecific refractive index, dispersion and birefringence are also needed. In the mean time, the rheological properties should be tuned to the processing method to make the optical product. Besides of the chemical synthesis, physical blending is an economic way to modifiy the existed polymer. Because of the advantages of mCOCs’ low polarity and dimensional stability, modification by polar functional groups is not a good choice. To utilize ven der Waal repulsion force from the small difference of the copolymer molecular microstructure, it might be a new way to manipulate the phase domain as well as the properties of the non-polar polymer blend and their inorganic particle filled nanocomposites. A series of Cyclo-olefin copolymer (COC) blends were prepared via solution blending process and showed various miscibility because of different norbornene content as well as copolymer microstructure. Two kinds of nano-silica particles, including hydrophilic silica (Hp-SiO2) and hydrophobic silica (Hb-SiO2) were inducted into COC blends to deform the phase separation domains of COC blends. The properties and morphologies of the composites were characterized after preparation. The tensile moduli of 8007 blended films increase with increasing 5013 or 6013 content. The tensile moduli of the COCs composites slightly decrease either with 1wt% Hp- or Hb-SiO2. But the tensile strength and elongation increase as the 6013 content higher than 30wt% in the 8007/6013 composites with 1wt% Hb-SiO2 particles. By adding either Hp- or Hb-SiO2 particles, the haze value decreased in the immiscible blends (8007/5013) but slightly increase in the miscible blends (8007/6013). For all COCs and their blends, the transmittances are all higher than 85% with 1wt% Hb-SiO2 loading. The phase separated domains deformed with nanosilica in 8007/5013 composites which might be a reason for lower haze. In addition, transparent composite materials can be manufactured from immiscible COC blends containing nanoparticles.