Flame retardancy and thermomechanical properties of the poly‐(glycidyloxypropyl) phenyl silsesquioxane/layered titanate nanocomposites

Abstract

Poly-(glycidyloxypropyl) phenyl silsesquioxane (PGPSQ) was combined with an organo-layered titanate filler. The phase structure of the obtained composite was evaluated by XRD and TEM observations. Moreover, a burning test was carried out according to the UL-94 test method. The extinguishing time of the nanocomposites was classified V-0 even for the 1 wt % layered titanate content. Based on the results, it was clarified that the frame retardancy of the PGPSQ/organo-layered titanate system was superior to the poly-(glycidyloxypropyl) silsesquioxane (PGSQ)/organo-layered titanate system, which was reported in a previous paper. In addition, the layered titanate as a filler also improved the ductility of the PGPSQ.

Thermomechanical Properties of Nanocomposites

“…This was attributed to the relaxation peak of the aliphatic chains between the inorganic moiety and the epoxy group. As expected, the PGPSQ system showed a slight shift in this relaxation peak due to the presence of the phenyl group, which was less mobile than the glycidyloxypropyl group [20] . The ductility of PGPSQ loaded with 27.4 wt% silica demonstrated a serious limitation of poor fracture toughness for practical applications of this material.…”

“…Another interesting concept was developed by Harada and coworkers [20,21] , who studied the effect of a layered titanate fi ller on the fl ame retardancy and thermomechanical properties of a poly(glycidyloxypropyl) phenyl silsesquioxane ( PGPSQ ) matrix, and of poly(glycidyloxypropyl) silsesquioxane ( PGSQ ). Although PGSQ showed a high thermal stability and fl ame retardancy due to the presence of an inorganic component, when the formulation was loaded with 5% of an organolayered titanate it exhibited a self -extinguishing property.…”

“…According to Harada et al . [20] , it may be possible to improve the ductility of the silsesquioxane by altering the organolayered titanate content; in other words, the toughness of the PGPSQ could be improved by adding a fi ller that would also act as a fl ame retardant. Based on these results, it was concluded that PGPSQ possessed much better fl ame -retardancy properties than PGSQ, with only 1 wt% of organolayered titanate being required to provide the self -extinguishing characteristic of PGPSQ (as measured with the UL -94 method).…”

New Trends in Reaction and Resistance to Fire of Fire-retardant Epoxies

“…Harada et al [ 57 , 58 ] studied silsesquioxane derivatives bearing epoxy rings. First, polyglycidyloxypropyl silsesquioxane (PGSQ) was mixed with titanate and cured with DDM.…”

“…These results highlight the importance of the shape of the used particles for flame-retardant purpose: different shapes for similar materials can lead to completely different dispersions. In a further study, Harada et al [ 58 ] chose poly(glycidyloxypropyl)phenylsilsesquioxane (PGPSQ), mainly because of the reported capability for enhancing flammability properties of phenyl groups. PGPSQ was then mixed with the same organo-titanate as before and cured with DDM.…”