Rheological and fire properties of a composite of unsaturated polyester resin and halogen‐free flame retardants

Abstract

ABSTRACTThe main subject of the present research is to determine the impact of flame retarding fillers on macroscopic properties of composites. The effect on rheological properties of composition unsaturated polyester resin (UP) and flame retardant blend (FR) consisting of expandable graphite (EG) and or not modified silica and: (1) melamine polyphosphate (MPP) with ammonium polyphosphate (APP), (2) MPP with aluminum trihydrate (ATH), (3) only MPP was examined. Next, their influence on thixotropic properties of UP was estimated. FR fillers were compared according to their grain size, specific surface, and shape factor. Rheological properties were determined by applying hysteresis loop surface and thixotropy factor measuring. For the UP + FR composition, the dependence of grain morphological parameters, such as shape factor and specific surface, on viscosity and hysteresis loop surface was determined experimentally. All of the tested composites consisting of UP + 40% FR blend exhibits high flame resistance. An addition of only 2% of modified silica to all of the FR blends caused significant enlargement of hysteresis loop surface and thixotropy index. Hence, for the next stage of the research (an industrial test of GRP pipes casted by the centrifugal method) FR blend without modified silica was chosen. A composite consisting of UP, MP, APP and EG is characterized by lower heat release rate (HRRmax) (ca. 83%) and lower TSR (ca. 80%), ALMR (55%), and MARHE (73%) in comparison to UP resin; and that UP + FR composition exhibit satisfactory rheological properties as well. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44371.