Improving Flame Retardant Properties of Aliphatic Polyketone (POK)-Based Composites.

The effect of zinc borate (ZB) and high-molecular-weight siloxane (SIL) on flame retardancy, mechanical, and thermal properties of aliphatic polyketone (POK)-containing aluminum diethyl phosphinate (OF) was investigated in this study. Ten wt % OF is sufficient to obtain V0 rating according to the UL94 test. As the weight fraction of OF was increased, the flame retardancy properties and LOI values improved, while the tensile and impact properties decreased. To avoid the degradation in mechanical and impact properties as much as possible and obtain the same and better flame retardancy properties, synergists such as SIL and ZB were used. Flame retardancy of POK-based composites was determined by the limiting oxygen index (LOI) test, UL94 measurement, and cone calorimeter test. The additions of 1 wt % SIL and ZB have not led to a considerable decrease in the tensile strength and impact properties of POK-10OF. While ZB and SIL are very efficient in decreasing the smoke density, ZB is more efficient than SIL in increasing the LOI value of the composite. The addition of 1, 2, and 4 wt % ZB and SIL synergists did not lower their UL94 ratings. Moreover, it can be added that ZB is more efficient than SIL in decreasing the fire growth rate (FIGRA) and maximum average rate of heat emission (MARHE) values. Using OF (10 wt %) and ZB (4 wt %), LOI values higher than 32% and smoke density values lower than 150 were obtained.

Comparison of the Thermal and Mechanical Properties of Poly(phenylene sulfide) and Poly(phenylene sulfide)-Syndiotactic Polystyrene-Based Thermal Conductive Composites.

Syndiotactic polystyrene (SPS) has attracted considerable attention recently due to its high melting temperature, low cost, and relatively low density value. The aim of the study is to reveal whether a blend of PPS and SPS (PPS-SPS) can be used instead of PPS for high thermal stability, high mechanical performance, and high thermal conductive material applications. For this aim, poly(phenylene sulfide)/syndiotactic polystyrene-based carbon-loaded composite materials were prepared using a twin screw extruder. Two carbon-based materials, carbon fiber (CF) and synthetic graphite (SG), were used to improve the mechanical properties and thermal conductivity of the PPS-SPS blends. Through-plane conductivity values of PPS-30SG-10CF and PPS-SPS-30SG-10CF were obtained to be 13.67 and 12.92 W/mK, with densities of 1.55 and 1.50 g/cm3, respectively. It was demonstrated that PPS-SPS blend-based carbon-loaded composites have great potential to be used in thermal management applications with the advantages of relatively low cost and lightweight compared to PPS-based composites.