Hybrid carbon filled thermoplastic composites: synergistic effect of synthetic graphite and graphene nanoplatelets on thermal and mechanical properties of polyamide 4.6

In comparison with conventional polyamides, polyamide 4.6 is known as one of the high-temperature polyamides due to polymer chain constituents which also enhances its dimensional stability, creep resistance, and chemical resistance. The effect of hybrid synthetic graphite and graphene nanoplatelets fillers on thermal conductivity of polyamide 4.6 based composites was investigated in this study. Synthetic graphite and graphene nanoplatelets filled polyamide 4.6 based composites were fabricated using a twin-screw extruder. The variations on electrical, mechanical, thermal, and morphological properties were also examined. The highest in-plane and through-plane thermal conductivity values were obtained for hybrid 40 wt.% synthetic graphite and 5 wt.% graphene nanoplatelets filled composites as 21.65 and 4.04 W/mK, respectively. It was reported that the usage of hybrid carbon fillers in polyamide 4.6 leads to better thermal conductivity value..Scientific and Technological Research Council of Turkey; Turkiye Bilimsel ve Teknolojik Arastirma Kurumu [117M088]The authors are grateful for the funding from the Scientific and Technological Research Council of Turkey; Turkiye Bilimsel ve Teknolojik Arastirma Kurumu [Project no: 117M088]

Enhanced in-plane and through-plane thermal conductivity and mechanical properties of polyamide 4.6 composites loaded with hybrid carbon fiber, synthetic graphite and graphene

Polyamide 4.6 has excellent properties, such as high temperature resistance, crystallinity, fatigue resistance, melting temperature, excellent creep resistance, toughness, and good wear properties, but low thermal conductivity values. For this reason, its use in thermal applications has been limited. In this study, its use in thermal applications can be increased by increasing its thermal conductivity with carbon-based fillers and reinforcements added to the PA46 structure. The aim of this study is to examine the carbon fiber (CF), synthetic graphite (SG) and graphene nanoplatelet (G) loading on the mechanical, thermal, physical, and electrical properties of polyamide 4.6, which are produced using co- rotating twin-screw extrusion. Tensile and flexural strength of polyamide 4.6 increased with the addition of CF at all weight fractions. The highest electrical conductivity value was measured as 4.01 S/cm in PA46-20CF-20SG-3G composite material. The highest in-plane thermal conductivity achieved in this study at 20 wt% CF, 20 wt% synthetic graphite, and 5 wt% graphene loading was 20.43 W/mK. However, the highest through-plane thermal conductivity value was obtained to be 4.19 W/mK at 20 wt% CF. Graphene and synthetic graphite are more efficient to increase the in-plane thermal conductivity, while CF is more efficient to increase the through-plane thermal conductivity.scientific and technological research council of Turkey (TUBITAK) [117M088]The scientific and technological research council of Turkey (TUBITAK), Grant/Award Number: Project No: 117M08

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

Nutritional Status of Syrian Refugees in Early Adolescence Living in Turkey

This study evaluated the nutritional status of Syrian refugees in the early adolescent period living in different vulnerable settings. Nutritional assessment of Syrian refugee adolescents is often neglected but essential for a healthy physical, pubertal and mental development. Growth parameters of Syrian refugee adolescents going to a public school in an urban area and in a temporary protection center (TPC) were recorded along with the Turkish adolescents. Stunting percentages were similar between the groups (p = 0.811). While the proportion of children with a BMI over 85th percentile were significantly higher among Syrian adolescents living in TPC, Turkish children have the highest percentage of underweight (p = 0.01). Both food insecurity and unhealthy weight gain continue to be major concerns for refugee adolescents after their resettlement to a host country. The findings suggest that nutritional assessment and intervention at early adolescence is critical for Syrian refugees depending on their living conditions