Construction of Carbon Microspheres-Based Silane Melamine Phosphate Hybrids for Flame Retardant Poly(ethylene Terephthalate)

To improve the flame retardancy and inhibit the smoke of poly(ethylene terephthalate) (PET), carbon microspheres (CMSs)-based melamine phosphate (MP) hybrids (MP-CMSs) were constructed in situ with the introduction of CMSs into the hydrothermal reaction system of MP. The integrated MP-CMSs were modified by 3-Aminopropyltriethoxysilane (APTS) to obtain the silane MP-CMSs (SiMP-CMSs) to strengthen the interface binding between the MP-CMSs and PET matrix. The results showed that the SiMP layer was loaded on the CMSs surface. The addition of only 3% SiMP-CMSs increased the limiting oxygen index (LOI) value of the PET from 21% ± 0.1% to 27.7% ± 0.3%, reaching a V-0 burning rate. The SiMP-CMSs not only reduced heat damage, but also inhibited the smoke release during PET combustion, whereupon the peak heat release rate (pk-HRR) reduced from 513.2 to 221.7 kW/m2, and the smoke parameters (SP) decreased from 229830.2 to 81892.3 kW/kg. The fire performance index (FPI) rose from 0.07 m2s/kW to 0.17 m2s/kW, demonstrating the lower fire risk. The proportion of the flame-retardant mode in the physical barrier, flame inhibition, and char effects were recorded as 44.53%, 19.04%, and 9.04%, respectively

Synergistic Effect of Activated Carbon, NiO and Al₂O₃ on Improving the Thermal Stability and Flame Retardancy of Polypropylene Composites

It is difficult to enhance the char yields of polypropylene (PP) due to the preferential complete combustion. Successful formation of abundant char layer structure of PP upon flammability was obtained due to the synergistic effect of NiO, Al2O3 and activated carbon (AC). From characterization of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it was revealed that the microstructure of residual char contained large amount of carbon nanotubes. Compared to the modification of AC, NiO and Al2O3 alone, the combination of AC, NiO and Al2O3 dramatically promotes the charring ability of PP. In the case of AC and NiO, NiO plays a role of dehydrogenation, resulting in the degradation product, while AC mainly acts as carbonization promoter. The addition of Al2O3 results in higher dispersion and smaller particle size of NiO, leading to greater exposure of active sites of NiO and higher dehydrogenation and carbonization activity. Compared to the neat PP, the decomposition temperature of the PP modified by combined AC, NiO and Al2O3 was increased by 90 ℃. The yield of residual char of AC-5Ni-Al-PP reached as high as 44.6%. From the cone calorimeter test, the heat release rate per unit area (HRR) and total heat release per unit area (THR) of PP composite follows the order AC-5Ni-Al-PP < AC-10Ni-Al-PP < AC-Ni-PP < AC-15Ni-Al-PP < AC-1Ni-Al-PP. Compared to the neat PP, the peak of HRR declined by 73.8%, 72.7%, 71.3%, 67.6% and 62.5%, respectively

Associations of physical activity types and intensity with cardiovascular diseases by age and gender among 18,730 Chinese adults

Abstract The associations of physical activity (PA) intensity and types with CVD (cardiovascular diseases) in different population are inconsistent and remains not very clear. A total of 7854 males and 10,876 females over 15 years were selected by multistage random sampling methods. In males, moderate-intensity physical activity (MPA) had no effect, while vigorous-intensity physical activity (VPA) played a significant protective role (OR = 1.319 and 0.615). However, in females, both MPA and VPA had significant protective effects (OR = 0.593 and 0.537). VPA presented as a significant protective factor in stroke patients and combined CVDs for males in all age groups; however, in females, the results suggested that, for those aged over 60–74 years, MPA was a protective factor. Furthermore, for the middle-aged or younger participants, the area under the curves (AUCs) of work, housework, and leisure activity were generally higher than that of other types, while for patients aged over 60 years, the AUCs of sedentary time and sleep activity seemed much higher. VPA had a better protective effect for preventing cardiovascular events, while the young and female population could benefit from MPA as well. Regardless of the types of PA, leisure activities were strongly recommended, and young people were much more likely to benefit from exercise than older people