Room temperature vulcanized（RTV） silicone rubber is usually exposed to a high-temperature and high-humidity environment

so it is urgent to develop the high-temperature-resistance RTV silicone rubber and understand its thermal decomposition mechanism. In this study

nano-ZnO was modified with a titanate coupling agent

and different amounts of nano-ZnO were dispersed into room temperature vulcanized（RTV） silicone rubber by ultrasonication and mechanical stirring

also

Fourier transform infrared spectroscopy（FTIR）

X-ray diffraction（XRD）

scanning electron microscope（SEM） and TG test methods were used to analyze the structure and properties of materials. The results show that the titanate coupling agent is successfully grafted on the surface of nano ZnO. The XRD test of nano ZnO shows that the modification of titanate coupling agent has no effect on the particle size of the nanoparticles. The TG test shows that

with the increase of nano ZnO content

the thermal stability of RTV composites increases continuously

the initial thermal decomposition temperature increases from 344.6 ℃ to 420 ℃

and reaches the highest value when 1.5% ZnO is added. In addition

in the three stages of thermal decomposition of RTV composites

with the addition of nano ZnO

the amount of decomposition in the first stage is continuously reduced

and the amount of decomposition in the second stage and the third stage is increasing. Therefore

it is shown that the addition of nano ZnO has a great influence on the thermal decomposition behavior of RTV materials. The thermal decomposition kinetics analysis of RTV and 1% ZnO–RTV shows that when the thermal conversion rate（α） is small

the activation energy（Eα） of RTV is less than that of 1% ZnO–RTV

which also explains the variation of decomposition amount of the three stages when different amounts of nano zinc oxide are added. The Eα values of RTV and 1% ZnO–RTV are 144.29 and 146.78 kJ/mol

respectively

the kinetic energy index（n） of RTV is 3.83

and the kinetic energy index（n） of 1%ZnO–RTV is 4.5

indicating that RTV passes through nano zinc oxide. After modification

the thermal decomposition process becomes more complicated. The results of this study can provide new ideas for the development of high heat resistance RTV silicone rubber.