Preparation Of Phenolic Resin Based Composites And Study Of Their Ablative Property

Light-weight ablative materials have distinguishing features such as having a lowdensity and thermal conductivity, having a high residual carbon rate and radiation rate,performing good in resisting the erosion of gas. So light-weight ablative materialsperform good in preventing the heat from conducting to the interior structure and arenow widely used in deep-space exploration aircrafts such as the Moon and the Mars.With the advancement of aerospace technology, there is a demond of good property forablative materials to face different heat environment. It is of great significance todevelop new and reliable light-weight ablative materials for improving the standard ofspacecraft thermal protection of China.In this paper different resins are used as matrix, different microspheres are used asfilling material to prepare light-weight ablative composites. The effects of ablative time,mass ratio and the varieties of matrix and filling material to ablative property are alsostudied for choosing better components and optimizing preparation process to preparematerials with better properties. Oxygen-acetylene flame is used for conducting ablationtest. Ablative property is characterized by mass ablation rate and linear ablation rate.The temperatures at different depth distance from ablative surface are tested tocharacterize the thermal insulation property. Compression strength is tested tocharacterize the mechanical property. TG-DTA is adoped to analyse the heat stability.SEM is used for the observation of the surface morphology of samples before and afterablation. XRD is used for analyzing the microcosmic structure of samples before andafter ablation. It’s found that TH400boron phenolic resin has a high residual carbon rateand perform good in high temnperature. Ablative composites using TH400boronphenolic resin as the matrix have a better ablative property. After ablation samples madeof glass S38microspheres will melt and condense having a lower mass ablation rate.Samples made of phenolic resin microspheres will turn into porous graphite carbonhaving a lower linear ablation rate. Samples made of glass S38microspheres havingbetter thermal insulation properties than samples made of phenolic resin microspheres.In this paper carbon nanotubes and chopped carbon fiber are added into fillingmaterials to improve the ablative property and thermal insulation property, couplingagent is added to improve the mechanical property. The modifying mechanism is alsostudied preliminarily. It’s found that adding3%carbon nanotubes can effectively reduceablation rate by increasing the planeness of residual carbon layer. Adding1.5%choppedcarbon fiber after surface treatment can effectively reduce ablation rate by increasingthe strength of residual carbon layer. Adding1%coupling agent during preparation can increase compressive strength effectively by enhancing the adhesive property of marixand filling material.