Effects of difunctional reactive polyhedral oligomeric silsesquioxane on the properties of EPDM

Abstract

Bifunctional reactive polyhedral oligomeric silsesquioxane (POSS) of 3, 13‐divinyl octyphenyl silsesquioxane (DV‐DDSQ) and 3, 13‐dihydro octyphenyl silsesquioxane (DH‐DDSQ) were used as additive to modify ethylene‐propylene‐diene rubber (EPDM), and double vinyl groups or active hydrogen groups of bifunctional reactive POSS (brPOSS) underwent a cross‐linking reaction with the active hydrogen groups and double bonds of EPDM, to investigate the effect of brPOSS regulating functional reaction group on the properties of EPDM. Crosslinking density, mechanical properties, thermal stability and ablation performance of brPOSS modified EPDM were investigated, and the pyrolysis behavior and surface structure of modified EPDM was analyzed by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Furthermore, the ablation performance of brPOSS modified insulation based on EPDM was investigated. The results showed that the tensile strength of EPDM/DV‐DDSQ and EPDM/DH‐DDSQ increased by 35.8% and 55.3% respectively compared with EPDM; the tear strength increased by 6.4% and 5% than that of EPDM. Moreover, the 5% initial thermal decomposition temperature based on thermogravimetric analysis (TGA) and mass (or linear) ablation rate ablative performance of brPOSS modified EPDM were optimized to a certain extent, and the ablative performance of brPOSS modified insulation based on is significantly improved, the mass ablation rate of DV‐DDSQ/insulation and DH‐DDSQ/insulation decreased by 35.4% and 41.6% respectively, and linear ablation rate decreased by 38.2% and 39.4% respectively.

Suppressed physical aging in PMMA‐titanium oxide nanocomposites by controlling alignment of nanoparticles

“…The mechanisms are of important significance to the studying of the materials' structural relaxation. 39,40 In the previous study of the mechanism of physical aging, there are two different process been found which follow different mathematical relationshiops 41,42 : one is the fast mechanism, which displays Arrhenius temperature dependence with low activation energy; while the other is the slow mechanism, which follows the super-Arrhenius temperature dependence. 43 For the neat PMMA, only one peak appears in Figure 7, since the fast recovery mechanism is thickness dependent and compatible with the assumption of the diffusion of the free volume holes toward surfaces.…”

Organosilicon‐functionalized polyolefins, a kind of designable and versatile polymer: From preparation to applications

“…After vulcanization, the ablative performance of the composite was also significantly increased; DH-DDSQ was superior to DV-DDSQ to improve the overall performance of EPDM. [129] 3 | APPLICATIONS OF ORGANOSILICON-FUNCTIONALIZED POLYOLEFIN…”

Influence of vinyl polyhedral oligomeric silsesquioxane with different functionalities and cage structures on the mechanical properties and ablation resistance of EPDM composites

“…Hao et al 29 and Ma et al 28 prepared and investigated EPDM composites with octa vinyl POSS or div-POSS for the mechanical and ablative properties, the tensile strength of the composites were decreased by 3.03% and 35.8%, the linear ablation rates of the composites were reduced by 21% and 38.2% by the adding of 5 phr octa vinyl POSS or div-POSS, respectively, which was demonstrated POSS with different functionalities present various degrees of improvement in the mechanical and thermal properties of EPDM composites. 27,28,30 Therefore, it is worthwhile to be explored that the relationship between the functionality and cage structure of POSS and the mechanical and ablative properties of EPDM composites, which is the novelty and originality of this paper.…”