The effect of polyhedral oligomeric silsesquioxanes (POSSs) incorporation in ethylene-propylene-diene-terpolymer (EPDM): a thermal study

Abstract

A series of ethylene-propylene-diene-terpolymer (EPDM)/polyhedral oligomeric silsesquioxane (POSS) composites at different percentage of POSS were prepared and subjected to γ-irradiation. Both irradiated and non-irradiated EPDM and composites were investigated by the means of thermal analysis to verify if the presence of POSS molecules is able to reduce the oxidation level of free radicals generated during the degradation and to evaluate the effects of the irradiation. EPDM composites at 1, 3 and 5 mass% of POSS were thus degraded in a thermogravimetric (TG) balance in dynamic heating conditions (25–700 °C), in both inert and oxidative atmosphere by flowing nitrogen and air respectively. Thermal characterization was then completed by carrying out Differential Scanning Calorimetry (DSC) analysis from sub-ambient to better highlight the melting of the polymer and polymer composites occurring just above the room temperature. FTIR spectroscopy was also performed for the prepared samples to check the presence of the molecular filler in the composites and for the TG’s residue at 700 °C, in order to evaluate its nature. DSC and TGA parameters were detected and discussed to have information about the effect of the degradation’s environment, the effect of irradiation on polymer stabilization and the effect of POSS content in the polymer matrix.

Irradiation Effects in Polymer Composites for Their Conversion into Hybrids

“…It places these elastomers through the strengths of polyethylene and polypropylene, where the most vulnerable sites on the backbones are the higher substituted carbon atoms [127]. According to the radiolytic behavior of EPDM [128], which has an unsaturated component (diene as the third structural unit), this thermoplastic material may gain a high oxidation strength by the addition of homogenously spread compounds playing the roles of microcomponent with a perfect interphase compatibility: synthesis antioxidants [129], substituted POSS structures [130], metallic oxides [47] and organically modified MMT [131]. The stability of the POSS modified structures characterized by the activation energies required for the oxidation of POSS filler-filled EPDM (Table 5) offers versatile solutions for the application of EPDM in the areas of beverage bottles, medical wear, food packaging and commodities that may be sterilized by γ-irradiation.…”

Unlocking the Potential Use of Reactive POSS as a Coagent for EPDM/PP-Based TPV

“…Blanco and Zaharescu prepared EPDM/POSS composites and subjected them to γ-irradiation. They stated that the POSS cage restricted the chain mobility of EPDM [ 47 ]. In a recently published study, a novel structure of norbornene reactive Double-Decker silsesquioxanes (DN-DDSQ) was designed and synthesized to covalently bonded into the EPDM molecular chain segment by the crosslinking reaction to form a denser cross-linked network and introduce a high-temperature resistant cage structures in EPDM to improve the crosslinking, mechanical, heat-shielding, and ablation properties of EPDM.…”