Editorial Type:
Article Category: Research Article
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Online Publication Date: 19 Jul 2021

EFFECTS OF GRAFTED VINYL TRIETHOXY SILANE ON MOISTURE CROSSLINKED EPDM

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Page Range: 759 – 773
DOI: 10.5254/rct.21.78982
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ABSTRACT

An EPDM terpolymer grafted with silane vinyl triethoxysilane (EPDM-g-VTES) was prepared by melt grafting, with dicumyl peroxide (DCP) as an initiator. Next, dibutyl tin dilaurate was added as a catalyst to promote moisture crosslinking of EPDM-g-VTES. By means of the rheological response of the rubber compound, Fourier transform infrared spectroscopy, and moving die rheometer, the VTES graft ratio and DCP partial crosslinking (pre-crosslinking) of EDPM-g-VTES were characterized to show the feasibility of moisture crosslinking. The mechanical properties of moisture crosslinked EPDM-g-VTES specimens were tested by universal material tester. The results showed that when the weight ratio of VTES to DCP was fixed at 15:1, the VTES graft ratio and DCP partial crosslinking of EDPM-g-VTES increased with the increase of VTES content. But the torque in the moisture crosslinking curve of EPDM-g-VTES increased significantly with the extension of crosslinking time, which proved that EPDM grafted with VTES was cured by moisture successfully. The tensile strength and elongation at break of EPDM-g-VTES were improved by moisture cure. Furthermore, the moisture cured specimen with 3 wt% VTES had the best mechanical performance.

Copyright: 2021
Fig. 1.
Fig. 1.

Preparation of EPDM-g-VTES and the reaction mechanism.

Fig. 2.
Fig. 2.

Process and reaction mechanism of moisture cured EPDM-g-VTES.

Fig. 3.
Fig. 3.

Torque curves of VTES grafting on EPDM.

Fig. 4.
Fig. 4.

Mooney viscosity of pure EPDM and EPDM-g-VTES compounds.

Fig. 5.
Fig. 5.

Photographs of pure EPDM and EPDM-g-VTES compounds dissolved in cyclohexane.

Fig. 6.
Fig. 6.

Schematic diagram of crosslink networks in DCP partial crosslinking of EPDM-g-VTES.

Fig. 7.
Fig. 7.

Effect of VTES content on moisture curing curves of EPDM-g-VTES compounds.

Fig. 8.
Fig. 8.

DCP partial crosslinking and moisture curing of EPDM-g-VTES.

Fig. 9.
Fig. 9.

Effect of VTES content on crosslink density and MH-ML of moisture cured EPDM-g-VTES.

Fig. 10.
Fig. 10.

Infrared spectra of pure EPDM, Si3, and moisture cured Si3.

Fig. 11.
Fig. 11.

(a) Calibration curve for the determination of the graft ratio of VTES onto EPDM; (b) infrared spectra of EPDM-g-VTES compounds; (c) IG of EPDM-g-VTES compounds; (d) VTES graft ratio of EPDM-g-VTES compounds.

Fig. 12.
Fig. 12.

DSC curves of EPDM compounds without VTES (D0) and with 2 wt% VTES (Si2).

Fig. 13.
Fig. 13.

(a) Frequency scanning; (b) Δδ (δ0.5-δ100) of pure EPDM and EPDM-g-VTES (60 °C × 7% strain).

Fig. 14.
Fig. 14.

Stress–strain curves of moisture cured EPDM-g-VTES.

Fig. 15.
Fig. 15.

Illustration of the crosslink networks in moisture crosslinked EPDM.

Fig. 16.
Fig. 16.

Trouser tear strength of moisture cured EPDM-g-VTES.

Fig. 17.
Fig. 17.

(a) Crosslink density; (b) stress–strain curves of EPDM with different vulcanization systems.

Contributor Notes

*Corresponding author. Ph: +8613953253106; email: lindashi88@hotmail.com
Received: 01 Mar 2021
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