Locating a silane coupling agent in silica-filled rubber composites by EFTEM.

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• Silica/rubber composites are vital in industries like tire manufacturing.
• Effective silica-rubber interaction is key to enhancing composite properties.
• Silane coupling agents (SAs) are used to improve interfacial adhesion.

Purpose of the Study:

• To investigate the formation of the coupling layer at the silica/rubber interface.
• To understand the effect of mixing temperature on coupling layer formation.
• To evaluate the role of silane coupling agents in polymeric composites.

Main Methods:

• Utilized energy-filtering transmission electron microscopy (EFTEM) for interface investigation.
• Employed electron energy loss spectroscopy (EELS) for elemental analysis (Si and S).
• Applied elemental mapping to characterize the in situ formed coupling layer.

Main Results:

• Bis(triethoxysilypropyl)tetrasulfane (TESPT) forms a coupling layer by reacting with silica and rubber.
• EELS allowed qualitative estimation of TESPT trapped within the rubber matrix.
• Elemental mapping confirmed the presence and characterization of the in situ coupling layer.
• The formation of the coupling layer was demonstrably affected by mixing temperature.

Conclusions:

• Mixing temperature is a critical factor influencing the formation and characteristics of the silica-rubber interfacial coupling layer.
• The described EFTEM and EELS technique provides valuable insights into interface-property relationships in composites.
• This methodology aids in evaluating the efficacy of silane coupling agents in optimizing composite performance.