Understanding and Control of the Elastomer/Filler Interphase: Role of the Coupling Agent and Impact on Mechanical Properties

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Context

Silica–elastomer composites are key materials in tire formulations, particularly for tread applications. Improving the mechanical and functional properties of these composites largely depends on the quality of the interaction between the elastomer and the filler. This interaction is generally achieved through the introduction of a silane coupling agent, composed of three functional blocks (foot/spacer/head), whose roles are well described in the literature.

However, several fundamental questions remain open:
– Is the chemical bonding between silica and the elastomer truly indispensable for reinforcement?
– How can we control the structure and characteristics of the filler/rubber interphase?
– What is the impact of the morphology of this interphase on the overall mechanical properties of the composite?

Addressing these questions is crucial to refine our understanding of reinforcement mechanisms and to open new perspectives in elastomer material formulation.

Subject Description

As part of the PolMixLab joint laboratory between IMP and Michelin, the objective of this PhD project is to understand and describe the formation of the elastomer/filler interphase in model systems and to study its consequences on mechanical properties.

The work will be structured around four main tasks:

  • Synthesis and functionalization of model silica particles with precise control over size and surface properties;
  • Advanced characterization of the interphase (chemical and topological), exploring the effect of silane structure (spacer, head);
  • Contact with the elastomer under various conditions to investigate polymer/filler anchoring mechanisms;
  • Multi-scale analysis of the composites to evaluate the impact of interphase formation on mechanical performance.

These studies will contribute to a better understanding of the fundamental reinforcement mechanisms in elastomer composites and support the optimization of industrial tire formulations.

Mots clés: Physicochemical modification of inorganic fillers, interfacial/interphase characterization, structure–property relationships

Host Institutions and Laboratories

A large part of the work will be carried out at IMP (Lyon). The PhD candidate will travel regularly to the Michelin/Ladoux site for project meetings and specific experimental work.

Candidate Profile and Expected Skills

Profile:
The candidate should have a strong background in materials science, polymer physical chemistry, and polymer/composite processing. Additional skills in materials characterization are highly desirable. Ideally, the candidate should hold a Master’s degree in Materials Science, Chemistry and Materials Science, or an equivalent Master’s in Polymer Materials Engineering and Processing. A solid foundation in polymer physicochemistry is essential.

Other expected skills:

  • Curiosity and ability to work effectively in a team

  • Capacity to conduct and develop an independent research project

  • Strong analytical and organizational skills

  • Good command of written and spoken English

Application Details

Deadline: Urgent – Selection will begin as soon as possible.
Start Date: Early November 2025.

Application Documents:

  • Detailed CV

  • Motivation letter

  • Copies of degrees and transcripts

Contact:
Prof. Jannick Duchet-Rumeau
INSA Lyon

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