INS2-1053
Nanoscale mechanisms of strain-induced crystallization of isoprene rubbers studied by electron diffraction mapping
Topic
S2. High-End Characterization/Polymer Physics/Properties
When and Where
Sep 29, 2026
11:40 - 12:05
Room 103
Session Chairs
Moon Jeong PARK
Presenter(s)
Hiroshi Jinnai (Tohoku University)
Co-Author(s)
Abstract
Owing to their elasticity and flexibility, rubber materials are widely used in applications such as tires and seismic isolation devices. Because they must bear substantial loads in service, nanofillers are commonly incorporated to increase the elastic modulus and improve fracture resistance. For several rubbers—natural rubber and isoprene rubber (IR), among them—an additional reinforcement mechanism called “strain-induced crystallization (SIC)” has long been established [1]. However, how SIC develops at the nanometer scale and how it relates to the spatial arrangement of nanofillers remain poorly understood.
A method capable of capturing the nanoscale structural changes in rubber during deformation has recently become available [2]. In parallel, an electron-diffraction-based imaging approach termed “nanodiffraction imaging (NDI)” has been shown to directly map the spatial distribution of polymer nanocrystals [3]. By combining these two advanced microscopy techniques, the present study investigates how crystals form and distribute as rubber is stretched.
We prepared IR specimens containing silica nanoparticles (filled IR) and filler-free counterparts (unfilled IR), and monitored their stretching in situ in a transmission electron microscope (JEM-F200, JEOL Ltd.) equipped with a single-electron counting camera (K3 camera, Gatan Inc.). NDI then resolved the spatial distribution of SIC crystals at 20 nm resolution. In unfilled IR, SIC appeared uniformly across the specimen, whereas in filled IR the crystals concentrated between silica-nanoparticle aggregates aligned along the stretching direction. Local strain analysis further revealed that SIC preferentially occurs in regions of high strain.
References
[1] X. Zhang et al., Macromolecules 53, 3082 (2020).
[2] T. Miyata et al., Appl. Nano Mater. 4, 4452 (2021).
[3] S. Kanomi et al., Nat. Commun. 14, 5531 (2023)
A method capable of capturing the nanoscale structural changes in rubber during deformation has recently become available [2]. In parallel, an electron-diffraction-based imaging approach termed “nanodiffraction imaging (NDI)” has been shown to directly map the spatial distribution of polymer nanocrystals [3]. By combining these two advanced microscopy techniques, the present study investigates how crystals form and distribute as rubber is stretched.
We prepared IR specimens containing silica nanoparticles (filled IR) and filler-free counterparts (unfilled IR), and monitored their stretching in situ in a transmission electron microscope (JEM-F200, JEOL Ltd.) equipped with a single-electron counting camera (K3 camera, Gatan Inc.). NDI then resolved the spatial distribution of SIC crystals at 20 nm resolution. In unfilled IR, SIC appeared uniformly across the specimen, whereas in filled IR the crystals concentrated between silica-nanoparticle aggregates aligned along the stretching direction. Local strain analysis further revealed that SIC preferentially occurs in regions of high strain.
References
[1] X. Zhang et al., Macromolecules 53, 3082 (2020).
[2] T. Miyata et al., Appl. Nano Mater. 4, 4452 (2021).
[3] S. Kanomi et al., Nat. Commun. 14, 5531 (2023)
