In this paper, we report the results of a study using finite element method (FEM) simulation on the relationship between the morphology and physical properties of a filler-filled blended rubber. In the blended rubber of styrene-butadiene rubber (SBR) and isoprene rubber (IR), the distributability of the silica fillers of both phases is different. As a result, when the blend ratio is changed, the effective filling amount of the filler in each rubber phase fluctuates, a difference in the reinforcing effect occurs, and the mechanical property value of the blended rubber changes discontinuously.

Furthermore, the phase separation structure of rubber changes in a complicated manner depending on the blend ratio. We expressed the input physical property value as a function of the distribution ratio of the filler, and devised a simulation model using a typical phase-separated structure model of the polymer blend. Using this model, we report the results of considering the relationship between filler dispersibility, phase structure, and Young’s modulus in blended rubber.

The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is a hazard classification and communication system for the safe chemical substance handling. The hazard class of the skin sensitization is defined as Category 1: sensitizer, and if applicable, subcategorized to 1A: strong sensitizer or 1B: other. Traditional radioisotopic Local Lymph Node Assay (LLNA-RI) is one of the tests available for GHS subcategorization by obtaining an estimated concentration that produces a stimulation index=3 (EC3) with criterion of 1A: EC3≤2% and 1B: 2%<EC3. The LLNA: BrdU-ELISA is a non-radioisotopic alternative to the LLNA-RI although criterion for the subcategorization has not been clarified in GHS document. Therefore, we proposed a new criterion for the LLNA: BrdU-ELISA as 1A: EC1.6≤6% and 1B: 6%<EC1.6 by retrospective analysis of the existing data of 32 sensitizers (1A: 13, 1B: 19) : the criterion was confirmed to be valid for the commonly used mouse strain of CBA/J with 15 sensitizers (1A: 6, 1B: 9). We also found incorrect application cases of existing subcategorization criterion to LLNA: BrdU-ELISA. To avoid incorrect application, immediate revision of the GHS document is necessary to include the new criterion for LLNA: BrdU-ELISA.

With the development of nanotechnology, there has been great progress in the preparation of various nanomaterials. Among them, nanofibers have unique functionalities based on their nanoscaled diameter, large surface-to-volume ratios, and high molecular orientation or confined polymer chains inside the fibers. Nanofibers and their assemblies (e.g., membranes, nonwovens, and yarns) have recently attracted much attention in applications such as high-performance air and liquid filter media, strong and tough fibers, battery separators, electrode materials, protective clothes, composites, drug delivery systems, and biomaterial scaffolds for tissue engineering. This review highlights production methods, fundamental aspects of functional design of nanofiber materials (by controlling their fiber diameter, surface chemistry and topology, and internal structure of the nanofibers), and recent advances of nanofiber materials in their environmental and energy applications (e.g., air filter, separation membrane, and electrolyte).

In the final series of this subject, the design, synthesis, and function of dynamic soft materials utilizing the rotaxane’s structural characteristics as the stimuli-responsive polymers are discussed in the two reviews including the present paper. A few rotaxane-cross-linked polymers were described as the dynamic soft materials capable of showing recyclable and photo-decross-linkable functions, i.e. rotaxane-cross-linked polymers of which characteristics came from the dynamic nature of disulfide bond via thiol-disulfide interexchange equilibrium and photodissociation of S-S bond. Reversible linear-cyclic polymer topological transformation was discussed using a few rotaxane switch-driven systems. The reversible linear-cyclic topological transformation was demonstrated using [1] polyrotaxane. The steadily repeated linear-cyclic polymer topological transformation was confirmed with the cyclic polymers prepared by an efficient synthetic method involving spontaneous cyclization process which enables the large-quantity synthesis, suggesting the significance of the stable (macro)molecular rotaxane switches. The development of the dynamic soft materials based on the linear-branched polymer topological transformation will be discussed in the last review of this series.