To investigate the influence of co-existed covalent cross-link in rotaxane cross-linked polymer (RCP) on the property, several hybrid cross-linked polymers (HCPs) containing both rotaxane- and covalent cross-linked structures were synthesized by the radical polymerization of N,N-dimethylacrylamide(DMAA)using ratio-different mixtures of a vinylic supramolecular cross-linker consisting of γ-cyclodextrin and PEG-based macromonomer as a rotaxane cross-linker and a terminal dimethacrylated polyethylene glycol (PEG) as a covalent cross-linker. The cross-linked polymers were subjected to the investigation on the swelling property and tensile strength. All HCPs showed similar properties to those of a covalently cross-linked polymer (CCP) but considerably different from those of RCP. In particular, the mechanical property of HCPs was much lower than that of RCP in fracture energy and stress. From the results obtained in this work, it was elucidated that the power of the rotaxane-cross-link only appears, when the cross-links of cross-linked polymer mainly contain the rotaxane cross-links, which guarantees the mobility of polymer chains at the cross-link points to prevent the stress concentration, even in water-containing gelled polymers. This finding would provide an important design guide for the polymer toughening.

On breaking behavior of elastomer in mixer, we explained the rheological unit and a subdivision of elastomer. We have considered that the flow unit is the same as the rheological unit. Then, it was confirmed that when elastomer was mixed with carbon black after sufficient mastication, elastomer was broken and was subdivided to a size of around 0.1 μm.

Time-temperature superposition principle (TTSP) is widely accepted to be applicable to viscoelastic functions for various polymers and rubbers. In general, we need to determine both horizontal and vertical shift factors (a_T and b_T, respectively) in practical application of TTSP. If elasticity mechanism in viscoelasticity of the aimed sample is known to be entropy elasticity, we may take vertical shifts of viscoelasticity curves at various temperatures by Tρ factors followed by horizontal shifts of curves, as is explained in many textbooks. However, if the mechanism is not known, we must determine a_T and b_T in independent and objective way. The best way is considered to determine a_T firstly by using curves of loss tangent (dimensionless quantity) then b_T by using curves of storage and loss moduli. The application of this method to the experimental data of linear viscoelasticity for SBR gum and filled SBRs showed the next facts: The mixing of various fillers showed no effect on a_T but change in b_T from entropic elasticity in gum to energetic elasticity of enough filled rubber. This may be due to formation of contact filler network at high loading.

Basic concepts in polymer alloys & blends are illustrated based on our experimental studies on several miscible polymer blends with phase diagram.

From poly (vinyl methyl ether)/polystyrene mixtures we could find out lower critical solution temperature type phase diagram. The diagram is highly molecular weight dependent and the behavior can be explained by the extension of polymer solution theory to polymer/polymer systems. Moreover, phase separation behavior in this system can be classified into nucleation & growth and spinodal decomposition.

From poly (vinylidene fluoride)(PVF₂)/poly (methyl methacrylate) mixtures, we could find out melting point depression of PVF₂ and even calculate the interaction parameter based on Nishi-Wang Equation.

From poly (vinyl chloride)(PVC)/copolyester thermoplastic elastomer (TPE) mixtures, we could control the dynamic mechanical properties of the system due to the miscibility between PVC and soft segment of TPE. The state of the miscibility influences the impact strength of the alloys.

Finally, from polycarbonate/poly (ethylene terephthalate) blends, we could show the importance of transesterification between two polymers.

These experimental facts can be generalized to study polymer alloys & blends and are essential for the application of these complex systems in practice.