In this study, we have developed modified poly (lacticacid) (PLA) resins by the addition of poly (ethylene vinylacetate) (EVA) and talc, and coated on the surface with the urethane and cashew paints. The effect on the adhesion and hardness of coating by the crystallization of resin and pretreatment of it ssurface was evaluated by JIS test methods andmicroscopic observations. The results showed that the adhesion of coating was improved by the addition of EVA and talc with synergetic effect. Further, the measurement of alkaline durability test showed that coating on its surface was effective method for increasing the durability of PLA products.

View full abstract

A large deformation simulation for pressure sensitive adhesives is descried. This paper focuses on viscoelasticity, which is a fundamental material characteristic of the pressure sensitive adhesive, and reports an Eulerian solution to simulate large deformation behavior of viscoelastic material. Thecomputational mesh control can be divided into Lagrangian and Eulerian solutions. Although the Lagrangian solution has been generally adopted for simulation of the pressure sensitive adhesive, the highly distorted Lagrangian mesh cannot retain numerical accuracy. This paper applies the Eulerianfinite element method to large deformation dynamics of pressure sensitive adhesives, and verifies the advantages of the present formulation by using various computational examples.

View full abstract

C60 fullerene/thermoplastic polyurethane elastomer (PUE) composites were prepared by using the roll-mixing method. Initially, the PUEs, with various hard segment contents (HSC), were synthesizedwith poly (oxytetramethylene) glycol (PTMG), 4,4'-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) by the prepolymer method. To control the HSC, a molar ratio of PTMG/MDI/BD was varied at 1/2/1, 1/3/2 and 1/4/3. The effects of HSC in PUEs on the relationship between tensile properties and microphase-separated structure of C60/PUE composites were investigated using a tensile test, dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) after annealing at 80 and 120℃. Tensile strength of the PUE composites was already improved at a fullerene concentration of 100ppm, moreover, that of the PUE composites with higher HSC increased with an increasing amount of C60, as annealing at higher temperature. The results of DSC and DMA indicate that the aggregation structure of hard segments in the PUEs has been influenced by the presence of the fullerene. It was found that the direct addition of a small amount of fullerene is a valuable modifying method of PUEs.

View full abstract