Thermoplastic Vulcanizate Based on Poly(lactic acid) and Acrylic Rubber Blended with Ethylene Ionomer

A new thermoplastic vulcanizate (TPV) was developed by meltblending of poly(lactic acid) (PLA), acrylic rubber (ACM), and ethylene-methacrylic acid with sodium ions (EMAA-Na). The PLA/ACM/EMAA-Na blend showed low-yield strength, low modulus, and excellent strain recovery. It also demonstrated an increase in complex viscosity and decrease in melting temperature due to the interfacial reaction between the PLA and the ACM phases. The Fourier transform infrared spectroscopy results indicate that EMAA-Na can interact with both PLA and ACM, and that the Na⁺ ions act as a catalyst for the interfacial reaction between PLA and ACM, while PLA does not react with ACM without EMAA-Na. Moreover, the tensile strength at break of the PLA/ACM/EMAA-Na blend was observed to be extremely improved by the addition of hexamethylenediaminecarbamate (HMDC) due to the increasing of the cross-link density inside the rubber phase. The morphology of the PLA/ACM/EMAA-Na blend with HMDC was finer than that of PLA/ACM/EMAA-Na without HMDC. From the results, it is suggested that the interfacial reaction between the PLA and the ACM phases, the cross-linking in the ACM phase, and the finer morphology improved the mechanical properties of the blend.     

Solid phase synthesis of nonadecathymidylic acid by the phosphotriester approach

Nonadecathymidylic acid was synthesized by the block coupling phosphotriester approach on a polymer support.     

Cation-binding properties of poly- and bis(benzo-21-crown-7)derivatives

Summary Poly- and bis(crown ether)s which contain the relatively large crown ether ring of benzo-21-crown-7 were synthesized, and their cation-binding properties for alkali metal cations were elucidated by solvent extraction and also conductometrically. The cation-binding ability was found to decrease in the order Cs⁺>Rb⁺>K⁺>Na⁺. They can extract alkali metal cations more efficiently than the corresponding monomeric analogue. The binding behaviour for some organic cations such as alkyl ammonium and guanidinium is also described.

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Kationen-Bindungsvermögen von Poly- und Bis(benzo-21-krone-7)-Derivaten

Zusammenfassung Poly- und Bis-kronenether mit dem relativ großen Kronenetherring Benzo-21-krone-7 wurden dargestellt und ihr Bindungsvermögen für Alkaliionen wurde durch Lösungsextraktion und auch konduktometrisch untersucht. Es ergab sich, daß das Bindungsvermögen in der Reihenfolge Cs⁺>Rb⁺>K⁺>Na⁺ abnimmt. Diese Substanzen können Alkaliionen wirksamer extrahieren als die entsprechenden Monomeren Analogen. Das Bindungsvermögen für einige organische Kationen, wie z.B. Alkylammonium und Guanidinium, wurde ebenfalls untersucht.

     

The relation between lattice-parameter and particle size in ZnS:Cu Phosphor

The effect of particle size on life time in electroluminescent phosphor was investigated using fractionated samples. The life time of large-particle size phosphors was longer than that of small-particle size phosphor. It was found that particle size has a close relation with the lattice-parameter magnitude; the lattice parameter was larger in a small-particle size phosphor when the activator and coactivator content were the same. It was concluded that the lattice parameter was an important brightness life-time factor.     

A new furoxan derivative and its precursors formed by the reaction of sorbic acid with sodium nitrite

A new furoxan derivative ($\text{3}$) and its precursors ($\text{4a}$ and $\text{4b}$) were isolated from the reaction mixture of sorbic acid with sodium nitrite, and their structures were determined by spectroscopic and X-ray crystallographic analysis.     

Electronic bond rupture of Si-Dimers on Si(001)-(2x1) induced by pulsed laser excitation

A scanning tunneling microscopy study has revealed that 532 nm laser pulses of fluences well below melt and ablation thresholds induce electronic bond rupture of Si-dimers on the Si(001)-(2x1), resulting in the formation of single dimer-vacancies followed by progressive growth into vacancy clusters. The rate of bond rupture on the intrinsic (2x1) structure shows super-linearity with respect to excitation intensity, and saturates as the number of vacancies reaches a few percent, relative to total dimer sites. The mechanism of laser-induced bond rupture is discussed based on these results. PACS 61.80.Ba; 61.82.Fk; 68.35.Bs; 79.20.La     

Random walk representations and the mayer expansion in theN-vector model

We consider a random walk representation of non-abelian statistical models, and apply it to represent the free energy in terms of the correlation functions of random walks. This enables us to find an analytic region of the free energy with respect to the inverse temperature. This method can be applied to the block spin transformations.Dedicated to Huzihiro Araki