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Data are presented on the properties of alkali metal and alkaline earth hydrofluorides. Melting, thermal decomposition and interaction of hydrofluorides with various classes of inorganic substances are discussed. Some regularities of changes in thermal properties within the sequences of the above hydrofluorides are established. Future directions of research in this field are outlined.

The heat capacities of MgO, CaO, SrO and BaO, reported in part I have been analysed in terms of the frequency spectrum of the lattice with the assumption that the effect of anharmonicity of the lattice may be neglected for T ≦ (ΘD/3). Following the usual procedure the n-th moments of the frequency spectrum with n = - 3, -2, - 1, 0, 1 to 6 were calculated from the experimental data. From the low frequency expansion the apparent Debye characteristic temperature at 0 °K, Θ0, is calculated to be in good agreement with Θ0 (elast.), calculated from elasticity data. Also the limiting values at high temperatures,Θ∞, and the zero point energy, Ez, have been calculated. A comparison between the heat capacity data, the elastic constants and thermal properties of these oxides and the alkali-halides suggest that the interatomic forces of the alkaline-earth-oxides are rather similar to those of the alkaline fluorides. But no specific divalent character has been detected for these oxides. An appreciable anharmonic effect is present for all oxides.

The DTA patterns of synthesized coprecipitated gels, SiO2–Al2O3–Ga2O3–H2O system, resembled that of allophane, and the exothermic peak temperature in the DTA was lowered continuously from 980 to 810 °C with an increase in the gallium content, while that on mixed gels scarcely lowered. The apparent activation energy for this exothermic reaction on the coprecipitated gels decreased with an increase in the gallium content, while that on the mixed gels hardly changed. The crystallization process during the heat treatment of the gels depended on the content and on the coexistence state of the gallium. A unit cell volume of a mullite crystallized at 1200 °C in the coprecipitated gels was enlarged by forming a solid solution with the gallium ion, in contrast to the small change in that formed in the mixed gels. Further, the exothermic peak in the DTA was considered to originate not only from the formation of the mullite, but also from that of the silico-alumina spinel in the gallium-bearing gels; the exothermic ...

高分子物質の10°K以下の低温域における比熱,熱伝導について述べる.具体的な例としてポリエチレンについて話を進める低温域では,高分子物質に高分子らしさを付与する原因となる結晶場の大きな異方性は薄れて,その熱的な性質は通常の三次元結晶と同様なふるまいを示すしかし,1°K以下の極低温になると,ラメラ結晶からなる特異な多結晶構造を反映して再び三次元結晶のふるまいからはずれてくる.このような挙動は,構造欠陥に伴う局在した振動モードの寄与によるものと思われる.低温における熱的性質の研究は,分子間相互作用の性質の解明に役立つだけでなく,固体構造の研究手段としても有効である.

高分子の熱的性質は高分子の加工に際し,重要な役割をもつと同時に,その熱力学的状態を決定する重要な指標である。熱力学的量である高分子の比容積およびエンタルピー,そしてこれらの温度依存性の係数である熱膨張率と比熱は,高分子の転移を決定するために用いられる。結晶性高分子における融解,無定形高分子におけるガラス転移は,熱力学的には一次および二次の転移とみなされる。またこれらの転移の起こる温度は,高分子を同定する有力な目安となる。これらの転移温度と高分子の構造との関係については多くの研究がなされているが,一般的にいえば,分子鎖の内部回転に対する障害が少なく,屈曲性の大きい高分子ほど,転移温度が低い。逆に剛直な分子構造をもつ高分子は転移温度が高く,軟化しにくい。高分子鎖に芳香環を導入することにより,その耐熱性が向上できる。

三酢酸繊維素の結晶化度をX線計数回折法によって決定した。本研究においてはその干渉性散乱強度よりデバイ環に沿っての散乱量を求め,これを一定の角度範囲に積分した散乱総量より結晶化度を決定する方法を検討した。この方法によれば,試料の種類による結晶態の相違,微結晶の配向,大きさ,形,分布等に基く誤差をさけうることが期待できる。すなわちNorelcoのX線計数回折計を用いて,各供試試料の干渉性散乱強度の決定,散乱量曲線の作図,結晶および無定形散乱総量の分離,結晶化度の決定法,散乱係数の算出,高結晶化試料に対する対策等について種々検討した結果を報告する。

塩化ビニルと他のビニル系単量体との共重合体の二次転移点, 柔軟温度および流動特性が, ビニル系モノマーの化学構造と含有率により受ける影響について調べた。これらの熱的諸性質は共重合体の塩素含有率が40%以上の範囲内で測定した。酢酸ビニル, アクリル酸メチル, マレイン酸ジブチルのような比較的低級のアルキル基を有するビニル系モノマーの影響はあまり大きくないが, アクリル酸オクチル, ラウリルビニルエーテル, ステアリン酸ビニルのような高級アルキル基を有するビニル系モノマーおよびエチレンモノマーは顕著な影響を及ぼし, 共重合体は30℃以下の二次転移点と柔軟温度ならびにすぐれた流動特性を示すようになることがわかった。

The thermal properties of sericin cocoon shells have been studied and discussed about their thermal structural changes from the results of calorimetric measurements (Rigaku Denki Differential Scanning Calorimeters; DSC), Thermal Mechanical Analysis and Dynamic Mechanical Loss Tangent (Tan δ). The obtained results were summarized as follows:(1) When the cocoon shells were treated in humid atmosphere, the degree of solubility of sericin cocoon shells in water decreased markedly. And sericin cocoon (Sericin A) dried at the room temperature and sericin cocoon (Sericin B) dried in humid atmosphere (90 C for 2 hours) begin to dissolve in water, at 60°C and 80°C, respectively. But the difference in the solubility between sericin A and B was not recognized in boiling water.(2) According to DSC curves of sericin treated with water of various temperatures for 30 min, the temperature of endothermic peaks shifts about 10 degrees to higher region. From the results of density measurements also suggest that this shift is mainly due to the structual change of sericin into more stable state.(3) It is recognized in tan δ measurement that the sericin's main chain begins to move at above 160°C. And this temperature is similar to the degradation temperature appeared on DSC curves of fibrous sericin. Furthermore it is confirmed by the measurements of tan δ and change in the length of fibrous sericin that the endothermic peaks appeared in the range from 230-240°C were caused by breakings of the inter and intra-molecules' bondings of sericin.(4) When the sericin was kept in an desiccator controlled at various humidities for a week, the bond breaking temperature shifts from 230°C to 260°C (260°C is for 96% RH). This fact shows the structure of sericin becomes more stable being kept in high R. H. When the treatment times is short, the structual changes do not occur.(5) It is generally known that the bad reelability of cocoon occurs when mounted at high temperature and humidity. This is partly attributable to the increase of the crystallinity of sericin.

Thermal properties of sericin have been studied by means of DSC method. The results obtained are summarized as follows:1. Soluble sericin with a low crystallinity gave a DSC curve where an endothermic main peak and a shoulder were observed at ca. 220°C to 230°C and ca. 250°C, respectively. The soluble sericin became highly crystalline by swelling in water and gradually drying. The crystalline sericin obtained showed a main peak at ca. 250°C and a shoulder at ca. 220 to 230°C on the DSC curve, subsequently the solubility of the specimen decreased remarkably, i. e. hardly soluble or insoluble sericin.2. It has been found from the DSC analysis that quickly dried sericin was a soluble type and gradually dried one was a insoluble type.3. The insoluble part of sericin in water found to be an insoluble type of sericin in cocoon filament.

Synthesis of barium feldspar (BaO · Al2O3· 2SiO2) from barium carbonate and kaolin was performed by the electrofusion method in order to study its application to ceramic purpose. During the investigation of the properties of the synthesized crystal, the authors happened to be able to furnish conclusive data on the existence of different modifications from the natural celsian. The clarifications of the crystallographic properties, crystal structure, and thermal properties proved the existence of hexagonal modification for high-temperature form against the monoclinic celsian for low-temperature form, as well as the α→β transformation in the hexagonal modification at about 300 °C.

SummaryGlass-ceramics based on the mineral cordierite have good mechanical and thermal properties. They can be easily prepared from glasses whose compositions lie in the primary phase field of cordierite on the 5 % CaO plane of the CaO-MgO-SiO2-Al2O3 system. For uniform crystallization in the bulk, addition of a suitable nucleating agent is essential. The addition of 10–12 wt % of TiO2 is considered to be suitable for both ternary and quaternary glasses. During controlled heat treatment of these glasses extensive phase separation occurs. The nucleation and crystallization processes that follow have been studied by differential thermal analysis, X-ray diffraction, and light and electron microscopy. Some of the physical and mechanical properties of these glass-ceramics have been measured.

Internally crosslinked polymer microgels were obtained with various molar ratios of methyl methacrylate/ethylene glycol dimethacrylate (MMA/EGDMA) using the solution polymerization method. For each molar ratio of MMA/EGDMA used, there was a critical gelation concentration of monomers for the microgel formation. Poly(methylmethacrylate-co-ethylene glycol dimethacrylate) microgel was soluble in various organic solvents and melted at a certain temperature. The physical properties of the microgels such as the intrinsic viscosity, coil density, molecular weight, particle size, and thermal properties were also investigated. It was observed that the microgels are compact and spherical particles within a range of 50∼100㎛. However the microgel particles were slightly elongated and aggregated at high monomer concentrations and molar ratios of MMA/EGDMA.

Foams are used for many and very different purposes. It seems nevertheless that a classification of their main uses is possible. Generally speaking, application of foams is based on 1. difference in composition between the bulk liquid and the collapsed foam 2. immobilization of gas and liquid (sometimes of solids also) in foams 3. their low density 4. their large surface 5. their mechanical properties 6. their thermal properties