著者

山口 章三郎 大柳 康 辻川 洋三郎 高橋 義男

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.23, no.250, pp.588-592, 1974-07-15

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The effects of dimensions and supporting conditions on the compressive strength and deformation of polyvinylchloride pipes under external pressure were discussed. The following four kinds of pipe supporting conditions were used; (A) compression between two steel plates, (B) compression between a steel plate and a concave wooden block, (C) compression between two concave wooden blocks, and (D) compression between two concave hard rubber supporters. The main results obtained are as follows. (1) The relation between the compressive strength P and the dimensions of PVC pipe is given by the following formula, similar to the mid load bending for a both end flxed straight beam with a rectangular section; P=(4σ_b・l・t^2)/(3・Dm)・c_1 (a) where, l, t and D_m are the length, thickness and diameter of pipe, respectively, c_1 the correction coefficient according to pipe supporting conditions, and σ_b the bending stress in kg/mm^2. The value of correction coefficient c_1 was 0.81〜1.35 for A-method, 1.35 for B-method, 8.0 for C-method and 2.3 for D-method, respectively. (2) The deflection δ under elastic deformation is given by the following formula; δ=(P・D_m^3)/(8E・l・t^3)c_2 (b) where, E is Young's modulus in kg/mm^2 of pipe material, and c_2 the correction coefficient similar to c_1. The value of c_2 was 2.22 for A-method. (3) It seems reasonable, therefore, that the theory of straight beam may be applied to the compressive strength and deflection of plastics-pipe under external pressure by using the correction coefficient c_1 or c_2.

著者

佐藤 貞雄 斉藤 工 大柳 康

出版者

The Japan Society of Polymer Processing

雑誌

成形加工 (ISSN:09154027)

巻号頁・発行日

vol.4, no.1, pp.55-61, 1992

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In order to determine the thermal conductivity of molten polymers with greater accuracy, we improved the measurement device proposed in our previous paper. The accuracy of measurement of the improved device was within ±2.5∼3%. This improvied device was used to investigate experimentally the effects of molecular structure and polymer temperature dependence on the thermal conductivity of liquid crystalline polymers (LCP), and general-purpose polymers (GPP). The results showed that both of the thermal conductivity of LCP and GPP increased with raising of polymer temperature, while the thermal conductivity of LCP is 1.2∼1.7 times larger than that of GPP. The measured results also showed that thermal conductivity of LCP excepting LCP-XD 138 is influenced by the molecular structure. Namely, the thermal conductivity of III type-LCP which has flexible structure is 40% larger than that of the I type-LCP which has rigid structure. Furthermore, using a relation between the thermal conductivity and the thermal diffusivity <i>a</i> (=<i>v</i>·λ/<i>C_p</i>, where <i>v</i>: specific volume, λ: thermal conductivity, <i>C_p</i>: specific heat), the temperature dependence of the thermal diffusivity of the GPP was examined and the thermal properties which dominate the behavior of those thermal diffusivity were discussed. The thermal diffusivity shows various behavior in accordance with raising of temperature. The temperature dependence of the thermal diffusivity is dominated by that of thermal conductivity in PC, PMMA and PA-6, by that of specific heat in PP, respectively. For all of these GPPs, the density change due to polymer temperature has little effect on the thermal diffusivity.

著者

佐藤 貞雄 斉藤 工 大柳 康

出版者

The Society of Polymer Science, Japan

雑誌

高分子論文集 (ISSN:03862186)

巻号頁・発行日

vol.48, no.1, pp.57-59, 1991

被引用文献数

1

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ガラス繊維を30%充填した液晶ポリマー (以下LCP-GF30と呼称) とポリカーボネートなど汎用樹脂の<I>p-v-T</I>特性を独自に設計-試作した装置を用い, 温度20~325℃, 圧力0~150MPaの節囲で, 等温圧力変化法によって検討した. その結果, ポリカーボネートの大気圧下溶融温度領域の比容積は熱膨張によって7%増大し, 負荷圧力の増加とともに漸次減少する. これに対してLCP-GF30の比容積は0.15% (325℃において) 程度増大するだけでその変化量は前者に比べて著しく小さく, また, 圧力 (最大150MPa) を負荷してもその比容積は大気圧下室温のものとあまり変わらない. したがって, 定常状態におけるこの種液晶ポリマーの比容積は温度・圧力の影響をあまり受けないことがわかった.