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Glass 전이점 이상과 이하에서 polystyrene의 자유 체적의 온도의 영향
류종하 영남이공대학 1982 論文集 Vol.11 No.-
On the assumption that a polymer molecule has constant occupied volume and variable free volume, an equation which describes fractional free volume as a function of temperature is derived as shown belowo; above T_g; f = 1-{exp(-∫_0^(T_g)αGdT-∫_(T_g)^TαLdT)}/1+f_0 below T_g; f = 1-{exp(-∫_0^T-αGdT)}/1+f_0 where αG and αL are thermal expansion coefficient below and above T_g, respectively, and f_0 is fractional free volume at 0˚K. The calculated f from this derived equation shows a good agreement with that calculated from Richardson's empirical equation. For polystyrene the calculated f deviates from that of Richardson's empirical equation with no more than 4.2% deviation limit.
류종하,유성구,박영해,류시옥,서길수 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.4
Calcite, vaterite 그리고 aragonite가 혼합되어 있는 탄산칼슘을 X-선 회절로 분석하였다. 이것은 2성분 혼합물에서 X-선회질의 특성피크의 높이로부터 표준곡선을 작성하여 각각의 조성을 구하였다. 즉, calcite-vaterite 혼합물에서, vaterite의 양은 calcite의 특성피크인 2θ값이 29.32°의 높이에 대한 vaterite의 특성피크인 2θ값이 24.81°, 27.09° 그리고 32.75° 특성피크의 높이비로부터 구하였으며, 이 식의 실험오차는 약 3%이다. 그리고 calcite-aragonite의 호합물에서 aragonite의 양은 calcite의 특성피크인 2θ값이 29.32°의 높이에 대한 aragonite의 특성피크인 2θ값이 26.06°, 38.40° 그리고 45.81° 특성피크의 높이비로부터 구하였으며, 이 식의 실험오차는 약 3%이다. 위의 표준곡선으로부터 3성분의 혼합물의 조성비를 계산할 수가 있다. 합성된 순수한 입자의 혼합물을 위의 방법으로 계산한 결과 실험치와 계산치가 아주 잘 일치하였다. Samples of calcium carbonate were analyzed by X-ray diffraction to determine the polymorphic compositions of calcite, vaterite and aragonite. Standard curves were taken from the peak heights of binary polymorphs mixtures. The content of vaterite in the mixture of calcite and vaterite was obtained from the ratio of the peak heights at 29.32 and 24.81° , 27.09° and 32.75° In this work the experimental error is estimated at about 3 %. For the binary mixture of calcite and aragonite the content of aragonite was determined from the ratio of the peak height of calcite, 29.32° to the peak heights of aragonite, 26.06° , 38.40° and 45.81° The experimental error is estimated at about 3%. Compositions of three polymorphs were estimated from the standard curves. The results from the experiments for the pure synthetic components gave excellent agreement with the calculations.
Polystrene내에서 기체 확산에 대한 자유체적의 영향 : CO₂Diffusion into Classy Polystrene
류종하 영남이공대학 1985 論文集 Vol.14 No.-
An analysis of diffusion coefficient, CO₂ diffusion into glassy polystyrene. has been -made. Temperature and pressuse (density of penetrants) dependences of diffusion coefficients are expressed as a function of fractional free volume. From this study it is found that one of the major factors controlling gas diffusion in polymer is the quantity of free volume. The increase of diffusion coefficient as a function of temperature is due to the increase of free volume, and this free volume increase is contributed by temperature increase and penetrant gas. This penetrant gas contribution is known as plasticization of polymer by absorbed gas.
류종하 영남이공대학 산업기술연구소 1988 産業技術硏究 Vol.2 No.-
An equation of state for liquid and glassy polymers is derived. The theoretical values of specific volume, thermal expansivity and isothermal compressibility calculated from the equation agree with experimental ones. It's been found that Rao constant for every polymer is different and the Rao constant of a glassy polymer is larger than that of the liquid polymer.
류종하 영남이공대학 1982 論文集 Vol.11 No.-
From Andrew's statistical model about fractional free volume following equation is derived, D=A_F·T·exp(-B_N/f - 0.232P) where D, T, f and A_F are diffusion coefficient, temperature, fractional free volume and constant (=2.7145×10^(7)), respectively, and B_(N) is given as a function of pressure, B_(N)=3.358-0.232P. This derived equation reads following results, ⅰ. diffusion coefficients increase as a equation of temperature and pressure (concentration of diffusion particles). ⅱ. factors governing diffusion rate are free volume and pressure. The calculated D from derived equation shows a fairly good agreement with Tokuda's experimental results for the case of CO² diffusion in polystyrene, especially, from this derived equation D can be calculated for temperature range above and below Tg.