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 Posted: Thu 22:15, 02 Dec 2010 Post subject: mbt sandals shoes The molecular weight distributio |
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The molecular weight distribution and polycarbosilane spinnability of
Spinnability, but easy to make products that further studies lower the melting point, PCS features more directly on the map with its high-GPC, summarized a large number of low molecular weight tailing on GPC chart,[link widoczny dla zalogowanych], you can weight 5000 (corresponding to elution time 12.5min) and 500 (elution time 17.5rain) is bounded by the GPC chart spider divided into high, medium and low molecular weight region of three parts (Figure 2), with the GPC curve of the ratio of the corresponding area integral A ~ / AM, An / A ~ Molecular characterization of the high and low levels respectively, the melting point can be calculated Pcs, spinning of the relationship between its high and low molecular content of the figure, shown in Figure 5. A 7 - high-tech communications 1996.1 can be seen, low molecular weight content increased the A / A \difficult to handle without melting. On the other hand. polymer content / A increases although the melting point increase, but significantly affect the spinnability of PCS. can be seen from Figure 5, when the A \spinnability even worse loss, when the value within 5 ~ 13% change. PCS has a good spinnability. This indicates that in order to get a good spinnability product must control the polymer part of the content. L, - () Figure 4 in the low molecular weight polycarbosilane content on the melting point of the tung ring in Figure 5 polycarbosilane polymer content on the melting point and spinnability of the tung ring 3. PCS under the control of molecular weight distribution can be seen above studies, in order to get good properties (high melting point and good spinnability) of PcS,[link widoczny dla zalogowanych], must control the molecular weight distribution,[link widoczny dla zalogowanych], so scatter factor ≤ 2.0, and control their low molecular weight content of ≤ l5,[link widoczny dla zalogowanych], polymer content ≤ l5 synthesized by careful control of temperature and time, the above conditions can be satisfied PCS. In addition, by controlling the synthesis conditions and post-treatment to be appropriate to regulate the products of high and low molecular weight content,[link widoczny dla zalogowanych], molecular weight distribution can be more evenly PcS. Figure 5 and Figure 3 results in the upper left of the sample represented a number of points that this is the product. They have high melting point, the smaller dispersion coefficient (<1.7) and good spinnability, is excellent for the manufacture of SiC fiber raw materials. References: [1] YajhrmS, OkatnuraKeta1Cl ~ ern. Lea. . 1975.931 [2] H. asegawaY. OkamuraKJ. Ma / er. . , 1983, l8: 3633Es] SongYC, FangCxeta1. J. . Ldt. , 1992,11:899] HasegawaY, OkamuraK. J. Mat, ~ r. . . 1986.21:312 AStudyonMolecularWeightDistributionandSpinnabilityofPolycarbosilane (receivedMar.2, 1995) SongYongcai, WangLing, FangChunxiang (DepartmentofMaterialsEngineeringandAppliedChemistry, NationalUniversityofDefenceTechnology, Changsha410073) AbstractThesynthesisofpolyearbosilaneanditsmolecularweightdistributionaredescribed. Theeffectofthemolecularweightdistribution, especiallyhighandlowmoleculecontento1 \Thecontrolstandardandmethodforpolycarbosilanemolecularweightdistributionarepresented. Keywords: Polycarbosilane, Synthesis, Molecularweightdistribution, Spinnabflity a 8 a
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