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991.
Konstantin V. Pochivalov Yaroslav V. Kudryavtsev Andrey V. Basko Tatyana N. Lebedeva Roman Y. Golovanov 《Journal of Macromolecular Science: Physics》2015,54(12):1427-1437
The full phase diagrams of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and isotactic polypropylene (i-PP) mixtures with 1,2,4,5-tetrachlorobenzene (TeCB), including the solubility curve of TeCB in a solid polymer, were constructed by an optical method. The diagrams contain a eutectic point that corresponds to the situation when the crystallization of TeCB out of its solution in a polyolefin is accompanied by the crystallization of monomer units of the macromolecules. As a result, the polymer acquires a gel structure with crystallites as crosslinks and amorphous regions saturated with TeCB. It is demonstrated that the eutectic point position on the phase diagram can be used for ranking polymers with respect to their thermodynamic affinity to a solvent. For the studied systems, the affinity to TeCB was decreased in the order i-PP, HDPE, and LDPE. Direct experimental evidence was obtained that TeCB crystals can be dissolved in a solid polymer via a vapor phase mechanism, which leads to the polymer amorphization. 相似文献
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996.
Bin Wang John R. Klaehn Robert H. Neilson 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4-5):821-825
Silicon-nitrogen-phosphorus compounds of the type Me 3 SiN═PR(R′)X(X= Cl, Br, OCH2CF 3 , OPh), known as N-silylphosphoranimines,are useful precursors to both cyclic and polymeric phosphazenes.Depending on the leaving group (X), thermolysis reactions afford either cyclic trimers, [N═PR(R′)] 3 (when X = Cl, Br), or linear polymers,[N═PR(R′)]n (when X = OCH 2 CF 3 or OPh). Treatment of the P-trifluoroethoxy and P-phenoxy derivatives, Me 3 SiN═PR(R′)X (X = OCH 2 CF 3 , OPh), with alcohols at lower temperature usually results in the formation of cyclic phosphazene trimers via silyl ether elimination. Recently, we have applied these synthetic methods to the preparation of some new phosphazene systems including a series of 4-aryl-functionalized trimers and polymers and a variety of non-geminal, mixed-substituent cyclic trimers. Representative examples of the synthesis, structural characterization, and reactivity of these new phosphazenes and their Si─N─P precursors are reported here. 相似文献
997.
A. B. A. Elgazzar A. M. Gafaar H. N. Hafez A. S. Aly 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1859-1883
Pyridopyrimidine derivatives 2 reacted with hydrazonoylchloride derivatives and yielded triazolopyridopyrimidines 6a–f. Compound 4b reacted with aliphatic acids and afforded triazolo-pyridopyrimidines 7a,b, and the reaction with carbon disulfide afforded 10-mercapto-triazolopyridopyrimidine (10). Moreover, the reaction of 4b with β -ketoesters afforded 10-pyrazolyl-pyridopyrimidines derivatives 11, 13, 14, and 15. Compound 4b reacted with nitrous acid to give tetrazolopyridopyrimidine 16, which reduced to 10-amino-derivative 17. On the other hand, the reaction of 4b with aromatic aldehydes afforded arylidines derivatives 18a–c, which were later cyclized to triazolo-pyridopyrimidines deivatives 19a–c. Finally, 4b reacted with α-haloketones to give triazines derivativrs 20, with new ring systems. 相似文献
998.
Mark D. Noirot Elizabeth G. Bent Arlan D. Norman 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):177-180
Abstract Reaction of the 1,3,2,4-diazadiphosphetidine, trans-[C6H5N(H)P(S)NC6H5]2 with LiR (R = Me, n-Bu) followed by treatment of the resulting dianions with Me3SiCl and Me3GeBr produced trans-[C6H5N(R)P(S)NC6H5]2(R = Me3Si, 2; Me3Ge, 3). Substitution occurs without cis-trans isomerization or significant cleavage of the 1,3,2,4-diazadiphosphetidine ring. 2 and 3 have been characterized by spectral (1H and 31P NMR, IR, and MS) and elemental analytical data. Analogous reactions involving Me3SnCl yield mixtures containing [C6H5N(SnMe3)P(S)NC6H5]2 which could not be isolated or completely characterized. 相似文献
999.
Dadkhoda Ghazanfari Mohammed M. Hashemi Mohammad Reza Akhgar Mohammad Mehdi Foroughi Fariba Najafi-Zadeh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):3018-3022
The ring-opening reaction of epoxides with thiols by SbCl 3 supported on Kieselguhr under solvent-free conditions, afforded high yields of β-hydroxy sulfides. Nucleophilic attack of the thiols occurs regioselectively at the less hindered side of the epoxides. 相似文献
1000.
Hossein A. Oskooie Azam Ranjbaran Majid M. Heravi Mitra Ghassemzadeh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1711-1714
Reduction of aromatic nitro compounds to amine with hydroiodic acid was revisited. Under microwave irradiation on solid support the reduction proceeded efficiently and rapidly. 相似文献