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聚对苯二甲酸丙二醇酯作为新型聚酯材料,具有非常优良的性能,但其易燃性很大的限制了它的应用范围。为了提高对苯二甲酸乙二醇酯的阻燃性能,本文以无卤膨胀型EPFR-300A为阻燃改性剂,马来酸酐接枝聚烯烃(POE-g-MAH)弹性体为增韧剂,对聚对苯二甲酸丙二醇酯树脂(PTT)进行阻燃改性。通过热重分析仪(TGA)、示差扫描量热仪(DSC)、扫描电子显微镜(SEM)、力学性能等技术手段研究了阻燃剂和增韧剂对PTT树脂力学、热学和阻燃性能的影响。结果表明,增韧剂POE和POE-g-MAH的添加提高了PTT树脂的综合力学性能。当质量分数相同时,POE-g-MAH对PTT树脂的增韧效果要优于POE,且当POE-g-MAH质量分数为7%时,综合力学性能最佳。当添加相同质量分数增韧剂,EPFR-300A质量分数达到20%时,阻燃PTT材料阻燃性能最佳,极限氧指数(LOI)达到28.0%,垂直燃烧阻燃等级达到UL94 V-0级。EPFR-300A阻燃剂与PTT树脂间相容性良好,可以有效地促进PTT树脂成炭并提高材料的阻燃性能。 相似文献
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用锥形量热仪研究聚乙烯膨胀阻燃体系的燃烧性 总被引:11,自引:0,他引:11
利用锥形量热仪在50kW·m6-2热辐照条件下,研究了含淀粉线性低密度聚乙烯(LLDPE)燃烧性,获得了最大热释放速率、总热释放、有铲燃烧热、最大烟产生叫烟释放量及质量损失速率等参数,实验结果淀粉膨胀阻燃剂能明显降低LLDPE的热释放速率,总热释放和有效燃烧热,淀粉作为膨胀型阻燃剂中的成炭剂,可以部分代替季戊四醇,而对热释放速率影响不大,达到阻燃和降低成本的目的,该膨胀体系使烟释放变得缓慢,但总烟 相似文献
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将Bi2O3、Sb2O3、SnO2添加到聚磷酸铵(APP)和双季戊四醇(DPER)膨胀型阻燃聚丙烯(PP)体系中,采用氧指数(OI)、热分析(TGA)、热红联用(TG-FTIR)和扫描电镜(SEM),考察它们对膨胀阻燃体系的催化协效作用,探讨其作用机理.结果表明,3种金属氧化物在适量的添加下都可以提高体系的氧指数.TG结果表明,Bi2O3的加入可以提高膨胀炭层在高温时的热稳定性,增加高温时残余物的量;TG-FTIR结果显示添加Bi2O3后,膨胀阻燃剂在热分解过程中,气体的释放过程发生了改变.膨胀炭层的SEM图表明,Bi2O3可以改善膨胀炭层的形貌,提高炭层的隔热隔质性能.0.1 wt%的Bi2O3和1 wt%的纳米黏土复配用于膨胀阻燃体系中,可以在阻燃剂添加20份下,样品氧指数达到28.3;在阻燃剂添加25时,样品(3.2 mm)通过UL-94 V-0级.0.1 wt%的Bi2O3和1 wt%纳黏粘土的添加,还可以提高体系的力学性能. 相似文献
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膨胀型阻燃UPR复合材料的阻燃及抑烟性能 总被引:2,自引:0,他引:2
将叶蜡石(PYR)与膨胀型阻燃剂[IFR,聚磷酸铵(APP)/季戊四醇(PER)/三聚氰胺(Mel))复配],应用于不饱和聚酯树脂(UPR),得到膨胀型阻燃UPR复合材料。通过氧指数(LOI)、垂直燃烧(UL94)、烟密度等级(SDR)、热分析(DSC-TG)对阻燃复合材料的阻燃、抑烟及热稳定性能进行了研究。结果表明:在该膨胀型复配阻燃体系中,叶蜡石与IFR存在明显的协效作用,在mPYR∶mAPP∶mPER∶mMel=4∶2∶1∶1,复合阻燃剂的含量为40%的情况下,LOI高达36.4,阻燃级别为UL94 V-0级,SDR为62.95,满足国家对B1级电器类热固性塑料的使用要求。 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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Mohammed KajjoutChristian Rolando 《Tetrahedron》2011,67(25):4731-4741
Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide. 相似文献