首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 734 毫秒
1.
通过氧指数(OI)、烟密度等级(SDR)、热性能和力学性能的测定,研究了锡酸锌包覆碳酸钙阻燃剂对聚氯乙烯(PVC)电缆料性能的影响。利用TG、DTG和DTA等分析方法,探讨了锡酸锌包覆碳酸钙对PVC的阻燃抑烟机理。结果表明:锡酸锌包覆碳酸钙的加入使PVC电缆料的SDR明显下降,而OI仅略有下降,对PVC电缆料的力学性能和热性能影响不大。  相似文献   

2.
徐跃年 《中国陶瓷》1996,32(1):28-29
本文采用法国Setaram TG一DTA92热分析仪对几种新型陶瓷材料——锰锌铁氧体和镍锌铁氧体进行了实验研究,并由热分析结果计算了它们的反应动力学参数,该工作对新型陶瓷材料的加工具有指导意义。  相似文献   

3.
甲烷磺酸锌的合成、表征及其催化酯化反应性能的研究   总被引:1,自引:0,他引:1  
苏婷婷  姜恒  宫红  王彩凤  王敏 《当代化工》2004,33(3):163-166
合成了甲烷磺酸锌,并利用红外、热重分析对其结构进行表征。热重分析结果表明,实验所合成的甲烷化磺酸锌分子中含有3个结晶水;ZnO含量的实测值与理论计算值基本相符。以甲烷磺酸锌作为催化剂,研究其催化正丁醇与冰乙酸反应生成乙酸正丁酯中各种因素对酯化率的影响。反应条件为:醇酸摩尔比1.2/1,催化剂用量1%(以酸的摩尔数计量),带水剂环己烷2.5mL,反应时间2.5h,反应温度为回流温度,最高酯化率可达到89.9%。甲烷磺酸锌在催化酯化反应过程中可以重复使用6次,酯化率仍然达到88.4%。  相似文献   

4.
脱氢枞酸在空气中的热分解动力学   总被引:1,自引:0,他引:1  
采用TG/DTA/DSC热分析技术,在线性升温速率为5、10、15和20 K·min-1和静态空气条件下,研究了脱氢枞酸在空气气氛中的热分解动力学。由热重/差热法(TG/DTA)得到脱氢枞酸在空气中是一步分解;运用差示扫描量热法(DSC)测定了脱氢枞酸的熔点为445.05K,摩尔熔化焓为19.74 kJ·mol-1和摩尔熔化熵为44.35J·mol-1·K-1;分别利用Kissinger法和Flynn-Wall-Ozawa法对脱氢枞酸非等温热分解数据进行了动力学分析,同时利用Satava-Sestak法研究了脱氢枞酸的热分解机理。结果表明,脱氢枞酸的热分解机理为收缩球状界面反应模型R3,热分解反应的表观活化能为107.89 kJ·mol-1,指前因子为9.33×108 s-1)。  相似文献   

5.
本文采用溶液聚合法制备出三元共聚物P(AALi-AN-BA),使聚聚丙烯酸锂PAALi成膜性能得到改善。利用红外(IR)、差热(DTA)、热重(TG)技术对共聚物进行了表征,通过特性黏数的测试表明当丙烯酸丁酯(BA)在聚合物中含量最大时成膜性最好。  相似文献   

6.
羟基锡酸锌包覆纳米氢氧化镁在PVC中的应用   总被引:2,自引:0,他引:2  
通过均匀沉淀法制备了羟基锡酸锌包覆纳米氢氧化镁并将其应用到聚氯乙烯(PVC)中。利用XRD、TG、DTA对羟基锡酸锌包覆纳米氢氧化镁的性能进行了研究,并通过氧指数、烟密度研究了羟基锡酸锌包覆纳米氢氧化镁对PVC的阻燃和抑烟性能的影响,同时对其力学性能也进行了研究。结果表明:纳米氢氧化镁表面均匀地包覆了羟基锡酸锌;羟基锡酸锌包覆纳米氢氧化镁对PVC的阻燃和抑烟性能明显优于单独添加羟基锡酸锌、纳米氢氧化镁以及羟基锡酸锌包覆微米氢氧化镁和羟基锡酸锌与纳米氢氧化镁混和物时的阻燃、抑烟性能;纳米材料的加入对PVC的力学性能也产生了有利的影响。  相似文献   

7.
偏锡酸锌是一种新型气敏材料,本文用差热分析法(DTA)探讨了诸因素对化学合成过程的影响,确定了制备稳定结构Zn[Sn(OH)_6]及其脱水得到性能良好的ZnSnO_3气敏材料的最佳条件。  相似文献   

8.
本文用HET酸、顺酐、新戊二醇、苯乙烯等为原料,研究了催化剂、温度和不同摩尔比对合成的影响,并用差热分析(DTA)、热重分析(TG)对树脂的热解过程进行了初步探讨。  相似文献   

9.
葡萄糖酸锌是一种重要的锌补充剂,在医药、食品、饲料、化妆品等领域有着重要的应用。本文综述了目前国内外生产葡萄糖酸锌的方法,并阐述了各个方法的优缺点,为葡萄糖酸锌的研究提供参考。  相似文献   

10.
以提高矾浆附加值为目的,拟用矾浆制备纳米氢氧化铝材料。利用酸熔法和碱浸法合成了Al(OH),材料,并针对两种不同制备方法的材料进行了比较,发现酸熔法得到的是拜耳石(d—Al(OH)3),而碱浸法得到的是勃姆石(γ-AlOOH)。并利用X射线衍射(xRD)、热重一差示热重(TG—DTA)和扫描电境分析(SEM)等现代测试手段对材料进行了表征。  相似文献   

11.
12.
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.  相似文献   

13.
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.  相似文献   

14.
15.
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.  相似文献   

16.
17.
18.
Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.  相似文献   

19.
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。  相似文献   

20.
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号