加巴喷丁的热分解过程及动力学

采用热重法(TG)和差示扫描量热法(DSC)测定加巴喷丁(GBP)在氮气氛和空气氛中的热分解过程,测定GBP、热分解过程中不同阶段残余物和气化物的红外光谱,探讨GBP的热分解机理.根据不同升温速率下的热重曲线计算GBP热分解反应的动力学参数,采用Dakin方程推算GBP在各种温度下的预期寿命.结果表明,GBP的热分解过...     

挤塑聚苯乙烯（XPS）的受热过程研究

本文采用不同的加热方式，在升温速率为10K/min时，研究挤塑聚苯乙烯（XPS）受热过程中的变化规律。采用热重- 红外（TG- FTIR）联用测试方法，研究XPS的热解特性，同时研究了其热分解过程中气体产物的释放规律。在烧结影像仪中观察试样加热过程中的膨胀收缩变形，确定其熔融和流动温度；试样的流动温度约为212℃。     

低爆速爆炸焊接炸药热安全性研究

文章利用DSC TG(差示扫描量热法与热重法)联用技术,在不同的升温速率((10℃/min,20℃/min,40℃/min),下用热分析仪研究了爆炸焊接炸药的热分解动力学规律,求出了混合前后体系的活化能E(kJ/mol),指前因子A(s-1)和动力学机理函数F(a),也给出了各体系在某一特定温度下的热分解速率常数k(s-1)以及热分解起始温度T(K)等。这样我们便得出了该种炸药的热安全性与否。使其能够在工业领域得到合理安全的应用。     

热重-红外联用法研究液晶聚合物的热解行为及其逸出气体组成

采用热重-红外(TGA-FTIR)联用技术研究液晶聚合物(LCP)的热分解行为,研究不同升温速率(10、20、30、40、50℃/min)对LCP热稳定性的影响,同时对LCP的逸出气体组成进行分析。结果表明:LCP受热分解过程主要为一个失重阶段,LCP组分受热后,分子链断裂,降解成三聚体、二聚体、单体等化合物,有些化合物裂解成烃类物质生成CO2逸出。升温速率对LCP热分解过程的影响主要表现在最大失重速率温度(T_m)和最大失重速率(D_m)上,随着升温速率的增加,D_m增加,T_m升高。     

废旧轮胎热裂解行为的热红联用研究

采用热红联用技术研究升温速率对废旧轮胎热裂解转化率及产物的影响。结果表明:升温速率为50,20和5℃·min-1的峰值温度规律性地依次递减,主要是由样品的热弛豫造成的;热裂解第1阶段天然橡胶和合成橡胶同时裂解,第2阶段为合成橡胶裂解;废旧轮胎在不同升温速率下的热裂解产物不同,升温速率大有利于得到相对分子质量小的成分。     

RDX基炸药热起爆临界温度的测试及数值计算

为了研究RDX基炸药在不同烤燃温度下的热分解规律,采用恒温控制技术,以1℃/min的升温速率对RDX基炸药进行了烤燃试验。利用FLUENT软件对不同温度下的热爆炸延滞期进行了数值模拟。结果表明,烤燃温度对RDX基炸药的热分解有重要影响,当恒定温度达到175℃时,RDX基炸药的分解速率发生明显变化。数值模拟结果表明,当以1℃/min的升温速率加热至178℃恒定660min时,RDX基炸药发生了自加热反应,最终导致点火。RDX基炸药发生自加热反应的临界温度为178℃。     

氟橡胶F2314黏结剂的热分解动力学

根据F2314黏结剂在升温速率分别为5,10,20K／min时的DSC-TG曲线,在20～500C温度范围内对F2314黏结剂的热分解过程进行了研究,用Coats-Redfern方法获得F2314黏结剂的热分解动力学参数和机理函数。结果表明,在不同升温速率的TG曲线上,F2314黏结剂热失重的起始温度大致相同,而结束温度随升温速率的增大而升高。同时,升温速率为10K／min的DSC曲线由一个熔化吸热峰和一个分解放热峰组成,在低于360℃时具有良好的热稳定性。得到F2314黏结剂热分解的活化能为294．76kJ／mol,指前因子为10^21.62s^-1,机理函数为f（α）=（1-α）^3/4。     

CHDM改性共聚酯的热降解动力学研究

采用热重分析法研究了在氮气氛围中不同用量1,4-环己烷二甲醇(CHDM)改性共聚酯(PETG)在不同升温速率下的热稳定性,利用Flynn-Wall-Ozawa方法、Friedman方法研究了PETG共聚酯的热降解动力学.结果表明:在相同的升温速率下,随着CHDM用量的提高,PETG共聚酯在较低的温度下开始降解,且降解加...     

对位芳纶耐光性能和热性能研究

聚对苯二甲酰对苯二胺(PPTA)经过紫外光照射后易产生变色，使用氙灯老化箱对PPTA粉体的耐光性能进行研究，使用热重分析方法对PPTA粉体的耐热性能以及热分解动力学进行了研究，通过分析得出PPTA热降解起始分解温度、最大分解速率和热分解动力学参数，这对于了解PPTA热稳定性以及光照条件下老化寿命等具有一定的指导意义。     

石油发酵尼龙1313热降解性能的研究

利用热重分析和差示热重分析法研究了石油发酵尼龙1313在N2气流中以不同速率升温时的热降解过程及其动力学，发现尼龙1313的热降解过程为一步反应；随着升温速率的增大，降解温度线性升高，降解率则变化不大；分别用Coats-Redfem方法、Ozawa方法和Friedman方法进行了反应动力学处理，确定尼龙1313的表观降解反应级数为1．0,反应活化能为277．8kJ／mol左右。     

Insect antifeedant properties of anthranoids from the genusVismia

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

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.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

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.     

2007～2008年世界塑料工业进展

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.     

2005～2006年国外塑料工业进展

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。