合成反式—1,4—聚异戊二烯的硫化与性能

考察了交联反式－１，４－聚异戊二烯的结构与性能，结果表明，合成ＴＰＩ能用普通不饱和橡胶的硫化体系一硫磺／ＴＥＴＤ交联，随着硫磺用量的增加，交联密度提高，结晶度和结晶速度降低，相应热刺激温度降低，当硫磺用量小于０．７５份时，表现为热塑性；当硫磺用量大于２．０份时，室温下为弹性体，当硫磺用量在０．７５～２．０份范围内，为热致弹性体，可作为形状记忆材料，其热刺激温度在３０－５０℃，硫磺用量大于２份时，材     

高反式—1,4—聚异戊二烯形状记忆材料的研究

低度交联反式－１,４－聚异戊二烯（ＴＰＩ）是一种交联度控制在一定范围,室温下可结晶,加热后具有热弹性,从而具有形状记忆功能的材料。本文研究了有机过氧化物硫化体系及填料对低度交联ＴＰＩ力学性能、电性能以及热刺激变形温度等的影响,并和硫磺硫化体系进行了对比。结果表明,有机过氧化物硫化比硫磺硫化ＴＰＩ形状记忆材料具有更高的硬度、拉伸强度,更低的回复残率,更大的体积电阻率,适合电绝缘性能要求较高的制品。     

NBR－40交联度影响因素的研究

用凝胶表征的方法，对以复合脂肪酸皂为乳化剂、叔十二碳硫醇为调节剂。高温高转化率的ＮＢＲ－４０交联度的影响因素进行了研究。结果表明：转化率小于７５％为非交联型，转化率大于７５％则交联度急剧上升；降低聚合温度、引发剂用量、丙烯腈配比以及使用调节剂丁均可降低交联度；未终止聚合的胶浆会发生交联反应；ＮＢＲ－４０在１７０℃受热也发生交联反应；交联度过高的产品会降低改性ＰＶＣ的强伸性能。     

动态硫化EPDM／PP热塑性弹性体分散相粒径

采用１．７Ｌ密炼机和动态硫化法，当三元乙丙橡胶／聚丙烯为７５／２５（质量比）时，仍可得到海一岛结构的热塑性弹性体，其分散相像胶粒子的平均粒径为０．０５８μｍ。对分散相平均粒径的研究表明，当共混剪切速率为２０９－６０２ｓ＾－＾１时，平均粒径为０．０６２－０．．０５６μｍ；当树脂的熔融指数（测定１０ｍｉｎ）为０．０８－１．２ｇ／ｍｉｎ时，则为０．０５８－０．０６２μｍ；当分散相的交联速率为５．０－６．     

氯化钙－正丙醇－水溶液稀释热

使用ＬＫＢ－２１０７型流动式微量热计测量了２８８．１５Ｋ，２９８．１５Ｋ和３０８．１５Ｋ下ＣａＣｌ_２－ｎ－Ｃ_３Ｈ_７ＯＨ－Ｈ_２Ｏ溶液的稀释热。混合溶剂中正丙醇摩尔分数Ｘα：０．００，０．１３，０．２５，０．５０，０．７５，０．８７和１．００。测量结果用扩展的Ｄｅｂｙｅ－Ｈｕｃｋｅｌ方程关联，计算了不同溶剂组成下溶液无限稀释热△Ｈ_Ｄ（ｍ＝０．５，Ｘα）。结果表明：Ｘα相同时，－△Ｈ_Ｄ随温度增加而增加；温度相同时，随Ｘα变化，当Ｘα≈０．８７时，－△Ｈ_Ｄ具最大值。     

交联程度对发泡杜仲胶基形状记忆材料性能的影响

以热膨胀物理微球作发泡剂制备了发泡杜仲胶(EUG)基形状记忆材料,并考察了硫黄用量及交联程度对其形状记忆行为的影响。结果表明,随着硫黄用量的增加,EUG的交联程度增大,结晶度和熔融温度降低,材料的发泡程度并不随交联程度变化呈线性变化。力学性能与其交联程度、结晶度和发泡程度有关;随着交联程度的增加,热致形变回复率和热刺激响应温度降低,形变回复速率增大,当硫黄用量为0.8份时形状记忆性能最佳。     

B阶段杜仲胶—形状记忆材料

B阶段杜仲胶是一种交联度控制在一定范围,室温下可结晶,加热后具有热弹性,从而具有形状记忆功能的材料.本文较系统地报导了硫磺及促进剂对B阶段杜仲胶力学性能(屈服强度、模量、抗拉强变及断裂仲长率)及热刺激变形温度的影响。结合DSC分析,找到了交联度、热刺激变形温度及DSC熔融转变温度间的对应关系.     

反－1，4－聚异戊二烯的结晶行为

用膨胀计法研究了负载型钛催化合成反－１，４－聚异戊二烯（ＴＰＩ）的结晶行为，其本体结晶动力学实验数据符合Ａｖｒａｍｉ方程。结晶速率常数ｋ在２０～４５℃时，随温度升高而减小；Ａｖｒａｍｉ指数ｎ在２０～３０℃时，接近１，在４５℃时，接近２。同时还考察了交联对ＴＰＩ结晶速度和结晶度的影响，并用ＤＳＣ观察了交联ＴＰＩ熔融吸热峰的变化。     

硫化剂对天然杜仲胶记忆材料的性能影响

依据杜仲胶橡塑二重性,以体系内硫化剂调整其硫化胶的结晶度,实现不同硫磺用量下的杜仲胶记忆材料制备,并进行相应的力学、动态力学、热性能的表征。结果表明,当硫黄用量增加到一份时,硫化胶交联密度没有明显变化,硫黄用量超出1份以后,交联密度显著增加。定伸应力和拉伸强度随硫黄用量的增加时呈先减小而后增大趋势,拉断伸长率表现相反;同时,热致回复温度范围降低,而且在硫黄用量为1份时最小。     

NBR—40交联度影响因素的研究

用凝胶表征的方法，对以复合脂肪酸皂为乳化剂。叔十二碳硫醇为调节剂，高温高转化率为ＮＢＲ－４０交联度的影响因素进行了。结果表明：转化率小于７５％为非交联型，转化率大于７５％则交联度急剧上升；降低聚合温度、引发剂用量、丙烯腈配比以及使用调节剂丁均可降低交联度；未张止聚合的胶浆会发生交联反应；ＮＢＲ－４０在１７０℃受热也发生交联反应；交联度过高的产品会降低改性ＰＶＣ的强伸性能。     

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。