纳米SiO2／胶清橡胶复合材料力学性能的研究

采用乳液共混法,研究了纳米SiO2/胶清橡胶复合材料的力学性能.结果表明,采用乳液共混法制备纳米SiO2/胶清橡胶复合材料的力学性能优于机械共混法.纳米SiO2改性剂(硅烷偶联剂 TESPT)用量为7.5%～10%,搅拌时间为30min,纳米SiO2用量为20～30份,可制备出力学性能较好的纳米SiO2/NR复合材料.     

纳米SiO_2/NR复合材料老化性能的研究

本文研究了纳米SiO2/NR复合材料制备方法。硅烷偶联剂Si69用量和纳米SiO2用量对纳米SiO2NR复合材料力学性能和老化性能的影响。结果表明,乳液共凝法制备的纳米SiO2NR复合材料力学性能和耐老化性能优于机械共混法制备的纳米SiO2NR复合材料力学性能和耐老化性能。加入Si69后,纳米SiO2NR复合材料力学性能和耐老化性能得到改善。在天然橡胶中加入纳米SiO2,改善了天然橡胶的力学性能和耐老化性能。     

不同制备方法对纳米SiO2/NR复合材料力学性能的影响

本文研究了不同制备方法对纳米SiO2/NR复合材料力学性能的影响,结果表明:乳液共凝法制备的纳米SiO2/NR复合材料的力学性能优于机械共混法制备的纳米SiO2/NR复合材料力学性能.而先用硅酸钠和乙酸乙酯等制备纳米SiO2乳液,再与天然胶乳共凝的方法比用市售纳米SiO2与天然胶乳共凝的方法,纳米SiO2/NR复合材料...     

TESPT改性纳米SiO_2原位补强NR的研究

控制制备工艺条件,Na2SiO3·9H2O与HCl在助剂作用下,先制备出改性的纳米SiO2乳液,再与天然胶乳共混共凝制备纳米SiO2/天然橡胶(NR)复合材料,采用红外光谱(IR)、高分辨透射电镜(TEM)、扫描电镜(SEM)和动态力学测试仪(DMA)等现代分析仪器研究不同用量的硅烷偶联剂双(γ-三乙氧基硅丙基-)四硫烷(TESPT)原位改性纳米SiO2对纳米SiO2/NR复合材料力学性能及其结构的影响。结果表明,TESPT的水解羟基与纳米SiO2粒子表面羟基发生化学反应,其最佳用量为纳米SiO2质量的15%,制备的纳米SiO2/NR复合材料具有优异的力学性能。     

纳米CaCO3/NR复合材料的制备研究

研究了乳液共沉法制备纳米CaCO3/NR复合材料的制备工艺。结果表明,乳液共沉法制备的复合材料的力学性能优于机械直接共混法制备的复合材料的力学性能。当搅拌时间为60 min,胶乳浓度为20%,纳米CaCO3用量为20～30份时,可制备出力学性能较好的纳米CaCO3/NR复合材料。     

纳米SiO2/NR复合材料制备工艺研究

本实验以工业水玻璃和天然胶乳为原料,根据乳液共凝原理,将纳米SiO2乳液与天然胶乳共混制备纳米SiO2/NR复合材料。通过正交实验设计分析制备工艺对复合材料力学性能的影响,得出了纳米SiO2/NR复合材料的最佳制备工艺条件为水玻璃浓度为5%,反应温度为50℃,反应时间I为25 min,反应时间II为45 min。     

聚氨酯弹性体/纳米SiO2复合材料的力学性能研究

采用预聚体的方法制备了聚氨酯弹性体(PUE)/纳米SiO2复合材料,通过AJ(OH)3对纳米SiO2表面改性以及超声波分散的方法来提高纳米SiO2在PUE基体中的分散性,并考查了表面处理前后的纳米SiO2对PUE/纳米SiO2复合材料力学性能的影响.结果表明:改性后的纳米SiO2能均匀分散于PUE基体中,复合材料的力学性能明显提高;纳米SiO2的用量对PUE/纳米SiO2复合材料的力学性能影响较大,并且当纳米SiO2的质量分数为2%和3%时,复合材料的拉伸强度和撕裂强度分别达到最大.     

纳米SiO2改性NR/SBR共混胶的结构与性能研究

研究了纳米SiO2加入方式及用量对NR/SBR共混胶的正硫化时间、力学性能的影响,并研究了纳米SiO2改性前后共混胶的耐热分解性能、耐热空气老化性能及微观形态结构.结果表明:纳米SiO2的加入对共混胶的正硫化时间、力学性能及耐热稳定性能有较大影响;当纳米SiO2加入量为7％(质量分数)并采用NR/SBR共混均匀后先加入纳米SiO2,再加入小料、硫磺的方式制备NR/SBR共混胶时,纳米SiO2通过使NR/SBR共混胶的分散相细化并使共混胶的整体交联密度提高,有效地提高了NR/SBR共混胶的综合力学性能和耐热稳定性能,达到了对NR/SBR共混胶良好的补强改性效果.     

PTT/PP-g-GMA/纳米SiO2三元复合材料的结构与性能研究

采用甲基丙烯酸缩水甘油酯接枝聚丙烯(PTT/PP-g-GMA)、纳米SiO2增韧聚对苯二甲酸丙二醇酯(PTT).研究了制备工艺、PTT/PP-g-GMA/纳米SiO2用量对三元复合材料的形态、力学性能及结晶性能的影响.研究表明,一步法制备的复合材料具有PTT/PP-g-GMA和纳米SiO2各自独立分散的形态,两步法制备的复合材料具有PTT/PP-g-GMA包覆纳米SiO2的核壳结构.两种方法制备的复合材料的拉伸强度接近,采用两步法制备的复合材料具有更好的增韧效果,冲击强度提高161.9%.PTT/PP-g-GMA与纳米SiO2对PTT的结晶都有促进作用,一步法中纳米SiO2的异相成核作用更为明显.     

PP/无机纳米粒子/POE-g-MAH三元复合材料的研究

采用熔融共混法分别制备了PP/纳米SiO2/POE-g-MAH和PP/纳米TiO2/POE-g-MAH两种复合材料;通过力学性能测试和SEM照片研究了其力学性能及微观形态结构。结果表明:纳米SiO2和纳米TiO2对PP/POE-g-MAH复合材料具有增强增韧作用,在POE-g-MAH的用量为5%、纳米粒子的用量为2%时,PP/无机纳米粒子/POE-g-MAH复合材料的综合力学性能达到最佳;SEM分析表明,该复合材料在断裂过程中发生塑性变形,因而韧性较佳;由DSC分析可知,纳米SiO2、TiO2均对PP基体有异相成核作用,此作用随POE-g-MAH的加入得到进一步促进。     

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。