硫化温度对天然橡胶硫化胶网络结构及性能的影响

研究了硫化温度对天然橡胶硫化胶的化学交联网络、填料网络以及动态性能和物理机械性能的影响。结果表明,随着硫化温度升高,天然橡胶硫化胶的交联密度降低,相应地物理机械性能有所下降。随着硫化温度升高,胶料的焦烧时间和硫化时间缩短,填料的絮凝时间也随之缩短,使得填料的网络化程度降低,硫化胶的滞后损失减小。     

三种不同硫化助剂对MVQ/EPDM共混胶性能的影响

研究了3种硫化助剂对MVQ/EPDM共混胶硫化特性、力学性能、耐热老化性能、高温压缩永久变形性能及动态力学性能的影响。结果表明,添加硫化助剂HVA—2的共混胶焦烧时间和正硫化时间均明显缩短;添加硫化助剂丁羟胶和TAIC的共混胶焦烧时间和正硫化时间均变化不大;添加硫化助剂丁羟胶的共混胶具有最好力学性能、耐热老化性能和压缩永久变形性能,其玻璃化温度也比空白样的低近3℃。     

水切割胶粉在胶鞋大底中的应用

采用水切割工艺制备胶粉,并将其应用于胶鞋大底中,研究了水切割胶粉用量及粒径大小对并用胶加工性能、硫化特性及物理机械性能的影响。结果表明,胶粉的加入使得混炼胶的门尼黏度升高;胶粉掺用量为10phr时对硫化特性影响较小,而用量增加到20phr时,250μm胶粉并用胶的交联密度下降,焦烧时间(t_(10))及正硫化时间(t_(90))缩短,120μm胶粉并用胶的焦烧时间缩短20s,交联密度及正硫化时间无变化;硫化胶的拉伸性能、撕裂性能及回弹性均随胶粉的掺入而降低,耐磨性提高,且硫化胶老化后性能保持率较高。     

硅烷偶联剂对丁腈橡胶和溶聚丁苯橡胶性能的影响

研究了双-(γ-三乙氧基硅基丙基)四硫化物(Si 69)作为硫给予体对硫黄硫化体系丁腈橡胶(NBR)和溶聚丁苯橡胶(SSBR)硫化特性及力学性能的影响。结果表明,Si 69参与了NBR和SSBR的硫化,导致NBR和SSBR的焦烧时间明显缩短,其中对SSBR焦烧时间的影响更大;但随着硫化温度的提高,Si 69对胶料焦烧时间的影响减弱。对添加Si 69后混炼胶的前期硫化行为进行一级动力学模拟发现,Si 69会降低NBR的硫化反应速率,使活化能减小,而对SSBR的硫化反应速率影响不大。硫化胶力学性能研究表明,随着硫化时间的延长,添加Si 69有利于提高NBR硫化胶的力学性能;但是与NBR相反,硫化时间过长,添加Si 69后SSBR硫化胶的力学性能明显下降。     

湿法白炭黑天然橡胶母胶在大型工程机械轮胎中的应用

研究湿法白炭黑天然橡胶母胶(简称湿法母胶)在大型工程机械轮胎中的应用。结果表明:在胎面胶配方中,当硫化60 min时,采用湿法母胶的硫化胶的拉断伸长率和撕裂强度增大,耐磨、抗切割及生热性能改善;在基部胶配方中,采用湿法母胶的胶料的门尼粘度降低,门尼焦烧时间延长,加工性能和焦烧安全性较好,硫化胶的撕裂强度增大;在胎侧胶配方中,采用湿法母胶的胶料门尼粘度减小,分散性改善,硫化胶的拉断伸长率减小,撕裂强度增大。     

均匀剂ZXJ3010在半钢子午线轮胎气密层胶中的应用

研究均匀剂ZXJ3010在半钢子午线轮胎气密层胶中的应用。结果表明:在气密层胶中以均匀剂ZXJ3010等量替代均匀树脂A,胶料的焦烧时间延长,硫化速度加快;硫化胶的300%定伸应力和拉伸强度增大,炭黑分散性和气密性能提高;成品轮胎的高速和耐久性能达到国家标准要求,且生产成本降低。     

模量增强剂8180在全钢子午线轮胎胎肩垫胶中的应用

研究模量增强剂8180在全钢子午线轮胎胎肩垫胶中的应用。结果表明：在胎肩垫胶中添加1.5份模量增强剂8180,胶料的门尼焦烧时间和正硫化时间缩短,最大转矩增大;硫化胶的拉伸强度增大,压缩生热降低;成品轮胎的耐久性能提高。     

杜仲粗胶对NR共混性能的研究

本文通过采用生物酶预处理的方法对杜仲叶子进行处理,得到杜仲粗胶,研究了杜仲粗胶的用量对NR共混性能的影响。结果表明：杜仲粗胶的用量对于硫化胶的焦烧时间,工艺正硫化时间影响不大;用量超过15份后门尼粘度明显增加;随着杜仲粗胶用量的增加,硫化胶的物理机械性能提高,老化后整体的拉伸强度升高,扯断伸长率降低;硫化胶的弹性模量降低,损耗因子升高。     

耐油高压钢丝胶管内胶硫化体系的探究

探讨了6种硫化体系对高压钢丝胶管内胶性能的影响。结果表明,在普通硫黄硫化体系、半有效硫化体系、有效硫化体系、过氧化物硫化体系、硫黄/过氧化物并用硫化体系、复合硫化体系中,半有效硫化体系及复合硫化体系胶料具有合适的焦烧时间,较短的正硫化时间、较高的拉伸强度、较低的压缩永久变形及优良的耐老化性能,且复合硫化体系更适合高硬度、高挺性高定伸的钢丝胶管内胶胶料,从而解决了内胶挤出过程中由于生热量大造成的胶料焦烧问题,满足了实际生产需求。     

热稳定剂TCA-90在全钢子午线轮胎胎肩垫胶中的应用

研究热稳定剂TCA-90在全钢子午线轮胎胎肩垫胶中的应用。结果表明:在胎肩垫胶中加入热稳定剂TCA-90,胶料的门尼焦烧时间相当,硫化速度稍慢,抗硫化返原性能改善;硫化胶的拉伸强度和回弹值增大,压缩生热降低,成品轮胎的耐热性能和耐久性能提高。     

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。