芳纶纤维在子午线轮胎中的应用

采用Abaqus有限元分析软件,研究芳纶纤维在子午线轮胎带束层和冠带层中的应用效果。结果表明:轮胎带束层采用芳纶纤维,第1和第2带束层轴向、横向对称面内周向应力以及带束层端点周向应力均有不同程度下降,提高了轮胎强度和承载能力;冠带层采用芳纶纤维,轴向接地中心线上冠带层肩部应力显著降低,冠带层端点周向应力大幅减小,应力分布均匀性显著提高,能够降低轮胎骨架材料端点破坏的可能性。     

芳纶纤维骨架轮胎的自由滚动数值模拟分析

以165/75R13和185/65R14两种常用规格轮胎为例,利用数值模拟法研究用芳纶替代钢丝作带束层或锦纶作冠带层骨架材料对高速自由滚动工况下轮胎力学性能的影响。结果表明:将芳纶用于带束层,在减小轮胎质量的同时不降低使用性能;芳纶冠带层轮胎在承载能力、耐久性和强度等方面与现有轮胎及芳纶带束层轮胎相比都有显著优势,且轮胎规格越大,芳纶冠带层对轮胎性能的改善效果越明显。     

芳纶/锦纶混纺帘线冠带条的开发及应用

开发了芳纶/锦纶混纺帘线冠带条,并研究冠带条对轮胎性能的影响。结果表明：冠带条材料强度增大、带束层角度减小,轮胎外直径减小;随着冠带条缠绕强度和材料强度增大、带束层角度的减小,轮胎静态接地印痕长轴和短轴长度及面积呈增大趋势;冠带条缠绕强度和材料强度增大,轮胎高速性能提高,带束层角度增大,V速度级别轮胎高速性能显著提升;冠带条缠绕强度和材料强度增大,轮胎滚动阻力降低,带束层角度微调对轮胎滚动阻力影响不大。     

芳纶复合帘布在半钢子午线轮胎骨架材料中的应用

用芳纶复合帘布替代钢丝帘布作为半钢子午线轮胎冠带层和带束层骨架材料。结果表明:与正常轮胎相比,芳纶复合帘布作为带束层骨架材料的轮胎高速性能较好,接地压力分布较均匀,胎肩接地压力较小,电阻较大;芳纶复合帘布可有效提高轮胎的脱圈阻力,轻量化效果明显;芳纶复合帘布胎坯与正常胎坯的外周长差异较大,芳纶复合帘布轮胎的压延、裁断、成型、硫化工艺中需作调整。     

从国(境)外轮胎剖析看纤维骨架材料的应用现状

介绍2000年以来国(境)外轮胎剖析的骨架材料应用情况.锦纶帘线主要用于载重斜交轮胎,也用于轿车子午线轮胎的冠带层;聚酯帘线,特别是DSP帘线正逐渐替代人造丝用于轿车和轻载子午线轮胎乃至Z速度级高性能轮胎;人造丝用量正逐渐削减;芳纶纤维可代替钢丝用于高档轿车子午线轮胎的带束层和冠带层,也用于重型载重子午线轮胎胎体和工程机械斜交轮胎的缓冲层;维尼纶纤维仅在日本生产的轮胎中用于胎圈包布等小部件.     

7.00R16轻型载重子午线轮胎结构有限元分析

采用有限元方法分析7.00R16轻型载重子午线轮胎两种不同带束层结构设计方案对其静态和稳态力学性能的影响。对比两方案胎肩部位骨架材料端点应力和应变能分析可见,方案二（优化带束层结构）的周向应力大于方案一,带束层端点接地区应变能略大于方案一。有限元分析结果表明,整体上方案二优于方案一,且与试验结果吻合较好,证明有限元分析可以有效用于轮胎结构优化设计。     

霍尼韦尔的Beltec冠带层

英国《轮胎与配件》2 0 0 2年 6期 5 8页报道 :子午线轮胎的钢丝带束层是保证轮胎操纵性能和预期使用寿命必不可少的部件。钢丝带束层在使用中有移动的倾向。为了控制轮胎在行驶中胀大 ,采用了一种锦纶冠带层。采用这种锦纶冠带层的目的是保持带束层的整体性 ,避免带束层与胎体帘布层之间发生脱层。在超高性能轮胎中 ,也可使用其它冠带层 ,如聚萘二甲酸二乙醇酯(ＰＥＮ)或芳纶冠带层。在高速行驶中 ,钢丝带束层承受应力 ,而且有从斜角向周向旋转的趋势。在这种情况下 ,钢丝帘线端头会腐蚀其周围的胶料并引发裂口 ,最终的结果是胎面脱层。轮…     

芳纶纤维在轮胎骨架材料中的应用

介绍芳纶纤维作为轮胎骨架材料的性能优势及国内外研究应用情况,对芳纶帘线在轮胎骨架材料中的应用进行总结和展望。芳纶纤维不仅能减小轮胎质量和降低滚动阻力,而且有利于提高轮胎的抗刺扎和抗切割性能,芳纶复合帘线及芳纶胎圈帘布、芳纶带束层的应用可作为开发重点,更有实际生产价值。     

国外子午线轮胎的带束层设计

以米其林、倍耐力、固特异和普利司通公司产品为例,分析国外子午线轮胎带束层材料和结构的发展变化。半钢子午线轮胎带束层用钢丝帘线向结构简单、单丝直径大的方向发展,冠带层帘线出现芳纶/锦纶复合帘线,带束层角度有所增大;全钢载重子午线轮胎带束层用钢丝帘线向高伸长、高抗冲击性方向发展,结构依使用要求不同而不同,带束层工作层端点垫胶厚度有增大趋势。     

国外子午线轮胎带束层材料和结构发展

以米其林、倍耐力、固特异和普利司通公司产品为例,分析国外子午线轮胎带束层材料和结构的发展变化。半钢子午线轮胎带束层用钢丝帘线向结构简单、单丝直径大的方向发展,冠带层帘线出现芳纶/锦纶复合帘线,带束层角度有所增大;全钢载重子午线轮胎带束层用钢丝帘线向高伸长、高抗冲击性方向发展,结构依使用要求不同而不同,带束层工作层端点垫胶厚度有增大趋势。     

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.     

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。     

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.