LDPE/SBR复合改性沥青的贮存稳定性

比较了直接添加LDPE、SBR改性沥青与LDPE／SBR熔融共混物改性沥青的高温贮存稳定性，并利用光学显微镜观察了各种改性沥青在高温下随时间的变化。结果表明：直接添加LDPE、SBR所得到的改性沥青，其高温贮存稳定性很差。而采用预先制备含有部分共聚物的LDPE／SBR共混物所得到的改性沥青能够在高温下稳定贮存。同时，相形态观察也表明，这种共混物改性沥青的高温相形态也不随时间变化，这一点与稳定性测试结果想吻合。     

贮存稳定的LDPE/SBS共混物改性沥青的动态力学性能

利用应变控制流变仪对LDPE／SBS共混物改性沥青的动态力学性能进行了研究，考察了反应剂及其用量，LDPE／SBS共混物用量等对改性沥青高温性能的影响。结果表明，LDPE／SBS共混物的加入提高了原始沥青的高温模量，同时降低了其损耗角正切值，并且随着共混物用量的增加。沥青的高温性能也随之提高，温度敏感性也显著减弱。反应剂的加入使得沥青高温性能得到了更进一步的改善。改善程度随反应剂用量的增加而更加明显。     

LDPE/SBR复合改性沥青动态力学性能的研究

利用应变控制流变仪考察了共混物、硫磺及其用量等因素对LDPE／SBR改性沥青动态力学性能的影响。结果表明：共混物的加入提高了原始沥青的高温复合模量,降低了其损耗角正切值;随着共混物用量的增加,沥青的高温性能也随之提高,温度敏感性也显著减弱;硫磺的加入更进一步改善了沥青的高温性能,改善程度随硫磺用量的增加而更加明显;采用废旧塑料所得到的改性沥青依然拥有良好的高温动态性能。     

丁苯橡胶改性沥青的高性能化和稳定化

在丁苯橡胶(SBR)改性沥青时加入稳定剂，运用反应共混方法研制出了高性能、高温贮存稳定的SBR改性沥青。利用动态力学性能分析和相形态观察分别比较了加入稳定剂对SBR改性沥青的动态力学性能和体系相形态在高温下的影响。结果表明，与未加稳定剂时相比，加入稳定剂的SBR改性沥青除能保持良好的低温性能之外，其高温物理机械性能有了明显的改善，且在高温下贮存数天后仍稳定。稳定剂的加入使得改性沥青体系内形成了弹性交联网络结构，显著改善了SBR改性沥青的高温贮存稳定性能和高温物理机械性能。     

LDPE改性沥青的研究

采用二阶二混法制备了能在沥青中微细分散的LDPE改性沥青。二阶共混物的动态粘弹分析表明：沥青中的部分组分可渗入LDPE颗粒内部，干扰了其部分结晶。LDPE改性沥青的显微结构显示沥青LDPE有一定的结合。通过对改性沥青结构与性能测试表明：LDPE提高了基质沥青的高温性能，明显减少了沥青的感温性。     

SBS/MMT共混物改性沥青性能的研究

利用苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)与蒙脱土(MMT)制备了不同m(SBS):m(MMT)的共混物,探讨了共混物中m(SBS):m(MMT)对改性沥青物理机械性能、高温贮存稳定性、相形态及动态力学性能的影响。同时,对SBS/MMT用量和质量比相同的共混物改性沥青与直接改性沥青的性能作了对比分析。结果表明:利用SBS/MMT共混物对沥青进行改性在保持试样较好的低温性能的同时,能够明显提高沥青的高温贮存稳定性及高温动态力学性能,整体改性效果优于SBS/MMT直接改性沥青。     

SBS改性沥青高温贮存稳定的新方法

SBS改性沥青在高温下贮存不稳定，使用SBS／炭黑共混物改性沥青，显著改善了SBS改性沥青的高温贮存稳定性。炭黑提高了SBS改性沥青的高温使用性能，而低温延伸性能有所降低。     

SBR/OMMT复合材料改性沥青的性能研究

采用SBR／有机蒙脱土（OMMT）复合材料对沥青进行改性，研究改性沥青的常规性能、流变性能及高温贮存稳定性。结果表明，与基质沥青相比，SBR／OMMT复合材料改性沥青的针入度减小，软化点升高，低温性能明显改善，高温弹性和抗变形性能提高；随着复合材料中OMMT用量的增大，改性沥青的针入度减小，软化点升高，高温弹性和抗变形性能提高；改性沥青的高温贮存稳定性较好。     

贮存稳定的SBS/PE共混物改性沥青

研究了用SBS／PE熔融共混物改性的沥青和直接添加SBS及PE所得改性沥青的高温贮存稳定性,结果表明,前者的高温贮存稳定性明显优于后者,可能是由于熔融共混过程中生成了SBS－g-PE,改善了SBS与PE的相容性,从而提高了改性沥青的高温贮存稳定性。     

丁苯橡胶与高压聚乙烯共混物的微观相结构形态

采用冷冻超薄切片,四氧化锇染色制备样品,用透射电子显微镜观察,研究了丁苯橡胶/高压聚乙烯(SBR/LDPE)共混物的微观相结构形态。当 LDPE用量为 5—35％时,LDPE为分散相,SBR为连续相,并随 LDPE用量的增加,分散相的区域尺寸由 0.5 μm增大到 3.0 μm,而其形态则由近似圆球形变成不规则的长条形。当 LDPB用量增大到50％时,LDPE 呈网状结构,在网络区包藏有小于0.2μm的SBR颗粒,即发生了相转变。共混温度以110±5℃为宜。二段共混与一段共混相比,共混均匀,分散相的最大区域尺寸可由 5 μm下降到小于 1μm,且相分布较密。加入助剂,能使相结构更为精细。     

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。