超声挤出DP/纳米SiO2复合材料的拉伸与流变性能

在高能超声波作用下,将纳米SiO2和一种新颖的共聚聚丙烯(DP)熔融共混,制备纳米复合材料,研究了纳米SiO2含量和超声波对复合材料拉伸和流变性能,以及脆断面形貌的影响。结果表明,低含量(≤2%)纳米SiO2对DP有增强作用,随着填料含量增加断裂强度下降。超声波的引入能提高含量较高SiO2(>2%)的复合材料的断裂强度和断裂伸长率,降低体系黏度,并有助于纳米SiO2在DP基体中均匀分散。     

热固性树脂/纳米SiO2复合材料性能影响因素的分析

热固性树脂/纳米SiO2复合材料在添加纳米SiO2微粒后具有明显的成核效应。复合材料可显示低诱导期、高结晶速率和较小的半结晶时间等特点。同时纳米SiO2微粒的加入可提高储能模量(Es)、玻璃化转变温度(Tg),且二者的变化都与纳米SiO2微粒的质量分数成正比关系。这表明纳米SiO2微粒与热固性树脂之间存在较强的界面作用。对热固性树脂/纳米SiO2复合材料性能影响因素进行了分析。     

LLDPE／纳米SiO2复合材料的制备与性能研究

利用超声波分散，偶联剂对纳米SiO2进行了表面改性，用共混法制备了LLDPE/纳米SiO2复合材料，系统研究了该种新型复合材料的静态，动态力学性能和红外吸收性能，并与球磨机分散，偶联剂表面处理的纳米SiO2制备的LLDPE/纳米SiO2复合材料进行了对比。结果表明，纳米SiO2对LLDPE具有一定的增强，增韧作用；复合材料的贮能模量和损耗模量随SiO2含量的增加而增大，阻尼在-15-30℃范围内逐渐降低；复合材料的红外吸收能力较LLDPE明显提高，不同的分散，表面处理方法对纳米SiO2在基体中的分散性能影响不同。仅填加3份纳米SiO2时，常规分散，表面处理方法比基体树脂的红外吸收性能提高了42.5%。超声波分散，偶联剂表面处理方法比基体树脂提高了106.7%。     

尼龙66/纳米SiO2复合材料的形态和力学性能

通过熔融共混法制备了尼龙66／纳米SiO2复合材料，并对复合材料的力学性能、动态力学性能以及拉伸断面形态进行了研究。结果表明，随着纳米SiO2含量的增加，复合材料的拉伸强度在纳米SiO2质量分数为3％时达到最大．较纯尼龙66提高7．6％；复合材料的简支梁缺口冲击强度随纳米SiO2含量的增加而增加，在纳米SiO2质量分数为4％时，比纯尼龙的简支梁缺口冲击强度提高51．3％。复合材料储能模量和损耗模量也较纯尼龙66有所增加；复合材料的断面出现明显的塑性变形。     

反应性增容对PP/纳米SiO2性能的影响

研究了反应性增容对聚丙烯(PP)／纳米SiO2复合材料结晶和流变性能的影响。反应性增容使PP的结晶峰温明显提高,结晶速率增大,球晶细化;复合材料的储能模量、损耗模量和复数黏度明显增大,熔体流动速率减小。在环氧功能化纳米SiO2质量分数为3％,反应性增容剂氨基化PP质量分数为10％时,复合材料的结晶峰温从115.8℃升到125．6℃,熔体流动速率从11．0g/10 min降到8．5 g/10 min。     

聚甲醛/纳米SiO2复合材料的力学性能、结晶行为及热稳定性研究

以改性纳米SiO2为填料,通过熔融共混工艺制备聚甲醛/纳米SiO2复合材料,对其力学性能、结晶行为及热稳定性进行了研究。结果表明:复合材料的拉伸强度和缺口冲击强度随着SiO2含量的增加呈先增大后减小的趋势,二者分别在SiO2质量分数为3%和1%时达到最大;而弹性模量的情况则有所不同,其随着SiO2含量的增加不断增大。DSC测试结果显示,纳米SiO2具有较好的形核作用,能够促进聚甲醛的结晶温度升高,但会抑制晶粒的生长,导致复合材料结晶度的降低。此外,纳米SiO2还能显著提高聚甲醛的热稳定性。与纯聚甲醛相比,复合材料的最大热分解温度在氮气和空气气氛下分别提高了约41.1℃和24.5℃。     

尼龙1010/十八烷基胺插层蒙脱土纳米复合材料研究

通过熔融加工制备了尼龙1010(PA1010)/十八烷基胺插层蒙脱土(OMMT)纳米复合材料。研究了OMMT含量对PA1010/OMMT纳米复合材料力学性能的影响。当OMMT质量分数为2%时,该纳米复合材料的综合力学性能达到最优。用TG、DMTA、DSC等分析方法对材料的热稳定性、结晶性能等进行了分析表征。结果表明,OMMT的加入提高了纳米复合材料的结晶温度、玻璃化转变温度和储能模量,但纳米复合材料的热稳定性稍有降低。     

偶联剂表面处理对复合材料动态力学性能的影响

利用纳米SiO2对氰酸酯树脂(CE)进行改性,研究了纳米SiO2的含量对纳米SiO2/CE复合材料动态力学性能的影响;在此基础上,分别选用小分子偶联剂KH-560和大分子偶联剂SEA-171对纳米SiO2进行表面处理,进一步研究了界面结构对纳米SiO2/氰酸酯树脂复合材料动态力学性能的影响。结果表明,经SEA-171表面处理后的3.0%纳米SiO2/CE复合材料的储能模量比纯CE可提高近4倍,损耗模量可提高2.4倍,力学损耗因子可提高1.8倍。初步探讨了其作用机理。     

偶联剂对SiO2／CE复合材料动态力学性能的影响

利用纳米SiO2对氰酸酯树脂(CE)进行改性,研究了纳米SiO2的含量对纳米SiO2/CE复合材料动态力学性能的影响.在此基础上,分别选用小分子偶联剂KH-560和大分子偶联剂SEA-171对纳米SiO2进行表面处理,进一步研究了界面结构对纳米SiO2/氰酸酯树脂复合材料动态力学性能的影响,初步探讨了其作用机理.结果表明,经SEA-171表面处理后的3.0wt%纳米SiO2/CE复合材料的储能模量比纯CE可提高近4倍,损耗模量可提高2.4倍,力学损耗因子可提高1.8倍.     

纳米二氧化硅/MC尼龙6原位复合材料非等温结晶动力学的研究

通过阴离子开环聚合法制备了纳米二氧化硅(SiO2)／MC尼龙6原位复合材料。采用差示扫描量热法研究了MC尼龙6及其原位纳米复合材料的非等温结晶行为；并利用修正Avrami方程的Jeziomy和Liu法进一步处理原位纳米复合材料的非等温结晶动力学。结果表明，在纳米SiO2／MC尼龙6原位复合材料中，纳米SiO2对基体MC尼龙6的结晶有一定的成核作用，并提高了其结晶速率。     

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。