熔融聚合耐高温聚酰胺流变性能研究

采用毛细管流变仪对熔融聚合耐高温聚酰胺(PA)的流变性能进行了研究。结果表明:熔融聚合耐高温聚酰胺PA10T、PA10T/11皆为假塑性流体,其非牛顿指数随着温度的升高而增加;表观黏度都随着剪切速率或剪切应力的增加而降低;随着剪切应力的增大,黏流活化能减小,表观黏度对于温度的敏感性减弱;与PA10T相比,PA10T/11通过引入第三单体11-氨基十一酸能有效地提高表观黏度对剪切应力、剪切速率和温度的敏感性,从而改善了PA10T的加工性能。利用DMA和DSC对PA10T、PA10T/11进行了分析,结果表明,PA10T引入第三单体11-氨基十一酸后,能提高其分子链的柔顺性,改善PA10T的加工性能。     

透明PA10Ⅰ/11的制备及流变性能研究

以癸二胺、间苯二甲酸和氨基十一酸为单体,水为溶剂,通过高温熔融缩聚合成了透明间苯二甲酰癸二胺-氨基十一酸共聚酰胺(PA10Ⅰ/11)。利用毛细管流变仪研究了PA10Ⅰ/11的熔体流变行为。结果表明:在215²30℃范围内,PA10Ⅰ/11熔体为假塑性流体,其非牛顿指数小于1;PA10Ⅰ/11熔体的表观黏度随着温度的提高、剪切速率和剪切应力的增大而降低;随着剪切应力的提高,PA10Ⅰ/11的黏流活化能降低,而熔体流变特性受温度影响较小,易成型加工。     

原位增容PA6/POE共混物流变行为的研究

使用毛细管流变仪研究了PA6/(乙烯/辛烯)共聚物(POE)共混物的流变行为,并对其lgω-lgτ、lgηa-lgγω、lgηa-1/T曲线进行了分析.研究表明,PA6/POE共混物为假塑性流体,其表观粘度随着剪切应力的增加而降低;加入马来酸酐和引发剂使得PA6/POE共混物的表观粘度增大;PA6/POE共混物的粘流活化能随着剪切应力的增大而降低,说明PA6/POE共混物在高剪切应力下可在较宽的温度范围内加工、成型.     

PET-PA/PA6共混纤维的酸性染料染色性能

为开发酸性染料可染改性聚酯(PET)纤维,将不同共聚比例的PET-聚酰胺(PA)共聚物与聚己内酰胺(PA6)以不同共混比例共混纺丝,制备PET-PA/PA6共混纤维,研究了PET-PA/PA6共混物的热性能、可纺性及共混纤维的酸性染料染色性能。结果表明:PET-PA/PA6共混物中,PET-PA与PA6在无定形区是部分相容的;PET-PA/PA6共混物具有良好的可纺性,其中PA嵌段和PA6共混质量分数均为20%(PET-PA-20/PA6-20)的共混纤维的断裂强度2.54 c N/dtex、断裂伸长率31.0%,满足后续加工的要求;PA嵌段和PA6共混质量分数均为10%(PET-PA-10/PA6-10)共混纤维采用酸性染料染色时,染浴p H值应控制在4.5~5.5;升高温度和延长染色时间都能提高PET-PA-10/PA6-10共混纤维的染料上染率;随PET-PA/PA6着共聚物中PA嵌段比例的增加,共混纤维染料上染率迅速增大,PET-PA-20/PA6-20共混纤维在100℃时,酸性染料上染率可达到99.03%。     

PA6/POE/OMMT纳米复合材料的流变行为

使用毛细管流变仪研究了尼龙6/乙烯-辛烯共聚物/有机改性蒙脱土(PA6/POE/OMMT)纳米复合材料的流变行为,并对lgΥω-lgγω、lgηα-lgγω、lgηα-1/T曲线进行了分析.研究结果表明,PA6/POE/OMMT纳米复合材料为假塑性流体,其表观粘度随着剪切应力的增加而降低;OMMT使得PA6/POE纳米...     

PA6-b-PPG嵌段共聚物的合成与表征

以己内酰胺、己二酸、聚丙二醇(PPG)等为原料,采用高压反应釜进行熔融缩聚,合成了一系列热塑性弹性体尼龙6-b-PPG(PA6-b-PPG)嵌段共聚物。通过傅立叶变换红外分析、核磁共振氢谱对其化学结构进行表征,通过差示扫描量热、热失重分析其热性能,通过差示扫描量热分析、广角X射线衍射及偏光显微镜分析其结晶性能,并测试了材料的力学性能。结果表明,聚合产物为PA6硬段与PPG软段的嵌段共聚物;制备的系列PA6-b-PPG嵌段共聚物熔点在209~225℃之间,起始热分解温度在380~397℃之间。随着PPG含量的增加,PA6-b-PPG嵌段共聚物从γ型结晶向α型结晶转变,密度、硬度、拉伸强度、弯曲强度逐渐降低,而断裂伸长率逐渐增加。可以通过调整软硬段的比例得到不同力学性能的PA6-b-PPG嵌段共聚物,以满足不同条件下的需求。     

尼龙6／高岭土纳米复合材料流变性能

采用XLY-Ⅱ型毛细管流变仪研究了尼龙6(PA6)和PA6/高岭土纳米复合材料的流变性能.结果表明,PA6和PA6/高岭土纳米复合材料均为假塑性流体.在210～240℃纳米复合材料的非牛顿指数为0.860～0.985,其表观黏度随着高岭土含量的增加先升高后下降.且在高剪切速率条件下,高岭土对纳米复合材料体系黏度的影响减小.高岭土的加入使PA6的黏流活化能降低,故在恒定剪切应力下其可在较宽的温度范围内成型加工.     

组分对PA6/PP/滑石粉三元复合材料的影响

通过双螺杆挤出制备了尼龙6(PA6)/聚丙烯(PP)/滑石粉三元复合材料,考察不同PA6、PP及滑石粉和增容剂种类及含量对PA6/PP/滑石粉三元复合材料力学性能的影响。结果表明,中黏度(2.4~2.7 Pa·s)PA6、聚乙烯(PE)含量达到7%~9%的嵌段共聚PP及粒径为2~5μm的滑石粉制备的PA/PP/滑石粉三元复合材料具有优异的力学性能;随着PA6含量增加,PA6/PP/滑石粉三元复合材料的拉伸、弯曲强度增加,吸水率上升,PP含量增加,PA6/PP/滑石粉三元复合材料吸水率下降,拉伸强度和弯曲强度也下降;滑石粉的粒径越大,PA6/PP/滑石粉三元复合材料的刚性越好,冲击强度越差,滑石粉的粒径越小,则容易团聚,三元复合材料形成应力集中点;增容剂马来酸酐接枝乙烯-醋酸乙烯酯共聚物(EVAC-g-MAH)和马来酸酐接枝三元乙丙橡胶(EPDM-g-MAH)复配对PA6/PP/滑石粉三元复合材料增容效果优于马来酸酐接枝聚丙烯(PP-g-MAH)或EPDM-g-MAH;当EVAC-gMAH和EPDM-g-MAH添加量各为5%,PA6/PP/滑石粉质量比为50/20/20时,制备出的PA6/PP/滑石粉三元复合材料具有较佳的力学性能,并有优异的加工性能,其缺口冲击强度可达6.6 k J/m^2。     

原位增容PA6/HDPE共混物流变性能研究

使用XL-YⅡ型毛细管流变仪研究了尼龙6/HDPE共混物的流变行为,并对其lgτω-lgγω、lgηa-lgγω、lgηa-1/T曲线进行了分析。实验结果表明：PA6/HDPE共混物为假塑性流体,其表观黏度随着剪切速率的增加而降低。加入HDPE、马来酸酐和L-101使得PA6/HDPE共混物的表观黏度增大,并且使得在同一剪切应力下的黏流活化能降低,故熔体的流动性受温度的影响较小。     

PA6/SEBS-g-MAH/OMMT/GMA共混物的制备和性能研究

以马来酸酐(MAH)接枝苯乙烯-(乙烯-丁烯)-苯乙烯共聚物SEBS(SEBS-g-MAH)为增韧剂,有机蒙脱土(OMMT)为增强填料,甲基丙烯酸缩水甘油酯(GMA)为相容剂,采用熔融挤出方法制备了PA6/SEBS-gMAH/OMMT复合材料.通过力学、毛细管流变性能测试,考察了SEBS-g-MAH、OMMT和GMA对共混物的力学性能及流变性能的影响.结果表明,共混材料能在保持基本强度及模量稳定的情况下提高冲击强度,获得良好的综合力学性能.PA6及其共混物均为假塑性流体,在230～260℃共混材料的非牛顿指数为0.603～0.931,表观黏度随着剪切应力的增加而降低;加入SEBS-g-MAH、OMMT和/或GMA使得PA6的表观黏度增大,黏流活化能降低;在恒定剪切应力下PA6共混物可在较宽的温度范围内成型加工.     

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。