纳米CaCO3及偶联剂对小本体PP结晶的影响

采用熔融共混法制备了小本体聚丙烯/纳米CaCO3复合材料(SBPP/纳米CaCO3),研究了经铝钛复合偶联剂处理前后的纳米CaCO3粒子对SBPP结晶性能的影响.结果表明纳米粒子能够诱导β晶的形成,提高SBPP的结晶度,降低SBPP球晶尺寸,使得球晶均匀程度增加,并且纳米CaCO3经偶联剂处理后以上几种效果更为显著;纳米CaCO3可以提高材料的结晶温度和结晶速率,但经偶联剂处理的纳米粒子的结晶速率却小于未经偶联剂处理的材料的结晶速率,说明偶联剂的加入在一定程度上抑制了纳米CaCO3对SBPP/纳米CaCO3复合材料的结晶过程.     

聚丙烯的高性能化研究

在小型反应器内合成了不含及含有成核剂的聚丙烯(PP)、双峰聚丙烯(BMPP)和聚丙烯共聚物(PPc)，并用纳米CaCO3改性PPc。研究结果表明：釜内成核的PP和BMPP的弯曲模量和热变形温度显著增加，结晶温度和结晶速率明显提高，BMPP的拉伸强度也较PP大幅增加；但成核剂对PPc的性能影响不大，而加入纳米CaCO3后则使PPc的力学性能和结晶温度同步显著增加。     

改性纳米CaCO3／PP复合材料结晶性能的研究进展

纳米CaCO3用于聚丙烯（PP）的改性研究及成果已有很多报导,主要体现在纳米CaCOH／PP复合材料的力学性能、热学性能及结晶性能等方面。文章着重介绍改性纳米CaCO3／PP复合材料结晶性能的研究状况,为人们后续的相关研究工作提供有价值的线索和依据。     

纳米CaCO3改性β成核聚丙烯的研究

采用经铝钛复合偶联剂处理的纳米CaCO3粒子对β成核聚丙烯（β-PP）进行改性，研究了pPP／纳米CaCO3复合材料的力学性能。结果表明，添加纳米CaCO3能够提高β-PP的综合力学性能，在纳米CaCO3用量为4％（质量分数，下同）时，冲击强度比β-PP提高了33％，是纯PP的3倍；拉伸模量、弯曲模量分别比β-PP提高了10％和15％。X射线衍射和偏光显微镜对β-PP／纳米CaCO3复合材料的结晶结构表征表明，添加纳米CaCO3可以提高β-PP的β晶含量。降低晶粒尺寸，但不会改变β-PP的束状结晶结构形态；差示扫描量热分析表明，纳米CaCO3粒子的存在降低了β-PP的结晶温度和结晶速率。     

单体接枝PP包覆纳米CaCO3对PP结晶动力学的影响

采用不同单体接枝聚丙烯(PP)包覆纳米CaCO3与PP复合制备PP/纳米CaCO3复合材料,用差示扫描量热法研究了复合材料中PP的等温和非等温结晶动力学。研究结果表明,不同单体接枝PP包覆纳米CaCO3填充PP复合材料中PP的结晶温度取决于单体类型。PP复合材料的结晶速率高低顺序依次为马来酸酐,丙烯酸丁酯,丙烯酸(或苯乙烯),PP。结晶速率快的复合材料具有低的结晶活化能。     

PP／GF／纳米CaCO3复合材料的加工与性能研究

采用熔融共混方法制备了纳米碳酸钙/玻纤/聚丙烯(纳米CaCO3/GF/PP)复合材料,探讨了纳米复合材料的配方、生产工艺及纳米CaCO3对复合材料力学性能的影响.结果表明:纳米CaCO3对玻纤增强聚丙烯具有增强增韧作用;采用稀土复合偶联剂对纳米CaCO3进行表面活化处理,添加适量增容剂,对提高复合材料的力学性能具有较好的效果;添加3%的纳米CaCO3后复合材料的综合力学性能最好.     

聚丙烯/纳米CaCO3复合材料的结晶行为研究

用超重力法制备的纳米CaCO3和PP熔融共混制备了PP/CaCO3复合材料,并对PP/CaCO3复合材料的结晶行为进行了详细研究。差示扫描量热分析表明,纳米CaCO3粒子的加入加快了PP的结晶速率,缩短了半结晶时间,130℃时含15份纳米CaCO3的PP/CaCO3复合材料的半结晶时间比纯PP的减少了8.92 min;结晶度有轻微下降,结晶温度为126.5 ℃时纯PP的结晶度为44.33 %,含15份纳米CaCO3的PP/CaCO3复合材料的结晶度为35.9 %。动力学研究数据表明,等温结晶过程符合Avrami方程,PP/CaCO3的n和k值都大于纯PP的;利用偏光显微镜观察了PP/CaCO3复合材料的结晶形貌及结晶生长过程,纳米CaCO3粒子的加入使球晶数量明显增多,意味着CaCO3起到了结晶成核剂的作用。     

纳米CaCO3对聚丙烯的增韧增强作用

用自制的脂肪酸盐和分散剂对超重力反应结晶法纳米CaCO3浆料进行湿法表面处理,在其质量分数为5%～6%时即可对聚丙烯进行增韧改性.SEM观察发现,该复合材料断面粗糙,基体发生了屈服形变.结晶性能研究表明,纳米CaCO3的加入对聚丙烯具有明显的异相成核作用,使得球晶变小,改善了复合材料的韧性.     

纳米无机填料增强增韧聚丙烯的研究

研究用纳米碳酸钙(Nano- CaCO3 ) ,纳米氧化铝(Nano- Al2 O3 )对PP改性,并利用扫描电镜(SEM )对改性PP的拉伸冲击断面进行观察。结果发现:将纳米材料引入聚丙烯体系后,聚丙烯的结晶行为发生较大改变,并引起聚丙烯的力学性能的变化。     

双单体改性对纳米CaCO3/PP结晶与熔融行为的影响

制备了界面改性纳米CaCO3／PP复合材料，用DSC研究了在有、无过氧化二异丙苯(DCP)存在下，反应单体丙烯酸(AA)及苯乙烯(St)对PP结晶与熔融行为的影响。结果表明：AA改性纳米CaCO3／PP可使结晶温度提高；St改性使纳米CaCO3／PP的结晶温度降低，但在DCP存在下结晶温度反而提高。AA和St双单体改性使纳米CaCO3／PP的结晶温度明显降低，但加有DCP的双单体改性却使纳米CaCO3／PP的结晶温度大幅提高，说明双单体接枝物有促进纳米CaCO3表面成核的作用。     

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。