硅烷偶联剂对超细蒙脱土的表面改性

采用不同结构的硅烷偶联剂(KH550、KH560、KH570)分别对超细蒙脱土进行接枝改性,并利用热失重分析(TGA)、X射线衍射分析(XRD)和扫描电子显微镜(SEM)对其结构性质进行表征,研究结果表明:经KH560接枝的细化蒙脱土层间距最大,其次为经KH550接枝的细化蒙脱土,而经KH570接枝的细化蒙脱土层间距最小。比较而言,经KH560接枝的细化蒙脱土颗粒表面分散片层最多,其次为经KH550接枝的细化蒙脱土,而经KH570接枝的细化蒙脱土表面分散片层最少。     

改性剂对MMT/尼龙6复合材料力学及吸水性能的影响

使用干法改性蒙脱土(MMT),比较硅烷偶联剂(KH550)、硬脂酸钙两种改性剂对MMT改性效果。通过吸油值、接触角、X射线衍射(XRD)等方式表征两种改性剂不同改性效果。结果表明,改性MMT较MMT原料的吸油值减小,接触角增大; MMT层间距在改性剂的作用下从1. 22 nm分别增加到1. 26 nm (硬脂酸钙),1. 28 nm (KH550),综合结果表明KH550改性效果较好。采用熔融挤出法制备改性MMT/PA6复合材料,并对两种改性MMT/PA6的力学性能、吸水性进行分析。力学结果显示KH550改性MMT/PA的拉伸强度为68. 69 MPa,较PA6原料拉伸性能提高了9. 89%,硬酯酸钙改性MMT/PA6拉伸强度为68. 06 MPa,较原料提高了8. 86%。改性MMT/PA6吸水性降低且拉伸强度稳定性保持良好。     

酚醛树脂改性纳米蒙脱土填充PA6的制备及性能研究

分别利用经十八烷基三甲基氯化铵(OTAC)、酚醛树脂(PF)表面改性的纳米蒙脱土(MMT)填充聚酰胺(PA)6,研究了不同表面改性剂及其用量对PA6的力学性能、热性能和吸水性的影响。结果表明,经OTAC改性的纳米MMT和经PF改性的纳米MMT对PA6的热性能改善效果有限,但有利于提高PA6的刚性和降低吸水性。PF改性纳米MMT对PA6的改性效果优于OTAC改性纳米MMT,当PF改性纳米MMT的质量分数为3%时,材料的拉伸强度、弯曲强度和维卡软化温度分别比纯PA6提高了12.3%、58.8%和2%,吸水率降低0.5%。     

改性剂种类对蒙脱土结构和性能的影响

为增加蒙脱土(montmorillonite,MMT)和有机物的相容性和研究插层剂种类对MMT结构和性能的影响,采用Cu,Co和Ni无机金属阳离子,十二烷基磺酸钠、十二烷基硫酸钠、α-烯烃磺酸盐和十二烷基苯磺酸钠等有机阴离子表面活性剂及十六烷基氯化吡啶、十六烷基三甲基溴化铵、十二烷基三甲基溴化铵等有机阳离子表面活性剂作为改性剂,对蒙脱土进行一次改性和二次改性,制备出一系列改性蒙脱土.研究了改性剂种类、插层方式、插层次序对插层效果的影响.X射线衍射分析表明:一次改性时,插层剂均能进入蒙脱土的层间,改性土的层间距由1.04nm增加到1.7～3.52nm;二次改性时,先阳离子后阴离子的插层顺序有利于层间距增大(4.14nm),还可利用配位作用将二次改性剂引入金属离子一次改性MMT中,使层间距增大.改性机理研究认为:阳离子改性机理为层间离子交换,而阴离子改性机理是改性剂和MMT表面形成了氢键.沉降实验表明一次改性土和二次改性土在有机溶剂中分散能力有所增强.     

甲苯-2,4-二异氰酸酯改性蒙脱土制备方法及结构表征的研究

研究了甲苯-2,4-二异氰酸酯(TDI)分子结构中的异氰酸酯基团(─NCO)与蒙脱土(MMT)表面羟基的修饰反应,以反应程度P(TDI)为指标,考察了反应时间、反应温度、TDI的用量以及蒙脱土活化条件对改性反应程度的影响。结果表明,TDI改性蒙脱土的最佳条件为:反应时间80 min,反应温度80℃,MMT与TDI质量比为1∶0.3,蒙脱土活化条件为250℃、反应2 h,反应程度可达到34.28%。IR,XRD测试改性物TDI/MMT,结果表明,TDI与蒙脱土片层表面的羟基发生反应,引入了─NCO基团,改性后的蒙脱土的层间距较原土有所增大,从而实现了蒙脱土的有机化改性。     

不同钠盐改性蒙脱土的制备及表征

为了后期制备有机改性蒙脱土,利用离子交换法将氯化钠、硫酸钠和碳酸钠三种钠盐表面活性剂插入到天然蒙脱土(MMT)层间,对其进行钠基化处理,并对改性后的蒙脱土结构和性能进行了表征。热重分析(TGA)结果表明,钠盐已成功插层到蒙脱土层间,改性后的蒙脱土热稳定性增强;X-射线衍射分析(XRD)结果表明,改性后的蒙脱土层间距增大,平均层间距分别从0.99 nm增大到1.25、1.23、1.21 nm,其中氯化钠改性效果最好。     

异氰酸酯改性蒙脱土的制备与表征

通过二苯基甲烷-4,4'-二异氰酸酯(MDI)改性酸化的钠基蒙脱土(Na-MMT),制得MDI-MMT,再利用MDI-MMT分别与水和乙醇反应,制备H2O-MDI-MMT和C2H5OH-MDI-MMT。利用十八烷基三甲基氯化铵(OTAC)改性的MMT和OTAC、MDI复配改性MMT,分别制得OTAC-MMT和OTAC-MDI-MMT。采用电感耦合等离子体发射光谱(ICP-OES)、FTIR、TG、XRD和SEM对改性MMT进行了表征。结果表明,MDI改性MMT对其层间阳离子含量不产生影响,且MDI-MMT、H2O-MDI-MMT和C2H5OH-MDI-MMT的层间距变化不大,保持在1.33~1.44 nm之间。OTAC改性MMT层间距得到了较大的改善,层间距在2.03~4.43 nm范围内,而OTAC、MDI复配改性MMT的层间距得到了进一步扩大,最大达到了15.98 nm,实现了充分剥离。     

PVC-U/蒙脱土复合材料的制备与力学性能研究

采用聚氧乙烯-聚氧丙烯(EP)嵌段共聚物对钠基蒙脱土进行有机化处理改性,XRD测试结果表明嵌段共聚物插层进入了蒙脱土层间.用熔融共混法制备了聚氯乙烯/蒙脱土复合材料,并研究了钠基蒙脱土和EP改性的有机蒙脱土对复合材料力学性能的影响.研究结果表明,采用EP对MMT进行改性能够提高MMT与PVC之间的相容性,PVC-U/MMT-EP复合材料的力学性能得到明显提高,EP对MMT改性是制备有机改性蒙脱土的有效方法之一.     

阳离子表面活性剂和硅烷偶联剂协同改性纳米凹凸棒土的研究

研究了纳米凹凸棒土的有机表面改性方法.采用阳离子表面活性剂十八烷基三甲基氯化铵(OTAC)和硅烷偶联剂(KH570)协同对纳米凹凸棒土进行改性,讨论了反应时间、反应温度、OTAC和KH570的添加量对改性效果的影响.利用X射线衍射(XRD)、红外光谱(IR)、热失重(TG)和热差(DTA)等分析方法对改性前后的纳米凹凸棒土进行表征.结果表明纳米凹凸棒土适宜的改性条件为:OTAC的添加量为2%、前期反应时间为3 h、KH570的添加量为20%、后期改性时间为2 h、改性温度为80℃.由此方法所得的纳米凹凸棒土粉体已由亲水性变为疏水性.     

用原位有机改性法制备的溴化丁基橡胶／蒙脱土复合材料的性能

采用原位有机改性法制备了溴化丁基橡胶(BIIR)/蒙脱土(MMT)复合材料,并对其硫化特性和力学性能进行了研究,用X射线衍射仪时复合材料中MMT的层间距进行了表征,并与钠基蒙脱土(Na-MMT)、有机蒙脱土(OMMT)和BIIR形成的复合材料进行了对比.结果表明,用原位有机改性法制备的BIIR/MMT复合材料的硫化特性和力学性能优于BIIR/Na/MMT复合材料,甚至优于BIIR/OMMT复合材料;采用原位有机改性法,可使BIIR/MMT体系中MMT的插层效果明显改善.     

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。