改性炭黑对多相聚烯烃/炭黑导电复合材料阻温特性的影响

以高密度聚乙烯(PE-HD)为基体,研究了不同组分及炭黑(CB)改性方法对PE/聚丙烯(PP)/CB多相聚烯烃导电复合材料阻温特性的影响.结果表明,在PE中添加PP能显著降低材料的室温体积电阻率,适量的CB能够提高材料的正温度系数(PTC)强度.经过硝酸和过硫酸钾改性的CB能够有效提高复合材料的导电性和PTC强度,其中硝酸改性的CB能与聚烯烃形成强物理吸附,使CB粒子高温下更容易分开,PTC强度比未改性时提高了25.65％.此外,改性CB能使复合材料的NTC效应降低,其中过硫酸钾使CB表面氧含量增加,提高了CB在聚烯烃中的吸附力,抑制高温团聚,经过硫酸钾改性CB的复合材料的NTC强度从未改性的0.675降低到改性后的0.339.     

超临界条件制备有机小分子接枝纳米炭黑及其对橡胶的补强作用

在超临界CO2流体中,用有机小分子(AO-80)对炭黑(CB)进行表面接枝,制备了有机小分子接枝的纳米炭黑粒子.红外分析表明:改性炭黑具有AO-80的分子结构特征,表明AO-80成功地接枝到炭黑表面,用TGA测得的接枝率为0.8%.粒径分析和透射电镜观察结果显示,与原始炭黑相比,改性炭黑的粒径明显减小,粒径分布变窄.将接枝炭黑(SCB)添加到苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)中,发现SCB对SBS具有明显的补强效果.SCB加入量为0.2%时,SBS/SCB的拉断伸长率由1039%(纯SBS)提高到1297%,提高了25%,而拉伸强度则由11.9MPa(纯SBS)提高到14.6MPa,提高了19%.     

丙烯酸和苯乙烯改性PP/PS结晶与熔融行为

制备了苯乙烯（St）、St与丙烯酸（AA）混合物、丙烯酸接枝聚丙烯（PP-g-AA）改性聚丙烯／聚苯乙烯（PP／PS）共混物以及AA，St改性PP（原位形成PP／PS共混物）。用差示扫描量热仪（DSC）研究了3种改性方法对共混物中PP结晶与熔融行为的影响。结果表明，PS对PP的结晶与熔融温度影响不大，PP-g-AA则提高共混物中PP的结晶温度。St以及St与AA混合单体对PP／PS中PP结晶温度影响不大，但AA改性提高PP／PS中PP结晶温度。St加入PP导致PP结晶温度下降，St与AA混合单体原位聚合则提高PP的结晶温度。改性对共混物中PP的熔融温度影响不大，但是熔融峰形与结晶温度高低有关。红外光谱证实St与AA混合单体改性PP中有PP-g-AA形成，但改性共混物中没有PP-g-AA形成。     

PP基纳米SiO2复合材料性能的研究

利用纳米SiO2、马来酸酐接枝聚乙烯（PE-g-MAH）和聚丙烯（PP）通过熔融共混的加工工艺制备了PP基纳米SiO2复合材料，考察了不同处理方法及用量的纳米SiO2对PP基体的影响。结果表明：经表面处理，用量4％（质量分数，下同）的纳米SiO2和4％PEgMAH协同作用，可以使复合材料的冲击强度提高40％，拉仲强度提高10％，耐热性较PP基体提高22℃。采用偏光显微镜（POM）、扫描电镜（SEM）对PP基纳米SiO2复合材料的微观结构进行了表征和分析，证明经表面改性的纳米SiO2（TS530）均匀地分散于PP基体中，从而起到良好的改性作用。     

聚丙烯／PE-g-MAH／纳米SiO2复合材料性能研究

以PE-g-MAH(马来酸酐接枝聚乙烯)作为聚丙烯(PP)/纳米二氧化硅(SiO2)共混物的增容剂,通过不同的加工工艺制备了聚丙烯/PE-g-MAH/纳米SiO2复合材料,考察了不同处理方法及用量的纳米SiO2对PP基体的影响。结果表明:经表面处理,用量为4％的纳米SiO2和3％PE-g-MAH协同作用对PP的改性效果最好,冲击强度提高30％,弯曲强度提高10％,而改性PP的拉伸强度与未改性PP保持一致,且对嵌段共聚聚丙烯(PP-B)的改性效果优于无规共聚聚丙烯(PP-R)。同时,PP/PE-g-MAH/纳米SiO2复合材料的耐热性得到明显提高,较PP基体提高22℃,增幅为20％。     

炭黑粒子偶联处理的HDPE复合材料PTC性能研究

研究了以HDPE为基体,工业炭黑（CB）为导电粒子的高分子复合材料的PTC（正温度系数）导电行为。考察了炭黑及偶联剂种类、用量对高分子PTC导电材料性能的影响,并探讨了偶联接枝机理,从理论上对改性效果进行了分析。结果表明,对炭黑,尤其是槽法炭黑 表面处理可显著提高复合材料的电导率及减小NTC（负温度系数）效应;钛酸酯偶联剂具有最佳改性效果,可明显改善炭黑粒子分散状态,增强材料的PTC效应,其最佳用量为1％质量份。     

滑石粉对聚丙烯微观形态和性能影响

以滑石粉为填料通过挤出机熔融共混制备聚丙烯（PP）/滑石粉复合材料,考察了硅烷偶联剂对滑石粉表面改性前后及添加不同含量的乙烯-辛烯共聚物（POE）对共混物力学性能、流变性能和微观形态的影响。结果表明,滑石粉表面改性后可以明显提高PP的缺口冲击强度,当PP/滑石粉质量比为100/10和100/30时,PP/滑石粉（改性）较PP/滑石粉（未改性）复合材料的缺口冲击强度分别提高37.8 %与36.4 %;表面改性后的滑石粉使复合材料的储能模量降低;POE的加入提高了滑石粉在PP基体中的分散性,随着其含量的增加,复合材料的缺口冲击强度提高,韧性提高。     

聚丙烯/接枝物/蒙脱土纳米复合材料的制备

采用熔融插层法制备聚丙烯／接枝物（PP－g－MAH）／有机蒙脱土（org-mont）纳米复合材料，用X射线衍射法（XRD）检测复合材料层间距的变化，用示差扫描量热法（DSC）研究其非等结晶动力学，并考察了纳米复合材料的力学性能。结果发现，非极性PP大分子链很难直接插入蒙脱土片层，引入适量的接枝物是制备聚丙烯基纳米复合材料的关键。适当用量的蒙脱土和接枝物可使PP的结晶温度和结晶速率提高，分别在10％、20％时出现最大值。随接枝物用量的增加，纳米复合材料拉伸强度先增加后减小，10％时最大，比纯PP增加了14％，“V”缺口冲击强度和纯PP相近。可以得出，org-mont含量为2％，接枝物含量为10％时，纳米复合材料的综合性能最佳。     

聚丙烯/高岭土复合材料的结构与性能

以钛酸酯偶联剂(NDZ-105)改性的高岭土为填料、马来酸酐接枝的聚丙烯(PP-g-MAH)为相容剂,与聚丙烯(PP)熔融共混制备复合材料,测定了复合材料的力学性能,并通过X射线衍射(XRD)、红外光谱(Fr-IR)、热失重分析(TG)、扫描电镜(SEM)等手段研究其结构.结果表明,NDZ-105分子包覆到高岭土颗粒表面,有效改善了高岭土与PP基体的相容性;改性高岭土在PP基体中起到异相成核作用,并诱导PP基体产生β晶型;与纯PP及PP/未改性高岭土复合材料相比,PP/改性高岭土复合材料的拉伸强度、冲击强度、屈服强度、弹性模量、维卡软化温度及外推起始失重温度均明显提高,分别增加了7.6％、31％、21％、89.3％、8.4℃及97℃.     

高流动熔融接枝改性聚丙烯的研究

用极性单体N-苯基马来酰亚胺（N-PMI）、二苯甲烷双马来酰亚胺（BMI）对聚丙烯（PP）进行熔融接枝改性以提高PP的分子极性和熔体流动性,在接枝PP的基础上加入邻苯二甲酰亚胺（PTI）进一步提高PP的流动性。用红外光谱分析了接枝物的结构,用静态水接触角表征了PP经熔融接枝改性后的极性变化,用差示扫描量热仪、X-射线衍射分析了改性PP的相结构。结果表明,N-PMI和BMI都成功接枝到PP分子链上;接枝单体N-PMI和BMI的加入提高了PP的极性,N-PMI和BMI的含量分别为2份和1份时,PP的水接触角分别从109 °降至97 °和99 °;在加工温度下,PTI可溶入接枝PP熔体,显著提高熔体的流动性,而当温度降低时可从熔体析出结晶,明显改善了PP的热变形温度和力学性能;经2份N-PMI、1份BMI、1份PTI改性后,PP在熔体流动速率提高2倍的同时,热变形温度上升了12 ℃,冲击强度增加了20 %,抗弯强度提高了10 %。     

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。