化学镀镍稳定剂的研究

以镀速、镀层中磷的质量分数、镀液稳定性为评价指标,考察了Pb2+、Cu2+分别作稳定剂时和Cu2+与硫酸铈复配使用时的效果。结果表明:Pb2+的添加量变化范围比Cu2+的窄,同时Cu2+作稳定剂时镀液中Ni 2+的利用率较高。将50mg/L Cu2+和5mg/L硫酸铈复配使用,获得的镀速为10.69μm/h,镀层中磷的质量分数为10.18%,稳定常数为0.97,且镀层为非晶态结构。     

化学复合镀Ni-P-金刚石的耐磨性研究

研究了金刚石和还原剂的质量浓度对镁合金Ni-P-金刚石复合镀层成分及耐磨性的影响.结果表明:镀层中金刚石的质量分数随镀液中金刚石的质量浓度的增加而增加,镀层中磷的质量分数随镀液中还原剂的质量浓度的增加而增加;随镀液中金刚石的质量浓度的增加,磨损量呈先降低后升高的趋势,当其质量浓度为8 g/L时,耐磨性最好;另外,随着镀...     

三种含硫稳定剂对化学镀镍的影响

以镀速、镀层中磷的质量分数及稳定常数为评价指标,考察了硫脲、硫代硫酸钠和DL-半胱氨酸分别作为稳定剂时的效果。结果表明:硫脲的质量浓度在0.5~3.0mg/L之间,硫代硫酸钠的质量浓度在3~7mg/L之间,DL-半胱氨酸的质量浓度在1~5mg/L之间时,DL-半胱氨酸为最佳稳定剂。此时,镀速为10.67μm/h,镀层中磷的质量分数为10.00%,稳定常数为95.51%。     

刷镀工艺对镍-磷合金刷镀层中磷含量的影响

用滴定法测出刷镀层中镍含量并推算出磷含量,研究了镍-磷合金刷镀工艺对刷镀层中磷含量的影响。实验表明:镀液中硫酸镍浓度对镀层磷含量有显著影响,硫酸镍浓度升高,对提高沉积速度有利,但会显著降低镀层磷含量;镀层磷含量随亚磷酸浓度增加而增加,但当亚磷酸增加到一定值(约60mL/L)时,镀层磷含量相对稳定;镀层的沉积速度随柠檬酸浓度的增加存在一个最大值,而镀层中的磷含量在镀速最快时降到最低点;操作温度和电压变化对镀层中的磷含量影响不大。     

稳定剂对低磷化学镀镍液及镀层的影响

在基础低磷化学镀镍液中,分别添加硫脲(TU)、KI、KIO3、含硫有机杂环化合物A和CuSO4等稳定荆,考察其对镀液的稳定性能、镀速、镀层中磷的质量分数和可焊性等的影响.研究表明:化合物A的加入能使镀液稳定性上升,并且可以进一步降低镀层中磷的质量分数.合适稳定荆的加入,不但可以提高镀液的稳定性,同时还能够获得镀速更快、磷的质量分数更低,并且可焊性良好的低磷化学镀镍层.     

乳酸-EDTA双配位剂体系化学镀镍的研究

配位剂的选择是化学镀镍技术的关键之一。以镀速和镀层中磷的质量分数为评价指标,研究乳酸与EDTA两种配位剂复配对化学镀镍的影响。结果表明:单独使用一种配位剂难以同时满足化学镀镍工艺对镀速与镀层中磷的质量分数的要求;使用双配位剂体系可以兼顾镀速与镀层中磷的质量分数这对矛盾,在乳酸20g/L,EDTA 8g/L的条件下,镀速为17.1μm/h,镀层中磷的质量分数为10.5%。     

乳酸对柠檬酸化学镀镍-磷合金的影响

以沉积速度、镀层磷含量、稳定常数为评价指标,考察了乳酸在0～10mL/L质量浓度范围内对柠檬酸化学镀镍-磷合金的影响。结果表明,在施镀θ为88℃、pH为4.80的条件下,在0～10 mL/L乳酸质量浓度范围内,沉积速度为10.851～11.930μm/h,稳定常数为0.738～0.978,镀层中磷质量分数为9.84%～10.40%,当镀液中乳酸质量浓度为5.0mL/L时,沉积速度最快,稳定常数最大,镀层磷质量分数较高。     

镁合金化学镀Ni—P-金刚石镀液稳定性的研究

研究了稳定剂和搅拌强度对镁合金化学镀Ni-P-金刚石敛液稳定性的影响.结果表明:镀液稳定性随稳定剂的质量浓度的增加而增加;随搅拌转速增加而增加,200 r/min时稳定性最好,之后随着转速的增加而降低.镀层中金刚石分布均匀,磷的质量分数为6.00%,镀态下镀层为非晶+微晶结构.     

化学镀镍-磷合金复合稳定剂的优化研究

采用正交试验研究了稳定剂硫酸铜、碘酸钾、DL-半胱氨酸和硫酸铈复合使用对化学镀Ni-P合金镀液稳定性、镀速、镀层磷含量和孔隙率等性能的影响变化规律。结果表明,各种稳定剂之间有相互促进作用,综合性能明显优于单一稳定剂,且复合使用采用了清洁的原料,替代了重金属Pb2+;稳定剂硫酸铜、碘酸钾、DL-半胱氨酸和硫酸铈最佳复配的质量浓度分别为:25、20、3和7.5mg/L,镀后测得镀速12.54μm/h、镀液稳定常数91.85%、孔隙率0、镀层磷质量分数为10.25%。     

柠檬酸-丁二酸双配位剂体系化学镀镍的研究

配位剂的选择是化学镀镍技术的关键之一.使用两种常用的有机酸——柠檬酸和丁二酸作为配位剂,以镀速和镀层中磷的质量分数为评价指标,先分别考察两者单独使用时的影响,然后在单因素实验的基础上,考察两者复配使用时的影响.结果表明:单一配位剂难以同时满足化学镀镍工艺对镀速和镀层中磷的质量分数的要求,配位剂复配使用可以克服镀速与镀层中磷的质量分数之间的矛盾;在柠檬酸20 g/L,丁二酸6 g/L的条件下,镀速适中且镀层中磷的质量分数较高.     

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.     

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。     

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.