聚乙二醇对羟基磷灰石纳米晶粒形成的影响

用聚乙二醇(PEG)对羟基磷灰石(HA)进行不同的表面改性处理,考察PEG对HA纳米晶粒形成的影响。以PEG作为反应物媒介对HA进行物理修饰和在HA合成煮沸后加入PEG进行表面修饰。结果表明:以PEG作反应媒介合成HA得到的浆料在静置12 h后能够保持51%的高度,HA颗粒通过一条或多条链串在一起;合成煮沸后加入PEG改性处理得到的HA浆料保持45%的高度,相对于无改性的HA,晶粒明显地呈现针状,但长度相等。改性后均使PEG吸附在HA表面,低温烧结后晶粒结构趋同。PEG作反应媒介,能够阻止HA晶粒的生长,减少晶粒的大小。而合成煮沸后PEG的加入,不影响HA晶粒的生长发育。     

非离子表面活性剂改性羟基磷灰石粉体的制备

采用化学沉淀法将硝酸钙、磷酸氢二铵按摩尔比5:3配成溶液,加入不同质量非离子表面活性剂聚乙二醇(PEG)、聚乙烯醇(PVA),使其质量占羟基磷灰石(HA)质量分别为1％、2％、3％、4％、5％,经750℃热处理2 h,从而制取表面活性剂改性的HA粉末.对粉末进行粒度分布测量、FT-IR测试、XRD衍射分析和SEM表征.结果表明:常压60℃下制备改性的HA粉末纯度高,结晶度低.其中PEG改性HA粉末物相为Ca10(PO4)6(OH)2、Ca3(PO4)2和Ca2P2O7,添加3％PEG粉体中位径(D50)为13.55μm,OH-吸收峰最强,HA含量为纯相,结晶程度趋于完善;PVA改性HA粉末物相只有Ca10(PO4)6(OH)2,添加3％PVA粉体中位径(D50)为7.068μm,结晶程度趋于完善,HA粉末的团聚程度最小,比表面积最大为607.4 m2/kg.PVA对HA团聚程度的分散性优于PEG.     

聚乙烯醇改性纳米羟基磷灰石的制备

本文以四水硝酸钙和磷酸氢二铵为原料,通过化学沉淀法合成了纳米羟基磷灰石(HA)粉,并引入聚乙烯醇(PVA)做HA的有机改性剂,制备了有机改性的羟基磷灰石纳米粉。用X射线衍射(XRD)、红外光谱(FTIR)和透射电镜(TEM)对HA粉体进行了分析表征。结果表明,引入聚乙烯醇做有机添加剂后,羟基磷灰石粉在700℃煅烧后的粒度在80nm左右。     

含锌羟基磷灰石的水热合成与结构表征

自然骨中的无机组分并不是纯的羟基磷灰石[Ca10(PO4)6(OH)2,hydroxyapatite,HA],还含有锌(Zn)、镁(Mg)等离子.为满足临床要求,常常需要在HA中添加一些元素来改善其性能.含锌羟基磷灰石(Zn-HA)就是其中的一类改性材料.目前多采用溶胶-凝胶法制备Zn-HA,需高温烧结,粉体易团聚.以硝酸钙[Ca(NO)3)2]、磷酸三铵[(NH4)3PO4]、硝酸锌[Zn(NO3)2为原料,在200℃下水热处理8h制得Zn-HA.通过X射线荧光光谱、X射线衍射、红外光谱、透射电镜和热重-差热分析对Zn-HA的晶相、化学组成、形貌和热稳定性进行分析.结果表明:Zn取替代部分钙(Ca)进入HA的晶格中.随着Zn含量的提高,Zn-HA晶粒尺寸呈减小趋势,晶胞参数a,c和晶胞体积也呈减小趋势.Zn的掺入降低了HA的热稳定性.采用水热法可以制备纳米到微米尺寸的棒状、针状或片状Zn-HA粉体,且Zn-HA粉体具有高结晶度以及合适化学计量比和晶型.     

水热合成羟基磷灰石表面修饰α-半水石膏复合颗粒

在柠檬酸和硫酸镁溶液中同时直接引入二水石膏与羟基磷灰石(hydroxyapatite,HA)共水热合成,获得了一种具有HA表面修饰的α-半水石膏的复合颗粒,并分析了该复合颗粒的成分、形貌、微观结构。结果表明:水热合成的颗粒是以α-半水石膏为主体,有HA在其表面修饰;随着HA的添加量的增加,HA表面修饰层的覆盖范围明显增加。     

羟基磷灰石微球的制备及表征与色谱性能

采用喷雾干燥法制备羟基磷灰石(hydroxyapatite,HA)微球。用扫描电镜、激光粒度分析仪及比表面积分析仪等表征HA的微观结构及性能。结果表明:HA微球具有理想的球形结构、比表面积为44.135m2/g,孔体积为0.2911cm3/g,且其粒度分布较窄。利用高压匀浆法填充HA色谱柱,并用高校液相色谱仪检测性能,结果表明色谱柱柱效较高。     

悬浮液粉体含量对电泳沉积羟基磷灰石涂层的影响

从不同羟基磷灰石(hydroxyapatite,HA)粉体含量的悬浮液中,在钛表面电泳沉积HA涂层.采用扫描电镜、X射线衍射表征涂层的微观形貌及物相组成,通过黏结-拉伸实验测定涂层与基底的结合强度.结果表明:提高悬浮液的HA粉体含量,有助于提高电泳沉积HA涂层的致密性,改善其烧结性能,提高烧结致密化程度;HA涂层致密性的提高,有效地抑制了钛基底表面氧化反应,改善了涂层与基底的界面结合状态,使HA涂层与钛基底的结合强度从悬浮液HA粉体含量为5g/L时的4.54MPa,提高到悬浮液HA粉体含量为20g/L时的19.92MPa.     

温度和pH值对羟基磷灰石粉体合成的影响

用液相沉淀法制备羟基磷灰石粉体,研究了温度和pH值对羟基磷灰石粉体合成的影响,结果表明:制备的羟基磷灰石粉体纯度较高,随着温度的增加其晶化程度增加,当pH值等于4.5,9和12.4时,制备的粉体分别为β-Ca2P2O7,HA+β-TCP和HA.TEM结果表明:羟基磷灰石沉淀颗粒形态呈针状或条状,其直径约10～20nm,长约100～200nm,当羟基磷灰石粉体加热至900℃时,颗粒发生团聚,晶粒长大,其尺寸约为200～400nm.     

取向性羟基磷灰石纳米片的合成与分析

采用机械球磨法,以乙醇做球磨介质,成功合成具有结晶取向性的羟基磷灰石(hydroxyapatite,HA)纳米片。采用X射线衍射、场发射扫描电子显微镜和透射电镜等表征方法对HA纳米片的结构进行了分析。结果表明:HA纳米片晶体为单晶结构,其宽度在200～400nm,厚度为50nm。球磨过程中,乙醇分子通过氢键作用,较易在HA晶体的(001)面上发生吸附并延缓该方向的生长,使(001)面成为显露面,最终得到沿(001)面定向排列的片状HA纳米晶。     

原位合成制备碳纳米管/羟基磷灰石复合粉体

对多壁碳纳米管进行了浓酸氧化处理,然后采用原位合成法制备了碳纳米管/羟基磷灰石复合粉体,并对氧化处理前后的碳纳米管及所得复合粉体进行了红外光谱、X射线衍射、透射电镜检测.实验表明:经过浓硝酸氧化处理之后,多壁碳纳米管的端口被打开并在缺陷处引入大量的羟基与羧基,这是原位合成复合材料的基础;所得复合粉体中仅有碳管和羟基磷灰石两种物相,其中纳米级的短棒状羟基磷灰石均匀吸附在碳纳米管表面,形成了较强的界面结合.     

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。