添加剂对石膏基固沙材料保水性能的影响

土地荒漠化是当今世界最严重的生态环境问题之一.采用石膏为主凝固材料,通过合理添加辅助材料,研究各辅助材料对固沙材料保水性能的影响.试验表明:保水剂、木屑、SDS均有利于提高材料保水性能,沙粒掺量为30％时材料保水性能最好.以固沙材料保水率为主要评价指标,当沙粒掺量为30％、保水剂掺量为4％、木屑掺量为8％、SDS掺量为0.3％时,固沙材料保水性能最好,此条件下保水率为79.24％.该固沙材料对环境无污染,保水性好,适合植物生长,在沙漠治理方面具有广泛应用前景.     

青海湖周边沙漠化沙粒基本性能研究

本文以青海湖周边沙漠化沙粒为研究对象,全面分析了其理化性能,研究了沙粒掺入对石膏力学性能的影响.试验表明:青海湖周边沙漠化沙粒主要矿物相为石英和钠长石;沙粒形状大小各异,表层有一定量的物理吸附物;沙粒在碱和水中的溶解量很小,在酸中的溶解量在3.5％ ～6.1％之间.沙粒使石膏胶凝材料强度先增加后降低,当沙粒的掺量为10％时,强度最大,其抗压强度为15 MPa,抗折强度为6.4 MPa;掺量为50％时,强度最小,其抗压强度为10.9 MPa,抗折强度为4.7 MPa.     

多孔纤维自修复固沙材料制备及性能研究

针对固沙材料在固结初期易破裂、耐受性差,以及破裂后无法再次成型等问题,研究了一种具有自修复功能的治沙材料。采用废旧棉布衣物及沙漠枯黄植物为原料,经改性发泡工艺制成多孔纤维作为固沙材料主体,利用尿醛树脂辅以GrubbsΙ型催化剂为封装材料,利用原位聚合法将二环戊二烯单体封装于多孔纤维体中,制成具有自修复功能的多孔纤维固沙材料。以西藏G317索县段细沙为实验对象,对自修复固沙材料的修复率、抗压强度、抗冻融性能和抗老化性能进行了实验研究。结果表明,自修复固沙材料在1.0%掺量下的初次固沙强度可达6.0 MPa;经3个自修复周期后修复率为74%,抗压强度为4.2 MPa;15次冻融循环后质量损失率仅为0.2%;600 h紫外光老化后抗压强度无明显损失,各项指标均高于国家标准。该材料具有原料来源广泛,固沙效果好及耐久性强等优点,在沙漠治理和水土保持方面有较高的利用价值。     

多孔纤维自修复固沙材料制备及性能研究

针对固沙材料在固结初期易破裂、耐受性差,以及破裂后无法再次成型等问题,研究了一种具有自修复功能的治沙材料。采用废旧棉布衣物及沙漠枯黄植物为原料,经改性发泡工艺制成多孔纤维作为固沙材料主体,利用尿醛树脂辅以GrubbsΙ型催化剂为封装材料,利用原位聚合法将二环戊二烯单体封装于多孔纤维体中,制成具有自修复功能的多孔纤维固沙材料。以西藏G317索县段细沙为实验对象,对自修复固沙材料的修复率、抗压强度、抗冻融性能和抗老化性能进行了实验研究。结果表明,自修复固沙材料在1.0%掺量下的初次固沙强度可达6.0 MPa;经3个自修复周期后修复率为74%,抗压强度为4.2 MPa;15次冻融循环后质量损失率仅为0.2%;600 h紫外光老化后抗压强度无明显损失,各项指标均高于国家标准。该材料具有原料来源广泛,固沙效果好及耐久性强等优点,在沙漠治理和水土保持方面有较高的利用价值。     

粉煤灰基轻质高强材料的制备及其防水性能的研究

本研究以循环流化床粉煤灰为主要胶凝材料,以中空玻化微珠为轻质填充料,通过碱激发的原理制备出一种新型的轻质高强材料.另外,通过掺入硬脂酸钙对该材料的防水性能进行了研究.结果表明,当玻璃微珠掺量为40wt％,硬脂酸钙掺量为3wt％时,该种材料综合性能最优,对应的表观密度、28 d抗压强度和吸水率分别为650kg/m3,21.19 MPa,15.3wt％.优良的力学性能和防水性等研究表明,该材料具有广阔的应用前景.     

玻璃纤维增强碱式硫酸镁水泥制备工艺研究

以玻璃纤维为增强材料,木屑为轻质骨料,碱式硫酸镁水泥为胶凝材料制备了复合板材.研究了水泥的氧化镁活性、摩尔比、水灰比、外加剂掺量、养护温度、玻璃纤维层数对复合板材不同龄期下的抗折强度和抗压强度的影响.研究结果表明,采用a-MgO/MgSO4摩尔比为6.0,水灰比为0.35,木屑掺量为20%,玻璃纤维层数为3时可制备出抗压强度为35.89 MPa,抗折强度为15.6 MPa的复合板材.采用高温养护,可提高复合板材的早期强度.采用XRD、SEM分析了外加剂和养护工艺对水化相组成和形貌的影响.     

疏水缔合聚丙烯酰胺固沙剂的制备及性能研究

研发了一种具有良好固沙性能的水溶性固沙剂,该固沙剂是一种可持续的固沙材料。首先就疏水缔合阳离子聚丙烯酰胺-腐植酸的化学固沙机理讨论了固沙剂与沙粒之间的粘附力。研究了凝固机理,测试了固沙剂的固化时间。然后研究了固沙剂的渗透性能。通过扫描电子显微镜(SEM)分析了固沙层的微观结构。在不同浓度的固沙剂条件下,研究了固沙层的抗压强度。最后,通过模拟风机实验研究了固沙层的抗风蚀性。结果表明,固沙剂水溶液与沙粒表面具有极好的亲和力,并且固沙剂与沙粒之间的粘附力主要是氢键作用和静电作用。固沙层的固结时间随着温度和浓度的增加而降低。     

氧化石墨烯沙漠砂水泥基复合材料力学性能研究

通过正交试验,分析了氧化石墨烯(GO)掺量、沙漠砂替代率、水灰比和胶砂比对GO-沙漠砂水泥基复合材料28 d的抗压强度、抗折强度和稠度值的影响趋势.在正交试验基础上,进一步揭示沙漠砂替代率和GO掺量对复合材料7d、28 d抗压强度和抗折强度的影响规律.试验研究表明:随着GO掺量的增加,水泥基复合材料抗折和抗压强度先提高后降低,且对于抗压强度增强效果略超过抗折强度.当GO掺量为0.03wt％时,GO-沙漠砂砂浆试块抗压强度和抗折强度达到最大值;随着沙漠砂替代率增加,GO-沙漠砂砂浆试块抗折和抗压强度呈现先增大后减小趋势,沙漠砂替代率为50％时,氧化石墨烯沙漠砂砂浆试块抗压强度和抗折强度均达到最大值;但沙漠砂替代率为100％时,掺量为0.03wt％的GO-全沙漠沙水泥基材料强度提升最高,且28 d抗压、抗折强度可达标准砂试块强度.通过SEM对GO增强沙漠砂水泥基复合材料微观结构进行表征,发现GO能够优化水泥水化产物的微观结构形态,并且与沙漠砂活性材料产生正相关作用,从而形成更加致密均匀的结构改善沙漠砂水泥基复合材料的宏观性能.     

铝盐浓度对铝硅酸盐固沙材料稳定性的影响

采用化学固沙方法,分别以水玻璃、氯化铝溶液作粘结剂和固化剂制备了固沙材料,重点讨论了氯化铝浓度对固沙材料的稳定性影响.结果表明:固沙块试样力学性能随固化剂浓度增加而提高.扫描电镜测试表明:随铝盐浓度增加粘结胶体中裂纹数量减少且胶质形态由针状转变为球体,沙粒覆盖效果更好.X-射线衍射、红外光谱分析、热重-差热分析表明,水玻璃中的Si(OH)4与AlCl3反应生成了含有Si-O-Si键、游离Si-OH键、Si-O-Al键的非晶态铝硅酸盐聚合物,从而使固沙体力学性能及热稳定性增强.     

疏水缔合聚丙烯酰胺固沙剂的制备及性能研究

研发了一种具有良好固沙性能的水溶性固沙剂,该固沙剂是一种可持续的固沙材料。首先就疏水缔合阳离子聚丙烯酰胺-腐植酸的化学固沙机理讨论了固沙剂与沙粒之间的粘附力。研究了凝固机理,测试了固沙剂的固化时间。然后研究了固沙剂的渗透性能。通过扫描电子显微镜(SEM)分析了固沙层的微观结构。在不同浓度的固沙剂条件下,研究了固沙层的抗压强度。最后,通过模拟风机实验研究了固沙层的抗风蚀性。结果表明,固沙剂水溶液与沙粒表面具有极好的亲和力,并且固沙剂与沙粒之间的粘附力主要是氢键作用和静电作用。固沙层的固结时间随着温度和浓度的增加而降低。     

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。