乙酸处理对玻璃离子水门汀性能的影响

玻璃离子水门汀(Glass ionomer cement,GIC)具备各种优良性能,广泛应用于口腔临床.但现有充填用GIC机械性能不足,限制了其临床应用.采用乙酸处理玻璃粉,提高其机械性能,扩大临床应用.在不同条件下用乙酸处理熔融法自制玻璃粉,用X射线衍射(XRD)表征并做粒径分析.用酸处理玻璃粉与市售液剂制备的GIC的抗压强度为标准,筛选优化处理条件.测试优化条件下GIC的抗压强度、维氏硬度和净固化时间,用扫描电子显微镜(SEM)观察GIC的表面形貌.所得数据用方差分析和t检验分析.自制未处理、处理、市售三种玻璃粉90％粒径分别分布在17μm、14μm、29μm以下.优化条件为1％乙酸处理2h,室温下储存1d的GIC抗压强度达114.79MPa,比未处理组和市售组分别提高了17.61％和21.92％ (P ＜0.05),7d达到126.91 MPa,比未处理组提高了9.71％(P＜0.05);维氏硬度1d,7d分别为32.2 MPa和47.4 MPa;净固化时间为4′39”.SEM显示酸处理的GIC表面孔洞裂纹分布较少.提示乙酸处理能有效提高GIC的机械性能,且优化条件下的抗压强度、维氏硬度和净固化时间满足临床要求.     

掺TiO2玻璃粉对玻璃离子水门汀性能的影响

采用不同TiO2掺杂量(0、0.5％、1％、3％和5％)制备的玻璃粉与聚丙烯酸制得玻璃离子水门汀(GIC),以及将含3％TiO2玻璃粉经不同温度(400℃、500℃、600℃和700℃)热处理后制得玻璃离子水门汀,测试GIC的固化时间和抗压强度.并使用DSC、XRD、SEM以及粒径分析仪,研究玻璃粉体热处理前后的结晶特性、玻璃转变和结构特征.结果表明,晶核剂TiO2的掺入使玻璃的结构致密性增强,不仅延长了玻璃离子水门汀的固化时间,而且明显提高GIC的抗压强度;热处理后的玻璃粉会发生团聚和结块现象,600℃以上时会有CaF2晶体析出.此外,玻璃粉经热处理后可以明显延长GIC的固化时间,然而过高温度的热处理改变玻璃颗粒表面形态,降低GIC的机械强度.     

掺低熔点玻璃粉水泥胶砂的耐热性能研究

对掺低熔点玻璃粉水泥胶砂性能进行了研究.测试了不同煅烧温度前后试件的抗压强度和抗折强度,分析了强度残值率、脆性系数和微观结构.试验结果表明,低熔点玻璃粉能显著改善水泥胶砂在高温煅烧(900℃)时的耐热性能,提高强度残值率和降低脆性系数,尤其与粉煤灰或矿渣粉复掺时效果更好.当掺10％低熔点玻璃粉和15％粉煤灰时,抗压强度残值率改善幅度最高,达40％,抗折强度残值率改善幅度达48％,脆性系数最低,为5.63;掺10％低熔点玻璃粉和15％矿渣粉的水泥胶砂,抗压强度残值率为52％,抗折强度残值率为50％.     

稻壳一次煅烧水热合成P型分子筛

稻壳经稀盐酸煮沸后,用去离子水洗涤至中性,干燥后粉碎并与一定质量的Na2CO3和Al(OH)3粉末混合均匀置于马弗炉中煅烧,煅烧产物采用水热合成法合成P型分子筛.研究发现(SiO2占干燥酸洗稻壳质量分数的20％)当煅烧温度为850℃,煅烧时间为8h,Na2 O/SiO2＝1.2,SiO2/Al2 O3＝4.0,H2 O...     

早强剂与缓凝剂对硅粉水泥性能影响的试验分析

研究了NaHCO3、Na／SiO3早强剂与柠檬酸、Na5P3O10缓凝剂对外掺硅粉的水泥性能的影响。试验表明：对掺量为8％硅粉的水泥,单掺1％NaHCO3、1％Na2SiO3后,其3d抗压强度均提高20％左右;单掺0．03％柠檬酸、0．1％Na5P3O10后其净浆初凝时间均推迟50％左右;复掺1％NaHCO3和0．03％柠檬酸,硅粉水泥出现了急凝现象,且3d、28d抗压强度损失率高达60．0％左右;与复掺1％NaHCO3、0．1％Na5P3O10和1％Na2SiO3、0．03％柠檬酸相比,复掺1％Na2SiO3、0．1％Na5P3O10的早强和缓凝作用均达到了其单掺时的效果。对试验结果进行了机理分析。     

锂渣粉在细缝专用无骨灌浆料中的应用研究

锂渣粉含有较丰富的活性矿物,主要为CaSO4·2H2O,SiO2,C3S和C3A,只含有部分非活性的SiO2。通过实验研究了锂渣粉对无骨灌浆料（NGM）各项性能的影响,结果表明,随着锂渣粉掺量的增加,NGM的凝结时间延长,30min流动度损失减小;1d抗压强度降低,28d抗压强度均高于空白样,最高可达83．2MPa。此外掺入锂渣粉的灌浆料竖向膨胀率有所增加,但不明显。目     

SiO2-Bi2O3-ZnO无铅玻璃油墨的制备

制备了软化温度在575℃左右的玻璃油墨用SiO2-Bi2 O3-ZnO系无铅玻璃粉,用纽扣实验比较了不同成分玻璃粉的成型流动性,以成玻性能最佳的玻璃粉为原料制备了不同玻璃粉含量的油墨并研究了玻璃粉含量对玻璃油墨成膜性能的影响,最后,用筛选的无铅玻璃油墨按照企业生产工艺制备了汽车后挡玻璃的黑色遮盖层,并与国外品牌荷兰庄信万丰公司的玻璃油墨进行了应用对比.采用差热分析(DTA)、X射线衍射仪(XRD)、扫描电镜(SEM)和热膨胀仪对玻璃粉和玻璃油墨涂层的组织性能进行了表征.试验结果表明,SiO2-Bi2 O3-ZnO系玻璃粉成玻性能良好;当玻璃粉含量为60%时,在680℃、保温1.5 min条件下制备了汽车后挡玻璃油墨涂层,适合目前汽车后挡玻璃生产线的工艺要求,油墨形成的玻璃薄膜具有良好的光泽度、耐酸性和抗粘性.     

石英块体表面制备氮化硅层的研究

高纯Si粉或Si3N4粉为反应原料,分别以SiO2粉、MgO粉、CaO粉,或者自制玻璃粉为粘结剂,按不同质量百分比与PVA饱和溶液混合,分层涂抹在石英块体表面.在N2气氛中,于1500℃高温氮化烧结180 min,在石英块体表面制备氮化硅层.XRD与EDS图谱的分析结果表明,以SiO2粉、MgO粉、CaO粉为粘结剂,产物层物相为氮化硅或氧氮化硅,产物层致密且有一定厚度和强度,但是产物层和石英块体的结合性差;以自制玻璃粉为粘结剂的实验结果表明:产物层主要物相为氮化硅,产物层有一定厚度和强度,而且与石英块体的结合性较好.     

古建筑用水硬性石灰的合成及力学性能研究

为了合成古建筑修复材料水硬性石灰,以天然姜石为原料,通过煅烧方式制备了水硬性石灰,利用XRD、SEM、伺服万能试验机和白光数字散斑相关方法等测试了水硬性石灰的成分、微观形貌、抗压强度和变形场演化等.结果表明:在900℃煅烧8 h时姜石中CaO、2CaO·SiO2和2CaO·Al2 O3·SiO2的含量与欧洲水硬性石灰NHL5的成分相近;随养护时间的增加,水硬性石灰中CaO和2CaO·SiO2的含量逐渐降低,CaCO3和1.5CaO·SiO2·xH2 O(C-S-H)的含量逐渐增加,而2CaO·Al2O3·SiO2的含量基本不变;养护1～5 d阶段收缩率随养护时间迅速增加,养护6～17 d阶段收缩率随养护时间缓慢增加,养护18 d后收缩率保持恒定;抗压强度随养护时间的增加而增加,养护28 d时抗压强度达到6.75 MPa,达到NHL5的标准;随着载荷的增加,局部区域的应变值逐渐变大,相邻的局部变形区合并成应变局部化带,在峰值载荷处应变局部化带演变成微裂隙,微裂隙扩展成宏观裂纹使试件发生破坏;随养护时间的增加,Ca(OH)2和2CaO·SiO2发生反应的数量增加,形成的CaCO3和C-S-H相互交织构成空间网络结构,水硬性石灰的孔隙率减少,力学强度显著提高.     

不同处理方法对冶金硅系产业回收微硅粉结构组成的影响

为研究不同处理方法对微硅粉结构组成、元素存在状态的影响,以冶金硅系产业回收微硅粉为原料,采用水洗磁选、水流分级、微波酸浸、700℃煅烧自然冷却、700℃水淬急冷、800℃煅烧自然冷却、800℃水淬急冷对微硅粉进行实验处理,得到了不同处理条件下的微硅粉样品.通过XRD、SEM、TEM、XPS对微硅粉样品物相组成、微观形貌和元素存在状态进行了表征分析.结果表明:水洗磁选、水流分级和微波酸浸处理微硅粉只去除了微硅粉中部分Fe3 O4、游离碳和金属氧化物杂质;高温煅烧微硅粉改变了微硅粉结晶状态,在800℃时,微硅粉由无定形的玻璃相转化为方石英相.通过对微硅粉元素拟合分析,发现微硅粉中除含有SiO2外,还有化合物(SiO2)0.694(Na2 O)0.306、(K,Ca)2[Mg4.3 Fe0.7][Si7.2 Al0.8 O22](OH)2、Mg3 H2(SiO3)4,并存在少量CaO、MgO等矿化剂.     

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。