酚醛树脂加入量对钢包渣线再生镁碳砖性能的影响

利用钢包渣线用后镁碳砖再生料制备了钢包渣线再生镁碳砖,在再生料加入质量分数为80%的基础上,研究了酚醛树脂5323加入量(质量分数分别为3.25%、3.5%、3.75%、4.0%、4.25%)对再生镁碳砖致密度、强度和抗氧化性的影响。结果表明:1)随着酚醛树脂加入量的增加,200℃热处理后再生镁碳砖的致密度、常温耐压强度、常温抗折强度及高温抗折强度均增大,抗氧化性增强;2)随着酚醛树脂加入量的增加,900℃埋炭处理后试样的致密度增大,但当酚醛树脂加入量(w)达到4%后其致密度变化不大;3)再生镁碳砖中酚醛树脂加入量(w)以3.5%～4%为宜。     

Carbores P加入量对镁碳砖性能的影响

为了进一步提高镁碳砖的使用性能,在镁碳砖配料中添加质量分数分别为0、0. 5%、1%、1. 5%、2%和2. 5%的Carbores P,经配料、混练、困料后,用630 t电动螺旋压力机压制成200 mm×150 mm×100 mm的样块,于220℃保温16 h固化后,切割成40 mm×40 mm×160 mm和50 mm×50 mm×50 mm试样,分别在1 000和1 500℃埋焦炭热处理3 h,然后检测固化及埋炭热处理后试样的显气孔率和常温耐压强度,以及固化后试样的高温抗折强度和抗氧化性,并由此优选出最佳Carbores P添加量的镁碳砖在某钢厂100 t钢包渣线部位进行了现场使用试验。结果表明:Carbores P加入量对固化试样的显气孔率和常温耐压强度影响不大,高温抗折强度随Carbores P加入量的增加而增大;对埋炭处理试样,添加0. 5%(w) Carbores P的试样显气孔率最低,常温耐压强度最大,抗氧化性最好。添加0. 5%(w) Carbores P的镁碳砖应用在某钢厂100 t钢包渣线部位,侵蚀速率为每炉2. 11 mm,与未添加Carbores P的镁碳砖相比,抗侵蚀性提高了10%。     

添加半成品废砖的再生镁碳砖研究

为了回收利用镁碳砖生产过程中产生的半成品废砖,将半成品废砖经拣选、破碎、筛分后制成3～1、≤1和≤0.088 mm三种粒度的再生料,然后在镁碳砖常规配方中添加20%(w)的再生料制成再生镁碳砖试样,研究了试样的颗粒级配(粗颗粒、中颗粒、细粉的质量分数分别为44%～56%、14%～26%、24%～36%),再生料加入方式(分级后分别与相同粒度的其他料混合后加入或不分级直接与电熔镁砂颗粒料混合后加入),树脂添加量(外加质量分数分别为3.8%、4.0%、4.2%、4.4%)对再生镁碳砖试样性能的影响,并与未添加再生料的镁碳砖试样进行了对比。结果表明:1)适当增加中颗粒料的量,减少细粉的量,可以提高再生镁碳砖试样的致密度和抗氧化性能,但对强度影响不大。2)再生镁碳砖试样中树脂的最佳外加量(w)为4.0%。3)与不分级直接加入相比,再生料分级加入可以有效提高再生镁碳砖试样的致密度和强度。4)通过工艺优化,添加20%(w)再生料的再生镁碳砖试样的性能可以达到YB 4074—91中镁碳砖MT14A的技术要求。     

引入碳纤维对低碳镁碳砖性能的影响

为了解决低碳镁碳砖使用过程中容易出现的热剥落问题,在w(C)≈6%的低碳镁碳砖中加入尺寸约为Φ10 mm×20 mm的碳纤维,并研究碳纤维加入量(w)分别为0.25%和0.5%时,试样经180℃保温10 h固化后以及经1 000和1 600℃保温3 h埋炭热处理后的强度、弹性模量、抗热震性以及热膨胀等性能的变化。结果表明:与未添加碳纤维材料相比,添加0.25%(w)碳纤维时,试样的抗氧化性和经不同温度处理后的强度均明显提高,常温弹性模量和高温线膨胀率有所降低,抗热震性能有明显改善;但碳纤维含量增加至0.5%(w)时,试样的抗氧化性和经不同温度埋炭热处理后的强度均下降,弹性模量和高温线膨胀率变化不大,但抗热震性能有下降的趋势。综合考虑,添加0.25%(w)碳纤维的低碳镁碳砖综合性能最佳。     

复合添加氮化钛和铝粉对镁碳砖高温性能的影响

首先研究了氮化钛(TiN)加入量(分别外加质量分数1%、2%和3%)对镁碳砖高温性能的影响,然后在确定其加入量的基础上研究了复合加入TiN和Al对镁碳砖高温抗折强度、抗氧化性和抗渣侵蚀性等高温性能的影响,并分析了渣蚀后试样的化学组成及物相变化。结果表明:镁碳砖中外加TiN的质量分数以不超过2%为宜;TiN和Al复合加入到镁碳砖中,可使镁碳砖的高温抗折强度、防氧化效果和抗渣侵蚀性等高温性能均有很大提高,且以复合外加2%质量分数TiN和1%质量分数Al的镁碳砖试样综合高温性能最佳。     

碳氮化钛对低碳镁碳砖性能的影响

研究了碳氮化钛加入到低碳镁碳砖中对其性能的影响,并采用XRD物相分析、SEM显微分析研究了碳氮化钛对低碳镁碳砖基质部分烧后性能的影响。结果表明:镁碳砖基质部分经1600℃3h埋炭处理后,碳氮化钛仍均匀分布在基质中,并和MgO发生一定程度的固溶;加有碳氮化钛的镁碳砖经1600℃3h埋炭处理后,体积密度有所降低,气孔率升高,线膨胀率增大,常温耐压强度有所减小;碳氮化钛对镁碳材料的抗氧化性有所改善,但不及传统的金属铝粉;材料同样表现出良好的抗渣性。     

氧化铝微粉加入量对低碳镁碳砖性能的影响

以电熔镁砂、石墨、金属Al和氧化铝微粉为主要原料,热塑性酚醛树脂为结合剂,制备了w(C)5%的低碳镁碳砖试样,研究了氧化铝微粉加入量(其质量分数分别为0、3%、5%、7%、9%)对低碳镁碳砖的常温物理性能、抗热震性和抗氧化性的影响。结果表明:(1)随着氧化铝微粉加入量的增加,低碳镁碳砖试样的体积密度、常温强度和高温强度均先升高后降低,显气孔率则先降低后升高;抗热震性和抗氧化性随微粉加入量的增加呈先改善后变差的趋势;其中,微粉加入量为5%的低碳镁碳试样综合性能最好。(2)低碳镁碳砖试样性能的改善主要是由于加入的氧化铝微粉和MgO在高温下原位反应生成连续分布的尖晶石,增强了基质的陶瓷结合;但氧化铝微粉加入量过大时,由于大量原位反应引起材料产生过大的体积膨胀,会导致基质结构疏松,从而恶化镁碳砖的性能。     

钢包渣线用后镁碳砖的回收再利用研究

对钢包渣线用后镁碳砖进行回收处理,用其制备了再生渣线镁碳砖,研究了回收料加入量(质量分数分别为60%、70%、80%)和混料量(分别为5、8 kg)对再生镁碳砖致密度、强度和抗氧化性的影响。结果表明:1)随着回收料加入量的增加及混料量的增大,再生镁碳砖的显气孔率增大,体积密度、常温耐压强度、高温抗折强度和抗氧化性减小;2)回收料加入量(质量分数)为60%时,再生镁碳砖的性能符合行业标准的要求;3)回收料中存在假颗粒,残碳量高,杂质多,是造成再生镁碳砖致密度、强度和抗氧化性差的原因;4)为了提高再生镁碳砖的质量,必须控制回收料的加入量,选择混练效果好的混碾设备,并注意回收料中残碳对再生镁碳砖性能的影响。     

防氧化剂TiN和Al对MgO-C砖性能的影响

以3~1mm、<1mm、<0.088mm的电熔镁砂和<0.15mm的鳞片石墨为原料,热固性酚醛树脂为结合剂,分别加入0.5%、1%、2%、4%的含碳TiN或2%的Al粉为防氧化剂,制备了镁碳砖试样,并与无防氧化剂的试样对比进行抗氧化性和抗渣侵蚀试验。结果表明:添加Al粉试样的抗氧化性能最好,TiN的次之,未加防氧化剂的最差;添加TiN试样的抗渣性能最好,无防氧化剂的次之,添加Al粉的最差。镁碳砖中引入适量TiN后明显提高抗渣侵蚀性能的原因是:TiN氧化生成TiO2时产生的体积膨胀堵塞气孔,阻止熔渣侵入;TiO2与渣中的CaO反应生成3CaO·2TiO2,提高渣的粘度。综合各项性能,TiN的最佳加入量为2%。     

Si-SiC复合粉添加量对低碳镁碳耐火材料性能的影响

为了综合利用在太阳能硅晶板生产过程中产生的大量工业废弃料Si-SiC复合粉,将其作为添加剂引入到镁碳砖中,研究了Si-SiC复合粉加入量(加入质量分数分别为0、1%、2%和3%)对低碳镁碳耐火材料性能的影响。结果表明,废弃Si-SiC复合粉可以提高低碳镁碳砖的抗氧化性与热处理后试样的常温力学性能。随Si-SiC复合粉添加量的提高,镁碳砖的抗氧化性提高。当添加量为2%(w)时,固化后试样及经1 600℃埋碳热处理后试样的力学性能最佳。综合考虑低碳镁碳砖的各项性能,Si-SiC复合粉的合适加入量为2%(w)。采用废弃Si-SiC复合粉作为低碳镁碳耐火材料的抗氧化剂可有效降低生产成本。     

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。