酯化淀粉原位凝固成型Al2O3陶瓷的研究

研究了以淀粉作凝胶剂原位凝固成型Al2O3陶瓷的新方法.当淀粉大分子在水溶液中加热到一定温度时,淀粉颗粒吸水溶胀,陶瓷浆料脱水并固化成坚硬的坯体;而且溶胀后的淀粉可作为粘结剂,有助于坯体固化并增加其强度.详细探讨了酯化淀粉添加量不同时,对陶瓷浆料流变特性的影响,以及对成型出素坯的线收缩、相对密度、干坯强度以及显微结构的影响.     

改性淀粉与丙烯酸接枝共聚物的合成及应用性能

研究经过热处理的改性淀粉与丙烯酸的接枝共聚反应。接枝共聚产物在 790cm-1、85 0cm-1(物理改性淀粉的特征吸收峰 )和 172 0cm-1(聚丙烯酸的特征吸收峰 )处的红外光谱验证了接枝共聚反应的发生。探讨了引发剂过硫酸铵浓度、丙烯酸浓度、反应温度和反应时间等因素对接枝率和接枝效率的影响。当 ρ(淀粉 ) =70 g/L、t =6 0℃、反应时间为 3h、c〔(NH4) 2 S2 O8〕 =3 0× 10 -3 mol/L、c(丙烯酸 ) =0 4 2mol/L时 ,合成胶粘剂的初粘力为 10 0 % ,吸水率为 15 0 14 % ,吸油率为 2 0 6 % ,其压制的纸板冲击强度为 3 2 5kN/m ,拉伸强度为 3 75MPa ,与纯淀粉粘接剂相比较 ,所压制纸板的应用性能得到较大的改善。     

改性淀粉对天然橡胶性能的影响

研究黄原酸酯化改性淀粉替代白炭黑对天然橡胶(NR)性能的影响。结果表明:当白炭黑和改性淀粉总用量为30份时,随着改性淀粉用量增大,改性淀粉/白炭黑/NR胶料t10延长,t90缩短;MH和结合胶含量先增大后减小,硫化胶定伸应力、拉伸强度、撕裂强度和耐磨性能先提高后降低;淀粉用量为15份时,胶料综合性能最好。     

季铵型阳离子淀粉合成及应用

介绍了季铵型阳离子淀粉的湿法生产工艺,着重讨论了合成反应过程中催化剂用量、醚化剂用量、反应温度、反应时间等因素对取代度和反应效率的影响。淀粉用量为100kg,醚化剂CHPT用量为5,2kg,催化剂用量为2．6kg,淀粉乳浓度58％,氢氧化钠水溶液浓度50％、反应温度50℃、反应时间15h。在此条件下,取代度可达0．0268,反应效率达80％以上。     

酯化改性多孔淀粉的制备研究

采用十二烯基琥珀酸酐对多孔淀粉进行酯化改性,探讨反应温度、反应时间和十二烯基琥珀酸酐用量对改性淀粉取代度的的影响,并采用傅立叶红外光谱仪对酯化多孔淀粉的结构进行表征。研究结果表明,当反应温度40℃、反应时间8h、十二烯基琥珀酸酐用量为多孔淀粉的6%时,酯化多孔淀粉的取代度最佳。     

氧化-酯化-MMA接枝复合变性木薯淀粉的合成与表征

以木薯淀粉为主要原料,经双氧水氧化、邻苯二甲酸酐酯化,再与甲基丙烯酸甲酯进行接枝合成出复合变性淀粉。实验得到较佳的反应条件为:氧化反应时间为2h,温度为40℃,氧化剂用量为5mL,酯化反应时间为4.5h,温度为45℃,催化剂用量为4%;接枝反应的接枝时间为4.0h,温度为40℃,投料比(MMA∶酯化淀粉)为1.75∶1,引发剂浓度为0.05mol/L。用红外光谱(FTIR)、扫描电镜(SEM)对原料和复合变性薯淀粉的结构进行了表征。     

高岭土的改性及其应用研究

以乙酸钾、三乙醇胺作为改性剂,用机械球磨的方法对高岭土进行改性。将改性高岭土以不同的比例添加到陶瓷坯料中,制备成试样在1250℃、1300℃下烧成。用XRD衍射技术来分析改性前后高岭土物相组成的变化,测试烧成后试样的抗折强度与吸水率,用SEM分析试样断面的微观形貌。研究结果表明,改性剂能够促进高岭土中莫来石的形成;将改性高岭土添加到陶瓷坯体中能够提高陶瓷的抗折强度,相对于未添加改性高岭土的陶瓷坯体抗折强度提高26.72%;添加改性高岭土的陶瓷坯体可以降低烧成温度50℃。     

高纯度醚化剂的合成及其应用

以环氧氯丙烷为原料合成了 3-氯 - 2 -羟丙基基三甲基氯化铵 ,后者作为改性淀粉的醚化剂。考察了不同催化剂的用量、反应时间等对剂收率的影响 ,在季铵型催化剂作用下 ,当反应时间 3h,原料配比 n(环氧氯丙烷 ) :n(胺盐 ) =1 .0 0 :1 .0 5时 ,醚化剂产品收率在 98%以上 ,其中环氧氯丙烷质量分数≤ 5× 1 0 -6,1 ,3-二氯丙醇质量分数≤ 1× 1 0 -5。用于合成洗涤留香剂 ,性能良好     

陶瓷添加剂对Al_2O_3陶瓷成形工艺的影响研究

陶瓷添加剂是陶瓷制备过程中添加的用以改善陶瓷浆料,坯体等性能的无机或有机精细化工原料。在氧化铝陶瓷浆料制备中,为获取更好流动性的浆体,往往添加一定数量的表面活性剂加以改善;为增强氧化铝成形坯体的强度,可通过添加一定的粘合剂进行改善。本文通过分散剂的基团分析,探究了分散剂分散机理,并研究了分散剂加入对氧化铝坯体致密度的影响;通过对改性淀粉的加热粘度分析,探究了改性淀粉在氧化铝陶瓷制备中的重要应用原理;通过添加消泡剂对气孔率影响的分析,使坯体气孔率有较显著改善。     

电子级玻璃纤维用改性高直链淀粉合成研究

以高直链淀粉为原料、甲醇为溶剂、环氧丙烷为醚化剂、环氧氯丙烷为交联剂,以聚乙二醇和烷基醇聚氧乙烯醚为复合催化剂,对电子级玻璃纤维浸润剂用改性高直链淀粉的合成工艺进行了研究。最佳工艺条件是反应温度为55℃,醚化剂用量为淀粉的16%,交联剂用量为淀粉的0.8%,反应时间为16 h,取代度约0.2。     

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。