乙基纤维素的一步法合成与表征

采用纤维素与过量的氯乙烷及氢氧化钠反应 ,以甲苯为稀释剂 ,用一步法成功地合成了乙基纤维素。通过元素分析、红外光谱和核磁共振氢谱对产物的分子结构进行表征 ,确定所合成的化合物即为目标产物。该法所得乙基纤维素产品的乙氧基含量为 4 3 98%。     

高取代度乙基纤维素的一步法合成机理及研究

采用正交试验方法，以甲苯为稀释剂，探讨了高取代度乙基纤维素一步法合成的反应机理及工艺条件，并采用红外光谱、核磁共振氢谱对产物分子结构进行了鉴定表征。以27g纤维素为基准，优选出一步法合成最佳工艺条件为：甲苯用量180g，氢氧化钠溶液质量浓度60％，氯乙烷用量477．5g，反应温度140℃，反应时间13h，该条件下，乙氧基含量(质量分数)可达44．8％。     

一步法合成乙基纤维素的实验研究

采用正交实验的方法,以甲苯为稀释剂,探讨了乙基纤维素一步法合成的工艺条件。研究结果表明:一步法合成工艺流程简单易行,生产成本较低,产品取代度相对略低,以1mol纤维素为基准,选出优惠工艺条件为:甲苯用量13mol,固体氢氧化钠用量30mol,氯乙烷用量35 mol,反应温度140℃,反应时间12 h,产品乙氧基含量可达44.2%。     

高乙氧基乙基纤维素合成实验研究

采用正交实验的方法，以醚化剂本身为稀释剂，探讨了高乙氧基含量乙基纤维素二步法合成的工艺条件，并采用红外光谱、核磁共振氢谱对产品结构进行了表征：以1mol纤维素为基准，优选出最佳工艺条件为：氢氧化钠溶液浓度50％，氢氧化钠用量16．2mol，碱化温度32℃，碱化时间3h，氯乙烷用量为40mol，醚化温度140℃，醚化时间12h，该条件下，乙氧基含量可高达45．8％。     

新型阳离子羟乙基纤维素醚的合成

以羟乙基纤维素为原料、2-氯-4,6-二（N,N-二甲基-N-苄基-1,3-丙二胺）-1,3,5-均三嗪（BT）为改性剂,合成新型季铵盐阳离子羟乙基纤维素醚,讨论了影响产物取代度的主要因素。结果表明：在异丙醇稀释剂中,NaOH和改性剂的物料量比为1．2：1,改性剂和羟乙基纤维素的物料量比为1．5：1,反应温度为95℃、反应时间为5h时,产物的取代度最高达0．24。     

国内简讯

国内简讯羟乙基羧甲基纤维素的合成羟乙基羧甲基纤维素（ＨＥＣＭＣ）是天然纤维素经过化学改性──醚化后获得的一类高分子化合物，是在纤维素结构单元中既含有羧甲基离子又含有非离子的羧乙基纤维素的混合醚。液相法合成ＨＥＣＭＣ是使碱纤维素和环氧乙烷在液相稀释剂中...     

FTIR法测定EC乙氧基含量

对富立叶变换红外光谱（FTIR）法用于测定乙基纤维素（EC）乙氧基含量进行了研究，讨论了制样条件和水分对红外结果的影响，采用不同乙氧基含量范围的标准样品分别进行了化学法和红外光谱法测定，确立了两种方法之间的换算关系式，R检验效果良好，对比试验表明，在统计意义上红外法结果比化学法结果平均仅高0．25左右。     

羟乙基纤维素在涂料工业中的应用

羟乙基纤维素（hydrooxyethylcellu－lose），简称HEC，是一种非离子型水溶性高聚物，由纤维素与环氧乙烷在碱催化下反应而成。其制法有溶媒法和水媒法两种。溶媒法是在有机溶剂（如异丙醇或特工醇）作为稀释剂的条件下进行的，所制得的HEC取代度高（DS＝0．8～1．5），是水溶性的。水媒法是在没有有机稀释剂存在的情况下进行，产物HEC取代度低（DS＝0．2～0．3），可以溶于稀碱而不溶于水。快速溶解的HEC葡萄糖单元的平均化合度（MS）是2．5。即是说，每个葡萄糖单元上的羟基与2．5个环氧乙烷分子发生了反应。羟乙基纤维素为白色或…     

烯烃配位聚合Ziegler-Natta催化剂烷氧基镁载体的研制

制备了直径在26.9~52.6μm区间的乙氧基镁颗粒,考察了搅拌速率以及二氧化硅、癸烷、戊五醇对乙氧基镁载体颗粒形态的影响。研究发现,在制备乙氧基镁载体的过程中加入适量的二氧化硅、癸烷和交联剂戊五醇,可以提高烷氧基镁颗粒的机械性能、堆密度、流动性。     

低VOC硝基纤维素型涂料组合物

木材用可固化硝基纤维素型涂料组合物有4种必须的成分:硝基纤维素、可聚合活性稀释剂(玻璃化转变温度都在25℃左右的均聚物),以及丙烯酸酯氨基甲酸酯。该组合物还可含引发剂,以使该组合物完成热固化或光固化。例如,将SR 502(乙氧基化三羟甲基丙烷三丙烯酸酯活性稀释剂)5.15份与Photomer 4095(烷氧基化三羟甲基丙烷三丙烯酸酯活     

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。