Et(Ind)_2ZrCl_2/MAO和(Ind)_2ZrCl_2/MAO对乙烯/α-烯烃共聚合比较研究

用立体刚性的亚乙基桥二茚基二氯化锆(Et(Ind)_2ZrCl_2)和非桥联的二茚基二氯化锆((Ind)_2ZrCl_2)为催化剂、甲基铝氧烷(MAO)为助催化剂,在相同共聚合条件下,乙烯与丙烯、1-丁烯、1-已烯和1-辛烯进行了比较试验,考察Et桥对乙烯/α-烯烃共聚合的作用。Et(Ind)_2ZrCl_2催化剂的活性,除乙烯/1-已烯共聚合外,比(Ind)_2ZrCl_2催化剂的高。用有桥联的催化剂得到的各共聚物中共聚单体含量都比无桥联的催化剂合成的共聚物高,但前者共聚物的相对分子质量、密度和熔点都低于后者。在用Et桥的催化剂得到的共聚物中,α-烯烃的含量下降次序为丙烯>1-丁烯>1-辛烯>1-已烯。     

双核茂金属催化剂催化乙烯／1-己烯共聚合

制备[CpTiCl2]2{μ,μ-[(Me2Si)2(η5-C5H3)2]}双核茂金属化合物,用1H NMR和IR分析进行了表征.合成的化合物经硅胶作载体负载,以MAO作助催化剂,催化乙烯/1-己烯共聚合.考察了茂金属用量,茂金属与硅胶/MAO处理温度,MAO的用量对负载催化剂的影响,以及己1烯-用量对聚合产物的影响.反应温度65℃,在1-己烯浓度为0.25mol/L条件下共聚活性可达4.01× 106gPE/molTi·h,催化所得聚乙烯的相对分子质量分布为7.32,己1烯-插入率8.45.     

双核茂金属催化剂催化乙烯／1-己烯共聚合

合成了[CpTiCl2]2 {μ,μ-[(Me2Si)2 (η5-C5H3)2]}双核茂金属化合物,用1H NMR和IR分析进行了表征.合成的化合物经硅胶作载体负载,以MAO作助催化剂,催化乙烯/1-己烯共聚合.考察了茂金属用量,茂金属与硅胶/MAO处理温度,MAO的用量对负载催化剂的影响,以及1-己烯用量对聚合产物的影响.反应温度65℃,在1-己烯浓度为0.25 mol·L-1条件下共聚活性可达4.01×106 gPE/mol Ti·h,催化所得聚乙烯的相对分子质量分布为7.32,1-己烯插入率8.45%.     

Cp_2ZrCl_2/MAO催化剂催化乙烯与环烯烃共聚合研究

本工作采用二氯二茂锆(Cp_2ZrCl_2)/甲基铝氧烷(MAO)催化剂催化乙烯分别与1,5-环辛二烯(COD),4-乙烯基环己烯(VCH),1,5,9-环十二碳三烯(CDT)的共聚合,研究了共聚单体类型和浓度对共聚合的影响,采用差示扫描量热仪、高温凝胶渗透色谱仪和核磁共振波谱仪研究了产物的链结构和热性能。研究发现:COD的共聚合性能最好,其不仅对催化剂的活性影响最小,而且COD插入到聚合物中的摩尔分数(插入率)较高,当COD浓度为1.0 mol/L时,COD插入率为0.6%。尽管VCH对催化剂的活性影响也较小,但其与乙烯进行共聚合的能力较差,而CDT不但使催化剂的活性明显下降,而且无法与乙烯进行共聚合。     

乙烯/1-己烯共聚物的制备及微观结构研究

采用2(叔丁氨基)二甲基(η_5-环戊二烯基)亚甲基二氯化锆[t-BuNC(Me)_2(η_5-C_5H_4)](ZrCl_2)_2为主催化剂,甲基铝氧烷为助催化剂、正庚烷为聚合溶剂,催化乙烯/1-己烯共聚合,考察了共聚单体浓度对催化活性及共聚物性能的影响。在不同聚合条件下,制备了系列共聚物,采用DSC、核磁碳谱、GPC等分析表征方法研究了共聚物的分子结构。研究结果表明,随着共聚单体浓度的增加对催化剂活性及共聚物基础物性、力学性能及分子结构均有较大影响,说明催化剂具有良好的共聚性能,可以对聚合物的分子结构具有良好的调控作用。     

单活性中心茂金属催化剂催化乙烯与1-己烯共聚合

采用自制的单活性中心茂金属催化剂为主催化剂,甲基铝氧烷为助催化剂进行乙烯与1-己烯的共聚合。考察了溶剂、助催化剂用量、反应温度、反应压力、共聚单体浓度等对催化剂活性和共聚物性能的影响。结果表明:单活性中心茂金属催化剂催化乙烯与1-己烯共聚合的适宜溶剂为正庚烷,适宜的工艺条件为n(Al)∶n(Zr)=700~1 000,反应温度100~120℃,反应压力1.20~2.00 MPa,1-己烯浓度1.00~1.84 mol/L。     

酚氧基单茂钛/MAO体系催化乙烯丙烯共聚竞聚率的计算

采用合成的催化剂五甲基环戊二烯基-（2，6二异丙基）苯氧基-二氯化钛{Cp^＊Ti[OCsH3（iPr）2]Cl2}与甲基铝氧烷（MAO）组成的新型催化体系进行乙烯／丙烯共聚合，利用简化的公式计算研究了乙烯、丙烯竞聚率。结果表明，与其它茂金属催化体系相比，Cp^＊Ti[OC6H3（iPr）2]Cl2／MAO催化体系的丙烯竞聚率相对较高，制得的聚合物为有嵌段共聚倾向的无规共聚胶。     

负载茂金属催化剂催化乙烯气相聚合

研究了负载茂金属催化剂(n-BuNeCp)_2ZrCl_2/SiO_2的乙烯气相聚合行为及其催化聚合产品的性能。三乙基铝加入聚合体系后可降低负载茂金属催化剂的初始活性,有利于聚合过程中的温度控制。气相聚合产品聚乙烯的重均分子量为(1 42～2.28)×10~5,相对分子质量分布为2.6～3.1,熔点在135℃以上,结晶度约为60%,聚乙烯产物颗粒形态以球形为主.堆密度大于0.35 g/cm~3。     

单环戊二烯基钛类茂金属催化剂的应用

综述了限制几何构型茂金属(单环戊二烯基钛类茂金属)催化剂在烯烃聚合方面的应用,包括乙烯/链烯烃共聚合,长链α-烯烃和降冰片烯的共聚,含乙烯端基大分子单体的共聚,乙烯和苯乙烯的聚合以及高分子量的无规聚丙烯的合成。研究表明,单环戊二烯基允许各种单体的插入,环戊二烯上的取代基团及配体基团的引入,影响催化烯烃聚合活性,控制聚合物的分子量和聚合分散度。     

FI催化剂在制备乙烯基共聚物中的应用

综述了带有芳氧基亚胺配体的ⅣB族金属络合物(FI催化剂)催化的乙烯类共聚合。Ti-FI催化剂可用于乙烯与α-烯烃、乙烯与环烯烃的共聚合。相比传统的茂金属催化剂,FI催化剂可以制备共聚单体含量更高的共聚物。FI催化剂对极性基团具有良好的耐受性,将其用于乙烯与极性单体的共聚合,可取得理想的效果。与亚胺N原子相连的芳香环上的邻位H原子被F原子所取代的Ti-FI催化剂催化乙烯类聚合时,表现出活性聚合的特征。因此可通过控制单体加入顺序制备嵌段共聚物。用两种不同的FI催化剂,且以二乙基锌为链穿梭剂,可制备多嵌段共聚物。优化配体结构可制备高效的乙烯类共聚合催化剂。这些将有利于实现聚烯烃的功能化和高性能化。     

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。