提高转化率对丁腈橡胶性能的影响

研究了丁腈橡胶合成过程中聚合时间对转化率和聚合速率的影响,考察了提高转化率对丁腈橡胶生胶的门尼黏度、凝胶含量、结合丙烯腈量、相对分子质量及其分布,胶乳的黏度和机械稳定性及硫化胶力学性能等的影响.结果表明,转化率从71%左右升高到75%以上,反应时间约需延长2.5 h,反应后期聚合速率变缓.与转化率为71%左右时相比,转...     

提高转化率对乳聚丁苯橡胶性能的影响

以吉林石化公司有机合成厂的乳聚丁苯橡胶(SBR)生产配方为标准配方,研究了聚合反应时间对转化率的影响,分析了提高转化率对SBR的生胶门尼黏度、结合苯乙烯含量、凝胶含量、相对分子质量及其分布、胶乳黏度等基本性能的影响。结果表明,在标准配方条件下,延长聚合反应时间,转化率可以达到70%。转化率为70%时所得SBR与转化率为62%时所得SBR相比,前者的生胶凝胶含量和胶乳黏度均增大了1倍,数均相对分子质量、重均相对分子质量和Z均相对分子质量均高于后者,相对分子质量分布变宽,且前者的生胶结合苯乙烯含量能够达到产品标准,而生胶门尼黏度和在50 m in时的300%定伸应力偏高于产品优级品要求。     

高转化率配方乳聚丁苯橡胶聚合过程中间产物性能考察

采用中国石油吉林石化公司乳聚丁苯橡胶高转化率大生产配方,考察了实验室聚合反应釜聚合反应单体转化率随反应时间的变化,测定了生胶的结合苯乙烯含量、有机酸和皂含量、门尼粘度等性质,结果表明：反应10 h,转化率为70%左右时生胶的各项性质均达到标准GB/T 8655—2006中规定的优等品指标要求;当反应12 h,转化率达到75%时,生胶的结合苯乙烯含量和门尼粘度不符合要求。     

不同门尼黏度反式-1，4-聚异戊二烯与炭黑的相互作用及其对硫化胶性能的影响

研究了不同门尼黏度反式-1,4-聚异戊二烯(TPI)与炭黑N 330的相互作用及其对TPI硫化胶物理机械性能和疲劳性能的影响.结果表明,随TPI生胶门尼黏度增大,炭黑结合胶含量减少,炭黑分散性变差,增强作用减弱.未填充炭黑TPI硫化胶的100%定伸应力和拉伸强度随TPI门尼黏度的增大而显著提高;用炭黑增强后,不同门尼黏度TPI硫化胶的100%定伸应力和拉伸强度差别不大.不同门尼黏度TPI硫化胶的压缩生热和压缩永久变形在填充炭黑后均增大,其中低门尼黏度的增加幅度显著大于高门尼黏度者;不同门尼黏度TPI硫化胶压缩生热的变化主要由炭黑与橡胶之间的作用引起.生胶门尼黏度为50～80的TPI硫化胶的动态疲劳性能较好.     

高转化率E－SBR1500生胶和硫化胶的性能研究

对用高活性引发体系在较短聚合周期（９—１１ｈ）内合成的高转化率（７％）Ｅ－ＳＢＲ１５００生胶的门尼粘度、凝胶含量、结合苯乙烯含量、分子量分布、组成分布和微观结构等基本特性参数和硫化胶的物性进行了试验研究。结果表明：生胶的各项特性指标和硫化胶物性均达到了６０％转化率的我国吉化和日本ＪＳＲ胶样的实测值水平。     

高转化率E-SBR1500生胶和硫化胶的性能研究

对用高活性引发体系在较短聚合周期（９－１１ｈ）内合成的高转化率（７０％）Ｅ－ＳＢＲ１５００生胶的门尼粘度、凝胶含量，结合苯乙烯含量，分子量分布，组成分布和微观结构等基本特性参数和硫化胶的物性进行了试验研究，结果表明，生胶的各项特性指标和硫化物性均达到了６０％转化率的我国吉化和日本ＪＳＲ胶样的实验值水平。     

相对分子质量及其分布对稀土顺丁橡胶性能的影响

研究了5种不同相对分子质量及其分布的稀土顺丁橡胶(NdBR)的性能。结果表明,NdBR生胶和混炼胶的门尼黏度随相对分子质量的增加而升高;窄相对分子质量分布(多分散指数小于3.00)NdBR的生胶门尼黏度略高于与其相对分子质量相近而分布较宽的NdBR。相对分子质量对NdBR的正硫化时间影响不大,但最小转矩和最大转矩有随相对分子质量的增加而增大之趋势。生胶相对分子质量较低的NdBR,其硫化胶的300%定伸应力和拉伸强度较低,生热值较高,耐磨性能下降,滚动阻力升高。生胶门尼黏度为39~49的NdBR,其硫化胶的综合性能良好。填充适量操作油可以提高硫化胶的物理机械性能。窄相对分子质量分布NdBR硫化胶的300%定伸应力、拉伸强度、扯断伸长率、回弹性、永久变形、耐磨性以及滚动阻力等都优于相对分子质量相近而分布较宽的NdBR。     

锡偶联型溶聚丁苯橡胶的热稳定性

考察了2种牌号充油锡偶联型溶聚丁苯橡胶(SSBR)生胶(NS 424和NS 560)的凝聚态结构与性能,并与充油非偶联型SSBR进行了对比。结果表明,与非偶联型SSBR相比,SSBR NS 424生胶的数均分子量和重均分子量均略小,而分子量分布相近,门尼黏度偏大,加工性能较差,弛豫时间较长;SSBR NS 560生胶的数均分子量和重均分子量均较小,分子量分布较窄,门尼黏度略大,热稳定性较好,弛豫时间较短。     

恒黏剂对恒黏天然橡胶生胶分子结构及动态力学性能的影响

用门尼黏度仪、凝胶渗透色谱仪和橡胶加工分析仪分析了恒黏剂盐酸羟胺、盐酸氨基脲制备的恒黏天然橡胶生胶的门尼黏度、相对分子质量及其分布和动态力学性能。结果表明,相比于盐酸氨基脲,盐酸羟胺对天然橡胶门尼黏度、相对分子质量及其分布和动态力学性能有更大的影响。盐酸羟胺基恒黏天然橡胶的门尼黏度和相对分子质量均明显低于天然橡胶,弹性模量在低频率范围随频率增大而增加的幅度明显小于天然橡胶,损耗因子随应变的增大明显大于天然橡胶,复数黏度对剪切速率的敏感度小于天然橡胶。     

采用BP神经网络预测乳聚丁苯橡胶的门尼黏度

在工业生产乳液聚合丁苯橡胶配方的基础上,于实验室聚合釜中考察了增加引发剂和乳化剂用量对聚合速率的影响以及补加相对分子质量调节剂及其加入时机对聚合产物门尼黏度的影响。结果表明,增加引发剂和乳化剂用量可以加快丁苯乳液聚合的速率,配合补加相对分子质量调节剂的手段可以使单体转化率达到70%时丁苯橡胶生胶的门尼黏度达到国家标准的要求。同时以原配方及其调整数据为基础,采用Levenberg-Marquardt算法对所建立的BP神经网络模型进行训练,仿真结果显示该网络的仿真数据与实验数据的误差小于1%,具有较好的一致性,可以用于判断丁苯乳液聚合不同配方在特定反应条件下产物的门尼黏度。     

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。