生物合成聚γ-谷氨酸的相对分子质量表征

为了确定特定条件下聚γ 谷氨酸(γ PGA)水溶液的Mark Houwink方程参数,在参数适用范围内通过特性粘度测量,对γ PGA的相对分子质量进行快捷、可靠的估计,在对钠盐型γ PGA稀溶液的粘度特性和流变性质进行了系统考察的基础上,采用凝胶渗透色谱-激光光散射联机试验(GPC LLS)和粘度方法,研究了钠盐型γ PGA的特性粘数、分子尺寸对重均相对分子质量的依赖性;建立了γ PGA在1.20mol LNaCl水溶液中的Mark Houwink方程。提出了相对分子质量的测定方法,并对均方末端距进行了估算。较大的α值表明:γ PGA大分子即使在1.20mol L的离子强度下由于聚离子的静电相斥作用仍然在溶剂中呈现出较伸展的构象,即呈棒状结构。     

生物合成聚γ-谷氨酸(钠盐型)稀溶液的粘度特性

为了确定特定条件下生物合成聚γ 谷氨酸(γ PGA)稀溶液的Mark Houwink方程参数,从而在关系适用范围内能够通过比较简单的特征粘数测量对γ PGA的相对分子质量进行快捷而可靠的估算,用毛细管粘度计法对钠盐型γ PGA稀溶液的粘度特性进行了系统考察。结果发现钠盐型γ PGA是一种典型的聚电解质,在一定浓度范围内显示了比浓粘度独特的浓度依赖性:不服从Huggins方程。中等离子强度的外加小分子强电解质会减小γ PGA稀溶液的特性粘数[η],并使之呈现出正常的粘度行为,且[η]与溶液中离子强度的-1/2次幂成较好的线性关系。[η]具有一定的时间依赖性。     

聚天冬氨酸合成工艺研究

探讨不同催化剂对聚天冬氨酸(PASP)聚合反应的影响,采用正交试验法优化合成工艺。研究结果表明:磷酸作为催化剂能有效改善PASP溶液颜色和提高聚合物的相对分子质量。最佳合成工艺条件为:马来酸酐和碳酸铵单体质量比为1∶1.2,磷酸用量为2.5%,聚合温度为200℃,聚合反应时间2 h时,制备的PASP的特性粘数为0.083 dL/g。阻垢实验结果显示,特性粘数高于0.05 dL/g的PASP的阀值质量浓度为10 mg/L,其阻垢率均达到85%以上。     

聚乙烯胺盐酸盐水溶液的粘度性质研究

通过聚丙烯酰胺的Hofmann降级重排反应制备聚乙烯胺盐酸盐,研究了聚乙烯胺盐酸盐水溶液的粘度性质。研究表明,浓度和pH值对聚乙烯胺盐酸盐水溶液的粘度有很大影响,其水溶液的比浓粘度在pH值为4左右时达到极值;聚乙烯胺盐酸盐的特性粘数明显高于其原料聚丙烯酰胺的特性粘数,分子量对特性粘数的影响十分明显,而胺化度对特性粘数的影响并不显著。     

《聚甲醛树脂稀溶液粘数和特性粘数测定》等两项行业标准修订介绍

《聚甲醛树脂稀溶液粘数和特性粘数测定》和《聚氯醚树脂稀溶液粘数和特性粘数测定》两项国家标准经清理整顿后调整为行业标准。该两项行业标准经化工部晨光化工研究院（成都）负责起草修订,于１９９７年１２月完成报批。现将两项标准简介如下。１标准制定的依据和意义合成树脂的粘度是直接反映工艺过程和材料性能的参数。因此,在产品开发和产品生产质量控制上都把粘度作为必测指标。ＧＢ１８４６－８０和ＧＢ１８４７－８０由上海合成树脂研究所组织起草。自发布以来,规范了聚氨酸和聚甲醛树脂稀溶液粘度的测试条件,被科研和生产实践所…     

相反电荷强聚电解质复合物盐溶液的粘度研究

合成了高电荷密度的磺酸基强聚电解质,考察了其与阳离子聚电解质聚二烯丙基二甲基氯化铵（PDADMAC）稀溶液复合体系的流动特性。无论外加盐浓度高低,剪切速率高于10s^-1时,复合体系都表现出牛顿流体的行为。在水溶液中,随PDADMAC的增加,复合体系的增比粘度逐渐减小;在高浓度的NaCl溶液中,随PDADMAC的增加,体系的增比粘度基本保持不变。随体系离子强度增大,复合体系增比粘度出现极大值,反映了复合聚集的加强;继续增大离子强度,则复合解离,增比粘度变小直至恒定。     

聚天冬氨酸的合成及其粘均分子量对阻垢性能的影响

通过L-天冬氨酸热缩聚合成聚天冬氨酸(PASP)的一系列试验，研究了聚合反应温度和时闻对PASP产率和粘均分子量的影响，分析了PASP对CaCO3阻垢性能的变化规律。并用红外光谱和核磁共振技术(NMR)对聚合物结构进行了分析。结果表明，不同反应条件下PASP产品粘均分子量相差很大，PASP粘均分子量对其阻CaCO3垢效果有显著影响。通过控制反应温度和时间能够改善PASP的阻垢性能，结果是230℃时反应5h所得PASP阻垢效果最好，此时PASP粘均分子量约为10000。     

固相法氯化等规聚丙烯的溶液性能

研究了固相法CIPP的稀溶液和浓溶液性能 ,结果表明 ,随着氯含量的增加CIPP稀溶液的特性粘数和浓溶液的粘度都呈下降趋势。溶液粘度随氯化反应温度的升高上升较快 ,在力化学降解下CIPP的溶液粘度下降较快。CIPP固含量超过 2 0 % ,粘度上升较快     

AM/DAAM二元共聚物的合成与表征

用一种氧化还原体系的引发剂,采用水溶液聚合法合成了丙烯酰胺-N-(1,1-二甲基-3-氧代丁基)丙烯酰胺(AM/DAAM)二元共聚物。实验中分别考察了原料中单体配比、反应时间、引发剂用量对共聚物的特性粘数的影响;同时采用定量的方法考察了共聚物的溶解性能。结果表明,当DAAM在共聚物中的摩尔百分含量为33.64%时,聚合物的特性粘数比相同条件下合成的聚丙烯酰胺提高9.9倍;当共聚物中DAAM的含量为15%时,共聚物的溶解速率是相同条件下合成的聚丙烯酰胺的4倍。通过对各种组成共聚物在不同盐溶液中的特性粘数的测定,结果显示该共聚物具有良好的耐盐性能。另外,采用红外光谱、核磁共振氢谱对共聚物进行了定性和定量的表征。     

表征聚氯乙烯分子量的各种指标的计算

本文汇编了以GB3401《聚氯乙烯树脂稀溶液粘数的测定》所得的相对粘度测定值计算表征聚氯乙烯分子量的粘数、K值、特性粘数、平均聚合度、绝对粘度等指标的计算式,供参考。     

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。