固相法低度氯化聚乙烯结构与性能的研究

在不同的温度下合成了氯含量小于等于30％的低度氯化聚乙烯(LCPE),讨论了氯含量,氯化温度等对LCPE的结晶度,物理机械性能的影响,同时也研究了LCPE的热氧化稳定性。发现氯含量为7.4％时,LCPE的脆化时间发生突跃,而氯含量小于7.4％的LCPE和原料HDPE在老化过程中都有一个从脆化状态到耐脆化的转变。     

固相法低度氯化聚乙烯的合成及其性能的研究

合成了几个系列氯含量≤30％的低度氯化聚乙烯(LCPE),讨论了氯含量、氯化温度、供氯速度、原料种类及分子量对LCPE力学性能、加工性能和耐油性能的影响。     

低温一步法固相氯化制备CPE弹性体

采用自制的氯化促进剂,在低于高密度聚乙烯结晶熔点(120—125℃)下反应,一步固相氯化制备了 CPE弹性体。由DSC谱图及溶剩值证实,与不加氯化促进剂的工艺相比,本工艺反应速度快,氯含量达到 30％时,反应温度仅为 123℃,一般工艺则需 135℃;氯含量达到 36％的产品基本上没有结晶存在,具有良好的橡胶性能,可在50—60℃下混炼,比一般混炼温度低50％左右。     

气-固相法氯化反式-1,4-聚异戊二烯

采用气-固相法对反式-1,4-聚异戊二烯(TPI)进行氯化改性,制得氯化反式-1,4-聚异戊二烯(CTPI)。主要探讨了氯含量对反式-1,4-聚异戊二烯结晶度的影响,以及氯化后TPI结构的变化。分析结果表明,随着氯含量的升高,CTPI的结晶度下降,熔点降低。随TPI粒径尺寸减小以及其相对分子质量分布变窄,氯化则越容易,氯化程度越均匀,结晶度降低越多。结构表征发现,CTPI分子链结构包括碳-碳双键氯加成、侧甲基氯取代、环氧基团等。     

高氯化聚乙烯的生产

目前,我国生产的氯化聚乙烯氯含量一般在30～40％,类似软橡胶。主要用做PVC塑料的抗冲击改性剂,屋顶防水卷材和难燃输送带等。一般地讲,随着氯含量的增大,其耐油性,难燃性,耐气透过性越好。高氯化聚乙烯就是氯含量超过60％的氯化聚乙烯。它具有良好的耐候性,耐臭氧,耐热老化及耐油性,可做为成膜材料。 高氯化聚乙烯对所有的无机和有机颜料都具有良好的相溶性。在空气受到严重污染的环境中,具有良好的耐候性,其稳定性优于氯化橡胶。因此,在许多领域,HCPE能有效     

固相法氯化聚乙烯弹性体的结构与性能

采用固相氯化法制备了不同氯含量的氯化聚乙烯弹性体(CPE),考察了氯含量及制备条件对产物性能的影响,利用示差扫描量热仪研究了产物结晶度随氯含量及氯化条件变化的规律。氯含量为37％左右的CPE具有较好的强度和伸长率,在合适的氯含量范围内,高温(130℃)氯化程度增加时,产物弹性增加,拉伸强度降低。     

甲基丙烯酸甲酯与氯化聚乙烯的力化学共聚物的性能

主要研究了甲基丙烯酸甲酯（PMMA）与氯化聚乙烯（CPE）力化学共聚物的力学性能和涂膜性能。结果表明：共聚物的抗张强度随CPE的氯含量及PMMA的含量的增加而增大；抗冲强度随CPE的氯含量的增加而降低，随PMMA的含量的增加而增大；共聚物的涂膜具有较好的光泽度及硬度。     

固相法氯化聚乙烯脱HCl热稳定性研究

本文采用固相氯化法制备了各种氯含量的氯化聚乙烯（ＣＰＥ）并用氯化氢吸收法系统考察了氯化条件、氯含量对固相法ＣＰＥ热稳定性的影响。结果表明氯化温度对ＣＰＥ的热稳定性有较大影响，高温氯化可以提高ＣＰＥ的热稳定性。在一定范围内随氯含量增加，ＣＰＥ热稳定性也相应增大。对ＣＰＥ脱除ＨＣｌ前后红外光谱及凝胶含量变化的研究表明ＣＰＥ热分解过程伴有交联结构形成。     

氯化聚乙烯与氯磺化聚乙烯的结构与性能及共混硫化体系

主要研究了氯化聚乙烯(CM)与氯磺化聚乙烯(CSM)的结构与性能及共混硫化体系。结果表明:随着氯含量的增加,CM的玻璃化温度逐渐升高。同样氯含量的CM的玻璃化温度高于CSM,且残余结晶度高于CSM。在CSM中并用适量的CM,可以提高CSM的加工安全性,并提高硫化效率;共混胶的拉伸强度和100%定伸应力随着CM用量增加逐渐增加,拉断伸长率和撕裂强度逐渐减小;随着CM用量的增加,共混胶的耐老化及耐油性能下降;噻二唑硫化体系硫化的共混胶硫化时间短,并且硫化胶的综合性能较好。     

力化学法制备氯化聚乙烯—甲基丙烯酸甲酯接枝聚合物

采用开炼机于辊温２５℃下将氯化聚乙烯和甲基丙烯酸甲酯按１：０．３混合后素炼１０ｍｉｎ，进行力化学接枝共聚合，可制香ＣＰＥ－ＭＭＡ接枝聚合（ＣＭ），ＭＭＡ接枝效率可达８２％。随ＣＰＥ氯含量增加，接枝率和接枝效率增大；增加ＭＭＡ用量可提高接枝率。ＣＭ用作ＰＶＣ的抗冲改性剂较之ＣＰＥ优越，冲击强度提高增大，拉伸强度降低较小。     

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。