电子束辐照交联PVC/EVA共混物的研究

以丙烯酸酯类多官能团不饱和单体为交联敏化剂，采用电子束对聚氯乙烯(PVC)与乙烯—酸酸乙烯共聚物(EVA)的共混物进行辐照交联。研究了VA质量分数、交联敏化剂种类及用量、辐照剂量、EVA用量对共混物凝胶质量分数、力学性能以及热延伸性能的影响。结果表明：EVA共聚物能促进PVC的辐照交联，增加共混体系的凝胶质量分数，改善其力学及热延伸性能；EVA共聚物中VA质量分数增大，共混体系的凝胶质量分数增大，力学及热延伸性能改善更明显。     

聚偏氟乙烯/氟橡胶合金/炭黑三元复合体系电热性能

以聚偏氟乙烯(PVDF)/氟橡胶(F2 6 )合金为基体,研究了两种不同炭黑类型及用量、不同环境温度、不同热历程及辐照交联对复合物PTC(正电阻温度系数)导电特性的影响。结果表明,聚偏氟乙烯/氟橡胶/炭黑三元复合体系具有强PTC特性,可用于制作电致发热稳定性良好的、自限温度 135± 5℃、具有商业用途的自控温型伴热带     

电子束辐照改性PVC／EVA共混物的研究

采用电子柬为辐照源，以三羟甲基丙烷三丙烯酸酯(TMPTA)单体为交联教化剂，对聚氯乙烯与乙烯-醋酸乙烯共聚物以及与改性乙烯-醋酸乙烯共聚物(mEVA)的共混物进行了辐照改性。研究了不同种类EVA对共混体系凝胶含量、力学以及热延伸性能的影响，测试结果表明VA含量越大，辐照改性后共混体系凝胶含量越高，力学及热延伸性能改善越明显，应用氯元素分析方法测定得到VA含量越高越有利于促进PVC接枝或交联反应。辐照剂量的研究表明，辐射剂量增大，共混体系凝胶含量增加，力学及热延伸性能提高，但通过对PVC／mEVA共混体系的研究，辐射剂量超过5Mrad，体系降解程度明显增加。实验中采用凝胶渗透色谱(GPc)、红外吸收光谱(IR)、扫描电镜(SEM)等方法，对性能表现优异的PVC／mEVA共混体系进行了形态与结构分析。     

复合型无卤阻燃聚烯烃辐照交联工艺与性能

采用有机膨胀型和无机金属氢氧化物型2种阻燃剂进行复配,制备了无卤阻燃辐照交联聚烯烃复合材料,克服了有机膨胀型阻燃体系辐照后阻燃性能明显下降和强度较低的问题,以及无机金属氢氧化物型阻燃体系断裂伸长率降低和阻燃性能效率低的问题。结果表明:当辐照剂量为30～90 kGy时,复合型聚烯烃体系的氧指数逐渐增加,当辐照剂量为90～150 kGy时,复合型聚烯烃体系的阻燃性能逐渐降低,当辐照剂量为90 kGy时,其综合性能最佳,氧指数为34.3%,拉伸强度为13.6 MPa,断裂伸长率达到了200%,而且该体系的击穿场强、体积电阻率和热稳定性等均有明显提高,碳层的稳定性也得到了提高。     

电子束辐照和氢氧化铝对LLDPE/EVA共混物凝胶含量和力学性能的影响

研究了电子束辐照剂量和氢氧化铝(ATH)的含量对线性低密度聚乙烯(LLDPE)/乙烯-醋酸乙烯酯(EVA)共混物凝胶含量和力学性能的影响。辐照剂量是影响LLDPE/EVA/ATH阻燃体系凝胶含量的主要因素,而ATH对其凝胶含量的影响较小。随着ATH含量的增加,LLDPE/EVA共混物的拉伸强度逐步增加,断裂伸长率迅速下降。所有阻燃体系的拉伸强度均是随着辐照剂量的增加而逐步增大,但辐照剂量对这些阻燃体系的断裂伸长率的影响却比较复杂。     

低剂量辐照PTFE的热稳定性能研究

采用γ射线辐照技术制备不同剂量的PTFE。在空气气氛、340℃温度条件下对试样热处理,利用热重和差示扫描量热仪研究试样的热稳定性能变化。结果表明:PTFE及射线辐照后PTFE的热解过程只有一个失重阶段,该热解为一步反应的吸热过程。与PTFE热稳定性相比,射线辐照后PTFE随剂量增加其热稳定性降低。在340℃温度条件下热处理PTFE后,其熔点、结晶温度及结晶焓未见明显变化。对射线辐照后的PTFE而言,随着热处理时间的增加,试样熔点、结晶焓增加,试样发生氧化裂解。与PTFE相比,射线辐照后PTFE的热稳定性降低。     

高分子量聚氯乙烯共混体系的性能研究

本文选用氯化聚乙烯、粉末丁腈橡胶和乙烯－醋酸乙烯－一氧化碳三元共聚物作为高分子量聚氯乙烯的改性剂,三窖种改性剂量对ＨＭＷＰＶＣ树脂力学性能及加工性能及动态热稳定性的影响。     

辐照交联聚乙烯管材专用树脂的研制

通过对辐照交联管材基体树脂及助剂体系的配方研究,讨论了敏化剂品种、用量及抗氧剂用量对体系交联度的影响,确定了辐照交联管材专用树脂的最佳配方,即高密度聚乙烯(6366M)和线形低密度聚乙烯(7042)的配比为80/20,敏化剂M-1和抗氧剂的加人量分别为2.5%和2.5%。还考察了辐照剂量对体系力学性能及结晶度的影响。结果表明:随着辐照剂量的增加,拉伸强度、断裂伸长率下降,材料发生交联的同时也发生了降解。随着辐照剂量的增加,结晶度基本没有发生变化,这说明交联只是发生在非晶区或晶区与非晶区的边缘。加工应用实验表明,专用树脂的各项性能达到进口树脂ME2592的水平。     

辐照交联聚烯烃/NR热塑性弹性体发泡材料辐照效应的研究

研究了辐射交联聚烯烃/NR热塑性弹性体发泡材料的辐照效应以及辐照对于泡沫材料性能的影响。凝胶含量的测试表明:发泡体系的交联度随辐照剂量的增加而逐渐增加,但是过大的辐照剂量(>60kGy)不利于辐射交联聚烯烃/NR热塑性弹性体泡沫材料的发泡;随着辐照剂量的增大,材料的表观密度和压缩性能增加。SEM研究表明:随辐照剂量的增加,材料的微观泡孔尺寸变小。DSC研究表明,辐照剂量的提高有利于混合材料耐热性能的提高。傅立叶红外光谱(IR)的研究表明,辐照剂量影响发泡材料的微观结构,辐照剂量的增大使材料内部发生降解反应。     

辐照交联PVC／EVA共混物的形态结构与性能

以电子束为辐照源，以三羟甲基丙烷三丙烯酸酯（TMPTA）单体为交联敏化剂，对聚氯乙烯与乙烯－醋酸乙烯共聚物（EVA）的共混物进行辐照交联。采用红外吸收光谱、扫描电镜方法分析了添加改性EVA的共混物形态结构。通过凝胶含量、力学性能的测定，得到结论：EVA共聚物与PVC共混可以促进PVC辐照交联，改性EVA促进效果更明显；辐照剂量增大、体系凝胶含量增加，力学性能及热延伸性能提高，但辐射剂量高于5Mrad之后，体系降解程度明显增加。     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.