丙烯酸酯低聚物改性环氧树脂的研究

以2,4-甲苯二异氰酸酯、甲基丙烯酸羟丙酯和E-03环氧树脂为原料合成了异氰酸酯化丙烯酸酯大单体,用其作为官能单体,同丙烯酸酯软硬单体在引发剂的作用下,以环氧树脂为分散介质,合成了异氰酸酯化丙烯酸酯低聚物。讨论了低聚物组成对体系粘接性能的影响。结果表明:BA为软单体,AN为硬单体,BA/AN质量比为80/20时体系的综合性能较好。改性后体系的剥离强度为7.5k N/m,25℃剪切强度为39.4MPa,150℃剪切强度为15.6MPa。     

异氰酸酯化丙烯酸酯低聚物的合成研究

以2,4-甲苯二异氰酸酯、甲基丙烯酸羟丙酯和E-03环氧树脂为原料合成了异氰酸酯化丙烯酸酯大单体,用其作为官能单体,同丙烯酸酯软硬单体在引发剂的作用下,以环氧树脂为分散介质,合成了异氰酸酯化丙烯酸酯低聚物。讨论了反应温度、引发剂种类及用量对体系粘接性能的影响。结果表明:聚合反应温度为85℃,BPO用量为总单体用量的1.2%时,体系的粘接性能有明显的提高,体系的剥离强度为7.5k N/m,25℃剪切强度为39.4MPa,150℃剪切强度为15.6MPa。     

丙烯酸酯核壳纳米粒子的合成及其改性环氧树脂

以丙烯酸丁酯(BA)为软单体、甲基丙烯酸甲酯(MMA)为硬单体和甲基丙烯酸缩水甘油脂(GMA)为官能单体,采用乳液聚合法合成出具有活性结构的BA/MMA/GMA核壳纳米粒子,并以此作为环氧树脂(EP)的增韧改性剂。研究结果表明:当w(核壳粒子)=10%、m(BA):m(MMA):m(GMA)=80:20:10时,与纯EP体系相比,改性EP体系的断裂伸长率提高了42.5%,剥高强度提高了近3倍,25℃和150℃时的剪切强度分别提高了48.6%和31.2%,坡璃化转变温度变化不大;红外光谱(FT-IR)证实,该核壳纳米粒子具有典型的特征吸收峰;透射电镜(TEM)观察结果表明,合成粒子具有纳米级核壳结构。     

丙烯酸酯低聚物改性环氧树脂的研究

以2-甲基-2-丙烯酸-2-异氰酸基乙酯(2-IEMA)和环氧树脂(E-03)生成物作为官能单体,同丙烯酸酯软硬单体在引发剂的作用下,以环氧树脂为分散介质,合成了丙烯酸酯低聚物。讨论了2-IEMA/E-03(质量比)及不同软单体对体系粘接性能的影响。结果表明:在2-IEMA/E-03为5.0/95.0,选BA作为软单体时,改性体系的综合性能较好。改性体系的剥离强度为9k N/m,常温剪切强度达到36.1MPa,断裂伸长率为8.7%。通过对体系DMA分析可以看出,BA改性体系的玻璃化转变温度最高为116.2℃。     

用液态含羧基丙烯酸酯低聚物改性环氧树脂

采用溶液聚合法合成了以丙烯酸丁酯、丙烯腈为主链结构的液态含羧基丙烯酸酯低聚物,用其对环氧树脂进行增韧改性,讨论了丙烯腈、丙烯酸以及丙烯酸酯低聚物质量分数对改性环氧树脂力学性能的影响,并研究了改性环氧树脂的微观形态和动态力学性能。结果表明,丙烯酸酯低聚物质量分数为5％时,丙烯酸丁酯／丙烯腈／丙烯酸（质量比）为75／20／5的改性环氧树脂的拉伸强度比纯环氧树脂提高4．3％;丙烯酸酯低聚物质量分数为10％时,该改性环氧树脂的冲击强度比纯环氧树脂提高近4倍,同时体系的耐热性能保持不变;环氧树脂改性体系呈两相结构,丙烯酸酯低聚物质量分数达到30％时,对环氧树脂的增韧效果变差;随着丙烯酸酯低聚物质量分数的增加,改性环氧树脂的玻璃化转变温度先升高后降低,其质量分数不超过10％时,改性环氧树脂的玻璃化转变温度高于纯环氧树脂。     

双酚A型苯并二噁嗪树脂粘接性能研究

以环氧树脂(EP)、双马来酰亚胺(BDM)作为纯双酚A型苯并二噁嗪(BA-a)树脂的改性共聚单体,研究了不同改性BA-a体系的粘接性能和热稳定性能。结果表明:纯BA-a树脂与钢材之间的拉伸剪切强度为15.34 MPa,说明纯BA-a树脂具有作为胶粘剂的潜力;当m(BA-a)∶m(EP)∶m(BDM)=100∶60∶0或100∶27∶27时,改性BA-a体系的拉伸剪切强度为24.81 MPa或21.36 MPa,160℃时凝胶时间为150 min或20 min;改性BA-a体系的热稳定性能依次为BA-a/甲基四氢苯酐体系>BA-a/EP体系>BA-a/BDM体系>纯BA-a体系。     

室温固化高剥离耐热环氧树脂胶粘剂

介绍了一种具有高剥离强度和剪切强度的室温固化耐热胶粘剂。室温固化10d后,室温剥离强度可达到7．0kN／m;室温剪切强度为30．8MPa,150℃剪切强度可达14．5MPa。重点讨论了环氧树脂种类、复配合固化剂比例以及促进剂用量对胶粘剂粘接强度和耐热性能的影响。     

聚氨酯纳米SiO2稀释剂复合改性环氧树脂性能测试与表征

为同时提高聚氨酯的强度、韧性以及热稳定性,采用聚氨酯、纳米SiO₂、稀释剂669复合改性环氧树脂。通过拉伸试验、弯曲试验评价复合改性环氧树脂的力学性能。结果表明,复合改性环氧树脂的拉伸强度、弯曲强度比纯环氧树脂提升6.23%,23.96%,断裂延伸率和弯曲变形比纯环氧树脂分别提高94.58%,8 mm,增韧的同时强度增加,且复合材料具有协同增韧效应。通过热重分析表明,复合改性环氧树脂的热稳定性最佳,热分解温度比纯环氧树脂提高了21℃;最后,通过红外光谱与SEM分析,表明在该改性过程中,聚氨酯接枝到环氧树脂上,对环氧树脂是化学改性,但纳米SiO₂和稀释剂669对环氧树脂的改性是物理改性,三者稳定分布在体系中;复合改性环氧树脂断裂时产生塑性剪切屈服带,纳米SiO₂引起裂纹偏转,同时颗粒与基质剥离,吸收能量,实现增韧。     

有机硅硼改性环氧树脂胶粘剂的研制

以环氧树脂(EP)和有机硅硼改性EP预聚物为主体材料,研制出一种可室温固化、高温使用且固化压力仅为接触压力的胶粘剂。并通过SEM、热重分析法和力学性能测试等手段对该胶粘剂的性能进行了研究。实验结果表明,有机硅硼改性EP预聚物与纯EP相容性很好,有机硅硼的加入明显提高了EP的韧性、耐热性和力学性能(尤其是高温时的剪切强度);当m(EP)∶m(有机硅硼改性EP预聚物)=100∶40时,剪切强度为14.84 MPa(20℃)和4.88 MPa(100℃),与未改性前相比,高温时的强度损失率由改性前的81.0%降低至67.1%;该胶粘剂可在100℃时长期使用,短期可耐150℃的高温。     

聚醚胺固化环氧树脂胶粘剂的研究

以聚醚胺D-230为固化剂,研究了多官能度环氧树脂和硫酸钙晶须的加入对环氧树脂胶粘剂粘接性能的影响。研究结果表明,多官能度环氧树脂和改性硫酸钙晶须的加入,很好地改善了环氧树脂胶粘剂的高温性能;当环氧树脂m(E-51)∶m(F-51)∶m(AG-80)=3∶3∶2、改性硫酸钙晶须为树脂总质量的10%时,体系的粘接性能最佳,室温和100℃剪切强度分别为25.91MPa和6.11MPa,室温剥离强度可达5.26kN/m。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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.