低温固化烯丙基酚氧树脂／双马来酰亚胺树脂的研究

为降低双马来酰亚胺树脂的固化温度,用2-甲基咪唑（2-MI）为烯丙基酚氧树脂／双马来酰亚胺树脂体系的固化催化剂,测试了改性树脂体系的凝胶化时间、力学性能和热性能,并探讨了催化剂含量对树脂性能的影响。结果表明,当催化剂质量分数为05％时,体系性能最佳。冲击强度为26．39kJ／m2,弯曲强度为14485MPa,热变形温度为202℃,树脂具有良好的韧性,并保持了优异的耐热性。     

烯丙基酚氧树脂改性双马来酰亚胺树脂基体的研究

以新型烯丙基酚氧树脂作为BMI(双马来酰亚胺)树脂的改性剂,制备相应的改性树脂,并采用红外光谱(FT-IR)法跟踪了该改性树脂的固化反应过程;探讨了活性稀释剂D和后固化工艺等对该改性树脂的黏度、凝胶时间、力学性能和热性能等影响。结果表明:当n(活性稀释剂D):n(BMI)=10:100时,改性树脂的综合性能相对最好,其冲击强度为30.52 kJ/m²、弯曲强度为157.1 MPa和HDT(热变形温度)为224℃;加入适量的活性稀释剂D,可明显降低体系的黏度、提高改性树脂的韧性;后处理工艺可以明显提高改性树脂的耐热性,当后处理工艺为"220℃/2 h→240℃/2 h"时,改性树脂的HDT达到了314℃。     

气干性耐腐蚀不饱和树脂的研究

采用顺酐和二醇制得耐腐蚀不饱和树脂,再将其与由三羟甲基丙烷二烯丙基醚(TMPDE)、TDI和苯乙烯反应得到的含有气干性基团的预聚物接枝聚合得到气干性耐腐蚀不饱和树脂。研究了预聚物加入量对树脂气干性以及接枝聚合反应温度和时间对反应程度的影响,并测试了产品的耐腐性和力学性能。结果表明,自制的耐腐蚀不饱和树脂、TDI、TMPDE及苯乙烯的质量配比为10∶1∶1∶2,聚合反应温度75～85℃,反应时间2.0 h时得到的不饱和树脂性能最佳,无缺口冲击强度为7.56 kJ/m2,弯曲强度为71.7 MPa,弯曲模量为3.21 GPa,热变形温度为110℃,产品可耐强酸、强碱、强氧化介质的长期腐蚀,气干性好,固化优良。     

烯丙基酚氧树脂/双马来酰亚胺改性树脂的制备及表征

用环氧树脂和二烯丙基双酚A(DP)合成了3种新型烯丙基酚氧树脂,测试了该树脂改性双马来酰亚胺(BMI)树脂体系的力学性能和热性能及黏度特性,探讨了后处理对改性树脂性能的影响。结果表明,改性树脂具有良好的2韧性和耐热性,冲击强度达到了22.31kJ/m,HDT仍有224℃,后处理使得体系耐热性大大提高,韧性略有降低。     

酚醛型氰酸酯的改性研究

以二烯丙基双酚A(DBA)和端乙烯基丁腈橡胶(VTBN)为增韧剂,两者与双马来酰亚胺(BMI)共聚后得到的预聚体作为酚醛型氰酸酯的改性剂,制备了一种改性酚醛型氰酸酯树脂。研究结果表明:DBA对酚醛型氰酸酯具有很好的催化作用,5%DBA[相对于氰酸酯(CE)质量而言]就可使CE在200℃以下固化;当m(DBA)∶m(VTBN)=5∶3时,体系的弯曲强度为132 MPa、冲击强度为12.6 J/m2、20℃和260℃剪切强度分别为16.88 MPa和9.77 MPa;改性体系的耐热性较好,其5%热失重分解温度和最大热分解速率温度分别为427.6℃和439.0℃。     

气干性环氧乙烯基树脂的合成

通过普通环氧乙烯基树脂与三羟甲基丙烷二烯丙基醚(TMPDE),甲苯二异氰酸酯(TDI)及苯乙烯的预聚物反应制得气干性环氧乙烯基树脂。通过表干时间和实干时间测试研究了不同预聚物含量对产物气干性的影响,并对产物的力学性能和耐腐蚀性能进行了测试。结果表明,预聚物与普通环氧乙烯基树脂的质量比为3.5∶10时,产物性能最佳。最佳配方为:m(普通环氧乙烯基树脂)∶m(TDI)∶m(TMPDE)∶m(苯乙烯)=10∶0.75∶0.75∶1.5,产物的表干时间为26 min,实干时间为1 h,无缺口冲击强度为8.95 kJ/m2,弯曲强度为104 MPa,弯曲模量为3.22 GPa,热变形温度为119.0℃,具有较好的耐腐蚀性。     

硼酸铝晶须改性双酚A二氰酸酯树脂性能研究

对硼酸铝(Al18B4O33)晶须改性双酚A二氰酸酯(BADCy)树脂基体的力学性能及热性能进行了研究。经硅烷偶联剂处理后,5％(质量含量,下同)Al18B4O33晶须改性体系的弯曲强度和冲击强度分别提高了14．3％和5．9％;当晶须含量为8％时,体系的弯曲强度和冲击强度分别由原来的112．4MPa和9．17kJ／m2提高到了121．7MPa和10．36kJ／m2,热变形温度提高8℃;经24h水煮后力学性能保持率都在70％以上。     

新型烯丙基化合物改性双马来酰亚胺树脂的制备及研究

利用环氧树脂和二烯丙基双酚A (DP)合成了一种新型烯丙基化合物(改性剂A),然后用该化合物改性双马来酰亚胺树脂(BMI),通过差示扫描量热法研究了BMI/DP/改性剂A体系的固化反应动力学,确定了固化工艺参数,并测试了该体系的力学性能、热性能和溶解性能。结果表明,该体系固化反应的表观活化能为88.512 kJ/mol,反应级数为0.91,为非整数,表明固化反应机理较为复杂;该体系较佳的固化工艺为150℃/1 h+170℃/2 h+200℃/2 h;相对于DP,改性剂A对BMI的增韧效果更为优异,当改性剂A用量为70份时,BMI/DP/改性剂A体系的力学性能最好,其冲击强度为23.31 kJ/m2,弯曲强度为155.8 MPa,热变形温度为224℃,质量损失5%时的温度为389.4℃,可溶于丙酮,具有良好的韧性、热性能和溶解性能。     

萘酚改性烯丙基化环保型酚醛树脂的合成及研究

分别以环保型PF(酚醛树脂)和萘酚改性环保型PF为母体,成功合成了烯丙基化PF和萘酚改性烯丙基化PF,并制备了萘酚改性烯丙基化PF/BMI(双马来酰亚胺)共聚树脂;然后分别以上述树脂作为基体树脂,制备了玻璃纤维增强型复合材料。结果表明:当基体树脂为萘酚改性烯丙基化PF/BMI共聚树脂时,相应复合材料的冲击强度(321.6 kJ/m2)和弯曲强度(524.1 MPa)比萘酚改性烯丙基化PF基复合材料提高了11.0%和46.3%,比未改性环保型烯丙基化PF基复合材料提高了42.8%和258.2%,说明萘酚改性烯丙基化PF/BMI共聚树脂的增韧效果优于萘酚改性烯丙基化PF;萘酚改性烯丙基化PF/BMI共聚树脂基复合材料的耐热性能优于未改性烯丙基化PF体系,这是因为前者800℃时的残炭率(39.62%)高于后者(10.92%)所致。     

复合材料模具用树脂基体的研究

以自制改性咪唑为固化剂,酚醛型EP(环氧树脂)为基体树脂,制备出复合材料模具用中温固化的耐高温EP体系。研究结果表明:当w(改性咪唑)=4%(相对于EP质量而言)时,EP浇铸体的中温(80℃)凝胶时间约为50 min、冲击强度为12.8 kJ/m2、弯曲强度为125 MPa、弯曲模量为3.20 GPa和热变形温度为280℃,具有良好的力学性能和优异的耐高温性能,满足复合材料模具中温固化高温使用的基本要求。     

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.     

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.     

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.     

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.     

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。