PP/POE/nano-SiO_2复合材料反应性增容的研究

采用反应性增容的方法,通过熔融共混制备聚丙烯/乙烯-辛烯共聚物/纳米二氧化硅(PP/POE/nano-SiO2)三元复合材料。研究了加入反应性增容剂聚丙烯与甲基丙烯酸缩水甘油酯接枝物(PP-g-GMA)后复合材料的力学性能、结晶性能及加工性能。结果表明:PP-g-GMA与氨基化改性纳米二氧化硅(NH2-SiO2)发生开环反应,能够增强基体树脂PP与nano-SiO2的界面作用和相容性,使nano-SiO2均匀分散于PP中,有助于PP的异相成核。当PP/PP-g-GMA/POE/NH2-SiO2质量比为70/10/20/2时,冲击强度达到52.9 kJ/m2,弯曲强度达到53.24 MPa;与纯PP和PP/POE(80/20)相比,力学性能得到了明显的提高,球晶尺寸明显减小。     

PTT/PP-g-GMA/纳米SiO2三元复合材料的结构与性能研究

采用甲基丙烯酸缩水甘油酯接枝聚丙烯(PTT/PP-g-GMA)、纳米SiO2增韧聚对苯二甲酸丙二醇酯(PTT).研究了制备工艺、PTT/PP-g-GMA/纳米SiO2用量对三元复合材料的形态、力学性能及结晶性能的影响.研究表明,一步法制备的复合材料具有PTT/PP-g-GMA和纳米SiO2各自独立分散的形态,两步法制备的复合材料具有PTT/PP-g-GMA包覆纳米SiO2的核壳结构.两种方法制备的复合材料的拉伸强度接近,采用两步法制备的复合材料具有更好的增韧效果,冲击强度提高161.9%.PTT/PP-g-GMA与纳米SiO2对PTT的结晶都有促进作用,一步法中纳米SiO2的异相成核作用更为明显.     

iPP/nano-CaCO3/PP-g-GMA复合材料的制备与性能

以等规聚丙烯(iPP)、纳米碳酸钙(nano-CaCO₃)和甲基丙烯酸缩水甘油酯接枝改性抗冲共聚聚丙烯(PP-g-GMA)为原料,通过熔融共混法制备了iPP/nano-CaCO₃/PP-g-GMA复合材料。研究了PP-g-GMA对iPP/nano-CaCO₃/PP-g-GMA复合材料力学性能、结晶行为和微观结构的影响,并分析了其增韧机理。结果表明：PP-g-GMA和nano-CaCO₃具有协同增韧作用,当两者用量均为40.0质量份时,iPP/nano-CaCO₃/PP-g-GMA复合材料23℃时的冲击强度约为纯iPP的6.9倍。PP-g-GMA和nano-CaCO₃均具有成核作用,促使基体球晶细化。PP-g-GMA中的橡胶相以球形海岛形式分散在iPP中,起到增韧作用。     

PP/废弃椰壳粉复合材料的增容改性研究

研究了聚丙烯(PP)与甲基丙烯酸缩水甘油酯(GMA)熔融接枝物PP-g-GMA增容PP/废弃椰壳粉复合材料的力学性能、热稳定性及微观形态结构。结果表明:PP-g-GMA用量为15%时,与未增容复合材料相比,PP-gGMA增容复合材料的拉伸强度和冲击强度分别提高了28.5%和56.9%,并且具有较优异的热稳定性;PP-gGMA增容的复合材料受外力作用时的破坏主要是结合较强的椰壳粉粒子的脱黏及椰壳粉粒子周围的PP基体的冷拉塑性变形破坏共同所致。     

纳米CaCO3填充改性聚丙烯复合材料的力学性能和结晶行为的研究

将经过表面处理的纳米CaCO₃分别用两种方法制备成母粒并与PP复合,制备成PP/CaCO₃与PP/PP-g-GMA/CaCO₃纳米复合材料。对纳米复合材料的力学性能和结晶行为进行了测试。结果表明,纳米碳酸钙对PP的β晶的形成具有诱导作用,并且在PP/PP-g-GMA/CaCO₃纳米复合材料中,纳米CaCO₃含量在低于20%时,可同时解决增韧和增强的问题。     

PP-g-GMA对长玻纤增强聚丙烯复合材料性能的影响

采用熔体浸渍工艺制备了长玻纤(LGF)增强聚丙烯材料。研究了甲基丙烯酸缩水甘油酯接枝聚丙烯(PP-g-GMA)对长玻璃纤维增强聚丙烯(PP)复合材料力学性能的影响。结果表明:PP-g-GMA影响长玻璃纤维增强PP复合材料的力学性能;当PP-g-GMA质量分数为1%时,PP/LGF复合材料的力学性能最好,拉伸强度、弯曲强度和悬臂梁缺口冲击强度分别提高32.34%、27.38%和74.51%。     

PP/POE-g-GMA/纳米SiO2复合材料性能研究

采用熔融共混法制备了聚丙烯/甲基丙烯酸缩水甘油酯接枝POE/纳米二氧化硅(PP/POE-g-GMA/纳米SiO2)复合材料,研究了材料的力学性能、动态力学性能与结晶性能.结果表明:5%的POE-g-GMA和3%的氨基功能化纳米SiO2(SiO2-g-NH2)具有明显的协同增韧效应,冲击强度提高157%,使PP出现较大的低温损耗模量峰和内耗峰;POE-g-GMA和纳米SiO2对PP的结晶均有促进作用,SiO2-g-NH2的异相成核作用更明显;POE-g-GMA能诱导PPβ晶的形成,添加纳米SiO2使β晶含量降低.     

SBS和纳米SiO2协同增韧增强PP复合材料的研究

将热塑性弹性体苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)及纳米Si O2同时添加到聚丙烯(PP)中,以期在熔融共混过程中发挥SBS与纳米Si O2的协同增强增韧作用,达到有效改善PP综合性能的目的。用硬脂酸(SA)对纳米Si O2粒子表面进行功能化包覆改性,再经熔融共混技术制备了PP/SBS/纳米Si O2复合材料,研究了纳米Si O2表面处理效果及其用量对复合材料力学性能、流变性能及热性能的影响。力学性能研究结果表明,纳米Si O2与SBS对PP具有明显的协同增强增韧作用。当纳米Si O2质量分数为3.84%时,PP/SBS/纳米Si O2复合材料的综合性能最佳,其拉伸强度、断裂强度和拉伸弹性模量分别为37.4,23.8,129.9 MPa,室温(25℃)断裂强度比纯PP提高了100%;其室温和–20℃下缺口冲击强度分别较纯PP提高了51.5%和66.7%。微观形貌分析表明,熔融共混过程中,纳米Si O2均匀分散于PP基体中,复合材料基体在室温冲击下发生明显塑性变形,导致其冲击韧性明显高于低温冲击韧性。与纯PP相比,PP/SBS/纳米Si O2复合材料的流动性增大,耐热变形性能提高。     

纳米CaCO_3增强增韧PP/弹性体复合材料的研究

采用钛酸酯偶联剂对纳米CaCO_3进行了表面接枝改性,并采用熔融共混法制备了聚丙烯(PP)/乙烯–辛烯嵌段共聚物(OBC)/纳米CaCO_3复合材料,研究了纳米CaCO_3的加入量对复合材料的力学、热力学及流变性能的影响,并观察了复合材料的断面形貌。结果表明,当改性纳米CaCO_3含量为2.5%时,复合材料的力学性能最佳,其中拉伸强度达到27.5 MPa,冲击强度达到16.1 k J/m2,进一步增加纳米CaCO_3含量时,由于纳米粒子之间发生了严重团聚使复合材料力学性能显著下降;纳米CaCO_3的加入对复合材料起到了异相成核的作用,提高了复合材料的结晶温度和结晶度;复合材料中纳米粒子的存在使其复合黏度和储能模量同时升高。     

PP/PLA/CaCO_3复合材料的制备与性能研究

以聚丙烯(PP)为基体,聚乳酸(PLA)和纳米碳酸钙(CaCO_3)为增韧、增强组分,利用熔融共混制得PP/PLA/CaCO_3复合材料,通过对复合材料力学性能、耐热性能、流变性能与结晶形态的表征,研究了PLA和纳米CaCO_3对复合材料性能的影响及其机理。结果表明,当PP与PLA共混时,形成连续空间网络结构PLA有助于改善PP的性能,PLA质量分数为20%时综合力学性能最佳,与纯PP相比,PP/PLA复合材料的拉伸强度和缺口冲击强度分别提高5. 14%和54. 35%,断裂伸长率降低62. 47%。向PP基体中引入的纳米CaCO_3通过"滚珠增韧"和"异相成核"作用明显改善复合材料力学性能,纳米CaCO_3质量分数为15%时,在PP/PLA中均匀分散产生的晶粒细化作用效果最为显著,PP/PLA/CaCO_3复合材料的综合力学性能达到最佳,拉伸强度、断裂伸长率和缺口冲击强度分别比未添加CaCO_3时提高了15. 23%、2. 67%和5. 63%。     

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.     

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.     

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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。