PVC/木粉复合材料的发泡研究

采用PVC树脂和木粉加入发泡剂制得PVC/木粉发泡复合材料。通过差示量热扫描分析(DSC)考察了偶氮二甲酰胺(AC)、NaHCO3及AC/NaHCO3/PVC稳定剂共混物的热分解特性。研究了木粉的不同粒径、AC发泡剂、NaHCO3、交联剂DCP和ACR的含量对复合材料力学性能的影响。结果表明:通过发泡能有效降低材料的密度;当AC含量为PVC用量的1%,木粉粒径为20目,NaHCO3与AC用量比为1∶1,DCP含量为PVC用量的0.4%,ACR含量为PVC用量的8%,所得的发泡复合材料综合性能较好。     

PVC木塑发泡材料性能的研究

研究了PVC树脂基本性能(聚合度、分子质量分布、表观密度)、助剂(发泡剂、发泡调节剂)、木粉及加工工艺(加工温度、挤出速度)对PVC木塑发泡材料性能的影响,并进行了工业化加工试验。结果表明:PVC树脂聚合度越高,发泡材料泡孔壁厚越大,发泡及加工都变得较为困难,适宜的聚合度为650~700;PVC树脂分子质量分布变宽,则发泡材料的密度增大,泡孔数量减少,泡孔增大,泡壁增厚,有串泡现象,适宜的分子质量分布指数为1.9~2.0;表观密度越高,机身压力越大,发泡材料泡孔数量越多,泡孔结构越均匀,适宜的表观密度为0.57~0.60 m L/g。对于S-700型PVC树脂而言,发泡剂AD C与助发泡剂Z n O的适宜质量比为1∶0.1,且二者的总用量以1.0份为宜;发泡调节剂ZB-530的适宜用量为8份;适宜的加工温度为185℃,适宜的挤出速度为20 r/min。宜采用硅烷偶联剂对木粉进行表面改性,发泡剂、发泡调节剂的用量应随着木粉用量的变化而调整。工业化加工试验结果表明:根据制品及生产设备的不同对试验得出的配方和加工工艺进行调整后,可顺利生产出质量优良的产品。     

甘蔗渣/LDPE发泡木塑复合材料的研究

用模压法制备了甘蔗渣／LDPE发泡木塑复合材料。考察了发泡剂用量、甘蔗渣含量及预热温度对发泡木塑复合材料性能的影响，并在扫描电镜下观察了材料断面的微观形态。结果表明：发泡后木塑材料的密度降低，发泡剂用量为1．0份时材料密度降低了近30％，化学发泡法可有效减轻材料的自重；冲击强度提高了近20％；虽然发泡造成拉伸强度和弯曲强度的降低，但由于发泡后密度也降低了，所以其比强度反而得到提高。甘蔗渣的加入降低了材料的性能，且随着用量的增加降低的幅度越大。预热温度为200℃时，材料的各项性能最佳。由扫描电镜可以看出，AC发泡剂为1．0份时的发泡木塑材料中分布着较均匀统一的圆形泡孔，而AC发泡剂为3．0份时，局部有泡孔坍塌破裂。     

木粉特性对PVC／木塑发泡材料性能的影响

对木粉进行了热重分析,考察了木粉粒径及表面处理方法对PVC／木塑发泡材料性能的影响。结果表明：采用粒径117μm（120目）、经过硅烷类偶联剂处理的木粉制得的PVC／木塑发泡材料的综合性能较优;相同发泡剂用量下,PVC／木塑发泡材料密度随木粉用量的增加而增大,发泡效果变差。     

改性AC发泡剂对PVC木塑复合材料力学性能影响

采用动态热流式差示扫描量热仪对自制改性偶氮二甲酰胺(AC)发泡剂进行了分析,并研究了其用量对聚氯乙烯（PVC）木塑复合材料力学性能的影响。结果表明,该改性AC发泡剂的分解温度在165~187 ℃,与传统AC发泡剂相比分解温度降低约40 ℃,且峰值放热量降低了39.5 ％;改性AC发泡剂的平均发气量为189 mL/mg;扫描电子显微镜分析表明,使用1.2份改性AC发泡剂时获得的PVC木塑复合材料的泡孔致密均匀,明显优于使用未改性AC发泡剂的情况;与未发泡的材料相比,使用1.2份改性AC发泡剂时, PVC木塑复合材料的冲击强度提高了34.6 %,表观密度降低了22.5 ％。     

改性AC发泡剂对PVC木塑复合材料性能影响

采用动态热流式差示扫描量热仪对自制改性偶氮二甲酰胺(AC)发泡剂进行了分析,并研究了其用量对聚氯乙烯(PVC)木塑复合材料力学性能的影响。结果表明,该改性AC发泡剂的分解温度在165~187℃,与传统AC发泡剂相比,分解温度降低约40℃,且峰值放热量降低了39.5%;改性AC发泡剂的平均发气量为189 mL/mg;扫描电子显微镜分析表明,添加1.2份改性AC发泡剂时获得的PVC木塑复合材料的泡孔致密均匀,明显优于未改性的;与未发泡的材料相比,添加1.2份改性AC发泡剂时,PVC木塑复合材料的冲击强度提高了34.6%,表观密度降低了22.5%。     

一步法模压成型软质PVC鞋底发泡材料

木文以软质聚氯乙烯（PVC）为主体材料。加入发泡剂AC、交联剂DCP、柠罐酸（L）、NBR、泡孔调节剂（A）等主要组分，采用一步法模压成型软质PVC鞋应发泡材料。研览置泡剂AC、交联剂DCP、柠檬酸（L）、NBR、泡孔调节剂（A）用量对软质PVC发泡材料密度和力学性的影响。结果表明：发泡剂AC4份，DCP0．2份，柠檬酸（L）0．2份．NBR40份，泡孔调节剂（A）11份时．发泡材特性能优异．其密度和力学性能满足软质PVC鞋鹿发泡材料的要求。     

木粉对PVC发泡木塑复合材料性能的影响

采用PVC树脂和木粉加入发泡剂制得PVC/木粉发泡复合材料。本文对木粉进行了热重分析,考察木粉粒径及含量对PVC/木塑发泡材料性能的影响,考察了木粉含量对发泡、熔融指数、转矩加工流变性以及耐候性的影响。结果表明:TG分析表明PVC/木塑复合材料加工的最佳温度200℃左右。随着木粉粒径的减小,PVC/木粉复合材料的冲击强度和弯曲强度出现先上升后下降的趋势,100目木粉,力学性能最好。随着木粉用量的增加,体系的拉伸强度、冲击强度和弯曲强度均呈降低的趋势,材料的发泡效果变差,流动性、稳定性、耐候性变差,因此PVC木塑复合材料应该控制其木粉含量。     

软质PVC鞋底发泡材料的研制

以软质聚氯乙烯（PVC）为主体材料，加入发泡剂偶氮二碳酰胺（AC）、交联剂过氧化二异丙苯（DCP）、柠朦酸、丁腈橡胶（NBR）、泡孔调节剂等，采用一步法模压成型软质PVC鞋底发泡材料。研究AC，DCP、柠朦酸、NBR、泡孔调节剂用量对软质PVC发泡材料密度和力学性能的影响。结果表明，在AC4．0份、DCP0．2份、柠朦酸0．2份、NBR40．0份、泡孔调节剂11.0份时，发泡材料性能优异，其密度和力学性能满足软质PVC鞋底发泡材料的要求。     

软质PVC鞋底发泡材料的研制

以软质聚氯乙烯（PVC）为主体材料，加入发泡剂偶氮二碳酰胺（AC）、交联剂过氧化二异丙苯（DCP）、柠朦酸、丁腈橡胶（NBR）、泡孔调节剂等，采用一步法模压成型软质PVC鞋底发泡材料。研究AC，DCP、柠朦酸、NBR、泡孔调节剂用量对软质PVC发泡材料密度和力学性能的影响。结果表明，在AC4．O份、DCPO．2份、柠朦酸O．2份、NBR40．0份、泡孔调节剂11．0份时，发泡材料性能优异，其密度和力学性能满足软质PVC鞋底发泡材料的要求。     

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.     

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。     

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.