PE-HD／PA6／EVOH阻透容器成型工艺与性能研究

将高密度聚乙烯（阻HD）、聚酰胺6（PA6）与乙烯-乙烯醇共聚物（EVOH）的复配体和相容剂初混合后，通过挤出机熔融共混、中空吹塑制得阻透容器。考察了树脂及共混物的流变性能，研究了相容剂用量、阻透树脂用量和成型工艺条件对容器阻透性能的影响。利用扫描电镜（SEM）观察了瓶壁的层状结构。实验结果表明，PA6／EVOH复配体增加了阻透树脂的熔体黏度，提高了层状共混工艺的稳定性。与PE-HD／PA6二元共混容器相比。PE-HD／PA6／EVOH三元共混容器所需相容剂更少。当阻透树脂用量为15～18份、相容剂用量为2～3份、加工温度在225～230℃之间、螺杆转速控制在30r／min左右、停留时间在3min时，PE-HD／PA6／EVOH共混容器的阻透性能得到明显提高。     

PP/EVOH/PA6共混物的性能研究

以聚丙烯接枝马来酸酐(PP-g-MAH)为相容剂,制备了聚丙烯(PP)/乙烯-乙烯醇共聚物(EVOH/)聚酰胺6(PA6)共混物,研究了PP/EVOH/PA6三元共混物的相容性、流变性能、阻隔性能、力学性能、热性能及形态结构。结果表明:相容剂与EVOH和PA6间发生了反应,提高了共混物的相容性;相容剂的加入提高了PP、EVOH、PA6的结晶温度,增强了PP与EVOH和PA6间的黏合力,降低了界面张力;EVOH占EVOH/PA6总量68%的三元共混物吸油率最小,当相容剂用量为5份时,PP/EVOH/PA6三元共混物吸油率比PP/EVOH二元共混物降低了8%。     

PBS/EVOH共混材料的阻透性能研究

通过对聚丁二酸丁二醇酯/乙烯-乙烯醇共聚物(PBS/EVOH)共混物的阻透性和力学性能测试,确定PBS/EVOH的最佳配比为90/10。研究了PBS接枝马来酸酐(PBS-g-MAH)用量对材料阻透性和相容性的影响;并通过DMA、SEM和IR对材料的相容性进行了分析。结果表明:PBS-g-MAH的加入,使材料的阻透性和相容性得到改善,力学性能有所提高;与未加相容剂相比,加入7 phr PBS-g-MAH后,阻透性提高了74%,缺口冲击强度提高了68%;SEM分析结果表明,相结构由两相海岛结构变为类层状结构。     

HDPE／EVOH共混阻透容器的研制

将HDPE、EVOH和PE－g-MAH等混合后，吹瓶制成共混阻透容器，考察了EVOH和PE－g-MAH的用量及成型工艺对容器阻透性能的影响。结果表明，较低的增容剂用量和剪切速率及在适当的温度下制备的容器，其阻透性能得到大幅度提高。     

EVOH／PE-HD共混相容性研究

使用三种功能化改性的聚乙烯作为相容剂改善EVOH／PE-HD共混体系的相容性，研究了共混体系的热性能和力学性能。SEM表明，相容共混体系中形成了高度分散和牢固的界面结合，二甲苯萃取实验和IR分析证实了相容性的改善来自于EVOH与相容剂之间的化学反应。相容共混体系中EVOH作为分散相时其结晶温度明显降低，结晶速度放慢；共混物中两组分的结晶熔点均低于纯组分。这些均可归因于体系更好的相容性以及强烈的界面作用。相容共混体系的力学性能较之简单共混体系得到明显改善，EVOH为分散相时拉伸强度提高幅度较大(50％)，而在PE-HD为分散相时缺口冲击强度的增幅达到30％。     

LDPE／PA6共混阻透薄膜的研制

将LDPE、PA6和PE-g-MAH等混合后加入单螺杆挤出机内,经熔融挤出吹塑制成LDPE/PA6共混阻透薄膜。通过考察成型工艺条件及PA6和PE-g-MAH的用量对薄膜阻透性能和力学性能的影响,确定了共混配方和薄膜制备工艺,阻透薄膜的阻透性能与纯LDPE薄膜相比提高了10倍以上。     

交联型聚酰胺11／乙烯-乙烯醇共聚物高阻透材料的研究

采用原位交联技术制备聚酰胺11(PA11)/乙烯-乙烯醇共聚物(EVOH)高阻透材料,以过氧化二异丙苯(DCP)为交联剂,研究其用量对体系凝胶含量、力学性能、阻透性能及形态结构的影响。结果表明:随着 DCP 含量的增加,体系的冲击强度、拉伸强度、凝胶含量、阻透性能均呈现先升高后降低的趋势;红外光谱(FT-IR)表明,PA11末端羧基和 EVOH 的侧羟基反应生成了酯基;差示扫描(DSC)分析表明,体系的玻璃化转变温度随着 DCP 含量的增加先升高后降低;扫描电子显微镜(SEM)分析显示,DCP 含量对 EVOH 在 PA11中分散形态有很大的影响,DCP 的质量分数为1.5%时,EVOH 以相互交叠的不连续的片层状结构分散于 PA11树脂中,其力学性能和阻透性能得到大幅度的提高。     

三层共挤阻透薄膜的加工与性能研究

选用乙烯-乙烯醇共聚物（EVOH）、聚酰胺6（PA6）、茂金属聚乙烯（mPE）和改性线形低密度聚乙烯（PE-LLD）为原料,制备了3种三层共挤阻透薄膜PA6/EVOH/PA6、PA6/PE-LLD/mPE和EVOH/PE-LLD/mPE。通过对原料树脂热性能与流变性能的分析,探讨了三层共挤薄膜的最佳加工工艺。结果表明,所得3种共挤薄膜中以PA6/EVOH/PA6三层共挤薄膜的力学性能和氦气阻透性能最佳。     

工艺配方对PE-HD/E-TMB共混物MFR的影响

用自制增韧母料(E-TMB)和PE-HD热机械共混制得PE-HD/E-TMB共混物,研究了E-TMB中弹性体不同配比[乙丙弹性体(M)/丁苯弹性体(N)]、基体树脂和弹性体不同配比(H/E)、不同阻交联剂、阻交联剂二甲亚砜(DMSO)的不同用量,以及PE-HD/E-TMB共混物中弹性体含量对共混物熔体流动速率(MFR)的影响.结果表明,PE-HD/E-TMB共混物的MFR随M/N中丁苯弹性体比例的增加而减小,随H/E中弹性体比例的增加而增大,随共混物中弹性体含量的增加而减小;含3种不同阻交联剂的E-TMB所得PE-HD/E-TMB共混物的MFR值差别不大且均低于纯PE-HD,当E-TMB中DMSO用量为0.024 mol时,PE-HD/E-TMB共混物的MFR值出现极小值为2.8 g/10 min.     

PA6/ABS共混及增容改性

以聚己内酰胺(PA6)为主体材料,将丙烯腈–丁二烯–苯乙烯塑料(ABS)与PA6共混,并加入马来酸酐接枝ABS (ABS-g-MAH)作相容剂,研究了ABS及相容剂ABS-g-MAH用量对PA6/ABS共混物力学性能的影响。结果表明,随着ABS用量增加,PA6/ABS共混物的拉伸强度下降,冲击强度先上升后下降,收缩率变化不大,ABS用量为10份时PA6/ABS共混物的综合性能较好。相容剂ABS-g-MAH对PA6/ABS共混物的力学性能有较明显的影响,随着相容剂用量增加,拉伸强度和冲击强度均先上升后下降,相容剂用量3～9份时有利于共混物保持较高的拉伸强度和冲击强度。     

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。