阳离子壳聚糖对纸的增强和助滤作用

增加纸的强度和改善纸料的滤水性以提高生产效率是造纸生产中的重要课题.本文研究了阳离子壳聚糖及其与羧甲基壳聚糖或羧甲基纤维素组成的聚电解质复合物对纸的抗张强度和纸料滤水性的影响,探讨了阳离子壳聚糖与钠基改性膨润土配合提高纸料滤水性的效果.实验结果表明,壳聚糖季铵盐与羧甲基壳聚糖或羧甲基纤维素的复合比例(质量比)分别为0.43和1.2时,聚电解质复合物的浊度最高.聚电解质复合物的加入有效的增加了纸张的抗张强度和滤水性能.阳离子壳聚与羧甲基壳聚糖复合物的增强和助滤效果最好,当其相对于纸浆的加入量为1％时,纸的抗张强度提高了27.69％,纸料的叩解度下降了35.9％.阳离子壳聚糖与膨润土组成的助滤体系可以显著降低纸浆的叩解度,特别是当阳离子化壳聚糖用量较少时,其助滤效果更好.     

阳离子淀粉包覆改性硅藻土制备及在造纸中应用研究

以阳离子淀粉和硅藻土为主要原料,采用阳离子淀粉对硅藻土进行改性,并将其用于造纸填料中.研究了阳离子淀粉改性硅藻土颗粒形态、Zeta电位、粒径、阳离子淀粉沉积率和改性硅藻土留着率的变化.结果表明,采用阳离子淀粉和三偏磷酸钠能有效对硅藻土进行改性,使硅藻土粒径增大,Zeta电位升高,淀粉沉积率达98％以上.在同一加入量的条件下,与加入未改性硅藻土纸张相比,加入改性硅藻土纸张的抗张指数、撕裂指数、耐折度和耐破度均有所提高和改善,改性硅藻土留着率超过85％.     

重钙的表面改性及在造纸中的应用

对阳离子改性重钙填料进行了研究,并应用于纸体系,改性重钙大大提高了纸张的填料留着率及纸张强度。     

壳聚糖/羧甲基纤维素缓释抗菌剂的制备及缓释抗菌性能表征

CaCl2作为交联剂,以天然可生物降解壳聚糖(CS)和和羧甲基纤维素(CMC)为原料,二甲酸钾(KDF)为目标药物,利用凝聚法制备壳聚糖/羧甲基纤维素/二甲酸钾缓释抗菌剂微球。经SEM、FT-IR、TGA分析表明:壳聚糖与羧甲基纤维素之间通过离子键形成聚电解质复合物,具有比天然壳聚糖、羧甲基纤维素更高的稳定性。溶胀测试表明制备的微球具有高pH敏感性,可对二甲酸钾起到良好的缓释效果。体外抗菌测试表明,制备的抗菌剂对大肠杆菌具有较高的抑菌率,有助于调节肠道pH值和微生物群的总数量平衡,有益于仔猪的健康生长。     

羧甲基纤维素-壳聚糖LbL空腔微胶囊的制备

微胶囊技术现已广泛应用于生物医药,环境保护,日用化工,农业科学及航空航天等领域,随着应用范围扩大,开发新技术与新方法制备微胶囊,使其具有更精确可控的结构已成为微胶囊技术发展的重大课题之一。选择两种生物相容性较好的天然聚电解质—羧甲基纤维素(CMC)和壳聚糖(CS),作为制备新型微胶囊的原料,利用聚阴离子羧甲基纤维素和聚阳离子壳聚糖之间的静电结合,成功制备出一种具有新结构的中空聚电解质微胶囊并初步研究了其形貌能基本性能。     

KH550改性凹凸棒土对纸张性能影响研究CSCD

使用硅烷偶联剂KH550对凹凸棒土进行湿法改性,探讨KH550改性对凹凸棒土和纸张性能的影响,研究发现,KH550以共价结合形式修饰在凹凸棒土表面,可以提高凹凸棒土的分散性能,降低颗粒的表面电荷。与未改性凹凸棒土相比,改性后的凹凸棒土可以提高纸张的填料留着率、白度、不透明度、抗张指数和撕裂指数。     

两性聚丙烯酰胺的性质、合成与应用研究进展

两性聚丙烯酰胺属于两性聚电解质,是一种新型功能高分子。本文首先阐述了两性聚丙烯酰胺的结构和特性,包括等电点、电荷密度、分子链形态、浊度、黏度、吸附特性等;接着概括了目前较为普遍的两性聚丙烯酰胺的合成反应,包括大分子改性、接枝共聚、阴/阳离子单体共聚,以及丙烯酰胺与甜菜碱型单体共聚;还总结了两性聚丙烯酰胺的合成方法,包括:水溶液聚合、反向乳液聚合、反向微乳液聚合、悬浮聚合、辐射聚合等;最后总结了其在各领域的应用,尤其是在造纸工业中的助留助滤和纸张增强等应用。     

季铵化羧甲基纤维素接枝聚丙烯酰胺对直接染料的吸附脱色性能

通过接枝共聚制备羧甲基纤维素接枝聚丙烯酰胺(CMC-g-PAM)树脂,进而通过Mannich反应制备羧甲基纤维素接枝季铵化聚丙烯酰胺阳离子接枝共聚物(CMC-g-CPAM).通过红外光谱表征了产物的结构.采用静态法测定该阳离子接枝共聚物对水溶性直接染料的吸附脱色性能.结果表明,该树脂对直接染料有很好的吸附脱色性能,脱色率可达98%左右.     

羧甲基纤维素纳米二氧化硅复合物制备及其结晶行为

羧甲基纤维素(CMC)是纤维素中羟基被羧甲基部分取代后的产物,取代后纤维素原有的结晶结构被破坏,羧甲基纤维素为非晶态结构。采用高分子表面活性剂聚二甲基二丙烯氯化铵改性纳米二氧化硅表面,以提高其与高分子材料的相容性,使其与羧甲基纤维素复合制备结晶型羧甲基纤维素。经红外光谱(FT-IR)、扫描电子显微镜(SEM)、热重分析(TGA)分析,对复合前后的结构形态进行比较,复合物尺寸大于100nm,因此它不是纳米复合物,但发现得到了羧甲基纤维素结晶,且热性能有了提高。     

水性环氧树脂改性聚乙烯亚胺的制备及其对纸张的增强作用

分别利用水乳性双酚A型环氧树脂(BAE)和水溶性甘油环氧树脂(GE)对聚乙烯亚胺(PEI)进行改性,制备出了具有强阳离子性的改性聚乙烯亚胺纸张增强剂.讨论了增强剂组成、添加量、助留剂等因素对纸张强度的影响,并用SEM对其纸样微观结构进行了表征.结果表明这两种环氧树脂的引入均可增加聚乙烯亚胺分子与纸纤维的结合强度,纸张湿强度从14.46%分别提高到了21.65%和22.84%.同时BAE改性PEI可使环压指数提高42%,GE改性PEI则能使耐折度提高10%以上.     

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。     

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.     

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.