温度/pH双敏型羧甲基壳聚糖/海藻酸钠凝胶微球的制备

以羧甲基壳聚糖和海藻酸钠为基材,氯化钙和戊二醛混合液为交联剂,制备温度/p H双敏型凝胶微球。以溶胀度为主要考察指标,采用单次单因子法得到了较适宜的制备条件:2%的羧甲基壳聚糖/海藻酸钠混合溶液和5%的氯化钙/戊二醛混合交联剂的配比均为1∶1(质量比),交联剂的p H为6.8⁷.4,交联温度为40℃。在此条件下制得的凝胶微球,溶胀度随p H和温度的升高均表现出先升高后降低的趋势,当p H和温度分别为7.4和45℃时溶胀度最大,具有明显的p H和温度敏感性,适用于作为药物控释载体材料。     

温度/pH双敏型羧甲基壳聚糖/海藻酸钠凝胶微球的制备

以羧甲基壳聚糖和海藻酸钠为基材,氯化钙和戊二醛混合液为交联剂,制备温度/p H双敏型凝胶微球。以溶胀度为主要考察指标,采用单次单因子法得到了较适宜的制备条件:2%的羧甲基壳聚糖/海藻酸钠混合溶液和5%的氯化钙/戊二醛混合交联剂的配比均为1∶1(质量比),交联剂的p H为6.8~7.4,交联温度为40℃。在此条件下制得的凝胶微球,溶胀度随p H和温度的升高均表现出先升高后降低的趋势,当p H和温度分别为7.4和45℃时溶胀度最大,具有明显的p H和温度敏感性,适用于作为药物控释载体材料。     

载脂肪酶壳聚糖/海藻酸钙微胶囊的制备

针对固定化脂肪酶的研究背景,以壳聚糖、海藻酸钠为微载体制备材料,采用脉冲电场液滴工艺制备壳聚糖/海藻酸钙微胶囊。以脂肪酶为生物模型,系统考察了制备条件对载脂肪酶壳聚糖/海藻酸钙微胶囊酶活力的影响。结果表明:海藻酸钠质量浓度和酶与海藻酸钠载体配比是影响固定化酶活力的主要因素,载酶量为15mg/mL,海藻酸钠质量浓度为10mg/mL时载酶微胶囊酶活力最高,球形度好。通过改变壳聚糖质量浓度和相对分子质量,可以调控微胶囊膜的厚密程度进而影响固定化酶活力。成膜液pH值依次影响壳聚糖与海藻酸盐分子中官能团的电离状态、成膜反应静电络合程度、酶蛋白包封率,最终影响固定化酶活力。在载酶量为15mg/mL,海藻酸钠质量浓度为10mg/mL,壳聚糖相对分子质量、质量浓度和pH值依次为50kDa、1mg/mL和3.0的条件下,固定化酶活力为187IU/g。     

壳聚糖/雷公藤微胶囊的制备及性能表征

探讨离子凝聚法制备壳聚糖L/雷公藤微胶囊的制备工艺。以壳聚糖为壁材,雷公藤提取物为芯材,通过离子凝聚法制备出壳聚糖/雷公藤微胶囊,运用正交设计试验,以反应温度、搅拌转速、反应时间、p H值为考察因素,以包封率为评价指标得出了微胶囊的最佳制备工艺为反应温度40℃,转速为400 r/min,反应时间1 h,p H值为6,此时微胶囊的包封率为83.2%。扫描电镜观察结果显示,制备的雷公藤微胶囊外形呈球状,部分微胶囊有凹陷,但并未出现破裂现象。同时通过研究微胶囊机械破损率发现,该工艺条件下制备的微胶囊的韧性相对较好,基本能满足实际应用。     

锐孔-凝固浴法制备橙子油微胶囊的工艺研究

以壳聚糖、海藻酸钠为壁材,采用锐孔-凝固浴法对制备橙子油微胶囊的工艺进行了研究。通过单因素实验和正交实验,以包埋率、成型效果为主要评价指标,系统探讨了橙子油微胶囊制备的工艺条件。结果表明,海藻酸钠浓度为3.5%,壳聚糖浓度为1.5%,壁材与芯材的质量比为1∶3,橙子油微胶囊的包埋率为89.20%。对制备的橙子油微胶囊的缓释性进行了研究,结果表明橙子油微胶囊的缓释性良好。     

海藻酸钠/壳聚糖/海藻酸钙微胶囊机械强度的研究

采用脱乙酰度≥95%的壳聚糖为原料,通过NaNO_2氧化法降解得到不同分子量的壳聚糖。通过单因素试验,考察不同反应条件对海藻酸钠/壳聚糖/海藻酸钙微胶囊机械强度的影响,再通过响应面试验优化微胶囊的制备工艺。研究结果表明,当成膜时间为32 min,壳聚糖浓度为6.1 g/L,壳聚糖分子量为58189,壳聚糖pH值为6.0时,海藻酸钠/壳聚糖/海藻酸钙微胶囊的机械强度最高。     

乳化法制备海藻酸钙/聚组氮酸微胶囊

采用乳化法制备海藻酸钙微球及海藻酸钙/聚组氨酸载药微胶囊,并考察不同海藻酸钠浓度、氯化钙浓度对微球表面形态、粒径分布、载药性能及微胶囊控制释放性能的影响。结果表明海藻酸钠浓度主要影响微球的粒径大小,氯化钙浓度主要影响微球的分散程度及粒径分布,微球载药量均随海藻酸钠浓度及氯化钙浓度的增加而减小,所制备的微胶囊均无明显的突释现象。     

灭幼脲缓释微胶囊的制备与性能

[目的]通过对灭幼脲缓释微胶囊的制备和对其性能的测试来提高灭幼脲的稳定性与环境的相容性。[方法]采用壳聚糖和海藻酸钠作为囊壁材料,利用静电吸附层层自组装技术(Layer-by-Layer,LbL法)制备灭幼脲微胶囊。正交优化灭幼脲微胶囊制备工艺,利用扫描电子显微镜和激光共聚焦显微镜表征微胶囊表面结构,研究了微胶囊的体外释放行为。[结果]实验结果表明:分别加入1 mL海藻酸钠(1.0 g/L)、1 mL壳聚糖(1.0 g/L)、20 mg灭幼脲、1 mL氯化钙(1.0 g/L)能得到相对更好的结果。正交试验4个因素中,氯化钙质量浓度对评估结果影响最大;利用优化后的体系制备的灭幼脲微胶囊,平均粒径为10μm,Zeta电位为+23.5 mV;载药量和包封率分别为(68.8±0.86)%和(69.1±0.86)%。[结论]利用这种方法制备的灭幼脲微胶囊具备明显的缓释性能。     

纳米缓释微胶囊的制备及其缓释性能

以海藻酸钠、壳聚糖、啶虫脒为原料,采用高压静电喷雾法制备了纳米海藻酸钠/壳聚糖微胶囊,并采用紫外分光光度计研究了其释药行为。结果表明:纳米海藻酸钠/壳聚糖微胶囊能够实现药物缓释作用,且药物释放比例高达90%。从纳米海藻酸钠/壳聚糖微胶囊释药表现发现其药物释放规律:当波长为250 nm时,吸光度(y)和浓度(x)的定量计算关系为y=0.095 2x-0.000 6,为进一步研究纳米海藻酸钠/壳聚糖微胶囊释药能力的提升奠定了基础。     

响应面法优化微胶囊复合壁材配比

采用高压静电微胶囊制备装置,以成囊合格率为检测指标,选择海藻酸钠等为壁材,运用Box-Behnken中心组合设计和响应面分析,研究了壁材配比对微胶囊特性的影响。得到的最优条件是:壁材组成为质量分数1.53%(以下都是质量分数)海藻酸钠,4.52%聚乙烯醇,1%明胶,1%甘油,成囊溶液氯化钙质量浓度为22.86g/L,微胶囊合格率为87.37%。在最优条件下制备出的微胶囊内外表面光滑,囊壁透明,分散性好,形态完整。可为食品、医药、化工等微胶囊化壁材配比选择提供参考。     

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.     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008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、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。