智能水凝胶应用研究进展

智能水凝胶是指在外界环境（如温度、pH、电场、溶剂性质、光强度和光波长、压力、离子强度等）发生变化时,性质随之发生相应变化的水凝胶,即具有环境响应性。作者详细介绍了智能水凝胶在药物控制释放、组织工程、物质分离、酶的固载及调光材料5个方面的应用研究情况。并对智能水凝胶未来的研究方向及应用前景进行了展望。     

智能水凝胶在生物载药领域的研究进展

智能水凝胶是一类具有三维网络结构、膨胀性好、吸水性强、易保水、超仿生等特点的新型功能高分子材料。由于其合成过程中加入了具有特殊结构、基团的单体或者大分子原料,如聚丙烯酰胺(PNIPA)类大分子、酸/碱基团(如羧基和氨基)、丙烯酸、聚氨类、偶氮苯(As)、聚电解质(高分子链上有可以离子化的基团)等,因此智能水凝胶是能够根据环境的温度、酸度、电场、磁场等变化做出有规律的结构和体积调整,或者导致凝胶组成发生变化的新型智能生物化学水凝胶材料,具有较高的智能性和响应性。本文根据水凝胶对外界环境的刺激不同表现出不同的响应情况,将凝胶分为:温度敏感性水凝胶、pH敏感性水凝胶、光敏感性水凝胶、压力敏感性水凝胶、电场敏感性水凝胶等。近年来,随着人们对医用水凝胶和药物缓释研究的深入,具有环境敏感性和较好生物相容性的智能水凝胶成为临床上药物控释材料的首选。     

电场敏感智能水凝胶的研究进展

水凝胶对于环境微小的物理化学刺激,如温度、pH值,离子强度、电场、磁场,光、压力等能够通过感知和自身作功来响应外界环境变化,因此水凝胶具有"智能凝胶"、"软性机械"之称.在众多外界响应条件中,电场由于易操作易调控等优点使得电场响应水凝胶具有更广阔的应用前景.本文对近年来已见报道的几类典型的电场敏感水凝胶进行了较为详细的综述.同时介绍了静电场、渗透压等电场敏感水凝胶的响应机理及其在人工爬虫、化学阀和仿生驱动器等方面的应用.     

环境刺激响应型水凝胶及其在药物控释中的应用

环境刺激响应型水凝胶又称智能水凝胶,因为它能感应到外界环境因素的变化,并且发出响应,从而导致药物可在定点,定时、定量地释放,所以近年来受到普遍重视.该文综述了近年来响应水凝胶中温度敏感型、pH敏感型以及葡萄糖、电场、磁场、光等敏感型水凝胶及其在药物控释中的应用的最新进展,指出目前研究环境刺激响应型水凝胶存在的问题及今后...     

刺激响应性水凝胶的研究现状及发展趋势

刺激响应性水凝胶在药物缓释、物质分离提纯等领域得到了广泛的应用,文章介绍了能响应温度、pH、光、电场和磁场等外界环境因素变化智能凝胶的结构特点和近期研究进展,并展望了智能凝胶的应用前景。     

水凝胶的最新研究进展

综述了近几年国内外对水凝胶研究的现状,简要介绍了基于水凝胶高吸水性、保水性能和机械性能的创新性研究,同时重点介绍了对温度、光照、pH、电场、磁场等外部环境刺激有响应的智能水凝胶的研究进展与其在药物释放体系、检测器、机器人驱动装置等领域应用。     

智能水凝胶的制备以及在药物缓释方面的研究进展

介绍了温度、pH、电场、磁场、光,葡萄糖敏感型智能水凝胶的制备方法以及智能水凝胶在药物缓释控释领域的应用研究进展,并对未来智能水凝胶的发展方向做了展望。     

智能水凝胶的研究进展

综述了智能水凝胶的应用研究进展,重点综述了pH值敏感性水凝胶、温度敏感性水凝胶的研究进展,同时还介绍了光敏感性水凝胶和电敏感性水凝胶。     

智能水凝胶的应用

智能水凝胶对于外界微小的物理化学刺激,如温度、电场、磁场、光、pH、离子强度或压力等能够感知并在响应过程中有显著的溶胀行为或响应性。本文重点介绍了智能水凝胶及与之密切相关的智能型大分子在药物控释、组织工程、活性酶的固定、调光材料等方面的应用。     

壳聚糖接枝PAAm半互穿网络凝胶的性能

以过硫酸钾(KPS)为自由基引发剂,在壳聚糖(CS)上接枝共聚了聚丙烯酰胺(PAAm).以亚甲基双丙烯酰胺(MBA)或甲醛为交联剂,并研究了试验因素,如交联剂浓度和单体比率对水凝胶溶胀能力的影响.试验表明水凝胶具有离子强度敏感性、pH敏感性和温度敏感性.这种可随外界因素响应及"开关"的性质,使此类智能水凝胶有望成为生物制品载体,例如药物载体.     

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。