PET食品接触材料热氧加速老化评估贮存寿命的研究

在实际生活中,PET会因为逐渐老化而失去使用价值。热氧加速老化实验可以帮助分析多个不同温度下PET各项力学性能的变化,研究温度对PET老化性能的影响。由此建立温度-寿命相关的阿伦尼乌斯模型,通过阿伦尼乌斯模型推算PET的实际使用寿命。     

紫外光固化涂料黄变影响因素及黄变度简易测试方法初探

通过比较不同材料所配制的UV固化涂料固化后的涂膜经氙灯老化后的黄变度,确定UV固化耐黄变涂料的最佳材料,并在此基础上探索简单易行的黄变度测试方法。     

聚丙烯使用寿命预测方法

研究了聚丙烯热老化性能,发现基于阿伦尼乌斯公式而采用外推法来预测聚丙烯的使用寿命误差非常大。该文提出采用修正的三参数阿伦尼乌斯公式来拟合聚丙烯热老化曲线,得到了非常好的拟合结果,并且提出一种很好的聚丙烯使用寿命预测方法。针对不同抗氧剂的聚丙烯配方,采用修正的三参数阿伦尼乌斯公式都能得到很好的拟合结果。最后还给出了不同抗氧剂的聚丙烯配方的使用寿命的预测参数。     

阳离子引发型紫外光固化涂料热老化黄变的研究

通过在阳离子引发型紫外光固化涂料中添加不同类型以及不同比例的抗氧剂,监测其在热老化过程中的黄变现象,考察了抗氧剂对涂料热老化黄变的影响和其不同的抗黄变能力。利用紫外-可见光谱仪表征老化过程试样的透光率变化。结果表明:抗氧剂能较好地减小阳离子型紫外光固化涂料的热老化黄变,抗氧剂中的羟基的抗黄变能力存在差异,羟基及羟基数量决定了抗氧剂的抗黄变能力。     

UV 固化涂料固化后黄变的探讨

UV 固化涂料固化后会出现黄变,尤其在白色或浅色基材上更加明显.针对上述问题,文章通过测量漆膜固化后放置不同时间的△b值,分析了几种单体、树脂、光引发剂、紫外光吸收剂及受阻胺光稳定剂等对此黄变的影响.通过试验可以看出,影响UV固化涂料固化后黄变特性的因素有UV低聚体(UV树脂)、单体、光引发剂及助剂.然而UV固化涂料固化后的黄变会随着放置时间的推移逐渐衰减,通常24 h后会趋于稳定,并且可以通过烘烤来加速颜色稳定的过程.     

耐热黄变阴极电泳涂料的制备及性能

合成了一种带有噁唑烷酮结构的全封闭多异氰酸酯,作为电泳涂料的交联剂。采用傅里叶变换红外光谱(FT-IR)、热重分析(TGA)表征了该交联剂的结构与性能。所制备的阴极电泳涂料具有良好的耐热黄变性能,且涂膜外观良好,各项性能指标优异。     

光稳定剂在聚氨酯涂料中的应用研究

采用人工加速老化的方法研究了光稳定剂对聚氨酯涂料光稳定性的影响.结果显示,添加光稳定剂对于防止紫外光作用引起的聚氨酯涂料表面失光非常有效,而对于漆膜的初期物理性能无不良影响.     

光稳定剂对热塑性聚氨酯胶粘剂性能的影响

采用一步法合成耐黄变热塑性聚氨酯(TPU)胶粘剂,研究了紫外线吸收剂UV-329、受阻胺光稳定剂UV-622、抗氧剂Chinox1010等对TPU胶粘剂性能的影响。结果表明,当UV-329、UV-622、Chinox1010质量比为3∶3∶2,且复合光稳定剂添加质量分数1.6%时,可提高TPU胶粘剂的耐黄变性能,有效延缓TPU胶粘剂的光老化速度。     

液态耐黄变剂在聚氨酯软泡中的应用

软质聚氨酯泡沫塑料简称聚氨酯软泡,在聚氨酯软泡受外在环境影响所造成的黄变问题,如光降解黄变、热氧老化黄变、工业废气(NOx)污染黄变等…,向来是聚氨酯软泡生产厂商困扰的问题,一般厂商利用添加光稳定剂或抗氧化剂来改善泡绵的耐黄变性能,但改善耐黄变的效能有限。因此永光化学身为世界级专业的紫外线吸收剂制造与供货商,开发了EVERSORB系列耐黄变剂产品,特别是新型液态的EVERSORBPU665与EVERSORBPU667产品,提供了聚氨酯软泡黄变问题的良好解决方案,并对于聚氨酯软泡在不同使用环境所遇到的黄变问题,提供了相对应的解决方案,提高聚氨酯软泡产品的附加价值。     

聚氨酯材料耐黄变的研究进展

介绍了聚氨酯材料在日常使用过程中发生老化变黄现象及其机理,探讨了能引发聚氨酯材料发生老化变黄的几个主要原因,综述了制备具有优良耐黄变性能聚氨酯材料的各种技术方法,指出从多元醇、异氰酸酯、光稳定剂、光屏蔽剂和纳米材料等方面进行改善,来制备耐黄变聚氨酯材料。最后对我国今后聚氨酯工业在耐黄变性能上的发展提出了几点看法与建议。     

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。