氰酸酯及其改性树脂体系的反应动力学研究

利用傅立叶变换红外光谱对纯氰酸酯及其改性树脂体系进行固化反应动力学的研究。研究表明,氰酸酯主催化剂能降低反应活化能,使固化反应速度明显加快,反应温度降低;而苯酚的加入可明显提高改性体系的最大固化度。     

酚类改性氰酸酯树脂体系介电性研究

采用DSC和红外等方法研究了酚对氰酸酯树脂固化反应的影响,以及不同酚含量的氰酸酯树脂体系及其复合材料在常温、高温、宽频(7~18 GHz)等条件下介电常数及介电损耗。结果表明,酚的加入可以显著促进氰酸酯树脂的固化反应;适量酚的加入能显著提高氰酸酯树脂体系的介电性但是会降低其玻璃化转变温度;含有壬基酚的氰酸酯树脂体系复合材料在宽频下表现出稳定的介电性。     

氰酸酯树脂/聚苯醚/纳米二氧化硅电子封装材料固化动力学研究

采用硅烷偶联剂表面处理过的纳米二氧化硅作为无机填料改性氰酸酯树脂/聚苯醚固化体系,并利用非等温差示扫描量热法研究了氰酸酯树脂/聚苯醚/纳米二氧化硅电子封装材料的固化动力学。结果表明,氰酸酯树脂/聚苯醚/3%纳米二氧化硅固化体系的凝胶温度为150℃、固化温度为181℃、后处理温度为239℃;固化动力学参数表观活化能为15.46kJ/mol、反应级数为0.82、频率因子为38174.38s-1;加入纳米二氧化硅可以降低氰酸酯树脂/聚苯醚固化体系的表观活化能,使其固化反应可以在较低温度下进行。     

环氧改性氰酸酯树脂的研究

综述采用环氧树脂增韧改性氰酸酯树脂的共聚反应机理、固化催化体系，以及环氧树脂／氰酸酯树脂固化体系的性能和复合材料的性能。环氧树脂与氰酸酯树脂反应生成恶唑啉酮五元环，降低了氰酸酯树脂的交联密度，使韧性提高；催化剂可以明显提高共聚反应速度，改变产物含量；改性后的氰酸酯树脂具有优良的综合力学性能和成型工艺性，且介电性能及耐热／湿热性能无较大损失。     

低溴环氧/氰酸酯树脂共固化反应及其层压板性能的研究

用差示扫描量热仪(DSC)、傅立叶交换红外光谱(FT-IR)对不同配比的低溴环氧／氰酸酯树脂的共固化反应机理以及固化物的结构特征进行了研究,同时测定和讨论了其层压板的耐热性和介电性能等。研究结果表明,在低溴环氧／氰酸酯树脂的固化体系中,氰酸酯和环氧树脂通过两种途径反应最终生成噁唑烷酮结构：固化反应温度与体系的组成有关,体系中低溴环氧树脂减少固化反应温度降低：加入催化剂能明显促进体系共固化反应,同时也降低了层压板的耐热性和介电性能。在性能方面,低溴环氧树脂中加入氰酸酯使共固化物耐热性增加、Tg升高,但氰酸酯用量增加到一定范围后,低溴环氧树脂／氰酸酯配比对Tg影响不大;低溴环氧树脂／氰酸酯层压板的耐热性和介电性能在一定实验范围内随着氰酸酯用量的增加明显提高。     

环氧树脂含量对氰酸酯热学性能的影响研究

采用示差扫描量热法(DSC)和热失重分析法(TGA)研究了环氧树脂含量对氰酸酯树脂固化反应特性、热稳定性以及热膨胀系数的影响。结果表明,环氧树脂的加入可有效降低改性体系的固化反应活化能,同时体系的热稳定性和尺寸稳定性有不同程度的削弱。当环氧树脂质量分数达到20%时,改性体系的表观活化能为65.4 kJ/mol,耐热温度指数为174℃,较纯氰酸酯树脂分别降低了25.8%和21.4%。当环氧树脂质量分数达到50%时,改性体系的热膨胀系数为65.3 922×10-6/℃(25～150℃),较纯氰酸酯树脂提高了8.13%。     

中温固化氰酸酯胶膜的研究

利用自制潜伏性催化剂加入经过增韧的氰酸酯树脂与环氧树脂共聚改性体系中制备出中温固化氰酸酯胶膜。通过DSC、DMA、IR对中温固化氰酸酯胶膜固化进行了研究,用流变仪对其贮存期与流变规律及其性能进行了研究,用万能拉力机研究了力学性能,以介电测试仪对其介电性能进行研究。该胶膜经135℃/4h固化,具有良好的力学性能,测试频率为9.375GHz时,胶膜的介电常数为2.7,介电损耗为0.007,具有良好贮存性。研究结果表明自制催化剂降低了氰酸酯胶膜的固化温度,实现了130～135℃固化。     

彩晶玻璃用热固型清漆有机钛酯化固化反应研究

以水溶性丙烯酸改性树脂为主要连结料,氨基树脂为固化剂,添加催化剂有机钛复配成彩晶玻璃用的热固型清漆。通过DSC测试,研究了有机钛用量对酯化固化反应的影响。结果表明,有机钛酯化催化剂对水溶性热固型清漆有固化催化作用,当钛酸四丁酯质量分数为3%时,能有效提高固化速度。     

金属离子螯合物作用下固化工艺对环氧/氰酸酯树脂的影响研究

采用差示扫描量热分析技术研究催化剂TE用量对环氧/氰酸酯树脂反应活性和固化度的影响,借助动态力学热分析仪研究TE用量及固化温度对树脂玻璃化温度的影响,采用傅立叶变换红外光谱（FTIR）对环氧/氰酸酯树脂的固化过程进行了表征,最后研究了固化温度对树脂力学性能的影响。结果表明,温度是影响树脂固化度的最主要关键因素;催化剂能够显著降低环氧/氰酸酯的反应温度,但对玻璃化温度有负作用,催化剂TE用量适宜比例为0.14phr。树脂在120～150℃下以氰酸酯自聚反应为主;温度升至180℃后,除了低聚体进一步发生交联反应外,还存在环氧基团与氨基甲酸酯（氰酸酯基团与水的反应产物）的反应。随着固化温度的增加,玻璃化温度逐渐升高,150℃力学性能大幅度增加。     

改性双马来酰亚胺/氰酸酯树脂固化工艺的研究

采用DSC法研究烯丙基双酚A(DBA)改性的双马来酰亚胺(BM I)和氰酸酯(CE)共混体系在催化剂存在下的固化动力学,并结合固化度测定和红外光谱分析确定固化工艺。由于加入的有机金属盐催化了CE的固化反应,使CE和改性BM I在不同温度范围内分别固化,该共混物经历了170℃/2h 225℃/2h 240℃/2h固化程序后,能够完全固化,形成具有IPN网络结构的聚合物。     

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。