热塑性木质素酚醛树脂固化动力学研究

采用差示扫描量热法对热塑性木质素酚醛树脂（LDP）在２５～２５０℃范围内,以５、１０、１５、２０℃／min升温速率进行了动态固化反应研究。研究表明,随着升温速率的提高,树脂的起始固化温度Ti、峰顶温度Tp以及终了固化温度Tf均有提高,LDF的固化过程可以通过改变固化剂用量来优化固化行为,当固化剂用量达到１２％（质量分数,下同）时其固化曲线与普通酚醛树脂固化曲线接近,且犜狆大幅降低（与普通酚醛树脂比较）。固化反应热随升温速率和固化剂用量的改变变化不明显。采用Ozawa方程对DSC数据进行动力学研究,得到LDF固化反应活化能为８５．６４KJ/mol     

酚醛树脂固化动力学研究

采用DSC方法探讨了酚醛物质的量比(F/P)为1.3、1.5、1.8的酚醛树脂的固化反应过程。在50~300℃温度范围内以不同升温速率(5、10、15、20℃/min)进行动态固化行为分析。运用Kissinger和Ozawa法进行了动力学研究,得到其固化反应活化能。结果表明:两种方法计算得到活化能的大小顺序是一致的。高物质的量比酚醛树脂在固化过程中具有的活化能比低物质的量比酚醛树脂的要低,这就意味着高物质的量比酚醛树脂固化时需要较少热量。因此,酚醛树脂的F/P物质的量比越高,固化反应的活化能就越低。随升温速率提高,该种树脂的起始固化温度Ti,峰顶固化温度Tp,终了固化温度Tf都有提高,同时固化时间tc缩短。     

硼改性酚醛树脂固化反应动力学的研究

采用非等温DSC技术分析了不同升温速率下硼改性酚醛树脂的固化行为,运用Kissinger和Ozawa方法对其固化反应动力学进行了研究,得到了固化反应活化能.结果表明,硼可以加速酚醛树脂的固化反应,使酚醛树脂的固化峰温度向低温方向移动,降低了酚醛树脂固化反应的活化能,使固化反应易于进行.     

耐热酚醛树脂固化机理研究

采用相同配比的酚类和醛类物质合成了两种酚醛树脂——普通酚醛树脂和耐热改性酚醛树脂。利用差示扫描量热仪(DSC)将两种树脂在不同升温速率下进行固化,并用Ozawa方程对这两种酚醛树脂固化过程的活化能进行了计算。结果表明:普通酚醛树脂的峰值固化温度为197.45℃,固化反应的活化能为41.4 k J/mol;耐热改性酚醛树脂的峰值固化温度为237.23℃,固化反应的活化能为50.0 k J/mol。     

基于高比例尿素改性PF树脂的固化特性及动力学研究

为探讨高比例尿素改性PF(酚醛树脂)的固化特性,采用差示扫描量热分析(DSC)方法,对不同升温速率条件下树脂的固化过程、特征放热峰温度等进行了检测分析;通过Kissinger和Ozawa方法,计算了固化反应表观活化能,建立了固化反应动力学模型。研究结果表明:高比例尿素改性PF树脂的固化反应活化能较低,反应易于进行,固化温度为131.3℃,较普通PF树脂降低了近20℃。     

DSC法研究MUF共缩聚树脂的固化行为

借助DSC分析技术,探讨了三聚氰胺-尿素-甲醛(MUF)共缩聚树脂在不同条件下的固化行为。运用Kissinger方法进行了动力学分析,得到了其固化反应的动力学参数和活化能。结果表明,随着升温速率的增加,MUF固化反应的最高固化温度会向高温方向移动,其固化表观活化能为50.30kJ/mol,用外推法得到了其最高固化温度为97℃。而且,固化剂的加入大大降低了树脂固化表观活化能。     

酚醛树脂注塑固化成型及流动特性的研究

考察了辊压工艺及酚醛树脂的邻对位比值(O／P)对酚醛注塑料的成型时间及流动性的影响。结果表明注塑料的辊炼温度及时间对其成型时间及流动性有明显的影响，其中流动性受影响的幅度随树脂O／P值的不同而差别较大。O／P值愈高，流动性随辊压温度或辊压时间的增加而降低的趋势愈明显，成型时间随辊压温度或辊压时间的增加而缩短，但缩短的幅度受树脂O／P值改变影响较小。在不同O／P值酚醛树脂注塑料的各自最佳辊压工艺的条件下，影响注塑料成型时间的最关键因素是酚醛树脂的O／P值，O／P值愈高，成型时间愈短，而O／P值对注塑料的流动性的影响不明显。     

新型酚醛树脂固化过程的表征研究

主要利用DSC、TG及IR技术研究了新型S157酚醛树脂体系的固化反应及其动力学、树脂体系中改性剂含量对固化反应的影响及固化过程中树脂体系结构变化规律，为确定新型S157酚醛树脂体系的固化工艺提供依据。新型S157酚醛树脂体系的固化反应表观活化能约为82kJ/mol，固化反应级数为0.91；有机硅改性剂的加入及其含量对树脂基体固化反应表现活化能、固化反应级数和热分解温度基本无影响，但失重率有所降低；在树脂基体等温固化过程中，活性羟甲基指数逐渐降低，树脂在高温固化过程中由于受到氧化而产生羰基吸收。     

二氧化硅粉体改性E—Si／CE固化动力学的研究

采用非等温差示扫描量热法（DSC）研究了纳米二氧化硅（SiO2）和微米SiO2的混合粉体改性环氧基硅烷（E—Si）／氰酸酯（CE）树脂体系固化动力学;用Kissinger、Crane和Ozawa法确定固化动力学参数。结果表明,Kissinger式求得的表观活化能为66．09kJ／mol;Ozawa法求得的表观活化能为7001kJ／mol;根据Crane理论计算该体系的固化反应级数为0.89。计算了不同升温速率所对应的不同温度的频率因子和反应速率常数;求得了改性体系的固化工艺参数：凝胶温度130．74℃、固化温度160．96℃和后处理温度199.16℃,确定了体系的最佳固化工艺。与E—Si／CE体系对比表明,SiO2的加入可以降低E—Si／CE体系的活化能,使其固化能在较低温度下进行。     

含三嗪结构环氧树脂的固化反应动力学研究

研究了邻甲酚醛环氧树脂／苯代三聚氰胺酚醛树脂的固化反应机理,邻甲酚醛环氧树脂（o—CFER）被固化剂苯代三聚氰胺酚醛树脂（BPR）固化,采用非等温扫描方法研究环氧树脂固化反应,用来确定其固化反应动力学参数以及最佳固化工艺条件。用差示扫描量热仪（DSC）对邻甲酚醛环氧树脂固化体系的固化反应过程进行了分析。采用不同升温速率,用Kissinger方法求得体系固化反应的表观活化能△E=63．6kJ／mol,根据Crane理论计算得到该体系的固化反应级数n=0．899。固化反应起始温度、峰值温度、终止温度分别为Tio=102．95℃、Tpo=132．16℃、Tpf=166．6℃,为确定苯代三聚氰胺酚醛树脂作为固化剂的固化反应条件提供了一定的理论依据。     

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。