聚偏氟乙烯乳液后处理工艺的研究

研究了聚偏氟乙烯(PVDF)乳液凝聚、洗涤分离、干燥等后处理工序。结果表明，用凝聚剂破乳、离心分离的PVDF乳液后处理工艺是可行的，凝聚效果明显，凝集粒径达到了28—321μm；离心分离完全，洗涤母液的电导率小于5μS／cm，制得的PVDF制品色泽纯白。合适的后处理工艺条件为：凝聚剂硝酸铝质量分数为1％、凝聚温度大于或等于60％、凝聚搅拌转速为100r／min、树脂干燥温度115～120℃、树脂干燥时间24h。     

新型聚偏氟乙烯树脂的合成研究

以无离子水为反应介质,采用处理过的全氟聚醚羧酸盐微乳液为乳化剂,IPP为有机引发剂,乙酸乙酯为链转移剂,在反应温度为65℃、反应压力为4.2 MPa条件下,以乳液聚合法制得PVDF乳液。经过机械破乳凝聚和液相粉碎处理等处理措施后,可得到纯度高、光泽好的白色PVDF树脂。     

高分子包覆凝聚法制备粉末丁苯橡胶

以丁苯胶乳为原料,脂肪酸类化合物与硅化合物为隔离剂,NaCl、ZnSO4和CaCl2混合溶液为凝聚剂,采用高分子包覆正凝聚法制备了粉末丁苯橡胶（PSBR）,研究了包覆剂的玻璃化转变温度及其用量、隔离剂种类、凝聚剂种类、搅拌转速、凝聚温度,凝聚方式及设备、熟化温度及时间、干燥方式及设备对PSBR平均粒径的影响。结果表明：当包覆剂玻璃化转变温度为60℃,包覆剂用量为2．5份,搅拌转速为400r／min,凝聚温度为60℃,熟化温度为80—95℃,熟化时间为15—30min时,以室温自然干燥方式制备的98％的PSBR粒径小于0．9mm。     

汽车仪表板用ABS乳注的凝聚及后处理

以汽车仪表用ＡＢＳ混合乳液为原料,经凝聚、离心、干燥而得汽车仪表板用ＡＢＳ树脂粉,是制作汽车仪表板表皮的主要原料之一。在５００ｔ／ａ规模的装置上进行凝聚、离心、干燥条件的研究,确定的较佳工艺条件为凝聚：适宜的进料比,乳液进料７００￣９００Ｌ／ｈ;离心：进料时转鼓转速７００ｒ／ｍｉｎ,脱水时１２００ｒ／ｍｉｎ,１２ｍｉｎ;干燥：介质温度小于等于１３８℃,在６５￣８５℃干燥。结果表明滤饼含水量由６０％     

非交联型粉末丁腈橡胶的制备

采用乳液直接凝聚法，将无凝胶、低门尼的非交联型丁腈制成粉末橡胶，讨论了水／胶比，反应温度，凝聚剂在成粉过程中的影响，并用过筛法对成粉粒径进行了检测。通过实验结果表明：在一定的温度条件，采用直接凝聚法使用选定的凝聚剂，可以制得无凝胶、低门尼的非交联性粉末橡胶。     

MBS树脂合成技术的中试研究(Ⅲ)MBS胶乳的凝聚

阐述了聚合物乳液的凝聚机理和MBS接枝胶乳的凝聚工艺,在MBS胶乳凝聚小试研究和MBS接枝胶乳中试研究的基础上进行了MBS接枝胶乳凝聚的中试研究,着重研究了凝聚剂种类、用量和加料方式以及凝聚温度、水胶比等对MBS粉料堆密度和粒度分布的影响,确定了MBS胶乳的凝聚工艺,为5 000 t/a MBS树脂生产装置提供了设计依据.     

氯乙烯-醋酸乙烯酯共聚糊树脂次级粒子特性研究

讨论氯乙烯-醋酸乙烯酯共聚乳液后处理工艺与树脂次级粒子特性间的关系。根据氯醋糊树脂性能特点,调整喷雾干燥器进出口温度,研究干燥工艺条件与树脂次级粒子结构及树脂增塑糊粘度间的关系,乳胶固含量对树脂次级粒子及糊粘度的影响规律,确定合适干燥工艺及乳液含固量,降低树脂糊粘度。对优化条件下制备的氯醋糊树脂颗粒特性、流变性能进行分析和对比,获得良好结果。     

双马来酰亚胺／烯丙基双酚A共聚物的后固化工艺研究

本文研究了用烯丙基双酚Ａ改性的双马来酰亚胺型树脂Ｘ４５０２的后处理工艺。考察了不同后处理温度和时间对Ｘ４５０２浇铸体的热变形温度、玻璃化温度及Ｔ－３００／Ｘ４５０２单向板的高温层间剪切强度的影响。确定了Ｘ４５０２树脂浇铸体及其碳纤维复合材料的后处理工艺为：２００℃／２ｈ＋２４０℃／６ｈ。     

填充型粉末丁苯橡胶的开发

确定了超细碳酸钙填充型粉末丁苯橡胶（PSBR）的制备工艺，研究了影响凝聚粉末化效果的因素，结果表明，影响粉末化效果的主要因素是包覆剂用量、凝聚条件、搅拌转速，次要因素是凝聚温度、干燥方式。适宜的粉末化条件是包覆剂用量为10份，将凝聚剂加入m(胶）：m(水）=8.5:100的凝聚体系中，搅拌转速为400-500r/min(3L凝聚釜），凝聚温度不小于40℃，湿粉采用闪蒸干燥方式干燥。     

模塑级聚偏氟乙烯乳液聚合工艺的研究

研究了乳液聚合工艺对模塑级聚偏氟乙烯(PVDF)树脂性能的影响。结果表明：将乳化剂全氟辛酸和乳液稳定剂石蜡复合使用，可得到粒径分布窄、稳定性良好的PVDF乳液，聚合用石蜡可循环使用，聚合残留的偏氟乙烯(VDF)单体经气液分离、干燥后可用于聚合反应；确定了在100L卧式釜中乳液聚合制备模塑级PVDF的工艺条件为：搅拌转速60r／min、过硫酸铵用量0．035％、链转移剂用量0．6％、全氟辛酸用量0．13％、石蜡用量0．2％，所制得的PVDF的性能可达到国外同类产品的水平。     

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。