集成橡胶增韧PS

应用集成橡胶[苯乙烯-异戊二烯-丁二烯橡胶(SIBR)]增韧聚苯乙烯(PS),当w(SIBR)为17.5% 时,所得高抗冲聚苯乙烯(HIPS)的冲击强度达380 J/m.与经典的PS增韧剂聚丁二烯橡胶、丁苯橡胶等相比,SIBR中包含异戊二烯成分.研究结果表明,异戊二烯起到了一定的增韧作用.该HIPS的透射电子显微镜照片显示,产品中没有经典的"海-岛"结构,而是出现了一种新的网络结构.     

苯乙烯-异戊二烯-丁二烯橡胶接枝苯乙烯聚合动力学

以自制的4种苯乙烯-异戊二烯-丁二烯橡胶(SIBR)为增韧组分,采用本体聚合工艺,以过氧化苯甲酰为引发剂进行苯乙烯接枝聚合以制备高抗冲聚苯乙烯,考察了用量、相对分子质量及分子链结构不同的SIBR对苯乙烯聚合速率的影响,并比较了用不同橡胶改性聚苯乙烯时的聚合动力学行为。结果表明,SIBR的用量越大聚合速率越小,相对分子质量越大则聚合速率越大;按SIBR分子链序列结构的不同聚合速率还呈现出从大到小依次为线型嵌段SIBR、线型无规SIBR、星形嵌段SIBR及星形无规SIBR的规律。用不同橡胶增韧聚苯乙烯时的聚合速率从大到小依次为SIBR、丁苯橡胶及顺丁橡胶。苯乙烯的表观接枝率随着SIBR用量或其相对分子质量的增大而减小,且远大于使用顺丁橡胶。     

ABS/HIPS相容性的研究

采用苯乙烯-马来酸酐共聚物(SMA)作为丙烯腈-丁二烯-苯乙烯共聚物/高抗冲聚苯乙烯(ABS/HIPS)的相容剂,研究了SMA对ABS/HIPS共混体系力学性能的影响,并用扫描电子显微镜对共混物的亚微观形态结构进行了分析。结果表明,SMA的加入起到了很好的增容作用。随着HIPS/SMA用量的增加,共混物的冲击性能先增大后减小,当HIPS/SMA=8.5/1.5(质量比),且HIPS/SMA质量分数为10%时,共混物的缺口冲击强度达到97.1J/m,同时拉伸强度和弯曲强度最大。     

低温超韧聚苯乙烯的配方研究

以高抗冲聚苯乙烯(HIPS)为基体树脂,采用双螺杆挤出机研究了不同抗冲击改性剂类苯乙烯弹性体、丙烯腈-丁二烯-苯乙烯共聚物(ABS)高胶粉、聚烯烃弹性体(POE)、丁苯弹性体、苯乙烯-丁二烯-苯乙烯弹性体(SBS)和苯乙烯-乙烯／丁二烯-苯乙烯共聚物(SEBS)对HIPS的增韧效果。结果表明,SBS和SEBS对HIPS具有最好的增韧效果,当SBS含量达到40.0份时,能使HIPS体系的常温简支梁缺口冲击强度达到42.1kJ／m~2,-40℃低温冲击强度可达25.3kJ／m~2,具有优异的低温韧性和优良的综合性能。     

溶液聚合法改性SBS对HIPS/SBS/纳米CaCO3复合材料形态和力学性能的影响

采用马来酸酐(MAH)和苯乙烯(St)作为接枝单体,通过溶液聚合法合成了接枝极性基团的苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS),然后与高抗冲聚苯乙烯(HIPS)基体、纳米碳酸钙(NCaCO3)粒子复合,用傅立叶红外光谱仪表征了接枝处理前后SBS表面化学结构的变化;并研究了SBS改性对复合材料微观结构和力学性能的影响.结果表明:双单体溶液聚合法成功地将极性基团接枝在SBS链上;填充SBS-g-MAH后,促进了NCaCO3在HIPS基体中的分散,改善了HIPS-NCaCO3粒子间的界面黏结,起到了良好的增容作用;SBS-g-MAH和NCaCO3粒子对HIPS基体具有协同增强增韧作用,能同时提高复合材料的拉伸屈服强度和冲击强度.     

国产聚苯醚合金改性的研究

研究了国产聚苯醚(PPO)与高抗冲聚苯乙烯(HIPS)合金的工程化,探讨了PPO含量与PPO/HIPS合金拉伸强度、弯曲强度、冲击强度的关系;研究发现(苯乙烯/乙烯-丁烯/苯乙烯)共聚物(SEBS)对此合金具有增韧效果,并研究了抗氧剂1010对PPO/HIPS合金性能的影响。     

橡胶增韧塑料的发展

橡胶增韧塑料起源于40年代,最早合成了高冲击强度聚苯乙烯(HIPS)。50年代初期,丙烯腈-丁二烯-苯乙烯聚合物(ABS)问世。目前,橡胶增韧的聚合物有聚氯乙烯(PVC)、聚丙烯(PP)、聚苯醚(PPO)、聚甲基丙烯酸甲酯(PMMA)、     

新型无卤阻燃增韧高抗冲聚苯乙烯的制备

研究了新型无卤阻燃增韧高抗冲聚苯乙烯(HIPS)的制备方法,并考察了阻燃剂配方及用量对HIPS阻燃性能的影响;同时,对HIPS进行增韧改性,探讨在最佳阻燃剂配方中添加增韧剂——聚氨酯与热塑性弹性体混合物(PU/SEBS)对HIPS阻燃及抗冲击性能的影响。结果表明:三聚氰胺尿酸盐与白度化红磷阻燃剂体系具有很好的协效阻燃作用;添加PU/SEBS可以显著提高HIPS的悬臂梁缺口冲击强度,当PU/SEBS,HIPS,阻燃剂,磷酸三苯酯助剂,硼酸锌质量比为15∶45∶30∶7∶3时,制备的无卤阻燃增韧HIPS复合材料具有优异的阻燃性能,而且可保持较高的冲击强度。     

PA 6纳米复合材料的多元增韧改性研究

采用熔融共混法制备了聚酰胺(PA)6/甲基丙烯酸甲酯-丁二烯-苯乙烯共聚物(MBS)/纳米SiO_2多元增韧复合材料,研究了复合材料的冲击强度、拉伸性能以及冲击断面形态。结果表明:MBS、纳米SiO_2可以协同增韧PA6,使其转变为超韧材料,在w(SiO_2)为0.5%时,复合材料的简支梁缺口冲击强度最高达91.3 kJ/m~2。同时,扫描电子显微镜照片显示,复合材料的冲击断面出现了明显的塑性变形,体现了剪切屈服的增韧机理,纳米粒子和相容剂共同作用使得MBS弹性体粒子均匀地分散在PA6基体中。     

硫酸钙晶须在HIPS中的应用

采用硫酸钙晶须为增强改性剂、苯乙烯-丁二烯-苯乙烯共聚物(SBS)为增韧改性剂、高抗冲聚苯乙烯(HIPS)为基体材料,通过采用熔融混合挤出,制得HIPS复合材料.对该复合材料的力学性能、热性能进行测试,研究了硫酸钙晶须用量对HIPS复合材料的力学性能、热性能的影响,观察了硫酸钙晶须/HIPS微观结构.结果表明,硫酸钙晶须对HIPS具有良好的增强作用.     

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。