聚苯乙烯的溴化及其与聚苯乙烯的共混

以通用聚苯乙烯(GPPS)为原料,液溴为溴化试剂,无水三氯化铝–铝粉为复合催化体系,采用溶液法合成了溴化聚苯乙烯(BPS)。讨论了溴化时间、主链卤代抑制剂(BHSA)、液溴、催化剂等对聚苯乙烯(PS)溴化的影响。结果表明,BPS的溴含量随溴化时间的增加而提高,但也使BPS的摩尔质量显著下降,而主链溴代抑制剂则可改善BPS的断链。增加液溴量和三氯化铝的用量,虽BPS中溴含量增加了,但主链骨架上的溴化使产物颜色加深。提高溴化反应温度,BPS的摩尔质量大为下降1。H NMR分析表明,增加溴化时间、增加液溴量和主链抑制剂量可有效增加苯环上溴代含量,而增加催化剂用量和升高溴化温度却使苯环上的溴代含量减少。BPS在300℃的热失重低于5%。通过溶液共混制备了GPPS/BPS的共混膜,用原子力显微镜观察了共混物的表面形貌。由结果可知,GPPS和BPS的共混体系相容性差,当共混质量比达1∶1时,BPS仍自成一相分散在连续的PS相中。     

溴化聚苯乙烯的制备及其与尼龙的共混

以阴离子聚合的聚苯乙烯(sPS)为原料,溶液中经液溴溴化制备了溴含量达60%以上的溴化聚苯乙烯(BsPS),在苯环上的溴代位置可达2个以上,阴离子聚合的聚苯乙烯溴化后断链程度远小于通用聚苯乙烯(GPPS)。通过溶液共混制备了聚酰胺PA-5034与溴化聚苯乙烯的共混膜,用原子力显微镜研究了共混膜的表面形貌,测试了共混膜的表面能,热重法分析了共混物的热性能。结果表明,BsPS与PA-5034相容性差,摩尔质量较小的BsPS与PA-5034相容性好于摩尔质量较大的BsPS,在PA-5034中呈球形突起分散。共混薄膜的表面能随共混体系中BsPS组分的增加或其摩尔质量的下降而增大,表面易为水润湿。共混物快速热失重温度范围在380～450℃内,共混体系有较好的加工热稳定性。     

聚苯乙烯的溴化及其与聚对苯二甲酸丁二酯的共混

采用液溴溴化阴离子聚合的聚苯乙烯(PS)溶液,制备了溴质量分数65%以上的溴化聚苯乙烯(PS-B),提高PS溶液的浓度,PS-B的分子量下降,但对溴质量分数的影响不大。在质量分数为28.5%的PS浓溶液中,30 min内可制备溴质量分数超过53%的PS-B。缩短溴化时间对PS-B分子量的影响不大。通过溶液共混、旋转涂膜制备了聚对苯二甲酸丁二酯(PBT)与PS-B的共混膜,用扫描探针显微镜、热失重分析仪和光学接触角测量仪研究了共混膜的相容性、热稳定性和表面性能。结果表明,PS-B与PBT的相容性较差,分子量相对较小的PS-B在PBT中的分散性较好,使共混膜的表面积增大。不同PBT/PS-B共混物的初始分解温度在380℃左右,共混体系体现出较好的热稳定性。共混膜的表面能随着共混体系中PS-B质量分数的增加而增大,却随PS-B的分子量增大而下降。     

HIPS/BPS共混物的燃烧行为研究

通过熔融共混方法将高分子阻燃剂溴代聚苯乙烯(BPS)引入高抗冲聚苯乙烯(HIPS)树脂基体中得到二者的共混体系,再向此共混体系中引入适量三氧化二锑(AO)和硼酸锌(ZB)作为阻燃协效剂,分别用水平燃烧、垂直燃烧、氧指数和高温热分解实验研究了共混物的燃烧行为.结果表明:加入适量BPS时可以使共混物在空气中点燃后自熄且水平...     

高分子阻燃剂BPS在PS-HI中的应用研究

通过熔融共混方法将高分子阻燃剂溴代聚苯乙烯 (BPS) 引入高抗冲聚苯乙烯 (PS-HI) 树脂基体中得到两者的共混体系,再在此共混体系中加入适量三氧化二锑 (AO) 和有机化改性蒙脱土 (OMMT) 作为阻燃协效剂,分别用水平燃烧、垂直燃烧、氧指数和高温热分解实验研究了共混体系的阻燃性能。结果表明,BPS本身对PS-HI的阻燃效率较低,加入少量AO就能够使PS-HI/BPS共混体系的阻燃性能显著提高。当PS-HI/BPS/AO的组成为100/30/10时,复合材料的氧指数达到28.1 %,水平和垂直燃烧级别分别达到FH-1级和FV-0级。同时加入AO和OMMT后,复合材料在高温下成炭能力明显增强,其阻燃机理由原来的气相阻燃变为气相与凝固相协同阻燃,但是由于材料的无焰燃烧时间过长,其垂直燃烧级别达不到FV-0级。     

溴化聚苯乙烯阻燃剂的合成及性能研究

以聚苯乙烯 (PS)、溴素为原料 ,在 40℃ ,2 5 %催化剂 (相对于PS的质量 ) ,溶剂CH2 Cl2 用量 1mL/ 0 1gPS ,时间 3h的反应条件下合成了溴化聚苯乙烯 (BPS)阻燃剂 ,溴的质量分数为6 0 % ,并用红外光谱和X射线光电子能谱表征了其基本结构。对于不同阻燃剂质量分数的高抗冲聚苯乙烯 (HIPS)体系进行了阻燃性能、力学性能和流变性能的初步研究 ,结果表明 :随阻燃剂质量分数的增加 ,阻燃性能逐渐提高 ,但力学性能和流变性能均有所降低。当在共混物中添加质量分数为 3%的BPS阻燃剂时 ,复合材料的水平燃烧速率为 33mm/min ,满足了我国关于家用电器的阻燃法规 (<40mm/min) ,而且此时体系的综合性能也较好。     

ABS及其复合材料的热性能研究

通过熔融共混法制备了ABS、ABS/MH(氢氧化镁)及ABS/MH/BPS(溴化聚苯乙烯)/Sb2O3(氧化锑)阻燃复合材料。使用扫描电子显微镜(SEM)观察了燃烧样条的表面形貌,利用热重分析法(TG)研究了不同升温速率下复合材料的热降解过程,分析了其阻燃机理。结果表明:MH可以增加体系的热稳定性,而加入BPS/Sb2O3会使热稳定性降低;MH和BPS/Sb2O3共同阻燃时,Br-Sb阻燃体系占主导地位,在气相中发挥阻燃效果,MH则在凝聚相起辅助作用,产生物理隔绝和阻止熔融流动的效果。     

支化聚苯乙烯的合成及其与ABS的共混

以对氯甲基苯乙烯(CMS)、苯乙烯、2,2′-联吡啶(Bpy)和CuCl组成过渡金属催化原子转移自由基聚合制备支化聚苯乙烯(BPS)。研究了少量BPS的引入对丙烯腈-丁二烯-苯乙烯共聚物(ABS)熔体流动性能和热性能的影响。以Bpy/CuCl作为络合催化剂,CMS和苯乙烯可顺利自缩合乙烯基聚合合成BPS。在ABS中加入少量的BPS后,共混物的拉伸强度小幅提高,耐热性能基本保持不变,而熔体黏度降低7%～18%,改善了ABS的加工性能。     

聚碳酸酯—聚苯乙烯的反应性挤出共混研究(Ⅰ)

研究了噁唑啉官能化聚苯乙烯(RPS)与聚碳酸酯(PC)的共混反应,对反应性共混物及相应的非反应性共混物作了应力-应变试验及动态力学分析(DMA),并测定其接枝率及密度,发现反应性挤出共混提高了PS/PC共混物的力学性能。     

八溴醚阻燃PP/PS共混物的性能研究

采用熔融共混法制备得到了八溴醚阻燃聚丙烯/聚苯乙烯共混物,讨论了共混物中聚苯乙烯含量对共混物力学性能,UL-94垂直燃烧性能及微观相形态的影响,以及八溴醚阻燃剂在共混物内聚丙烯及聚苯乙烯相的分布情况。在此基础上,还讨论了增溶剂种类对八溴醚阻燃聚丙烯/聚苯乙烯共混物力学性能,UL-94垂直燃烧性能及微观相形态的影响。     

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。