交联型单分散聚苯乙烯微球的制备

以聚乙烯吡咯烷酮（PVP）为分散剂，偶氮二异丁腈（AIBN）为引发剂，乙醇为分散介质，二乙烯基苯（DVB）为交联剂进行了苯乙烯（St）的分散聚合；讨论了引发剂、交联剂、分散剂、单体用量对聚合物粒径及分布的影响，制备了交联型单分散聚苯乙烯微球。实验表明：当交联剂质量分数达到单体质量分数的1％时，微球依然可以保持良好的单分散性。在聚合体系中引入抗坏血酸，使其与微量的氧结合，有效地提高了微球的均匀度。     

单分散羧基化PS微球的制备及自组装

通过无皂乳液聚合法制备羧基化的聚苯乙烯(PS)微球,并讨论了甲基丙烯酸(MAA)用量、引发剂过硫酸铵(APS)用量对单体转化率、微球粒径及其分布的影响。分别使用漂浮自组装法、单基片垂直沉积法和双基片垂直沉积法对聚合物微球进行自组装。结果表明:当MAA的摩尔分数为2%~8%,APS用量为0.168~0.504 g时,可制备单分散性良好的聚合物微球,且随着MAA,APS用量的增加,单体转化率增大,聚合物微球的粒径减小。与漂浮自组装法和单基片垂直沉积法相比,使用双基片垂直沉积法,当乳液固体质量分数为1.0%,微球自组装效果好,排列规整有序。     

异丙醇-水介质中微米级单分散聚(苯乙烯-甲基丙烯酸)微球的制备

以苯乙烯和甲基丙烯酸为单体、PVP为分散剂,AIBN为引发剂,在异丙醇-水介质中,用分散聚合方法制备了微米级单分散的聚(苯乙烯-甲基丙烯酸)[P(St-MAA)]微球。结果表明,采用反应初期低温、中后期升温的聚合工艺可制得单分散的聚合物微球,并提高聚合反应的速率和转化率。P(St-MAA)微球的粒径及其分布可通过改变介质组成来控制。分散介质中异丙醇质量分数降低,聚合反应速率增大,转化率升高,微球的粒径减小。当分散介质中异丙醇的质量分数降低到60％时,聚合反应中有凝胶生成,粒径分布呈多分散性。     

聚苯乙烯/聚酯共混微球的制备及性能

采用相反转乳化工艺制备了亚微米级聚苯乙烯/聚酯共混微球。分析了制备机理、微球中聚酯与聚苯乙烯的相容性及微球形貌,讨论了聚酯用量对微球粒径及分布的影响,测试了共混微球的抗冲击性能、软化温度、附着性以及熔体流动性能。结果表明:微球中聚酯与聚苯乙烯构成不相容体系;共混微球表面粗糙;微球粒径及分布随聚酯用量变化显著,当聚酯质量分数约为14%、乳化剂用量为11%时[乳化剂用量为乳化剂与单体相(苯乙烯和聚酯)质量比],可以得到平均粒径365.3 nm、分散性系数为0.101的亚微米级共混微球;当聚酯质量分数为12%～18%时,随着聚酯含量的增加,共混微球的冲击强度、附着力显著增加,但熔体流动速率降低。     

SiO2用量对单分散聚脲多孔微球的影响

通过沉淀聚合,以异佛尔酮二异氰酸酯(IPDI)为单体,质量比为3:7的水与丙酮的混合溶液为溶剂,Si O2纳米颗粒为模板制备Si O2/聚脲复合微球,用Na OH溶液刻蚀掉Si O2后得到聚脲多孔微球。固定IPDI用量,改变模板Si O2纳米颗粒的用量制取聚脲多孔微球,用扫描电子显微镜观察微球的形貌,并对聚脲多孔微球的粒径、单分散性进行了测算。结果表明,不加Si O2纳米颗粒制得的实心聚脲微球粒径不均一,加入Si O2纳米颗粒后,制得的聚多孔脲微球的粒径增大,单分散性提高。     

无皂乳液聚合法合成聚苯乙烯微球的研究

选用无皂乳液聚合法合成了聚苯乙烯微球乳液,并对无皂乳液聚合的最新研究动态及应用进行了介绍和总结。为了得到制备单分散微球的有利反应条件,本文研究了无皂乳液聚合体系中反应温度、单体用量、引发剂用量、反应时间等因素对聚苯乙烯微球的粒径及粒径分布的影响,同时通过透射电子显微镜(TEM)对聚苯乙烯微球进行了表征分析。实验结果表明:无皂乳液聚合法可以制备出大小均一、单分散性好的PS微球乳液;反应温度在80~95℃范围内时,温度升高,微球粒径减小,且粒径范围在300~500 nm之间;改变单体用量可以制备粒径大小不同的聚苯乙烯微球乳液;改变引发剂用量也是制备不同粒径微球的一种有效途径;延长反应聚合时间,主要是为了提高转化率,而对微球的聚合度基本没有影响。     

氯乙烯-醋酸乙烯酯-马来酸酐乳液共聚转化率和胶乳特性

以十二烷基硫酸钠(SDS)和α-丙烯基烷基酚聚氧乙烯醚(10)硫酸铵(HS-10)为复合乳化体系、偶氮二异丁脒盐酸盐(AIBA)为引发剂,采用间歇乳液聚合合成氯乙烯-醋酸乙烯酯-马来酸酐(VC-VAc-MAH)共聚物胶乳,研究了聚合温度、AIBA用量、SDS和HS-10用量及初始单体投料比对聚合转化率、胶乳稳定性和乳胶粒子粒径的影响。结果表明:MAH的加入使胶乳稳定性下降,加入HS-10虽使聚合转化率略有降低,但胶乳稳定性增加;聚合转化率随聚合温度和引发剂用量的增加而增加;当SDS用量为3%(质量分数)时,胶乳稳定,聚合转化率较大;乳胶粒子粒径随着SDS用量的增加而减小,HS-10用量对乳胶粒子粒径的影响较小;随着投料单体中VAc或MAH含量的增加,聚合转化率降低;固定投料单体组成时,共聚物中VAc和MAH含量随转化率的增加而增加。     

单分散窄分布聚苯乙烯微球的制备研究

以苯乙烯为单体,聚乙烯基吡咯烷酮(PVP)为分散剂,偶氮二异丁腈(AIBN)为引发剂,甲醇为分散介质,利用分散聚合法制备了微米级单分散聚苯乙烯微球。通过傅立叶红外分析(FT-IR),扫描电子显微镜(SEM),激光粒度分析(LPS)等方法对微球进行测试表征。研究了PVP用量对微球产物的影响。结果表明:单体的转化率随PVP用量的增加而增大,PS微球的粒径随着PVP用量的增大而减小,其粒径分布先变窄后变宽。当PVP用量为1.5%时微球的粒径分布最窄,单分散性最好。改变PVP用量可以得到不同粒径的PS微球。     

分子印迹聚合物中种子微球的合成及应用研究

采用辛醇和乳化剂(OS)作为复合分散剂,用悬浮聚合法制备了4-氨基吡啶分子印迹聚合物微球。采用无皂乳液聚合法对分子印迹聚合物种子微球的制备与性能进行了研究。结果表明,辛醇与极少数乳化剂复合使用,提高了乳液的稳定性,改善了种子微球粒径大小及粒径分布。当辛醇用量为单体质量的3.0%、丙烯酸乙醋与苯乙烯质量比为1:0.229、反应温度为85℃、pH值为8.0时,能够制备出期盼的分子印迹聚合物微球。     

丙烯酸酯微乳液的聚合研究

运用OP-10／JFC非离子复合乳化剂成功合成了丙烯酸酯微乳液,以聚合过程的现象为基础,从紫外光谱分析、聚合温度、单体时间-转化率、体系时间-粘度关系、pH值等方面系统研究了聚合过程中的相分离和凝胶现象。结果表明:聚合温度75-76℃,聚合结束后pH值控制在7-8,聚合过程中补加助乳化剂戊醇和引发剂KPS溶液,能有效抑制凝胶和相分离现象。     

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.     

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。     

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.