种子乳液聚合法制备有机硅改性聚丙烯酸酯乳液

采用核壳乳液聚合技术,以端乙烯基硅油与丙烯酸酯类单体共聚,合成了有机硅改性聚丙烯酸酯乳液.考察了乳化剂类型、比例、用量以及甲基丙烯酸、甲基丙烯酸缩水甘油酯、乙烯基硅油的用量对乳液聚合稳定性及乳液性能的影响.结果表明,十二烷基苯磺酸钠(SDBS)和辛基酚聚氧乙烯(10)醚(OP-10)复配可产生协同效应,且m(SDBS):m(OP-10)=2、质量分数为3%～4%(相对于单体总质量)时,乳液的稳定性好;甲基丙烯酸缩水甘油酯的质量分数小于4%、端乙烯基硅油的质量分数小于8%时,乳液的聚合稳定性较好;随着甲基丙烯酸用量的增加,乳液的聚合稳定性增加,乳胶粒粒径变小.     

两性乳化剂体系对有机硅改性丙烯酸酯乳液合成的影响

采用新型琥珀酸类两性乳化剂(A1)与非离子乳化剂壬基酚聚氧乙烯醚(CA407)复配体系,合成了有机硅γ-甲基丙烯酰氧基丙三甲氧基硅烷(A174)改性的丙烯酸酯乳液。系统研究了两性乳化剂体系与非离子乳化剂复配比例、用量及乳化剂在种子乳液与预乳液中分布比例(R/F)E对乳液聚合及其性能的影响。研究表明:乳化剂配比m(A1)∶m(CA407)=30∶70时,乳液聚合稳定性及抗电解质稳定性较好;乳化剂用量越大,乳胶粒径越小,粒径分布越宽,乳液黏度越大,涂膜吸水率也越大;乳化剂在种子乳液与预乳液中的分布比例主要影响乳液聚合的稳定性。同时通过TEM乳胶粒形态分析及DSC涂膜的玻璃化转变温度分析认为,A174主要在乳液聚合时分布在乳胶粒表面,易水解交联。     

水性上光油用苯丙共聚乳液的合成及性能表征

以苯乙烯(St)、丙烯酸丁酯(BA)和马来酸酐(MAH)为共聚单体,过硫酸钾(KPS)为引发剂,十二烷基硫酸钠(SDS)/壬基酚聚氧乙烯醚(OP-10)为复合乳化剂,采用半连续加料的乳液聚合法合成出一种水性上光油用苯丙共聚乳液。考察了玻璃化转变温度(Tg)、引发剂和乳化剂含量等对该乳液单体转化率、平均粒径、黏度和表干时间等影响,并对该乳液的热稳定性能进行了研究。结果表明:当w(引发剂)=0.6%、w(复合乳化剂)=1.2%和m(MAH)∶m(BA)∶m(St)=4.6∶36.3∶50.5时,该乳液具有良好的综合性能,完全满足水性上光油的使用要求,并且可在高温环境中使用。     

丙烯酸酯乳液型压敏胶的聚合稳定性研究

以丙烯酸丁酯(BA)、丙烯酸-2-羟基丙基酯(HPA)、β-羧乙基丙烯酸酯(β-CEA)和苯乙烯(St)为共聚单体,过硫酸铵(APS)为引发剂,碳酸氢钠(NaHCO3)为缓冲剂,DNS-458(铵盐型阴离子乳化剂)/OP-10(普通非离子乳化剂)为复合乳化剂,采用半连续种子乳液聚合法合成了丙烯酸酯乳液型PSA(压敏胶)。研究了单体、乳化剂、引发剂及缓冲剂等对乳液聚合稳定性的影响。结果表明:共聚单体对乳液聚合稳定性的影响依次为β-CEABA≈HPASt,β-CEA单体对聚合稳定性影响最显著;当w(APS)=0.6%、w(NaHCO3)≥0.3%、复合乳化剂中m(DNS-458)∶m(OP-10)=1∶1且w(DNS-458+OP-10)=0.5%时,乳液的聚合稳定性相对较好。     

羟基硅油改性苯丙乳液的合成及性能

研究了羟基硅油改性苯丙乳液的聚合工艺条件，并对其性能及涂膜的性能进行了初步探讨。最佳工艺条件为：采用阴离子型乳化剂SDBS与非离子型乳化剂OP-10并用的复合乳化剂及过硫酸铵/硫酸亚铁/雕白粉氧化还原引发剂，m（BA)：m(St):m（硅油）为45:44:11。反应温度为65～70℃，反应时间为4～5h，改性后的乳液机械稳定性、化学稳定性、耐水性均达到要求；用此乳液配制的乳胶涂料的耐水性、耐碱性、耐擦洗性和耐候性大大提高。     

高固含量苯丙微乳液的合成与表征

以过硫酸铵(APS)为引发剂,反应性乳化剂烷基酰胺乙烯磺酸钠(DNS-86)和辛基酚聚氧乙烯醚(OP-10)为复配型乳化剂,正戊醇(n-PTL)为助乳化剂,采用种子乳液聚合法制备苯乙烯(St)、丙烯酸甲酯(MA)、丙烯酸丁酯(BA)、丙烯酸(AA)的四元共聚微乳液。讨论了引发剂用量、乳化剂用量及配比、软硬单体配比等因素的影响。FT-IR和DSC测试结果表明,苯乙烯、丙烯酸酯类单体间发生了自由基共聚反应;TEM测得乳胶粒子平均粒径为35 nm。当m(BA)∶m(St MA)=4∶6,m(DNS-86)∶m(OP-10)∶m(n-PTL)=11∶3∶2,引发剂用量为单体质量的0.7%时,所得乳液性能优良,粒径在纳米范围内。     

核壳型苯丙乳液的制备

采用预乳化工艺和种子乳液聚合技术合成了具有核壳结构的苯丙乳液,并讨论了引发剂、乳化剂、单体、反应温度、聚合工艺等对乳液合成的影响。最佳反应条件为:m(引发剂)∶m(总单体)=0.4∶100.0,m(乳化剂)∶m(总单体)=2.2∶100.0,m(苯乙烯)∶m(丙烯酸丁酯)=1∶1,反应温度控制在80～82℃。     

苯丙乳液聚合中粒径及稳定性的影响因素研究

以辛基酚聚氧乙烯醚(OP-10)和十二烷基硫酸钠(SDS)为乳化剂、过硫酸铵(APS)为引发剂和碳酸氢钠为缓冲剂,采用种子乳液聚合法合成了苯丙乳液,并探讨了各因素对乳液粒径和聚合稳定性的影响。研究结果表明:聚合温度升高虽会提高单体转化率,但也会降低乳液的聚合稳定性;当m(SDS)∶m(OP-10)=2∶1、w(打底乳化剂)=30%(相对于总乳化剂质量而言)、w(引发剂)=0.6%和w(缓冲剂)=0.3%(均相对于总单体质量而言)时,乳液的聚合稳定性相对较好;总乳化剂含量和打底单体含量是粒径的主要影响因素,乳液粒径随前者含量增加而下降,随后者含量增加而增大。     

高硅含量四甲基甲乙烯基环四硅氧烷改性丙烯酸酯乳液的聚合稳定性

以四甲基四乙烯基环四硅氧烷(Vi-D4)为有机硅单体,在乳液体系中开环聚合得到有机硅中间体,采用种子乳液聚合工艺,与丙烯酸单体共聚得到高硅含量的硅丙乳液。研究了体系的pH、加料方式、乳化剂的用量、引发剂的用量对乳液聚合稳定性的影响,发现Vi-D4在pH=3下开环聚合,引发剂用量为单体总量的0.4%,且其配比为3∶2,乳化剂的用量为3%,控制丙烯酸有机硅中间体的滴加时间分别为2 h和3 h制得的乳液稳定性高。     

硅-丙共聚物纳米乳液的合成条件优化

采用种子半连续乳液聚合法制备有机硅改性丙烯酸酯纳米乳液。以胶膜吸水率和单体转化率为实验指标,通过正交实验得到42%固含量(质量分数,下同)的硅-丙共聚物纳米乳液的最佳合成工艺条件为:反应温度85℃,乳化剂、引发剂、有机硅用量分别占单体质量的3%、0.1%、7%,单体配比m(MMA)∶m(BA)为28∶20。对最优方案所得样品的粒径及其分布分析发现,粒子93%以上小于100nm,平均粒径为71.0nm,粒径分布相对较宽;红外分析及交联度测定均表明有机硅与丙烯酸酯发生了共聚。所得乳液的胶膜具有较低的吸水率,乳液具有较好的钙离子稳定性、机械稳定性、耐热性、稀释稳定性。     

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。