氟硅共聚改性提高聚丙烯酸酯力学和疏水性能的研究

为改善聚丙烯酸酯表面能高、力学性能较差的缺点,以丙烯酸酯为主要单体,甲基丙烯酸十二氟庚酯、四甲基四乙烯基环四硅氧烷为功能单体,采用核壳乳液聚合法合成了水性聚氟硅丙烯酸酯.结果表明,四甲基四乙烯基环四硅氧烷可有效提高乳液膜的疏水角、断裂伸长率以及硬度;其质量分数为5％时,乳液的平均粒径为166.8 nm,转化率为98.6...     

含氟丙烯酸酯核壳乳液的制备与性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为主单体,分别加入丙烯酸六氟丁酯(HFBMA)和甲基丙烯酸十二氟庚酯(DFHM)作为聚丙烯酸酯改性剂,制备了2种含氟丙烯酸酯核壳乳液。采用1H-NMR、TEM、DSC、EDS-SEM、Zeta电位及纳米激光粒度仪等表征了乳胶粒子的组成、结构、粒径及其分布以及乳胶膜表面氟元素的含量。研究了2种含氟单体的用量对乳液稳定性、乳胶膜吸水率、单体转化率、乳胶膜表面疏水疏油性等的影响;研究结果表明:DFHM的改性效果明显好于HFBMA。当DFHM的加入量为4%时,乳胶膜对水的接触角达到93.5°,吸水率降为11.54%,对正己烷的接触角达到82.0°;乳胶粒子的平均粒径70.02 nm,粒径分布窄(PDI=0.082),且具有核壳结构;SEM-EDS测试结果显示,制备的含氟聚合物在成膜过程中,氟元素更易向表面迁移,从理论的5.70%上升到13.47%,从而使乳胶膜具有更好的疏水和疏油性能。     

核壳型聚硅氧烷改性丙烯酸酯乳液的合成与表征

以八甲基环四硅氧烷(D4)和四乙烯基四甲基环四硅氧烷(D4Vi)为有机硅单体,十二烷基苯磺酸(DBSA)为催化剂,采用预乳化半连续种子乳液聚合工艺,在核壳型丙烯酸酯乳液的合成过程中,通过壳层聚合阶段的接枝共聚反应引入聚有机硅氧烷,制备出核壳型聚有机硅氧烷改性丙烯酸酯乳液。考察了DBSA、D4Vi和D4用量对乳液和乳胶膜性能的影响,并借助透射电镜和全反射红外光谱仪进行了表征。结果表明:有机硅单体的加入可显著改善聚丙烯酸酯乳胶膜的耐水性,当DBSA、DV4i和D4的质量分数分别为2%、4%和15%时,乳胶膜的吸水率为4.7%,对水的接触角为84°,冲击强度为53 cm,弯曲强度为2 mm,铅笔硬度为H。     

交联剂含量对核壳型聚丙烯酸酯乳液及胶膜性能的影响

以三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)为交联单体,采用半连续种子乳液聚合法,以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为主要单体合成了核壳型聚丙烯酸酯乳液,研究了核层TMPTMA含量对乳液及胶膜性能的影响。结果表明,在一定范围内,随着核层TMPTMA含量的增加,乳胶粒子的平均粒径减小,凝聚率增大;胶膜的拉伸强度及断裂伸长率均增大,与水的接触角变小;在反应条件、单体种类及配比相同的情况下,核壳型丙烯酸酯乳胶膜比非核壳型乳胶膜的杨氏模量及拉伸强度明显变大。     

叔碳酸乙烯酯/有机硅改性丙烯酸酯乳液的制备与性能研究

采用预乳化半连续种子乳液聚合法,以反应型阴离子乳化剂(DNS-86)和非离子型乳化剂(OP-10)复配,引入叔碳酸乙烯酯(V-10)和乙烯基三甲氧基硅烷(A-171)为改性单体合成了叔碳酸乙烯酯/有机硅改性丙烯酸酯乳液.通过红外光谱(FT-IR)、透射电镜(TEM)、粒径分布分析(PSD)、差示扫描量热法(DSC)和热重分析(TG)对乳液结构、粒子形态和乳胶膜性能进行了分析和表征.结果表明:叔碳酸乙烯酯、有机硅氧烷与丙烯酸酯发生了共聚反应,生成的乳胶粒子为核壳型结构,粒子大小比较均一,粒径较小.通过与丙烯酸酯、叔碳酸乙烯酯改性丙烯酸酯、有机硅改性丙烯酸酯的乳液对比可知,核壳型叔碳酸乙烯酯/有机硅改性丙烯酸酯乳液的性能较佳.其涂膜吸水率仅为2.19％;接触角为109.5°,达到了对乳液改性的目的.     

核壳型短链含氟丙烯酸酯乳液的合成及表征

该文研究了核壳型短链含氟丙烯酸酯乳液的合成与表征。以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)的共聚体为核,短氟碳链2-(全氟己基)乙基甲基丙烯酸酯(FMA6)和非氟烷基丙烯酸酯的共聚体为壳,采用多步乳液聚合法,合成系列具有核壳结构的含氟丙烯酸酯乳液,研究了壳相中氟单体用量和非氟烷基丙烯酸酯的烷基链长度n(链长n=4、8、12、16、18)对产物疏水疏油性能的影响,并对产物进行表征。结果表明:当采用氟单体用量为总单体质量的8.5%,甲基丙烯酸十六酯(CMA)的共聚体为壳层时,由合成乳液制得的乳胶膜的疏水疏油性最佳,对水接触角为124.67°,对二碘甲烷接触角为112.76°。FTIR、TEM和DSC/TGA表征表明,原料单体均参加了反应;乳液颗粒具有明显的核壳结构;聚合物存在两个玻璃化温度(-18.87℃和32.08℃),热分解温度比不含氟的聚合物提高了近20℃。由此说明,用合成的核壳型短链含氟丙烯酸酯乳液制得的涂膜具有优异的疏水疏油性和耐热性能。     

氟硅改性水性丙烯酸酯乳液的合成及其对胶膜的影响

以甲基丙烯酸甲酯、丙烯酸丁酯和丙烯酸为主要原料,1,3,5-三(甲基三氟丙基)环三硅氧烷(D3F)和硅烷偶联剂γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)分别为含氟及含硅改性单体,采用酮肼交联体系,通过溶液聚合合成了改性水性聚丙烯酸酯乳液。考察了改性单体用量对乳液稳定性、粒径及浇铸膜吸水率的影响,并对乳液浇铸膜进行了表面水接触角的测定,热重分析及红外表征。结果表明,D_3F与KH-570接入丙烯酸酯链段中,改性单体的加入使丙烯酸酯膜的吸水率降低,表面性能提升,热稳定性提高。当D_3F∶KH-570质量比约为4∶1时,胶膜吸水率低,表面接触角超过90°,热稳定性高,综合性能更好。     

具有核壳结构的有机硅改性丙烯酸酯乳液的结构及性能

采用甲基三甲氧基硅烷在丙烯酸酯单体中水解的原位乳液聚合法,制备了具有核壳结构的有机硅改性丙烯酸酯乳液(硅丙乳液),并用傅里叶变换红外光谱、透射电子显微镜和x射线光电子能谱对其结构进行了表征,考察了硅丙乳液的疏水性.结果表明,所合成的硅丙乳液具有稳定的核壳结构,核为甲基三甲氧基硅烷树脂,壳为丙烯酸酯聚合物;硅丙乳液的疏水性较纯丙乳液强.     

氟代聚丙烯酸酯改性聚氨酯复合乳液的制备及其疏水性

为了提高聚氨酯-丙烯酸酯复合乳液的耐水性和耐溶剂性,将聚氨酯溶液作为反应介质,以丙烯酸十二氟庚酯(FA)和丙烯酸羟丙酯为单体,偶氮二异丁腈为引发剂,在溶液中进行聚丙烯酸酯自由基聚合,然后用N-甲基二乙醇胺进行亲水基扩链,通过溶液聚合相转化法制得新型阳离子氟代聚丙烯酸酯改性聚氨酯复合乳液。通过红外光谱、透射电镜、光电子能谱仪和接触角测定仪分别对复合乳液的结构、乳胶粒形态、膜表面的化学元素组成及疏水性进行了研究。结果表明,含氟链段成功接入了大分子链中,乳液形成稳定的核-壳结构,在膜材料表面形成了主要由含氟丙烯酸酯链段组成的界面,FA的引入可使复合乳液胶膜与水的接触角(PUA膜与水的接触角)由65°提高至98°。     

聚丙烯酸酯乳液的制备方法对性能的影响

本文考察了在合成聚丙烯酸酯乳液时,丙烯酸的加入次序对性能的影响。结果表明,在制备的五种丙烯酸酯乳液共聚物中,加入丙烯酸单体的总量一定,但加入次序及各次序中的用量不同,所测得乳液的碱耗量、碱增稠粘度以及胶膜的耐水性等明显不同。可以推断,这是由胶乳粒子具有二相核一壳结构,并发生核壳结构的转化。     

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.