聚醋酸乙烯酯乳液的中温合成

采用过硫酸铵/亚硫酸氢钠/甲醛合次硫酸氢钠氧化还原体系在中温条件下引发醋酸乙烯酯乳液聚合,分别讨论了引发剂用量、乳化剂用量、聚合温度等因素对聚醋酸乙烯酯中温合成的影响。乳化剂、引发剂用量分别为单体总量的0.15%和0.6%时,反应温度可降低到45℃,并得到粘度为5.8 Pa.s、固含量为50%的乳白色聚醋酸乙烯酯乳液。     

生产工艺参数对聚醋酸乙烯酯乳液黏度的影响研究

考查了聚醋酸乙烯酯乳液生产工艺参数如醋酸乙烯酯单体活性度、保护胶体聚乙烯醇、引发剂以及乳化剂用量、搅拌速度、pH值调节剂和反应温度对乳液黏度的影响.实验结果表明,要制备目标使用黏度(25℃)为4 000 mPa·s左右的聚醋酸乙烯酯乳液,其优化的配方和工艺条件为:单体活性度600 s;聚乙烯醇缩醛化改性;引发剂用量为单体的0.2%(其中前期种子聚合的加入量为总量的20%);乳化剂用量为单体的1.6%;聚合反应初期和后期都需加入pH值调节剂;搅拌线速度为0.6 m/s;种子聚合温度65℃,反应温度75℃.     

提高聚醋酸乙烯酯乳液性能的实验研究

目的:提高聚醋酸乙烯酯乳液的稳定性和耐水性.方法:采用醋酸乙烯酯为聚合单体、聚乙烯醇为胶体保护剂及乳化剂壬基酚聚氧乙烯醚的聚合反应,制备聚醋酸乙烯酯乳液.再利用单组实验法研究聚乙烯醇、乳化剂、引发剂、加料方式及反应温度等对制备稳定性和耐水性好的聚醋酸乙烯酯乳液的影响规律.结果:制备粘接强度、稳定性和耐水性良好的聚醋酸乙...     

聚醋酸乙烯酯共聚乳液的改性研究

以醋酸乙烯酯为原料,聚乙烯醇为保护胶体,丙烯酸、丙烯酸丁酯为改性单体,研究了单体配比、引发剂、乳化剂用量和温度对醋酸乙烯酯共聚乳液性能的影响。研究表明,当丙烯酸丁酯与醋酸乙烯酯的质量比为12/30,引发剂的质量分数为0.15%,乳化剂的质量分数为0.3%,在反应温度为75℃时,可制得性能优异的聚醋酸乙烯酯胶粘剂,其T型剥离强度和耐水性能可达105 N/25mm和67 N/25mm。     

高乙烯含量VAE乳液的研究与生产

以聚乙烯醇（PVA1788、PVA0588）复配做保护胶体,醋酸乙烯酯及乙烯为单体,采用氧化还原法制备不同乙烯含量的VAE乳液。研究原料、聚合工艺和反应条件及加料方式对VAE乳液乙烯含量、固含量、粘度、玻璃化转变温度和相对分子质量的影响,考查改性PVA对VAE乳液耐水性能的影响。结果表明,最佳初始反应温度为65℃,后期温度为70℃～85℃,最佳乳化剂含量为4%,最佳引发剂用量为2.5%,VAE乳液的乙烯含量为9%～23%,使用疏水基改性PVA代替部分保护胶体,乳液耐水性明显提高。     

甲基丙烯酸甲酯/羟甲基丙烯酰胺无皂乳液共聚合的研究

以甲基丙烯酸甲酯为主单体、N-羟甲基丙烯酰胺为功能性单体、K2 S2 O8为引发剂进行了无皂乳液共聚合的研究 ;探讨了固含量、单体配比、反应温度、引发剂含量等对乳液稳定性和粒径大小的影响 ,制备了固含量较高 ( 30 %)、稳定性较好的丙烯酸酯无皂乳液。研究结果表明甲基丙烯酸甲酯 /N-羟甲基丙烯酰胺无皂共聚合的最佳条件为固含量 30 %、功能性单体 2 0 %、引发剂 1 %、反应温度 75℃。     

苯丙微乳液的聚合工艺研究

采用半连续种子微乳液聚合法,制备了固含量为40％的聚丙烯酸酯微乳液。通过单因素实验确定乳化剂与引发剂分别为MS-1和过硫酸铵（APS）。探讨了乳化剂种类与用量、引发剂种类与用量、反应温度、搅拌速度和单体滴加速度对丙烯酸酯类聚合体系粒径和乳液性能的影响。实验得到：在反应温度78℃左右,质量分数6％-8％的MS-1为乳化剂;质量分数0．7％的APS为引发剂;搅拌速度150—200r／min;反应时间为5h的聚合工艺下,可制得粒径为45．57nm,粒径分布窄（PDI为0．207）和转化率高达95％的微乳液。     

水性压敏粘合剂的研制

采用种子乳液聚合法,将阴离子型乳化剂和非离子型乳化剂进行复配,以丙烯酸酯、醋酸乙烯酯为主要原料,引入功能单体,制备成醋丙乳液胶粘剂。试验表明:乳化剂用量为2%～3%、功能单体AA为2%～4%、引发剂用量为0.3%～0.4%、反应温度在80～85℃制得的胶粘剂,胶膜综合性能良好。     

复合可聚合乳化剂制备高固含量低黏度聚丙烯酸酯乳液

以DNS-86和F-6为复合可聚合乳化剂APS为引发剂,MMA、BA为单体采用半连续法制备20%固含量种子乳液,以种子乳液为介质,选用4种不同类型乳化剂:非离子可聚合乳化剂F-6,阴离子可聚合乳化剂DNS-86、常规非离子乳化剂OP-10、常规阴离子乳化剂SDS进行不同组合,同时滴加预乳化液、引发剂、缓冲剂直接二次成核制备62%固含量二元粒径分布乳液。重点研究了乳化剂复合方式、用量及配比、反应温度等对聚合稳定性、乳液流变性等的影响。,     

多组分聚醋酸乙烯酯乳液胶粘剂的制备

以丙烯酸丁酯为软单体、醋酸乙烯酯为硬单体、丙烯酸为交联剂、过硫酸钾为引发剂、十二烷基硫酸钠(SDS)+聚乙二醇辛基苯基醚(OP-10)为复合乳化剂,采用半连续种子乳液聚合法制备得到多组分聚醋酸乙烯酯乳液胶粘剂,并研究了复合乳化剂质量比、过硫酸钾用量、软硬单体质量比和丙烯酸用量对聚醋酸乙烯酯乳液性能的影响。结果表明,在单体质量占体系总质量的30%(丙烯酸丁酯与醋酸乙烯酯质量比1∶6、丙烯酸用量1%)、过硫酸钾用量为0.5%~0.6%、复合乳化剂(SDS与OP-10质量比1∶15)用量为2.5%时,制备得到的多组分聚醋酸乙烯酯乳液胶粘剂性能最好。     

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。