防老剂S789在轮胎胎侧胶中的应用性能研究

研究防老剂S789在轮胎胎侧胶中的应用性能。结果表明:防老剂S789胶料的门尼粘度大于防老剂4020和OPPD胶料,焦烧时间和正硫化时间缩短;硫化胶的物理性能基本相当;耐热氧老化性优于防老剂4020胶料;耐屈挠性能和耐臭氧老化性能介于防老剂4020和OPPD胶料之间;国产防老剂S789胶料的综合性能与进口同类产品基本相当。     

不同老化条件对防老剂6PPD及其应用性能的影响

对不同老化条件处理的防老剂6PPD进行微观分析及颜色变化研究,并研究其老化对胎侧胶性能的影响。结果表明：防老剂6PPD在热氧、臭氧和紫外线老化条件下性能稳定,主要成分没有发生明显变化;放置相同时间条件下,紫外线环境中的防老剂6PPD颜色变深程度最大,因此建议避光储存防老剂6PPD;不同老化条件处理的6PPD均不会对胶料的硫化特性、物理性能和耐臭氧老化性能产生不利影响。     

维生素C镧配合物对天然橡胶的防护作用

将自制的维生素C镧配合物（VCLa）作为新型防老剂用于天然橡胶（NR）中,考察VCLa对胶料性能的影响。结果表明：VCLa对NR具有一定的硫化促进作用,显著缩短胶料的t90,略微提高硫化胶拉伸性能;VCLa对NR具有优良的防护作用,其防臭氧老化效果显著优于常用防老剂4010NA,RD和MB,防热氧老化效果与防老剂4010NA和RD相当,优于防老剂MB,防紫外光老化效果接近于防老剂4010NA和RD,但优于防老剂MB;VCLa减缓NR应力老化,提高硫化胶的耐磨性和耐屈挠疲劳性能。     

新型环保防老剂木质素ECOLIG-75在SBR/NR胎面胶中的应用

研究木质素ECOLIG-75替代防老剂TMQ以及与防老剂6PPD和防护石蜡并用在丁苯橡胶/天然橡胶胎面胶中的应用。结果表明：与防老剂TMQ胶料相比,木质素ECOLIG-75胶料具有较大的交联密度,物理性能基本相当,耐臭氧老化性能较好;木质素ECOLIG-75与防老剂6PPD并用时的热氧老化防护效果优于单用防老剂6PPD。木质素ECOLIG-75无毒、无污染,是防老剂TMQ的可持续环保替代品。     

防老剂DDA的使用性能研究

试验研究防老剂DDA的抗硫化返原性能、耐热氧老化性能和耐臭氧老化性能,并与几种常用防老剂进行对比。结果表明,防老剂DDA具有优异的抗硫化返原性能和耐臭氧老化性能,并兼具防老剂4020的耐臭氧老化与防老剂RD的耐热氧老化的双重效果,其与防老剂4020并用后具有一定的协同效应。     

防老剂CX-40在自行车轮胎胎面胶中的应用

考察防老剂CX-40等量替代防老剂RD在自行车轮胎胎面胶中的应用。结果表明:防老剂CX-40胶料的硫化特性、物理性能、耐磨性能和耐热氧老化性能与防老剂RD胶料相当,而耐屈挠性能、耐天候老化性能和耐臭氧老化性能明显优于防老剂RD胶料,防老剂CX-40表现出较好的综合防护性能。     

防老剂AW—P在橡胶中的防老化效能

本文介绍防老剂AW－P在天然胶和丁苯腔中的应用情况。通过与含4010和4010NA试样进行热氧老化和臭氧老化性能对比实验,结果表明AW－P具有良好的抗臭氧老化性能;而老化龟裂现象与含4010NA的试样相似,但比含4010的试样好;抗热氧老化性能则比含4010和4010NA的试样稍差.     

稀土防老剂对轮胎胎面胶的老化防护研究

研究稀土防老剂对轮胎胎面胶热氧和臭氧老化前后主要性能的影响,并与防老剂4010NA进行对比。结果表明:稀土防老剂对胶料热氧老化和臭氧老化的防护效果均优于防老剂4010NA;加入稀土防老剂Ⅰ的胶料具有较好的耐切割性能,热氧老化后撕裂强度保持率最大,对臭氧老化的防护效果最优;加入稀土防老剂Ⅱ的胶料经热氧老化后拉伸强度保持率最大,耐磨性能提高。     

防老剂RD的质量改进技术

从防老剂RD的反应机理，分析了防老剂RD聚合体的分子结构与其抗热氧老化，抗屈挠龟裂性能的关系。以及影响防老剂RD质量的主要因素。并且通过研究改进。使防老剂RD质量达到国外先进水平。     

二芳基对苯二胺类防老剂的制备及性能研究

制备二苯基对苯二胺(防老剂BBPD)、苯基甲苯基对苯二胺(防老剂BTPD)和苯基(二甲基)苯基对苯二胺(防老剂BXPD)3种二芳基对苯二胺类防老剂,测试其熔点和研究其应用性能,并与市售防老剂DTPD进行对比。结果表明:3种自制的二芳基对苯二胺类防老剂的熔点高于防老剂DTPD,胶料的加工性能、硫化特性和耐臭氧老化性能与防老剂DTPD胶料相当,物理性能和耐热氧老化性能比防老剂DTPD胶料好,防老剂BTPD和BXPD胶料的耐屈挠疲劳性能优于防老剂DTPD胶料。     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.     

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.