聚苯乙烯磺酸钠对抗静电PET树脂的性能影响

研究了聚苯乙烯磺酸钠(PSSNa)对抗静电聚对苯二甲酸乙二醇酯(PET)树脂的性能的影响.通过电阻率测试、热失重分析(TG)、差示扫描量热分析(DSC)等测试方法考察了PSSNa对抗静电PET树脂的抗静电性能、热稳定性及结晶行为的影响.研究发现,在抗静电PET树脂中加入PSSNa,提高了抗静电PET树脂的热稳定性及结晶温度,并且进一步降低了抗静电PET树脂的电阻率.     

热成型RPET为包装材料

包装行业正在寻找有较的方法以满足社会对解决包装材料影响环境问题的要求。对回收的聚对苯二甲酸二乙酯(RPET)进行热成型是极为理想的途径,因为所使用的PET材料有30％能得到回收,有PET软饮料瓶和常用包装回收料的稳定供应,而且PET是回收料成本低于新树脂成本的少数树脂之一。     

纳米银-二氧化硅粒子的制备及其在抗静电PET中的应用

以正硅酸乙酯(TEOS)、硝酸银、硼氢化钠等为原料,通过溶胶凝胶法制备了纳米银-二氧化硅粒子,用扫描电子显微镜(SEM)、X射线能谱(EDS)对纳米银-二氧化硅粒子进行了表征.将所制得的纳米银-二氧化硅粒子应用于聚对苯二甲酸乙二醇酯(PET)中,制得到了抗静电的聚对苯二甲酸乙二醇酯,对其电阻率的测试表明聚酯/纳米银-二氧化硅粒子复合材料有较好的抗静电性能.     

PET／PEG共聚酯及共混物的抗静电性能研究

对PET(聚对苯二甲酸乙二醇酯 ) /PEG(聚乙二醇 )共聚酯及共混物的抗静电改性效果进行了比较 ,结果表明共聚酯的抗静电效果及抗静电耐久性等均远优于PET/PEG共混物 ,且可避免共混改性中的二次降解问题。这种共聚酯易于在聚酯合成厂实现大规模生产 ,既可直接用于制造抗静电聚酯产品 ,也可用作PET的抗静电改性母粒     

利用聚酯PET装置生产聚酯PBT工艺设备研究

1、前言聚对苯二甲酸丁二酯(PBT)主要用于生产工程塑料,合成纤维。国内生产PBT树脂的装置大都是利用聚对苯二甲酸乙二酯(PET)生产装置改造而成。我们针对PBT树脂生产工艺条件及反应特性与PET树脂的差异,对PET生产装置进行了改造,满足了PBT树脂生产的需要。 2 PBT树脂与PET树脂生产的差异 PBT树脂和PET树脂都是聚脂,但是二者所采用的原料二醇不同,其生产工艺及对设备的要求也不尽相同,主要表现在几个方面: (1)反应温度不同 PBT树脂缩聚反应温度为230～260℃;PET树脂缩聚反应温度为270～285℃。     

聚对苯二甲酸乙二酯合金的研究进展

概述了近些年聚对苯二甲酸乙二酯(PET)的热塑性聚酯合金,如PET与聚烯烃(PO)、聚碳酸酯(PC)、聚对苯二甲酸丙二酯(PTT)、聚对苯二甲酸丁二酯(PBT)等的研究进展。叙述包括PET,PO,PC,PTT,PBT纯树脂和相应合金的性能优缺点以及近期关于此类合金相容性、酯交换反应、结晶性能和力学性能的研究进展,并分析了研究过程中存在的问题。     

PET生产工艺以及在服装设计中的应用

介绍了聚对苯二甲酸乙二酯(PET)的生产工艺路线,以及对PET纤维进行改性制备亲水抗静电纤维、抗菌防臭纤维、防紫外线纤维、远红外纤维、阻燃纤维等应用于服装设计中。目前,主要采用直接酯化法合成PET,该方法原料消耗低,PET产量大、质量好、可直接纺丝、产品成本低。     

季铵盐型阳离子抗静电剂的合成及应用

针对合成纤维的静电问题，研制了十二烷基二甲基乙基溴化铵、十二烷基二甲基羟乙基氯化铵和马来酸二乙酯双（十二烷基二甲基氯化铵）３种抗静电剂。应用于已脱油的腈纶纤维和丙纶纤维，抗静电效果良好。对３种抗静电剂在不同浓度时的抗静电效果进行了比较，选取了适宜的低浓度范围０．５％￣１％。进行了耐水洗试验。     

啤酒瓶用共缩聚PET/PEN的研究

采用对苯二甲酸二甲酯(DMT)与2，6-萘二甲酸二甲酯(DMN)合成了聚对苯二甲酸二乙酯(PET)和聚2，6-萘二甲酸二乙酯(PEN)共缩聚物，研究了PEN用量对共缩聚PET／PEN热性能的影响，并研究了采用PET／PEN制成的啤酒瓶的物理性能、气体阻隔性能和贮藏性。结果表明：PET／PEN的性能与普通聚酯切片的相近，PEN质量分数为30％的PET／PEN制成的啤酒瓶可耐95℃高温，对O2、CO2气体的阻隔性比普通PET瓶提高6倍。     

溶胶-凝胶法制备PET/SiO2纳米复合材料及其TG、DSC分析

采用溶胶-凝胶（sol-gel）法，将正硅酸乙酯和水加入到制备聚对苯二甲酸乙二酯（PET）的中间产物对苯二甲酸双羟乙酯(BHET)中,在液态下均匀混合，高温下快速发生溶胶-凝胶反应，再按PET缩聚反应制得PET/SiO₂纳米复合材料。通过TEM、TG、DSC对材料进行了表征和研究。结果表明，SiO₂在PET中均匀分散，其尺寸在10～100 nm之间，PET/SiO₂纳米复合材料的热降解活化能较普通PET有明显提高，但初始降解温度和结晶性能均有所降低。     

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.