酚醛树脂增韧及耐热改性研究进展

介绍了酚醛树脂在增韧改性、耐热改性等方面的研究进展。增韧改性方法包括:腰果油改性、丁腈橡胶改性、聚醚改性、聚酰胺改性等方法;耐热改性方法包括:硼酸改性、钼改性、有机硅改性、磷改性、聚砜改性等方法。     

水性聚氨酯的改性研究进展

综述了水性聚氨酯的改性,包括交联改性、丙烯酸酯改性、环氧树脂改性、有机硅改性、有机氟改性、纳米改性、超支化预聚体改性和复合改性。比较了不同改性技术的方法和优势,展望了水性聚氨酯的改性发展趋势。     

聚苯乙烯改性研究进展

叙述了聚苯乙烯(PS)的物理方法、化学方法、其他方法改性的研究进展。其中,物理改性技术包括填充改性、共混改性和增强增韧改性;化学改性技术包括共聚改性、接枝改性和交联改性;其他改性包括纳米、发泡、阻燃、废旧回收改性等。阐述了PS改性的目的和作用及发展建议。     

酚醛树脂的耐热改性研究进展

对酚醛树脂的耐热改性研究进行了综述。研究表明,改性后酚醛树脂的耐热性得到了显著的改善。改性的方法包括:硼酸改性、钼改性、双马来酰亚胺改性、聚砜改性、苯并口恶嗪化合物改性、酚三嗪树脂改性、腰果壳油改性及桐油改性。     

用作耐热性材料的酚醛树脂研究动态

介绍了酚醛树脂的耐热改性研究方法以及改性后酚醛树脂应用,耐热改性的方法包括：芳烃改性、焦油改性、聚酰亚胺改性、硼酸改性、有机硅改性、钼酸改性、苯并噁嚓化合物、纳米材料等改性酚醛树脂。     

粉煤灰改性及其吸附应用研究进展

从物理改性(机械磨细改性和高温改性、微波改性、超声波改性)、化学改性(酸改性、碱改性、盐改性)和联合改性三个方面,介绍了近年来国内外对粉煤灰进行改性研究的各种方法,指出了粉煤灰改性及应用中需进一步解决的问题,为其未来的研究方向提出了展望。     

聚乳酸改性研究进展

对近年来国内外聚乳酸(PLA)改性的研究进展进行综述,并对PLA的物理改性和化学改性进行总结。PLA的主要改性方式分为物理改性和化学改性。物理改性的主要方法为熔融共混改性,其改性方式包含:粉体颗粒改性、弹性胶体改性、植物纤维改性和聚酯改性。化学改性的主要方法为聚合改性,其改性方式包含:共聚改性、扩链改性和接枝交联改性。对PLA未来的应用前景进行了展望。     

聚丙烯改性研究进展

综述了聚丙烯物理改性、化学改性和其他改性技术的研究和应用现状。其中,物理改性技术包括填充改性、共混改性和增强增韧改性;化学改性技术包括共聚改性、接枝改性和交联改性。展望了聚丙烯改性技术的发展前景。     

粉煤灰改性及其吸附应用研究进展

从物理改性(机械磨细改性和高温改性、微波改性、超声波改性)、化学改性(酸改性、碱改性、盐改性)和联合改性三个方面,介绍了近年来国内外对粉煤灰进行改性研究的各种方法,指出了粉煤灰改性及应用中需进一步解决的问题,为其未来的研究方向提出了展望。     

酚醛树脂耐热性的改性研究进展

介绍了酚醛树脂的耐热改性研究方法以及改性后酚醛树脂应用,改性后酚醛树脂的耐热性和强度得到了显著的改善,应用范围得到了大大的拓展。耐热改性的方法包括:芳烃改型、焦油改性、聚酰亚胺改性、硼酸改性、有机硅改性、钼酸改性、苯并噁嗪化合物改性、纳米材料等改性酚醛树脂。     

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.