纳米CaCO3增强增韧不饱和聚酯树脂(UPR/CaCO3)的研究

用未经表面处理和经表面处理的纳米CaCO3对不饱和聚酯树脂进行填充改性,研究了纳米CaCO3用量对不饱和聚酯树脂的拉伸强度、弯曲强度、冲击强度的影响。结果表明:当纳米CaCO3填充量为6%时,材料的增强增韧效果最好,而且当粉体的加入量为4%～6%时,UPR/CaCO3出现了明显的脆韧转变。用DSC测定复合材料的玻璃化温度(Tg),可以发现复合材料的玻璃化温度比纯不饱和聚酯树脂大,且烷基化纳米CaCO3填充的UPRTg更高,这与力学性能结果相一致。     

纳米SiO_2改性不饱和聚酯树脂的研究进展

综述了国内纳米SiO2改性不饱和聚酯树脂(UPR)研究的最新进展,重点介绍了纳米SiO2用量、粒子尺寸、表面改性处理等因素对纳米SiO2/UPR复合材料性能的影响及纳米粒子增韧增强的机理,指出了纳米SiO2改性UPR存在的问题和可能的发展方向。     

UPR/GF/纳米SiO2复合材料的摩擦学性能和力学性能研究

采用手糊成型室温固化的方法制备纳米SiO2/玻璃纤维(GF)布混杂增强不饱和聚酯树脂(UPR)复合材料,并对UPR复合材料的摩擦学性能和力学性能进行了研究。结果表明,加入纳米SiO2和GF布能大幅提高复合材料的摩擦学性能和力学性能。当复合材料中纳米SiO2含量分别为0.5%(质量分数,下同)和1%时,复合材料的耐磨性分别是纯UPR的5.3倍和3.1倍,拉伸强度是纯UPR的5.8倍和5.1倍,弯曲强度是纯UPR的3.9倍和3.2倍左右。在实验条件下,以含量为0.5%纳米SiO2和GF布混杂填充UPR复合材料的改性效果最好。扫描电镜分析表明,纯UPR的磨损机理是黏着磨损,复合材料磨损机理主要表现为黏着磨损和磨粒磨损。     

纳米SiO2增强增韧聚氯乙烯复合材料的研究

采用超声波，振磨等方法对纳米SiO2粒子进行表面处理。通过熔融共混的方法制备了PVC/SiO2纳米复合材料，研究了纳米粒子对PVC的增强，增韧效果。研究结果表明；通过超声波，振磨等方法对纳米粒子进行表面处理。可以促进纳米粒子在基体中的均匀分散，大幅度提高复合材料的强度和韧性；纳米SiO2的添加量为3%时，复合材料的综合力学性能最好，其拉伸强度，冲击强度和杨氏模量均有较大的提高。     

纳米SiO2／双马来酰亚胺复合材料的性能研究

采用浇铸成型法制备了纳米SiO2粒子填充双马来酰亚胺(BMI-BA)复合材料，研究了纳米SiO2的填充量对复合材料滑动磨损性能的影响。在磨损机上测试该复合材料的摩擦和磨损性能，利用扫描电镜(SEM)观察了复合材料的磨损表面和对磨环的表面形貌。结果表明，纳米SiO2能够有效地提高复合材料的力学性能和摩擦学性能。当纳米SiO2粒子的添加量为0．75％(质量含量，下同)时，复合材料的综合力学性能最好；当纳米SiO2粒子的的添加量为1．0％时，复合材料的耐磨性能最好。SEM显示复合材料主要是黏着磨损，能在对磨环上形成薄而连续的均匀转移膜，而BMI-BA树脂主要发生的是疲劳磨损，并伴有塑性变形。     

纳米二氧化硅颗粒表面设计及其填充聚氯乙烯复合材料的性能

利用表面原位接枝聚合在纳米二氧化硅颗粒表面引入聚甲基丙烯酸甲酯(PMMA)高分子链段,用共混法制备了nano-SiO2/PVC复合材料,研究了不同界面特性时SiO2/PVC复合材料的力学性能.研究结果表明通过表面原位接枝聚合反应可以在纳米二氧化硅颗粒表面接枝聚甲基丙烯酸甲酯;表面接枝PMMA的nano-SiO2/PVC复合材料在力学和加工性能等方面都优于偶联剂处理和表面未处理样品.在纳米二氧化硅颗粒填充量为0%～8%(wt)时,复合材料的拉伸强度和冲击强度随着填充量的提高先上升后下降,并在4%～6%(wt)达到最大值.经PMMA表面接枝后SiO2/PVC具有更强的界面作用,偶联剂KH570处理的次之,表面未处理样品的最差.     

原位聚合法制备钼酚醛树脂纳米复合材料的研究

采用原位聚合法，用表面处理过的二氧化硅(SiO2)纳米粒子对钼酚醛树脂进行填充改性，制备了钼酚醛脂／SiO2纳米复合材料，研究了SiO2纳米粒子填充改性对复合材料耐热性和力学性能的影响。实验结果表明，SiO2质量分数为2％时，材料的耐热性和冲击强度达到最大值，分别为105℃和4．3kd／m^2；SiO2质量分数为4％时，材料的拉伸模量和拉伸强度达到最大值，分别为1288MPa和30．3MPa。     

木粉/UPR复合材料的制备及力学性质研究

使用硅烷偶联剂表面处理的木粉(MW)和未改性木粉(UW)填充不饱和聚酯树脂(UPR)制备了复合材料.研究了表面改性处理和木粉粒径对复合材料力学强度的影响.结果表明,相对于未改性的木粉,用硅烷偶联剂处理的木粉对不饱和聚酯树脂有更强的增强作用,添加量为20(wt)％的MW/UPR复合材料的拉伸强度比纯UPR提高74.4％,...     

偶联剂表面处理对复合材料静态力学性能的影响

利用纳米SiO2对氰酸酯树脂(CE)进行增韧改性,采用冲击强度、弯曲强度测试及扫描电子显微镜等手段研究了纳米SiO2含量对纳米SiO2/CE复合材料静态力学性能的影响;在此基础上,分别选用小分子偶联剂KH-560和大分子偶联剂SEA-171对纳米SiO2进行表面处理,进一步研究了界面结构对纳米SiO2/CE复合材料静态力学性能的影响,初步探讨了其作用机理。结果表明,纳米SiO2(尤其是以大分子偶联剂处理后的纳米SiO2)的加入提高了复合材料的冲击强度和弯曲强度。当SiO2质量分数为3%时,复合材料的冲击强度、弯曲强度达到最大,增幅分别为61.9%,44.2%。     

聚氨酯弹性体/纳米二氧化硅协同改性聚氯乙烯及其力学性能

用聚氨酯(PU)弹性体/纳米SiO2复合材料协同改性聚氯乙烯(PVC),用反应挤出一步法成型工艺制备了PU弹性体/纳米SiO2/PVC复合材料,对挤出速率和温度进行了考察,并对复合材料力学性能的影响因素进行了研究。结果表明,制备该复合材料的最佳工艺条件是螺杆转速为40～50r/min、挤出机均化段温度为180～190℃;用分散于液化二异氰酸酯中的纳米SiO2制备的复合材料的性能优于用分散于聚醚二元醇中的纳米SiO2;PU弹性体和纳米SiO2能协同增韧PVC,两者质量比为5/1时增韧改性的效果最佳。当PU弹性体/纳米SiO2/PVC(质量比)为5/1/20时,复合材料的综合力学性能最优,冲击强度达到45.6kJ/m2,拉伸强度为50.3MPa。     

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。