陶瓷防护树脂基复合材料的磨损性能及机理研究

为了提高树脂基复合材料的耐磨损性能,采用Al2O3陶瓷贴片制备了陶瓷防护复合材料,通过往复式摩擦磨损试验机对陶瓷片材和复合材料进行了磨损性能试验,得到了防护复合材料在不同加载参数下的磨损形貌,进一步采用三维白光干涉表面形貌仪测试了磨损试样的表面形貌、磨痕深度与宽度,并据此建立了磨损性能数据分析与评价模型,分析了防护复合材料的耐磨损机理。结果表明:复合材料采用陶瓷贴片进行防护可大大提高其耐磨损性能,经陶瓷防护后,复合材料的可承受加载载荷从40 N提高至100 N;随着载荷的进一步增加,陶瓷防护复合材料的磨痕深度大大增加,而钢球的磨损程度迅速下降,其磨损机制发生了变化。分析了造成复合材料磨损性能发生变化的原因。     

网带炉烧结工艺对PTFE基三层复合材料摩擦学性能的影响

通过湿法压轧复合工艺制备了聚四氟乙烯(PTFE)基三层复合材料,采用网带炉对复合材料试样进行了烧结,对试样分别进行了油循环和干摩擦两种端面摩擦磨损试验,研究了网带炉不同烧结温度和烧结频率对PTFE基三层复合材料摩擦学性能的影响,对试样承载能力、摩擦系数、磨痕深度及磨痕形貌进行了表征.结果表明,随着烧结温度和烧结频率在一...     

石墨的取向对聚酰亚胺摩擦性能的影响

通过热模压成型工艺制备了聚酰亚胺(PI)/石墨(NG)复合材料,对其摩擦性能、断面及磨痕形貌进行了测试与表征。结果表明,NG在PI基体中沿着与成型压力垂直的方向取向;当载荷不变且滑动速度较低时,垂直于摩擦面的NG比平行于摩擦面的NG更能降低PI的摩擦因数;随着滑动速度的提高,这种情况发生转变,而提高载荷后,转变点向低速移动;对比摩擦性能与磨痕形貌的结果发现二者存在紧密的联系,磨痕的表面越光滑、粗糙度越低,摩擦因数与磨损率也越低。     

不同玻璃纤维含量对PTFE增强PEEK复合材料摩擦学性能的影响

以聚四氟乙烯(PTFE)为增强相,加入不同含量的玻璃纤维(GF),通过注塑成型方式,制备PEEK/PTFE复合材料,使用力学试验机进行拉伸试验,利用摩擦试验机进行表面摩擦试验,利用白光仪对磨痕数据和三维形貌进行观测,使用扫描电子显微镜对磨痕进行观测与分析。结果表明：当GF含量越高,复合材料最大应力越高,应力增大的斜率越明显。当GF含量增至30%,复合材料的最大应力提高至183 MPa。当GF含量逐渐升高,复合材料表面的摩擦系数降低。当GF含量为30%,复合材料的摩擦系数降至0.08。当GF含量为0、15%、30%,复合材料磨损率分别为3.59×10^-6、2.30×10^-6、1.78×10^-6 mm³/(N·m)。GF含量越高,复合材料的硬度越高,耐磨损性能越好。     

纳米氧化铝改性聚四氟乙烯的摩擦磨损性能研究

以纳米Al2O3作为填料填充改性聚四氟乙烯(PTFE),采用模压烧结成型的方法制备了不同纳米Al2O3含量的PTFE/纳米Al2O3复合材料,考察了偶联剂改性前后纳米Al2O3及其含量对复合材料硬度、摩擦系数和磨痕宽度的影响,并利用扫描电子显微镜对复合材料的磨屑和磨损表面进行了微观分析。结果表明,随着纳米Al2O3含量的增加,复合材料的硬度和摩擦系数逐渐增大,磨痕宽度先大幅下降而后略有增加。另外,相对于未改性纳米Al2O3,PTFE/偶联剂改性纳米Al2O3复合材料的硬度和摩擦系数均较低,其磨痕宽度则较高。     

固体润滑涂层用陶瓷材料的摩擦性能研究

以聚氨酯树脂作为粘结剂,WS_2纳米棒、MoS_2及NbSe_2纳米纤维陶瓷材料为固体润滑剂的固体润滑涂层在摩擦实验机上进行摩擦试验,观察固体润滑涂层的摩擦系数变化曲线和磨痕形貌,并简单分析了其减摩机理。     

体育器械用SiC改性铝基复合材料组织与性能研究

文章主要是对SiC改性铝基复合材料的组织和性能进行研究,为了得到体积分数不同的SiC改性铝基复合材料,借助粉末挤压法来参与本次试验。着重分析了复合材料本身硬度、在显微镜下的形状外貌、摩擦系数和磨损程度受体积分数不同的SiC的影响。结果发现SiC/2024铝基复合材料中SiC颗粒体积分数与复合材料硬度呈正比,前者增加,后者硬度也增大。但当0.7～0.8为平均摩擦系数时,出现减小的是磨损体积、短轴宽度、磨痕长轴宽度以及表面磨痕深度。椭球面状为所形成的磨损形貌。     

聚四氟乙烯基耐磨涂层的摩擦学性能研究

通过喷涂的方法将聚四氟乙烯基耐磨涂料喷涂在摩擦试验样件基体表面,将该摩擦试验样件及其配对的摩擦副进行摩擦磨损试验、表面形貌分析和改变喷枪压力及表面粗糙度的工艺参数以分析涂层性能。结果表明:聚四氟乙烯基耐磨涂层经摩擦系数、磨损量测试后,摩擦系数先增大再稳定不变,最后稳定在0.15;磨损量先增大再减小最后稳定,即磨损量最后为恒定值。从表面形貌分析得出摩擦副的磨损主要是磨料磨损造成的。当喷枪压力为0.3 MPa时,耐磨涂层的膜层均匀性最佳;表面粗糙度为6.3μm时,耐磨涂层与基体的附着效果较好。其结论得出该涂层摩擦系数和磨损量较低,耐磨性能较好,同时,当喷枪压力和表面粗糙度工艺参数合适时,耐磨涂层的性能效果最佳。     

VE扩散对辐照交联GO/UHMWPE复合材料生物摩擦学性能的影响

利用浸泡的方式将维生素-E(VE)溶液扩散至辐照交联氧化石墨烯/超高相对分子质量聚乙烯(GO/UHMWPE)复合材料,提高其生物摩擦学性能.采用摩擦磨损试验机与三维形貌仪相结合的方式检测了复合材料的磨痕表面微观形貌及表面粗糙度,计算了磨损率并分析了耐磨减摩机理.结果表明,在120℃下,将GO/UHMWPE复合材料在VE...     

碳纤维和纳米氮化硼增强聚醚醚酮/聚四氟乙烯复合材料的摩擦学性能研究

以碳纤维（CF）为增强相，添加不同含量的纳米氮化硼（h-BN），通过注塑成型的方式，制备了聚醚醚酮/聚四氟乙烯（PEEK/PTFE）复合材料样条，使用力学试验机进行拉伸试验，利用摩擦试验机进行表面摩擦试验，并利用白光仪对磨痕数据和三维形貌进行观测，使用SEM对磨痕进行观测与分析。结果表明：随着h-BN含量的增加，PEEK/PTFE复合材料样条最大应力先增加后减小；当h-BN含量分别为3%、6%时，PEEK/PTFE复合材料样条的最大应力分别为174 MPa、165 MPa。与PEEK/PTFE相比，单独添加CF的样品摩擦系数降至0.23。同时添加CF、h-BN时，复合材料样条的摩擦系数均降低；h-BN含量分别为3%、6%时，复合材料样条的摩擦系数分别为0.06、0.09。随着h-BN含量的升高，PEEK/PTFE/CF/h-BN复合材料的磨损率先降低后升高。h-BN含量为3%时，复合材料样条的磨损率最低。     

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.     

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。