丙烯腈-丁二烯-苯乙烯三元共聚物／碳纳米管复合材料电磁性能的初步研究

通过紫外光辐照制备了丙烯腈-丁二烯-苯乙烯三元共聚物脓纳米管（ABS／CNTs）复合材料。在CNTs的质量分数为5％时，复合材料体积电阻率（ρv）比基体树脂下降了10^7Ω·cm。在20～100℃温度范围内，复合材料的ρv受温度影响不大。扫描电镜观察表明：紫外光辐照下的CNTs在ABS基体中均匀分布，容易形成导电网络。复合材料在2～10GHz的微波频段内，具有较宽的介电损耗（约为21-50）。     

溶液法反式-1,4-聚异戊二烯/天然橡胶共混胶的性能

研究了用负载钛催化剂、通过溶液聚合法合成的高纯度反式-1,4-聚异戊二烯(TPI)与天然橡胶(NR)共混胶的硫化特性、力学性能、老化性能以及动态疲劳性能。结果表明,与NR相比,TPI与NR质量比为20/80共混胶的门尼黏度稍高,硫化特性基本相当,力学性能略有下降,而其动态疲劳性能则提高至NR的3~4倍。当硫黄与促进剂M的质量比为2.5/1.0时,TPI/NR共混胶的综合性能达到最佳。     

PF/玄武岩纤维/CNTs复合材料的研究

利用碳纳米管(CNTs)对酚醛树脂(PF)/玄武岩纤维(CBF)复合材料进行改性.研究了CNTs含量对PF/CBF复合材料力学性能和烧蚀性能的影响.研究表明,CNTs的加入能明显提高复合材料的力学性能,当CNTs质量分数为1.5％时,复合材料的弯曲强度最大,较未加入CNTs的复合材料提高约39.5％;当CNTs质量分数...     

紫外光辐照反-1,4-聚异戊二烯/碳纳米管复合材料

在室温和氮气环境下 ,用反 - 1,4 -聚异戊二烯 (TPI)与碳纳米管 (CNT)经紫外光辐照制备了TPI/CNT复合材料。实验表明 ,TPI与CNT的复合材料或二者直接共混物的电阻率 (ρv)均随CNT质量分数的增加而下降 ;前者的导电性优于后者。CNT质量分数为 5 %时 ,TPI/CNT复合材料的 ρv 与TPI相比 ,下降了 7个数量级 ,为 6 .0 7× 10 8Ω·cm。在紫外光辐照下 ,CNT可在TPI基质中均匀分布 ,形成导电网络     

碳纳米管/碳纤维增强聚苯硫醚复合材料研究

研究了采用碳纤维(CF)和碳纳米管(CNTs)增强聚苯硫醚(PPS)的力学性能和导电性能。实验分别采用CF和CNTs为添加剂,通过球磨混合后在平板硫化机上进行模压成型,制备出CF/PPS、CNTs/PPS和CNTs/CFPPS/复合材料。采用万能试验机测试复合材料的拉伸性能;采用数字式四探针测试仪测试材料的电导率。实验研究了CF和CNTs含量对其复合材料的导电性能和力学性能的影响,并进一步研究同时添加CF和CNTs对复合材料增强作用。通过分析复合材料的导电性能和力学性能,分别得出CF含量为20%、CNTs含量为15%时复合材料的力学性能和导电性能较理想。采用CF和CNTs同时增强PPS时,当CF添加16%、CNTs添加4%时,CNTs/CF/PPS复合材料性能较好。此外,对CF和CNTs增强机制进行初步讨论。     

硫黄用量对TPI/CNTs硫化胶性能的影响

<正>一、研究目标及主要研究内容本论文拟在综合国内外重要文献和对TPI的实验研究基础上,将碳纳米管填充到TPI交联网络中制备CNTs/TPI纳米复合材料。研究硫黄用量对CNTs/TPI纳米复合材料的力学性能、动态力学性能的影响,探索其结构与性能的关系。本论文的主要内容包括三方面:一是CNTs/TPI纳米复合材料的制备;二是CNTs/TPI纳米复合材料的硫化性能;三是CNTs/TPI纳米复合材料的形态与结构表征。     

反式-1,4-聚异戊二烯改性氯丁橡胶的研究

研究了不同门尼粘度的反式-1，4-聚异戊二烯（TPI）与氯丁橡胶（CR）并用胶的性能，并对比了CR／TPI与CR硫化胶的性能。结果表明，CR中并用10份TPI可明显改善开炼机混炼时的粘辊性、胶料在硫化过程中产生气泡等缺陷；并用TPI后。硫化胶的物理机械性能、耐热老化性能和耐臭氧性能有所下降，但当TPI与CR门尼粘度相近时，硫化胶的耐屈挠疲劳性能可提高1倍左右。     

门尼黏度对反式-1,4-聚异戊二烯及其并用胶性能的影响

研究了门尼黏度对反式-1,4-聚异戊二烯(TPI)及丁苯橡胶(SBR)／TPI并用胶性能的影响。结果表明,TPI生胶的邵尔A型硬度随其门尼黏度的增大而增大,当门尼黏度为70左右时,TPI生胶的拉伸强度、扯断伸长率、100％定伸应力、撕裂强度及结晶度出现最大值;随着TPI门尼黏度的增大,其硫化胶的力学性能提高,Goodrich压缩生热减小,撕裂强度在门尼黏度为90左右时存在最大值,TPI的最佳门尼黏度为50～100：TPI硫化胶的热氧老化以断链反应为主,门尼黏度越高,混炼难度越大,同时硫化胶的耐老化性能越差。TPI的门尼黏度越高,SBR／TPI并用胶60℃的损耗因子越低,0℃的损耗因子基本不变,其硫化胶的力学性能较好,但混炼困难,TPI适宜的门尼黏度为50～100。     

PLA/EGMA/CNTs复合材料的制备与性能研究

采用反应共混法制备了聚乳酸/乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯三元共聚物(PLA/EGMA)共混物及PLA/EGMA/碳纳米管(CNTs)复合材料,并对复合材料的熔体流变行为、结晶行为和拉伸性能进行了表征。流变测试结果表明,EGMA和CNTs的加入均可提高PLA的储能模量及熔体强度。DSC测试结果表明,EGMA的添加会使PLA的结晶受到抑制,CNTs则因其成核作用而有利于结晶。偏光显微镜(POM)测试结果表明,球晶径向生长速率随着EGMA及CNTs的添加而逐渐降低。拉伸性能分析结果表明,当PLA/EGMA=80/20时,复合材料的断裂伸长率随着CNTs含量的增加呈现先增大后减小的趋势,并在CNTs含量为2.0%时达到最大值26.7%。     

碳纳米管对聚4-甲基1-戊烯结晶及力学性能的影响

在聚4-甲基1-戊烯(TPX)中分别加入多壁碳纳米管(MWNT)、羟基化多壁碳纳米管(MWNT-OH)、羧基化多壁碳纳米管(MWNT-COOH),制备了TPX/碳纳米管(CNTs)复合材料。研究了CNTs对复合材料结晶性能与力学性能的影响。结果表明:加入CNTs对TPX的熔点与晶体结构没有影响,但复合材料的结晶度有所降低;加入CNTs可提高复合材料的弹性模量,与MWNT-OH相比,MWNT更能提高复合材料的弹性模量;随着MWNT-COOH含量的增加,TPX/MWNT-COOH复合材料的弹性模量也得到很大提高,当w(MWNT-COOH)为5.0%时,复合材料的弹性模量达257 MPa。     

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。