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1.
以聚丙烯(T36F)为基料,考察了核-壳结构共聚物(SEP)和三元乙丙橡胶(EPDM)对聚丙烯的增韧作用。结果表明:SEP作为聚丙烯(PP)的增韧添加剂比EPDM有更好的增韧效果。当SEP用量为10phr时,PP/SEP共混材料的缺口冲击强度是纯PP的7.7倍,超过了20份EPDM增韧PP的效果,是优良的PP抗冲增韧改性剂。  相似文献   

2.
对聚丙烯(PP)/三元乙丙橡胶(EPDM)共混合金的结构与性能进行了研究。结果表明:国产三元乙丙橡胶J3080P能够大幅度提高PP的常温和低温缺口冲击强度;PP基体的性质和EPDM的用量对增韧效果有明显影响。PP/EPDM共混合金发生脆韧转变所需的EPDM用量为20~30份。EPDM对PP增韧机理遵从银纹-剪切带机理。J3080P对PP的增韧效果优于日本产EPDM 501A。  相似文献   

3.
茂金属聚乙烯弹性体和三元乙丙橡胶增韧聚丙烯的比较   总被引:9,自引:1,他引:8  
用茂金属聚乙烯弹性体(mPE)代替三元乙丙橡胶(EPDM)对聚丙烯(PP)增韧改性并进行了比较。结果表明,mPE共聚物中的辛烯质量分数越高,其中对PP的增韧效果越好;随着共混物中弹性体质量分数的增加,共混物的拉伸强度和弹性模量降低,扯断伸长率增大。PP/mPE与PP/EPDM增韧体系相比,二者的拉伸强度差别不大,但PP/mPE的弹性模量和扯断伸长率稍低;与EPDM相比,mPE对PP具有较好的增韧效果,含有质量分数40% mPE的共混物试样在-30℃下的缺口冲击强度已超过纯PP的20倍,约是相同弹性体质量分数PP/EPDM的近9倍。另外,PP/mPE还具有较低的拉伸永久变形、压缩永久变形和蠕变变形。  相似文献   

4.
反式—1,4—聚异戊二烯改性聚丙烯的研究   总被引:1,自引:0,他引:1  
研究了反式-1,4-聚异戊二烯(TPI)的力学性能与交联的关系及不同产联度的TPI对PP的增韧效果。发现TPI能显著提高一种韧性PP(PP/EPDM)的冲击强度,使球晶细化,均一,讨论了其增韧机理。  相似文献   

5.
高流动性PP增韧体系流变性能的研究   总被引:1,自引:0,他引:1  
利用毛细管流变仪和转矩流变仪对高流动性聚丙烯(PP)增韧体系的流变性能进行分析,讨论了聚烯烃弹性体(POE)、三元乙丙橡胶(EPDM)=增韧母料和降温母料等助剂对高流动性PP共混体系流变性能的影响,并对PP/POE共混体系和PP/EPDM共混体系的转矩流变曲线进行了对比,考察了不同共混体系的微观结构、力学性能和加工性能。  相似文献   

6.
PP/EPDM共混物断裂性能的研究   总被引:3,自引:1,他引:3  
采用三元乙丙橡胶(EPDM)对共聚聚丙烯(PP)增韧改性。研究了共混物的力学性能和断裂性能,着重采用基本断裂功方法探讨了材料组成对共混体系断裂性能的影响。研究发现:随EPDM用量的增加,共混物的拉伸强度逐渐下降,冲击强度均较纯PP有一定程度的提高。不同组成的PP/EPDM共混物的ωe均高于纯PP,ωe值随EPDM用量的增加呈先增大后减小的趋势,且ωe主要受ωe,n变化的影响,同样βωp的变化主要受βnωp,n变化的影响。  相似文献   

7.
POE的性能及其在聚丙烯共混改性中的应用   总被引:8,自引:0,他引:8  
介绍了茂金属催化剂合成的聚烯烃弹性体(POE)的优异特性,分析比较了其与传统三元乙丙橡胶(EPDM)的差异,综述了聚烯烃弹性体在聚丙烯(PP)增韧改性中的广泛应用及其研究进展。  相似文献   

8.
POE和EPDM增韧PP/CaCO3复合材料的研究   总被引:3,自引:0,他引:3  
用聚烯烃弹性体(POE)和两种三元乙丙橡胶(EPDM)增韧PP/纳米CaCO3,研究了弹性体种类和用量对复合材料的力学性能和流动性能的影响。结果表明:随弹性体用量增加至30份,3种复合材料的拉伸强度下降,断裂伸长率上升,硬度下降,常温和低温冲击强度都有较大幅度提高;在20~25份填充范围内,POE增韧效果良好,PP/POE/CaCO3的综合性能优良;弹性体填充量为30份时,3体系为典型的假塑性流体,PP/POE/CaCO3体系有更强的非牛顿性(粘切敏感性)。  相似文献   

9.
SEP/蒙脱土混杂材料对PP/PS共混物性能的影响   总被引:1,自引:0,他引:1  
研究了苯乙烯一乙烯/丙烯二嵌段的共取物(SEP)及其与改性蒙脱土的混杂材料对PP/PS共混物的形态、冲击强度和拉伸强度的影响。结果表明,对于PP/PS共混物,SEP/CJ1-MONT混杂材料对PP/PS共混物的增韧增强效果比SEP更强。  相似文献   

10.
采用机械共混方法对粉状聚丙烯(PP)进行了增韧增强研究,探讨了增韧剂、增强剂和有少量自制的固相甲基丙烯酸(MAA)接枝粉状聚丙烯(PP-g-MAA)作增容剂存在下对粉状PP共混体系力学性能的影响,用热重分析法考察了改性粉状PP的热性能。结果表明,(乙烯/丙烯/二烯)共聚物(EPDM)/高密度聚乙烯(HDPE)为复合增韧剂,具有协同作用,可显著提高共混物的冲击强度:PP-g-MAA能明显改善PP/玻纤两相的界面结合力;PP/EPDM/HDPE玻璃纤维共混体系可以获得理想的增韧增强效果。  相似文献   

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12.
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.  相似文献   

13.
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.  相似文献   

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15.
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.  相似文献   

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18.
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.  相似文献   

19.
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。  相似文献   

20.
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.  相似文献   

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