甲基丙烯酸镁助交联氯化聚乙烯橡胶耐老化性能的研究

研究甲基丙烯酸镁[Mg(MAA)2]助交联氯化聚乙烯橡胶(CM)的耐热空气、紫外光和臭氧老化性能,并与助交联剂TAIC助交联CM进行对比。结果表明,与采用助交联剂TAIC的CM硫化胶相比,采用助交联剂Mg(MAA)2的CM硫化胶热空气老化前后的拉伸性能和耐臭氧老化性能较好,耐紫外光老化性能相差不大。     

不同硫化体系对SBR/CM共混胶的性能研究

分别以硫磺(S)、硫磺(S)/过氧化二异丙苯(DCP)/助交联剂(TAIC)作为硫化体系,研究了不同共混比对SBR/CM共混胶的硫化特性、力学性能、耐热老化性能和动态力学性能的影响。结果表明:以硫磺/过氧化二异丙苯/助交联剂作为硫化体系下的共混胶,焦烧时间缩短,硫化速度快,交联程度高,弹性大,耐磨性能和耐热老化性能优异;随着CM用量的增加直到10仹,SBR/CM共混胶的交联程度稍微下降,定伸应力、硬度、拉伸永久变形逐渐增大,回弹值、tanδ峰值逐渐减小,DIN磨耗值变化不大,耐热老化性能好。     

过氧化物交联体系硫化CM橡胶的研究

研究了交联剂过氧化二异丙苯(DCP)、双叔丁基过氧异丙基苯(BIPB)、2,5-二甲基-双(叔丁基过氧基)己烷(DBPMH)和助交联剂三烯丙基异氰脲酸酯(TAIC)、三烯丙基氰脲酸酯(TAC)、三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)以及白炭黑、轻质碳酸钙、滑石粉、氢氧化镁等无机填料对氯化聚乙烯橡胶(CM)硫化特性以及力学性能的影响。结果表明,当以BIPB和TAIC为交联体系,且其质量比为2.5/3时,CM橡胶有较好的交联效率、交联速率和力学性能。添加无机填料后,CM胶料的硫化速度有所下降。另外,填料品种对胶料的补强作用有明显区别,白炭黑对胶料的补强作用最为明显,而碳酸钙则使胶料的力学性能降低。     

AC发泡剂在橡胶型CM中的应用

利用发泡流变仪研究了CM的硫化条件和硫化特性,得出硫化交联反应速度V、硫化指数CCRI和表观活化能E;同时研究了助交联剂TAIC以及工艺条件对发泡橡胶性能的影响。结果表明:添加助交联剂TAIC发泡试样的硫化交联反应速度V加快,硫化指数CCRI和交联反应活化能E变大;添加助交联剂TAIC发泡试样在保持低密度的同时,获得较高的机械强度,综合发泡性能好;充模质量对发泡行为影响大,33 g充模的胶料综合发泡性能好;170℃时,10 MPa压力下硫化会得到综合性能较好的发泡效果。     

EPDM过氧化物硫化体系的研究

研究了过氧化物二-(叔丁基过氧异丙基)苯(BIPB)与助交联剂异氰脲酸三烯丙酯(TAIC)对三元乙丙橡胶(EPDM)硫化特性和交联密度的影响。结果表明,增大2者用量均能促进EPDM的硫化反应,使得交联密度增大;当过氧化物用量大时,助交联剂用量不宜过大。通过理论计算,TAIC对BIPB的交联效率几乎没有影响;在过氧化物自由基存在下,TAIC可自身发生环化聚合反应,提高交联密度。     

EPDM/NR并用胶的复合交联

采用硫黄硫化体系和过氧化物（硫化剂DCP）硫化体系对EPDM／NR并用胶实施复合交联，研究并用比和复合交联体系对胶料的硫化特性、物理性能和耐热老化性能的影响。结果表明，在大部分并用比下，复合交联可以改善胶料的硫化特性；在硫化剂DCP和助交联剂TAIC的用量均为2份、EPDM／NR／ENR并用比为30／68．5／1．5时，并用胶的物理性能优良；以NR为主的并用胶在复合交联时硫化剂DCP和助交联剂TAIC的用量宜取1～2份。     

助交联剂对CM胶料性能的影响

试验研究在过氧化物硫化体系中助交联剂TAIC，PDM和TCY对氯化聚乙烯橡胶（CM）胶料性能的影响，并与噻二唑硫化体系胶料进行对比。结果表明，过氧化物硫化体系中TAIC胶料的正硫化时间最短，交联程度最大，硫化反应表观活化能最小，高温耐油性能最优PDM硫化胶的综合物理性能和耐热老化性能较好，但耐热老化性能不如噻二唑硫化体系硫化胶，其常温耐油性能最优。     

液体三元乙丙橡胶的交联及其拉伸性能

研究了由过氧化二异丙苯(DCP)和助交联剂三烯丙基异氰脲酸酯(TAIC)组成的过氧化物体系对液体三元乙丙橡胶(EPDM)的交联及产物拉伸性能的影响.结果表明,液体EPDM的凝胶含量随DCP的增加无明显变化,随TAIC的增加而增加;交联产物的拉伸性能有相似的变化趋势.     

耐热助剂和硫化助剂对丁腈橡胶耐热性能的影响

研究耐热助剂氧化镁和甲基丙烯酸镁(MMG)、助交联剂三烯丙基异氰脲酸酯(TAIC)、N,N'-间亚苯基双马来酰亚胺(HVA-2)和硫黄对过氧化物硫化体系丁腈橡胶(NBR)耐热性能的影响。结果表明:氧化镁和MMG可以提高胶料的耐热性能,二者单用或并用的适合用量均为7~12份;助交联剂TAIC和HVA-2可以提高胶料的耐热性能,用量为1~2份较好;硫黄不适合用作过氧化物硫化的耐热NBR助交联剂。     

TMPTMA和TAIC对PP发泡材料性能的影响

在过氧化二异丙苯引发下,分别以三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)和三烯丙基异氰脲酸酯(TAIC)作助交联剂,考察其对发泡聚丙烯(EPP)材料力学性能的影响。结果表明:TAIC与TMPTMA均可有效提高PP的交联度;与TMPTMA相比,TAIC助交联的EPP不仅凝胶率提高了18.67%,还具有更优的硬度、拉伸强度、撕裂强度和压缩永久变形等力学性能。     

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。