LDPE熔融接枝MAH及其增容PA6/LDPE合金的研究

以过氧化二异丙苯(DCP)为引发剂,马来酸酐(MAH)为接枝单体,采用熔融法制备了MAH接枝低密度聚乙烯(LDPE-g-MAH)。研究了不同DCP和MAH配比对接枝反应的影响,并以相对接枝率较高的LDPE-g-MAH作为增容剂,讨论了其用量对尼龙6(PA6)/LDPE合金力学性能的影响。结果表明:LDPE/DCP/MAH质量比为100/0.2/2时,相对接枝率较高,该种配方的接枝物可显著改善PA6/LDPE体系的相容性,在PA6/LDPE(质量比50/50)和PA6/LDPE(质量比80/20)两种体系中,增容剂的最佳用量分别为4~5 phr和2~3 phr。     

多组分HDPE的HDPE /PA6共混合金性能特征

摘 要：采用熔融法制备了高密度聚乙烯（HDPE）与马来酸酐（MAH）接枝物（HDPE-g-MAH）,并以此接枝物制备了 HDPE-g-MAH/PA6共混合金,通过调整引发剂过氧化二异丙苯（DCP）和马来酸酐（MAH)的用量来控制接枝率,并研究该共混合金的性能与接枝率之间的关系。结果表明：HDPE-g-MAH/PA6共混合金的力学性能、耐热性等均较纯高密度聚乙烯有很大提高,当HDPE:PA6:MAH:DCP份数比例为60:40:1:0.3时,共混合金表现出较佳的性能。     

溶液法制备POE-g-MAH及其影响因素

采用溶液接枝法,以过氧化二异丙苯(DCP)为引发剂,马来酸酐(MAH)为单体,制备了POE-g-MAH。通过红外光谱确定了接枝物的结构,采用酸碱滴定法测定了产物的接枝率,详细研究了POE、MAH、DCP用量及反应温度等对接枝率的影响规律。结果表明,当POE∶MAH∶DCP为13∶6∶1、反应温度为150℃、反应时间5h时接枝率达到最大值9.5%。     

ABS反应挤出接枝马来酸酐研究

要反应挤出接枝技术,在ABS上接枝MAH,探讨了ABS性能、MAH用量、引发剂品种和用量对MAH接枝率的影响。并用MAH接枝ABS与PA6制成合金,其性能达到国内外同类产品水平。     

MAH接枝HDPE及HDPE-g-MAH/PA6共混合金的性能

采用熔融法制备高密度聚乙烯与马来酸酐接枝物(HDPE-g-MAH),并以此接枝物制备HDPE-g-MAH/PA6共混合金,通过调整引发剂过氧化二异丙苯(DCP)和马来酸酐的用量来控制接枝率,并研究该共混合金的性能与接枝率之间的关系.结果表明:HDPE-g-MAH/PA6共混合金的力学性能、耐热性等均较纯高密度聚乙烯有很大提高,当质量比HDPE:PA6:MAH:DCP为60:40:1:0.3时,共混合金表现出较佳的性能.     

UHMWPE混炼接枝马来酸酐研究

讨论了超高相对分子质量聚乙烯(UHMWPE)混炼接枝马来酸酐(MAH)过程中，单体MAH用量、引发剂DCP用量、交联抑制剂己内酰胺(CAILA)用量、流动改性剂硬脂酸钙(CaSt2)用量及混炼温度、时间等工艺条件对UHMWPE接枝率和凝胶含量的影响。用红外光谱表征了接枝物的存在。并用滴定分析法和重量分析法测定了接枝物UHMWPE～g～MAH的接枝率和凝胶含量。实验表明，MAH用量为5份、DCP为0．15份、CALA为0．1份、CaSt2为1份时。混炼温度175∽180℃。混炼时间14min时，可得到接枝率0．75％、凝胶含量1．48%的UHMWPE接枝物。     

PP-g-MAH改性PC/ABS合金的研究

用自制马来酸酐接枝聚丙烯(PP-g—MAH)对PC／ABS舍金进行改性研究。结果表明，PP-g-MAH对PC／ABS合金有明显增容作用，可使合金的缺口冲击强度显著提高，当接枝物中马来酸酐(MAH)含量为5％、引发剂过氧化二异丙苯(DCP)含量为0．27％，PC／ABS合金中PP—g—MAH用量为2．5份时，合金综合性能最佳，其缺口冲击强度可达44kJ／m^2。     

聚丙烯熔融挤出接枝马来酸酐的研究

研究了通过双螺杆挤出机聚丙烯熔融挤出接枝马来酸酐制马来酸酐接枝聚丙烯（PP—g—MAH）的工艺，包括单体马来酸酐（MAH）、引发剂DCP的用量及熔融反应温度和时间对聚丙烯（PP）熔融接枝MAH的接枝率的影响。结果表明：DCP、MAH的用量对PP—g—MAH接枝率影响比较明显，其最佳配比为DCP0．15份、MAH2份；最佳工艺条件为挤出螺杆转速40r／min，反应温度195-200℃。     

马来酸酐熔融接枝二元乙丙橡胶的研究

在转矩流变仪中,以过氧化二异丙苯(DCP)为引发剂,采用多单体熔融接枝技术,研究了二元乙丙橡胶(EPM)熔融接枝马来酸酐(MAH),考察了MAH含量、DCP用量、反应温度、反应时间、转子转速以及第二单体苯乙烯(St)的用量对接枝反应的影响,并用红外光谱(FTIR)对接枝产物进行了表征.研究结果表明:对于EPM-g-MAH体系,MAH和DCP最佳用量分别为3.0 phr和0.22 phr,最佳反应温度为170℃,反应时间8 min,转子转速60 r/min,此时接枝率最高达到0.46％;加入第二单体St后,当n(St) /n(MAH)为1/1时,EPM-g-(MAH-co-St)的接枝率为0.64％,接枝率明显提高.     

马来酸酐接枝天然橡胶的制备及应用研究

以过氧化二异丙苯(DCP)为引发剂,在转矩流变仪中以马来酸酐(MAH)单体对天然橡胶(NR)进行接枝改性。通过傅里叶变换红外光谱对接枝物进行了定性表征;采用化学滴定法测定了反应产物中MAH的接枝率和接枝效率。研究了MAH单体用量、DCP用量、反应温度、转子转速等因素对反应产物接枝率和接枝效率的影响,研究结果表明,以转矩流变仪作为反应器,NR为100份(质量份数,以下同此),MAH和DCP分别为5份、0.75份,温度为130℃,转子转速为50 r/min的条件下反应3min,产物接枝率和接枝效率较高,分别为1.45%和30.63%。将所制备的马来酸酐接枝天然橡胶(NR-g-MAH)应用于尼龙短纤维增强天然橡胶复合材料(NR/SF)体系中,可有效改善尼龙短纤维与NR基体间的界面结合。     

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。