EVA的熔体皂化及其与PP动态硫化共混物的研究

为研究乙烯-醋酸乙烯共聚物(EVA)的熔体皂化并拓展其应用,直接将氢氧化钠和EVA熔体共混进行皂化反应制备皂化EVA,并以马来酸酐为交联剂,采用动态硫化技术将其同聚丙烯(PP)共混制备PP/EVA共混物。结果表明:熔体皂化可在EVA的侧链上生成游离的羟基;通过改变混炼时间、混炼温度和碱用量可实现EVA的可控熔体皂化。以皂化EVA为原料制备的PP/EVA共混物拉伸、冲击性能均高于PP/未经皂化处理的EVA共混物。当EVA的皂化度为49.5%时,PP/EVA共混物具有最佳的力学性能和熔体流动性。经EVA熔体皂化、动态硫化技术制备的PP/EVA共混物中EVA具有更好的分散效果。     

EVA/TPU共混物热氧老化性能研究

研究4种不同组合的乙烯-乙酸乙烯酯共聚物（EVA）／热塑性聚氨酯（TPU）共混物热氧老化前后物理性能的变化规律。结果表明，EVA／TPU共混物老化后总体趋势是邵尔A型硬度、100％定伸应力和拉伸强度增大，拉断伸长率减小；在EVA／聚醚型TPU（T8）并用比为50／50时，共混物老化后出现气泡，老化规律异常。乙酸乙烯酯质量分数为0．4的EVA（E4）／T8共混物在E4／T8并用比为75／25时，老化前后平均的物理性能变化率较小，为较佳组合。     

CM/EVA热塑性硫化胶制备工艺与性能的研究

采用HAAKE转矩流变仪制备了氯化聚乙烯橡胶(CM)/乙烯-醋酸乙烯共聚物(EVA)热塑性硫化胶(TPV),研究了初始加工温度、转速以及动态硫化时间对共混物物理力学性能、流变行为以及动态力学性能的影响。结果表明:初始加工温度为150℃、转速60 r/min、动态硫化时间13 min时TPV的综合性能最好;橡胶加工分析仪(RPA)的研究表明,在没有填料加入的情况下共混物呈现出明显的Payne效应。返炼实验表明:通过此种工艺制备的CM/EVA为性能稳定的TPV。     

木质素填充LDPE、EVA对复合物性能的影响

以木质素为填充剂分别与低密度聚乙烯(LDPE)、乙烯-乙酸乙烯酯共聚物(EVA)共混,经双螺杆造粒机共混挤出造粒,再经吹塑成膜。研究了木质素/LDPE、木质素/EVA共混物薄膜的表面形貌、力学性能、热性能和红外光谱。热分析表明木质素与EVA共混物的热稳定性比木质素与LDPE的共混物热稳定性好;红外光谱分析表明木质素与EVA分子间产生了强烈的相互作用,扫描电镜分析表明木质素与EVA共混的相容性较好,力学性能分析表明低于30%的木质素与LDPE、EVA共混力学性能较好。     

PE/EVA共混改性材料力学性能的研究

主要对不同配比的PE、聚乙烯-乙酸乙烯酯（EVA）树脂进行共混改性研究.使用正交实验法设计、运用方差分析法分析,测试了PE/EVA共混物的拉伸强度和屈服强度,使用差示扫描量热法（DSC）研究了PE/EVA的相容性,使用扫描电镜（SEM）二次电子成像分析试样液氮脆断的断口.从而讨论分析EVA在PE/EVA共混物当中的含量、挤出机的螺杆转速以及挤出机出口模的模温对PE/EVA共混物力学性能的影响.     

低EVA含量PA6/EVA共混物双连续相形成机理

利用密炼机对PA6/EVA共混物进行熔融共混并对熔融过程进行可视化分析,通过扫描电镜观察低EVA含量PA6/EVA共混物的相形态,分析了不同加工条件对共混物相形态的影响,基于基本假设建立了A/B(低含量)两相聚合物的熔融模型,并且,提出了低含量两相聚合物共混体系双连续相的形成机理。结果表明,当温度为230℃、转子转速为60 r/min、PA6/EVA共混物熔融2.5 min时,共混物充分熔融,随着转子转速的增大,熔融时间显著缩短。低EVA含量PA6/EVA共混物的相形态主要受到共混时间和转子转速的影响,并且,双连续结构不稳定,当共混时间在3～5 min范围内时,EVA能够形成连续相;当共混时间为8 min时,EVA转变为分散相,转子转速增大加快了EVA由连续相转变为分散相。     

木质素-EVA扭矩流变性能试验研究

研究了影响木质素与乙烯醋酸乙烯酯共聚物（EVA）共混物在扭矩流变仪中的共混最大扭矩、平衡扭矩以及达到平衡扭矩时间的各个因素。结果表明，木质素、增容剂、增塑剂、转速、温度对扭矩值有明显影响；木质素／EVA共混体系达到平衡扭矩时的平均时间随木质素的含量增加，扭矩值减小到最小后又逐渐增加。木质素／EVA共混物热溶胶的粘度表现出非牛顿流体的假塑性流体，热溶胶粘度随温度的上升而减小，木质素／EVA共混体系具有可加工性。     

EVA熔体流动速率对PLA/EVA共混物性能的影响

通过熔融共混法制备了聚乳酸（PLA）/乙烯-乙酸乙烯酯共聚物（EVA）共混物,采用SEM、DSC、旋转流变仪等研究了VA质量分数为28%,熔体流动速率（MFR）不同的EVA对PLA/EVA共混物性能的影响。结果表明,EVA熔体流动速率越小,其在PLA基体中分散越均匀,EVA颗粒粒径也越小。共混物的结晶度随EVA熔体流动速率的增大而增大,但PLA的玻璃化转变温度（Tg）基本不受EVA的影响。PLA/EVA共混物的复数黏度和储能模量均随EVA的熔体流动速率的增高而减小。力学性能测试结果表明,当EVA的质量分数为15%时,PLA的断裂伸长率明显升高,冲击强度约是纯PLA的2倍。     

动态硫化TPU/EVM共混物的结构与性能研究

采用熔融共混法制备热塑性聚氨酯(TPU)/乙烯-乙酸乙烯酯橡胶(EVM)动态硫化共混物,并对其结构与性能进行研究.结果表明,TPU/EVM共混体系实施动态硫化的最佳共混比为75/25,硫化剂BIPB用量为0.8份时共混物性能最佳,且不同共混比的TPU/EVM共混物需要的硫化剂最佳用量不同;动态硫化后的EVM以较大尺寸的相畴分散在TPU中;TPU/EVM动态硫化共混物返炼后仍具有较高的重复使用价值.     

EVA改性硅橡胶海绵

中国工程物理研究院的赵祺等人将100份甲基乙烯基硅橡胶与30份2^#白炭黑共混均匀后,加入适量的乙烯-乙酸乙烯酯（EVA）,在120℃下混炼均匀;冷却后加入硫化剂、发泡剂,返炼均匀,在160℃下模压硫化发泡,制成了EVA改性硅橡胶海绵。加入约10％的EVA可以大幅度提高硅橡胶海绵的拉伸强度,而其压缩应力松弛变化不大;通过调整EVA的用量,可以得到具有不同压缩模量、不同压缩应力应变性能的硅橡胶海绵。     

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。