PP-g-MAH对PA6/PP共混体系性能的影响

以PP-g-MAH为相容剂,研究了PP-g-MAH对PA6/PP共混体系性能的影响。探讨了PP-g-MAH对PA6/PP共混物增容作用,提高共混物的各项性能指标。当PP-g-MAH为4份时,共混物的力学性能最好,当PA6/PP=90/10时,其力学性能有最大值;SEM照片显示,未加PP-g-MAH时,PP在PA6基体上分散不均,颗粒大,当加入适量的PP-g-MAH(4份)时,PP分散比较均匀,颗粒尺寸明显降低。以PP-g-MAH4份,PA6/PP=80/20制备的共混物,吸水率约是PA6的15%:冲击强度、热变形温度分别比PA6、PP提高了72%和106%,13.5℃和5.5℃。     

接枝聚丙烯增容改性PP/PA合金性能的研究

用PP接枝物增容PP/PA6共混体系,观察分析了共混合金的形态结构特点,测试了共混物的力学性能.结果表明：单独加入PP-g-MAH,力学性能均呈现先升后降的趋势,峰值时拉伸强度比未加接枝物时可提高20%,弯曲强度比未加接枝物时提高了54%,冲击强度比不添加接枝物时提高了3.6%.添加PP-g-MAH对不同比例PP/PA6共混物力学性能的影响不同,固定PP-g-MAH用量为4%,PA6质量分数为30%时共混物的综合力学性能达到最好.用PP-g-MAH和PP-g-GMA两种接枝物共同作为相容剂加入到PP/PA6共混物中比单独使用一种的效果要好,拉伸、弯曲和冲击强度都得到显著的提高.由共混物的SEM照片可以看到,PP-g-MAH使分散相的粒径变小,分布均匀,界面相互作用加强,所以是PP/PA6共混物的有效增容剂.     

相容剂对PA6/PP合金性能的影响

分别采用聚丙烯接枝马来酸酐(PP-g-MAH)和硬脂酸(ST)作为相容剂,通过熔融共混法制备了PA6/PP(聚酰胺6/聚丙烯)合金,研究相容剂用量对该合金性能的影响。结果表明,随着相容剂的增加,PA6/PP合金的吸水性和熔体流动速率下降,拉伸强度和缺口冲击强度先增大后减小。当PP-g-MAH和ST用量分别为PA6/PP合金的4.0%(质量分数,下同)和2.0%时,复合材料的综合性能更佳。     

PP-g-MAH增容PP/PA 6的形态结构与流变性能

研究了用马来酸酐接枝聚丙烯（PP-g-MAH)来增容聚丙烯/聚酰胺6（PP/PA6）共混物的形态结构，探讨了PP-g-MAH增容PP/P6共混物的流动行为。结果表明，PP/PA6共混物为热力学不相容的海岛型两相结构，PP-g-MAH的加入改善了PA6与P宾相容性，使两相分散均匀。用PP-g-MAH为增容剂增容PP/PA6共混物，在加工成型温度下为非牛顿流体，在PP-g-MAH质量分数为10%，PP/PA6的配比为95：5-75：25，其流动行为可用T=1580γw^0.65模型描述。     

马来酸酐接枝物对PE/PA6共混物相容性的影响

采用熔融共混法制备了PP/PA6/POE-g-MAH和PP/PA6/PP-g-MAH共混物。通过扫描电子显微镜(SEM)、差示扫描量热(DSC)仪分析和力学性能测试研究了增容剂POE-g-MAH和PP-g-MAH对PP/PA6共混物相容性、形态结构和宏观力学性能的影响。结果表明,在PP/PA6共混体系中分别加入POE-g-MAH和PP-g-MAH不仅能显著改善两相界面的相容性,减小分散相的粒径,而且能使共混物的力学性能显著提高。当增容剂的用量为5份时,PP/PA6共混物有较好的综合力学性能。POE-g-MAH和PP-g-MAH增容PP/PA6共混体系非等温结晶行为的研究表明,POE-g-MAH和PP-g-MAH均能促进PA6对PP基体的异相成核作用。     

长玻纤增强PP/PA6合金材料的性能

以连续长玻璃纤维为增强材料,以聚丙烯(PP)与尼龙(PA)6树脂为基体,以马来酸酐接枝PP(PP-g-MAH)作为相容剂,经过双螺杆挤出机和特制的浸润装置制备了长玻纤增强PP/PA6合金材料。通过常规力学性能、球压痕硬度、耐划伤、热变形温度等测试和微观结构分析,考察了PA6含量及其与PP-g-MAH质量比对合金材料强度、刚性、常低温冲击性能、硬度、耐刮擦以及耐热性能的影响。结果显示,当PA6/PP-g-MAH质量比为2,即PA6含量为10份,PP-g-MAH含量为5份时,合金材料的综合性能达到最佳;当PA6/PP-g-MAH质量比低于2时,PA6特性优势随着其含量增加而提升,而当PA6/PP-g-MAH质量比高于2时,相容剂不足以增容PP/PA6两相,综合性能有所衰减。所制备的长玻纤增强PP/PA6合金材料具有较好的强度、刚性、韧性、硬度以及更好的–40℃冲击性能,且其密度低,耐刮擦性能优异,在特殊领域如电动工具外壳具有广阔的应用前景。     

增强PA6／PP合金的研究

研究了影响玻璃纤维增强尼龙6(增强PA6)/聚丙烯接枝马来酸酐(PP-g-MAH)二元合金和增强PA6/PP/PP-g-MAH三元合金的吸水性、流动性、机械和热性能的诸因素。结果表明,当增强合金中的PP-g-MAH或PP/PP-g-MAH含量为10％～20％(质量含量)时,材料的拉伸强度和弯曲强度、热变形温度(HDT)基本保持增强PA6的水平,其冲击强度、吸水性和流动性得到改善,增强合金的界面化学键数量在3×10~(-9)mol/m~2以上;当PP-g-MAH或PP/PP-g-MAH含量增至30％时,增强合金的干湿态机械性能趋于一致。     

PP/EVOH/PA6共混物的性能研究

以聚丙烯接枝马来酸酐(PP-g-MAH)为相容剂,制备了聚丙烯(PP)/乙烯-乙烯醇共聚物(EVOH/)聚酰胺6(PA6)共混物,研究了PP/EVOH/PA6三元共混物的相容性、流变性能、阻隔性能、力学性能、热性能及形态结构。结果表明:相容剂与EVOH和PA6间发生了反应,提高了共混物的相容性;相容剂的加入提高了PP、EVOH、PA6的结晶温度,增强了PP与EVOH和PA6间的黏合力,降低了界面张力;EVOH占EVOH/PA6总量68%的三元共混物吸油率最小,当相容剂用量为5份时,PP/EVOH/PA6三元共混物吸油率比PP/EVOH二元共混物降低了8%。     

反应增容PP/PA 6共混体系的形态与性能

采用侧向注入增容剂和直接混合的方法制备了不同配比的聚丙烯(PP)/马来酸酐接枝聚丙烯(PP-g-MAH)/聚酰胺(PA) 6共混物.考察了侧向注入和直接混合2种增容方式对PP/PP-g-MAH/PA 6共混体系形态与性能的影响.结果表明:加入PP-g-MAH可以同时提高PP/PA 6共混体系的刚性和韧性,侧向注入的增容效果尤为明显.侧向注入PP-g-MAH (5 phr) 的复合体系拉伸强度较纯PP提高了23.6%;侧向注入PP-g-MAH (20 phr)的复合体系拉伸断裂应变大于1 000%;PP-g-MAH能有效改善PP/PA 6体系的相容性,提高两相界面结合力,降低分散相粒子尺寸,且侧向注入比直接混合的效果更显著.     

相容剂PP-g-MAH对PP/PA12形貌及性能影响

采用熔融共混制备了不同相容剂马来酸酐接枝聚丙烯(PP-g-MAH)含量的聚丙烯(PP)/PP-g-MAH/聚酰胺12(PA12)共混体系,通过对体系的平衡扭矩、差式扫描量热法(DSC)、扫描电子显微镜(SEM)及力学性能等测试,分析了共混体系中相容剂PP-g-MAH对PP/PAl2形貌及性能的影响.结果表明,PP-g-MAH能改善PP/PAl2的界面相容性,PA12能更好地分散在PP基体中,最佳相容剂添加质量分数为12%.此时,杨氏模量比未添加相容剂时提高了60.7%,断裂伸长率提高了79.9%,冲击强度提高了345.2%.     

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。