MCPA6/埃洛石纳米管复合材料性能研究

以氢氧化钠为催化剂,N–乙酰己内酰胺为活化剂,原位聚合制备MCPA6/埃洛石纳米管(MCPA6/HNT)复合材料,并利用凝胶渗透色谱、场发射扫描电子显微镜、差示扫描量热、热重分析和力学性能测试等方法研究HNT用量对复合材料结构和性能的影响。结果表明,HNT的引入使得PA6的分子量下降,分子量分布变宽;经硅烷偶联剂(KH–550)处理后的HNT能均匀分布在MCPA6中,且与基体具有较好的界面性能;HNT可以明显提高复合材料的结晶速率、结晶度以及分解温度;随着HNT含量增加,体系的拉伸强度和缺口冲击强度呈先增大后减小的趋势,而断裂伸长率逐渐下降,当HNT含量为1.5%时,MCPA6/HNT的综合力学性能最佳,拉伸强度和缺口冲击强度分别较MCPA6提高21.3%和14.9%。     

硅灰石晶须/MCPA6复合材料的结构与性能

采用阴离子聚合制备了硅灰石晶须/浇铸尼龙6(MCPA6)复合材料,探讨了硅灰石晶须对复合材料微观结构、性能的影响以及增强机理。FTIR结果表明硅灰石晶须加入未改变MCPA6的化学结构,复合材料属于物理共混改性。SEM分析显示硅灰石晶须的用量决定了两相界面的黏结状态;当硅灰石晶须质量分数为5%时,晶须能均匀地分散在复合材料中,界面相容性好,此时复合材料综合性能最佳。与纯MCPA6相比,硅灰石晶须/MCPA6复合材料的拉伸强度、弯曲强度和冲击强度分别提高55.3%、71.5%和58.5%,吸水率降低36%。     

MCPA–聚醚嵌段共聚物/MoS_2复合材料的制备及性能研究

用原位聚合法制备了单体浇铸尼龙(MCPA)–聚醚嵌段共聚物/MoS2复合材料,并对其性能进行了表征。结果表明,聚醚和MoS2配合使用,可显著降低MCPA的磨耗体积并大幅度提高MCPA的断裂伸长率和缺口冲击强度,但会使MCPA的拉伸强度和硬度降低;随MoS2用量增加,复合材料的拉伸强度先升后降,断裂伸长率逐渐下降,缺口冲击强度、硬度、密度和磨耗体积基本没有变化。当MoS2质量分数为0.5%、聚醚预聚体的质量分数为8%时,复合材料具有最好的韧性和耐磨性。     

MC尼龙6/聚砜原位复合材料的性能研究

采用阴离子聚合法制备了MC尼龙6(MCPA6)/聚砜(PSU)原位复合材料。利用差示扫描量热、热重分析等方法表征了复合材料的热性能,利用X射线衍射研究了复合材料中MCPA6基体的晶型变化,并对复合材料的力学性能进行了表征。结果表明,随着PSU含量的增加,原位复合材料中MCPA6的结晶温度下降,但复合材料的热分解温度不断增加;纯MCPA6和复合材料中的MCPA6均呈现典型的α晶型衍射峰;当PSU质量分数为2%时,MCPA6的结晶度最小,为30.99%,复合材料的拉伸强度和拉伸弹性模量均达最大值,分别为84.78 MPa和830.50 MPa。     

NMA与纳米SiO2复配对PA6热性能及力学性能的影响

N-苯基马来酰亚胺与马来酸酐的共聚物(NMA)对尼龙(PA)6具有良好的耐热改性作用,纳米Si O2能够较好地改善PA6的力学性能。采用自制的NMA与纳米Si O2以不同质量配比复配,对PA6进行共混改性,利用差示扫描量热法、热重分析、热变形温度和力学性能等表征方法研究了不同复配比例对PA6热性能及力学性能的影响。结果表明,随着纳米Si O2含量增加,PA6/NMA/纳米Si O2复合材料的熔融温度、结晶温度、结晶度及熔融焓均呈现先上升后下降的趋势;当NMA与纳米Si O2的质量比为10∶0时,复合材料的热稳定性最好;当NMA与纳米Si O2的质量比为8∶2时,复合材料的弯曲强度、弯曲弹性模量、拉伸强度和热变形温度均达到最大值,分别为108.3,2 989,77.6 MPa以及68.4℃,较纯PA6分别提高了19.0%,25.3%,11.7%和19.2%。随着纳米Si O2含量的增加,复合材料的熔体流动速率呈现先增加后减小的趋势。     

竹纤维含量对其增强聚己内酯复合材料性能的影响

将竹纤维（BF）与聚己内酯（PCL）熔融共混,通过模压工艺制备了竹纤维增强聚己内酯（PCL/BF）复合材料。研究和分析了BF含量对复合材料力学性能、热稳定性以及熔融、结晶行为的影响。结果表明,随着BF含量的增加,复合材料的拉伸性能、冲击性能和断裂伸长率均先升高后降低,当BF含量为40 %（质量分数,下同）时,分别达到最大值13.6 MPa、14.64 kJ/m^2和7.03 %;复合材料的热稳定性与BF和PCL的配比息息相关,受热过程中对彼此热解会产生抑制作用;BF的加入在一定程度上降低了PCL的熔融温度和结晶度,但结晶温度提高;BF含量超过40 %时,BF含量对复合材料吸水率的影响显著,且随着BF含量的增加,复合材料的吸水率快速增长。     

CaCl_2用量对PA6/CaCl_2/GF共混物聚集态结构及性能影响研究

采用双螺杆挤岀机制备了PA6/CaCl_2/玻璃纤维(GF)复合材料,通过X射线衍射仪(XRD)、差示扫描量热(DSC)研究了CaCl_2用量对复合材料的结晶性能、力学性能、耐热性能的影响。结果表明,CaCl_2的加入促进了PA6/CaCl_2/GF中α晶型的生成,且y晶型用量逐渐减小。随着CaCl_2用量的增加,PA6的熔点和结晶度都逐渐降低,当CaCl_2用量大于8%后,复合材料已不结晶。随着CaCl_2加入量的增加,PA6的熔点和结晶度都逐渐降低,当CaCl_2用量大于8%后,复合材料已不结晶。随着随着CaCl_2用量的增大复合材料的拉伸强度先增大后减小,最大值为115MPa,复合材料的缺口冲击强度和维卡软化温度都逐渐减小,当CaCl_2用量为4%时分别为5.2 kJ/m~2、100.2℃。     

MCPA6/聚酯型PUR-T原位复合材料的制备及表征

采用阴离子原位聚合法制备了单体浇铸尼龙6(MCPA6)/聚酯型热塑性聚氨酯弹性体(PUR-T)复合材料,考察了其性能及结构.力学性能测试表明,当PUR-T质量分数为1.1%时,复合材料的断裂伸长率达到214.5%,相比MCPA6提高了147%,随着PUR-T含量的增加,复合材料的缺口冲击强度逐渐提高.扫描电子显微镜观察...     

用硫化仪数学分析法确定白炭黑在丁苯橡胶中最佳填充量

以谷氨酸二硫代氨基甲酸镧(La-GDTC)改性白炭黑(Si O2)填充丁苯橡胶(SBR),采用硫化仪数学分析法确定了Si O2最佳用量,通过橡胶加工分析仪分析了填料网络结构的形成,研究了SBR/La-GDTC/Si O2复合材料的拉伸性能。结果表明,采用硫化仪数学分析法确定Si O2最佳用量为40份;当Si O2用量不超过40份时,SBR/La-GDTC/Si O2复合材料的Payne效应不明显,当Si O2用量为50份时,复合材料出现了明显的Payne效应;随着Si O2用量的增加,SBR/La-GDTC/Si O2复合材料的拉伸强度先升高后下降,当Si O2用量为40份时达到最大值(28.03 MPa),表明采用硫化仪数学分析法可以快捷、准确确定在橡胶复合材料中无机填料的最佳用量。     

浇铸尼龙6/ABS聚合物合金的研究

将丁二烯组分含量不同的丙烯腈-丁二烯-苯乙烯(ABS)加入到单体己内酰胺中,通过阴离子聚合制备浇铸尼龙6(MCPA6)/ABS聚合物合金。采用傅立叶红外光谱、扫描电子显微镜、热重分析以及力学性能测试,研究了ABS的加入对浇铸尼龙6的微观结构、热性能以及力学性能影响。结果表明:ABS通过腈基在己内酰胺的阴离子聚合过程中发生共聚合反应,生成的ABS/MCPA6共聚物对合金两相起到增容作用;合金两相之间相容性随ABS中丁二烯含量的降低有所提高;热稳定性随丁二烯含量的减少而提高,但较MCPA6均有所降低。ABS的加入提高了合金的韧性,其中MCPA6/ABS749S(质量比90/10)较MCPA6缺口冲击强度提高39.73%,但硬度有所下降。     

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。