阻燃型NBR/PVC发泡材料的研究

以丁腈橡胶(NBR)和聚氯乙烯(PVC)为主体材料,以偶氮二甲酰胺(AC)为发泡剂,以三氧化二锑(Sb2O3)、十溴二苯乙烷(DBDPE)为阻燃剂,用一步模压法制备了阻燃型NBR/PVC泡沫材料,研究了橡塑比、阻燃剂用量对NBR/PVC发泡材料泡孔结构、密度、阻燃性能和力学性能的影响。结果表明:当橡塑比为50∶50,DB-DPE/Sb2O3的用量分别为12、4份时,NBR/PVC发泡材料的综合性能最佳。     

PVC交联剂DB的合成与表征

采用一种新的工艺路线合成了聚氯乙烯 (PVC)交联剂 2 -正丁胺基 - 4 ,6 -二巯基均三嗪 (DB) ,用傅立叶变换红外光谱仪和差示扫描量热仪测定分析证实了合成产物 ,并用硫化仪测试得到的交联曲线验证了DB对PVC的交联效果 ,应用研究表明 ,DB交联PVC具有良好的改性作用     

NBR/PVC发泡材料性能的研究

以PVC、NBR为主要原料,加入硫化剂、发泡剂及其他助剂经动态硫化法制备了密度较低的NBR/PVC发泡材料.研究了橡塑比变化、硫磺用量、发泡剂用量、促进剂用量及填料用量对NBR/PVC发泡材料性能及泡孔结构的影响.结果表明:当NBR:PVC质量比为70:30、硫磺用量为0.8份、发泡剂用量为9份、促进剂TT与CZ质量比为1:2时,发泡材料的综合性能最佳.     

动态硫化CR/PVC热塑性弹性体的性能

以CR胶乳和PVC乳液共沉物为原料,通过动态硫化法制成CR/PVC热塑性弹性体.研究了混炼温度和橡塑共混比对CR/PVC共混物力学性能的影响,并通过电镜观察CR/PVC共混物的微观结构.结果表明,在(165±10)℃下制得的CR/PVC共混物的综合性能较好;动态硫化CR/PVC共混物比静态硫化CR/PVC共混物具有更好的力学性能.     

三唑二巯基铵盐交联聚氯乙烯的制备及性能

选用三唑二巯基铵盐(FSH)作为聚氯乙烯(PVC)的交联剂,考察了模压温度、模压时间和交联剂用量对PVC交联的影响,并通过红外分析、无转子硫化仪、电子万能试验机、维卡软化温度试验机和扫描电镜等,研究了交联PVC的化学结构、交联过程、力学性能、耐热性能和断面形貌。结果表明:FSH能使PVC交联且凝胶率较高;交联程度受模压温度和模压时间影响很大,当模压温度为180℃、模压时间为120 s时比较适宜;交联后PVC的拉伸强度和缺口冲击强度提高,断裂伸长率降低。交联剂用量为1.5份时,综合性能最好,拉伸强度达48.9 MPa,缺口冲击强度达16.3 kJ/m^2,维卡软化点达到75.9℃,较未交联PVC提高了18.4℃。     

热可逆交联剂对PVC力学性能及热性能的影响

用一种热可逆交联剂与聚氯乙烯(PVC)树脂熔融共混,研究了交联剂用量和交联时间对交联PVC制品力学性能和热性能的影响,分析了交联产物的热可逆转化行为。结果表明:热可逆交联剂能有效提高PVC制品的力学性能和热稳定性,当交联剂用量为3份时,PVC制品的力学性能达到最大值,维卡软化温度提高了4℃;PVC制品的凝胶含量随交联剂用量的增多而增大;交联时间为20 min时,PVC有较高的力学性能和热性能,更为重要的是PVC交联后具有热可逆转化特性。     

乳胶／EVA／LDPE／PVC四元共混橡塑并用发泡的研究

采用模压发泡一次成型法研究了橡塑并用,乳胶/EVA/LDPE/PVC四元共混发泡材料的制备,着重讨论了配方和加工工艺、橡塑比、交联剂、发泡剂、填料等用量对发泡体性能的影响,交联与发泡的协调与配合,并用电镜扫描观察了四元动态硫化共混物材料和共混交联发泡体的断面结构。实验结果表明,当橡塑比R/P=20/80时,共混发泡体的密度0.10g/cm~3,扯断强度1.15MPa,断裂伸长率180％,硬度(邵氏A)36,挠曲>4万次,适合于制作轻质泡沫衬垫或包装材料;当橡塑比R/P=5/95时,发泡体密度(g/cm~3)0.23,扯断强度2.13MPa、断裂伸长率(％)243、硬度60(邵氏A)、挠曲>4万次,成品适合于制作大、中底等鞋用材料。     

交联改性聚丙烯的研究

以过氧化二异丙苯(DCP)为交联剂,苯乙烯(St)为助交联剂对聚丙烯(PP)进行交联改性。研究了交联剂(DCP)及交联剂(St)的用量对交联PP的力学及结晶性能的影响。结果表明,交联可以改善PP的性能。在DCP用量为0.05%,St为4%时,交联PP冲击强度达到3.83 kJ/m2,比纯PP提高了27%;拉伸强度由纯PP的36.02 MPa升高到37.22 MPa;交联PP的球晶尺寸减小,球晶间的界面模糊。     

NBR/PVC热塑性弹性体的耐油性能研究

考察了硫化剂种类及用量、橡塑比和PVC的相对分子质量对NBR／PVC热塑性弹性体(TPE)耐油性能的影响。实验结果表明，TCY(三聚硫氰酸)硫化体系制备的NBR／PVC的耐油性能最好，TMTD(二硫化四甲基秋兰姆)体系次之，酚醛树脂和硫磺2种体系最差；TCY的用量越大，TPE的耐油性越强，其最佳用量为2．0份；橡塑比中PVC所占比例增大，TPE的耐油性下降；增加PVC的相对分子质量，TPE的耐油性明显提高。     

硬质交联PVC泡沫塑料的制备

以聚氯乙烯(PVC)为基体,马来酸酐为接枝剂,异氰酸酯、三聚氰胺为交联剂,制备出性能优异的硬质交联PVC泡沫塑料;通过红外光谱、热失重和热机械分析及凝胶含量测定对硬质交联PVC泡沫塑料进行分析,证实交联反应发生在水煮工艺阶段,玻璃化转变温度在180℃左右;研究了马来酸酐用量对硬质交联PVC泡沫塑料凝胶含量的影响,马来酸酐的用量在塑化成型阶段对交联度的影响较小,硬质交联PVC泡沫塑料的凝胶含量随着马来酸酐用量的增加而增大;用光学显微镜对硬质交联PVC泡沫塑料的泡孔直径进行了测量。结果表明,硬质交联PVC泡沫塑料的泡孔直径分布较为均匀,密度为60 kg/m3的泡孔直径主要分布在100~130μm,密度为90 kg/m3的泡孔直径主要分布在70~80μm;测定了硬质交联PVC泡沫塑料的力学性能,结果显示,其具备同瑞士Airex C70产品相当的力学性能。     

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。