氯化聚乙烯对ABS/PVC合金性能的影响

以氯化聚乙烯(CPE)为增韧剂,用双螺杆挤出机共混制备丙烯腈-丁二烯-苯乙烯塑料(ABS)/聚氯乙烯(PVC)合金。研究了PVC及CPE用量对ABS/PVC合金的拉伸强度、弯曲强度、缺口冲击强度、维卡软化温度、氧指数和熔体流动性的影响。结果表明,随着PVC用量的增加,ABS/PVC合金的拉伸强度略有增加,弯曲强度基本不变,冲击强度呈现先略增加然后显著降低的趋势,维卡软化温度降低,氧指数增加;随着CPE用量增加,ABS/PVC合金的缺口冲击强度增加,拉伸强度和弯曲强度降低,氧指数和维卡软化温度变化很小,当ABS/PVC/CPE为40/60/15时,合金的拉伸强度为39.8 MPa、弯曲强度为60.8 MPa、缺口冲击强度为18.3 kJ/m2,氧指数为29.7%。     

纳米碳酸钙在聚氯乙烯中的应用研究

文章研究了纳米碳酸钙PVC中的应用。结果表明,在PVC混配料中用纳米碳酸钙等体积取代CPE后材料韧性略有下降,对拉伸强度几乎没有影响,材料刚度有所增加。PVC型材混配料中直接加入纳米碳酸钙后,材料拉伸强度略有下降,冲击强度提高,材料弯曲模量增加。合适比例的纳米碳酸钙与滑石粉并用加入到PVC混配料中后,可使材料的拉伸强度和冲击强度提高不变,材料弯曲模量增加。     

环氧树脂基磁性复合材料的起始磁导率研究

以环氧树脂为基体,以经退火的Fe73.5Cu1Nb3Si13.5B9非晶粉体为增强材料,制备了树脂基磁性复合材料,并研究了磁粉种类、非晶粉体粒径、非晶粉体退火条件、纳米晶粉体含量以及复合材料去应力退火条件对复合材料的起始磁导率的影响.结果表明,以经550℃×0.5h退火的Fe73.5Cu1Nb3Si13.5B9纳米晶粉体为磁性增强体的复合材料的起始磁导率最大;随着纳米晶粉体含量的增加,复合材料的起始磁导率增大;对复合材料进行去应力退火可以提高其起始磁导率.     

玻璃纤维/聚氯乙烯复合材料的制备与性能研究

采用注塑成型法制备了玻璃纤维/PVC(聚氯乙烯)复合材料。研究了制备过程中成型压力、成型温度及模具温度等对该复合材料拉伸强度、剪切强度和弯曲强度的影响。研究结果表明:当成型射压为130 MPa、保压为100 MPa、背压为0.5 MPa、成型温度为420℃、模具温度为100℃和w(玻璃纤维)=15%(相对于复合材料质量而言)时,复合材料的综合性能相对最好,其拉伸强度(77.4 MPa)和剪切强度(57.4 MPa)相对最大,并且制品表面光滑且颜色正常,而且弯曲强度比纯PVC提高了68.4%。     

助剂对PVC/稻壳粉复合建筑模板性能的影响

主要考察了ACR、CPE和DOP等改性助剂对PVC/稻壳粉复合建筑模板力学性能的影响,结果表明:ACR与CPE对复合材料的冲击强度、拉伸强度和弯曲强度都有一定增强作用;DOP对复合材料的冲击强度和弯曲强度有增强作用,但不利于拉伸强度的提高;ACR、CPE和DOP的最佳用量分别为4 phr、6 phr和6 phr,复合材料的拉伸强度为61 MPa、冲击强度为18.5 k J/m2,弯曲强度可达64 MPa。     

白泥/氯化聚乙烯母粒料的制备及在PVC型材中的应用

利用不同添加剂,将白泥与氯化聚乙烯(CPE)湿法混炼,利用添加助剂的不同,通过双螺杆挤出机挤出造粒制备了两种白泥/CPE(A,B)母粒料;将白泥/CPE母粒料与PVC树脂以及其他助剂共挤制备了PVC型材。研究了两种母粒料制备及使用方法对PVC型材性能的影响,母粒料A法制备的PVC型材弯曲强度、弯曲弹性模量、拉伸强度、拉伸弹性模量、冲击强度、维卡软化温度分别为65.4 MPa、2900MPa、44.5 MPa、1 100 MPa、14.5 kJ/m2、85.0℃,母粒料B法分别为63.5 MPa、2 800 MPa、42.9 MPa、1 000 MPa、16.2 kJ/m2、82.3℃,两种方法制备的PVC型材弯曲弹性模量、维卡软化温度均高于GB/T8814-2004门、窗用未增塑聚氯乙烯(PVC-U)型材要求(弯曲弹性模量≥2 200 MPa,维卡软化温度≥75℃)。SEM分析结果表明白泥粒子与PVC基体界面结合良好,分散均匀,颗粒粒径约为0.5~1.0μm。实验结果表明利用两种母粒料制备的PVC型材在性能上无显著差异,均可达到均匀分散白泥粒子的目的。     

PC/聚硅氧烷体系的力学性能和阻燃性能

采用水解缩合法,通过改变正硅酸乙酯含量(TE/Si)以及烷硅比(R/Si),制备一系列聚硅氧烷阻燃剂,并将该系列阻燃剂以5%的添加量应用到PC中,研究PC/聚硅氧烷复合体系的力学性能和阻燃性能.结果表明:复合材料的拉伸强度在54.8～61.0 MPa之间,弯曲强度在98.0～104.0 MPa之间,与纯PC的拉伸强度59.7 MPa和弯曲强度105.7 MPa相比可知,阻燃剂对材料的力学性能影响不大.复合材料阻燃性能和极限氧指数(LOI)明显提高,在燃烧过程中,复合材料的热释放速率和烟气产生速率都有不同程度的降低.     

连续玻纤增强PVC预浸料的制备成型工艺

以聚氯乙烯(PVC)树脂为基相,连续玻纤为增强相,利用湿法粉末浸渍法制备了连续玻璃纤维增强PVC预浸料,研究了牵拉速度、悬浮液浓度和树脂槽压辊包覆角对预浸料纤维含量的影响。结果表明:增加牵拉速度、降低悬浮液浓度和包覆角可以提高预浸料中纤维质量分数,但是当悬浮液浓度大于15%,包覆角大于300°时,纤维含量基本保持不变。将制得的预浸料经热压和冷压后制备了连续玻纤增强PVC复合板材,研究了纤维含量和丙烯酸酯聚合物(ACR)流动改性剂对复合材料力学性能的影响,结果表明:材料拉伸强度和弯曲强度随着纤维含量增加而呈先升后降趋势,在65%时达到最优性能,分别为302MPa和261MPa,加入ACR流动改性剂后材料拉伸强度提升15%左右,弯曲强度提升19%左右。     

PVC曲面模板的基本性能及在建筑墙体中的应用

聚氯乙烯(PVC)材料和曲面模板形式是建筑模板的发展趋势。对PVC复合材料曲面模板拉伸和弯曲受力性能分析,获得了不同材料和相同材料不同方向间拉伸强度和拉伸弹性模量的大小关系,以及最大弯曲荷载、弯曲强度、弯曲弹性模量的大小关系。模拟混凝土施工加载过程,探究PVC曲面模板抗形变性能,确定了PVC材料在不同支撑间距条件下,PVC模板各跨跨中的挠度变化。最后根据PVC曲面模板的性能特点,提出在建筑墙体中的应用。     

PVC/α-MSAN共混物的性能研究

采用机械共混法制备了PVC与α-甲基苯乙烯类-丙烯腈共聚物(α-MSAN)共混材料,探讨了α-MSAN用量对共混材料的力学性能、耐热性能和加工性能的影响。结果表明:α-MSAN可以改善共混材料的耐热性能和加工性能;随着α-MSAN用量的增多,共混材料的热变形温度(最大弯曲正应力分别为1.80 MPa和0.45MPa)、拉伸强度、弯曲强度、弯曲模量和熔体流动速率上升,而冲击强度、断裂伸长率下降。综合考虑性能与成本等因素,α-MSAN用量为30份最佳,此时,共混材料的热变形温度由72.4℃提高至81.6℃(最大弯曲正应力为1.80 MPa)。     

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。