耐热高韧汽车保险杠用OBC增韧PP专用料研究

以嵌段共聚聚丙烯(PP–B)为基体,乙烯–辛烯嵌段共聚物(OBC)为增韧剂,通过添加质量分数为15%的滑石粉及其它助剂,采用双螺杆挤出机制备了OBC增韧PP–B汽车保险杠专用料。研究了OBC和乙烯–辛烯无规共聚物(POE)的用量对专用料力学性能和热变形温度(HDT)的影响。结果表明,OBC可使PP–B晶区细化,与POE相比,其增韧的专用料具有更高的常、低温缺口冲击强度、弯曲强度和HDT,拉伸强度和断裂伸长率则相差不大。当OBC质量分数为20%时,其增韧的专用料在23℃和-20℃的缺口冲击强度分别为64.3,52.7 k J/m2,弯曲强度为38.8 MPa,HDT为105℃,与相同用量下POE增韧的专用料相比分别提高了28.3%,28.9%,24.4%和23.5%。     

退火工艺对PP–R复合材料性能的影响

通过注塑工艺制备无规共聚聚丙烯(PP–R)样条,并将样条置于热处理设备进行退火处理。运用差示扫描量热仪、广角X射线衍射仪、偏光显微镜和扫描电子显微镜等方法,分析了退火对PP–R的结晶行为和力学性能的影响。结果表明,退火可以消除热应力,促进结晶的完善,使得PP–R的结晶度从41.2%提高到48.4%,诱导β晶的生成,能有效改善材料的力学性能。退火使得PP–R的拉伸强度有所提高;对冲击性能影响明显,在25℃时,PP–R的冲击强度从41.67 k J/m2提高到66.84 k J/m2,提高了60.4%;在0℃时,PP–R的冲击强度从11.54 k J/m2提高到32.68 k J/m2,提高了1.8倍。     

PP-R复合材料结晶行为和低温韧性的研究

采用熔融共混技术,在无规共聚聚丙烯(PP-R)中分别添加改性剂(苯乙烯-丁二烯-苯乙烯共聚物SBS、热塑性聚氨酯TPU、聚丙烯树脂PP(EPS30R))制备PP-R复合材料,通过差示扫描量热仪、X射线衍射仪和扫描电子显微镜分析了改性剂对PP-R复合材料结晶行为和低温韧性的影响规律。结果表明,SBS、TPU能够使PP-R的结晶度降低,诱导β晶的形成;在常温和低温下,SBS和TPU均能提高PP-R复合材料的冲击韧性,当SBS的含量为15%时,在-10℃下PP-R复合材料的冲击强度从10.54 k J/m~2增加到15.75 k J/m~2,即提高了49%,是一种理想的PP-R抗低温改性剂。     

增韧剂及成核剂对PP–R复合材料性能的影响

采用注射成型法制备无规共聚聚丙烯(PP–R)复合材料,结合差示扫描量热仪、扫描电子显微镜、X射线衍射仪及偏光显微镜等技术,分析了乙烯–辛烯共聚物+高密度聚乙烯增韧剂及WBGⅡ型β成核剂对PP–R复合材料力学性能和结晶行为的影响。结果表明,增韧剂与成核剂对复合材料的综合性能有明显的影响,β成核剂和增韧剂同时加入到PP–R材料中,协效提高了复合材料的冲击强度,为78.7 k J/m~2,与纯PP–R材料比较提高了175%,而对拉伸及弯曲强度影响较小。同时,加入增韧剂及成核剂均能诱导α晶向β晶转变,晶粒细化,进而改善其冲击韧性。     

PP–R管材及专用料的研究进展

综述了无规共聚聚丙烯(PP–R)管材及专用料的研究进展,重点从加工工艺和改性方法两个方面介绍了PP–R管材的研究开发现状。分析了PP–R管材研发存在的主要问题,提出了未来几年PP–R管材及专用料的研究开发方向。     

两种弹性体对PPR材料低温抗冲击性能的影响

无规共聚聚丙烯(PPR)管材作为一种新型绿色建筑材料,被广泛应用在民用建筑和工业给排水设施等方面,但由于PPR耐热性和耐低温冲击性能较差,限制了应用,因此提高PPR的韧性尤其是低温韧性成为研究的重点。以PPR为基体,通过挤出机造粒、注塑机成型等手段与聚烯烃弹性体POE、聚苯乙烯弹性体TPE两种不同的增韧剂共混并进行研究,分析了不同配方对二元共混体系的拉伸强度、断裂伸长率、缺口冲击韧性以及低温冲击性能的影响;通过DSC、XRD、冲击试验机等仪器设备研究PPR复合材料的熔融结晶性能和力学性能。根据研究结果,得到耐低温抗冲击性能较为理想的PPR复合材料最优增韧方法。结果表明:随着弹性体TPE、POE用量的增加,在室温、0、-15和-25℃时共混体系的缺口冲击强度都有所增强。与POE相比较,弹性体TPE对PPR的增韧作用尤为明显,TPE填量为15%时,PPR/TPE共混料的冲击韧性最理想,体系的断裂伸长率增幅更大,其综合力学性能最好,改性材料常温冲击强度较纯PPR提高82.5%,低温0、-15、-25℃冲击强度分别增加9.25、9.13、8.53 k J/m~2,断裂伸长率由279.62%增加到584.53%,而拉伸强度仅仅降低3.43 MPa。     

β成核剂用于PPR管材专用料研究

研究了新型β晶型成核剂对无规共聚聚丙烯（PPR）管材专用料力学性能和熔融行为的影响。结果表明,β晶型成核剂的添加大幅提高了PPR管材专用料的Izod常温冲击强度和低温冲击强度,热变形温度也得到明显改善,材料的结晶形态由原来的α晶型转变为以β晶型为主。     

β-PP管材专用料的研究进展

综述了近年来国内外聚丙烯(PP)管材专用料的发展现状,重点介绍了有关β晶型聚丙烯(β-PP)管材专用料的制备方法,并对β-PP管材专用料——尤其是β晶型无规共聚聚丙烯(β-PPR)管材专用料的发展前景进行了展望。     

PP-R树脂专用色母粒的研制

通过筛选颜料、分散剂和载体，采用两步法工艺路线制备出无规共聚聚丙烯(PP—R)树脂专用色母粒，并详细讨论了色母粒的性能指标以及色母粒对PP—R管材专用树脂性能的影响。实验结果表明，研制出的色母粒与PP—R树脂兼容性较好，提高了PP—R管材专用树脂的加工性能和力学性能。     

载货车内饰护板用改性聚丙烯专用料研究

利用双螺杆挤出机,通过熔融共混工艺制备了载货车内饰护板改性聚丙烯(PP)专用材料,并对专用料进行了力学性能测试.研究结果表明.以共聚PP为基体树脂、聚烯烃弹性体(POE)为增韧剂、滑石粒为填料制备的载货车内饰护板专用料·其缺口冲击强度达到18.6 kJ/m2,弯曲强度为30.2 MPa.拉伸强度达24.2 MPa,能满足载货车内饰护板类零部件的性能要求.     

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。