聚丙烯透明改性的研究

实验研究了基体树脂、成核剂及其他助剂对PP透明性的影响.结果表明:共聚PP透明性优于均聚PP,进口 Milleda3988成核剂增透效果优于国产成核剂,且成核剂的适宜添加量为0.25%左右.以PPR为基体树脂,加入成核剂及适宜的分散剂等其他助剂,对PP进行共混改性提高其透明性,研究和生产出高透明的PP改性料.     

饮料瓶用透明PP专用料应用开发

剖析了国内外饮料瓶用透明聚丙烯熔体指数,乙烯含量。经过对原料、成核剂及其他助剂的筛选,确定以RF075为基础树脂,以成核剂、抗氧剂、分散剂为组分的透明专用料配方。叙述了各种助剂对雾度的影响以及加工条件对聚丙烯光学性能的影响。应用实验结果表明,该透明专用料适合饮料瓶加工工艺,所生产的饮料瓶符合用户要求。     

热成型用透明PP的工业开发

在生产无规共聚聚丙烯(PP)的基础上,添加少量的成核剂,生产出热成型用透明PP;探讨了乙烯含量、成核剂的种类及添加量对专用树脂性能的影响.结果表明:产品具有高透明性,适宜的刚韧平衡性;常温简支梁缺口冲击强度为19～21 kJ/m2弯曲模量1.11 GPa;耐热性能较好,热变形温度85℃.专用树脂的性能达到国外同类产品的水平.     

注塑级透明聚丙烯专用料的研制与生产

以均聚聚丙烯(PP)为基体树脂,通过添加成核剂制备了注塑级透明PP专用料。成核剂的加入．不但改善了PP的光学性能,而且提高了PP的刚性,在某种程度上改善了其加工性能。为降低生产成本和提高透明PP的性能,研制了复配成核剂体系,添加该成核剂生产的透明PP的各项性能均达到技术指标;并讨论了加工温度和树脂熔体流动速率对透明PP光学性能的影响。     

透明PP片材专用树脂的研制

以均聚聚丙烯(PP)为基础树脂,通过加入成核剂生产透明PP片材专用树脂。探讨了成核剂的加入量及片材加工温度对片材透明性能的影响,确定PP片材最佳加工温度为230℃。成核剂的加入使PP的结晶度由 44．1％提高到51．4％,结晶温度、熔点等均有不同程度的提高。     

成核剂在热成型专用聚丙烯树脂开发中的应用

采用差示扫描量热仪、偏光显微镜等考察了添加成核剂对热成型专用聚丙烯(PP)树脂透明性及加工性能的影响。结果表明:两种成核剂A,B都能达到降低PP雾度、提高透明性的要求;成核剂用量相同时,添加成核剂A的PP试样雾度下降较明显,力学性能和添加成核剂B的试样接近;添加300,400,500μg/g的成核剂A对试样的雾度影响程度接近;添加300μg/g成核剂A时,试样的刚韧平衡性最佳。     

加工助剂对聚丙烯透明性能的影响

采用成核剂复配加工助剂对聚丙烯(PP)进行物理共混增透改性,利用差示扫描量热(DSC)、雾度测试等手段研究了成核剂对PP结晶行为、透明性的影响。结果表明,成核剂的引入提高了结晶温度和结晶度,透明性能得到明显改善;润滑剂类型对PP透明性能影响较大,硬脂酸钙降低PP透明性,而芥酸酰胺提高了PP的透明性;抗氧剂168对PP透明性影响较大,而9228对PP透明性影响较小。     

熔融非敏感型成核剂在聚丙烯加工中的应用研究

分别将熔融非敏感型成核剂A、成核剂B及通过特殊工艺处理后的混合成核剂(A+B)按添加质量分数0.08%,在加有其他助剂的情况下,分别与一定质量的超高流动均聚聚丙烯(PP)、高流动抗冲共聚PP、中流动丙丁无规共聚PP混合均匀,经双螺杆挤出造粒机熔融挤出、造粒,制得不同PP树脂,并对PP树脂的力学性能、光学性能、结晶行为及结晶形态进行研究。结果表明:与未添加熔融非敏感型成核剂的同牌号PP树脂相比,添加熔融非敏感型成核剂后,同牌号PP树脂的弯曲模量和拉伸屈服强度均得到提高。其中,超高流动均聚PP的弯曲模量最大提高了41.9%,拉伸屈服强度最大提高了13.2%;高流动抗冲共聚PP弯曲模量最大提高了48.7%,拉伸屈服强度最大提高了12.4%;中流动丙丁无规共聚PP弯曲模量最大提高了25.2%,拉伸屈服强度最大提高了14.2%。3种PP树脂的熔体质量流动速率、简支梁缺口冲击强度、模塑收缩率保持不变。熔融非敏感型成核剂的加入,提高了PP树脂的白度、光泽度,以及热变形温度和结晶温度,较大改善了PP树脂的黄色指数和雾度,显著降低了PP树脂的半结晶时间。熔融非敏感型成核剂(A+B)对超高流动均聚PP、高流动抗冲共聚PP、中流动丙丁无规共聚PP的改性效果更加显著。     

聚丙烯保险杠专用料收缩率控制

通过调节原辅材料及成核剂等组分及加入量,可以控制聚丙烯(PP)保险杠专用料收缩率,使保险杠成型脱模容易,装车尺寸匹配。粗细填料配合使用可使PP收缩率控制在0.614%～0.940%,加入成核剂使PP收缩率由1.301%下降到1.138%,功能PP与成核剂协同使用,可使专用料收缩率由单独使用成核剂时的1.007%下降到0.931%。前后保险杠专用料和侧护板专用料的收缩率与进口专用料基本一致。     

相对分子质量及其分布对成核聚丙烯性能的影响

通过加入过氧化二异丙苯（DCP）来改变聚丙烯（PP）的相对分子质量及其分布，研究了成核PP相对分子质量及其分布对其性能的影响。结果表明：加入DCP后。成核PP的相对分子质量降低、分布变窄，促使PP结晶速度进一步提高，晶体尺寸进一步减小。成核PP中的β晶型消失。当成核剂TM-3和降解剂DCP的含量分别为0．4％和0．05％时。成核PP的透明性最好。随成核PP的相对分子质量降低、分布变窄，成核PP的力学性能略微下降。     

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。