PE-UHMW树脂的冲击性能和结晶性能试验研究

利用程序控制压机对超高相对分子质量聚乙烯（PE-UHMW）树脂进行成型加工,并测试成型材料的简支梁冲击性能;针对加工工艺中的不同影响因素,通过单因素试验和方差分析考查各参数对PE-UHMW结晶性能的影响,得到了成型条件下分子链段运动、分子间自由体积以及分子间的相互作用与冲击性能的相关性;利用多因素均匀设计和逐步回归研究,确定温度为PE-UHMW树脂模压成型的最显著因素。     

PE-UHMW微孔滤材成型工艺研究

采用烧结法制备了超高相对分子质量聚乙烯（PE-UHMW）微孔材料,并对微孔材料的各项性能进行了分析。结果表明,采用烧结法成型的PE-UHMW粉末的颗粒与颗粒间相互堆砌,堆砌形成的间隙便是微孔形成的原因。微孔材料的性能与PE-UHMW的相对分子质量、粉末粒径、堆砌密度、烧结温度、烧结时间等因素有关。PE-UHMW的相对分子质量越大,微孔材料的压缩强度越大;粉末粒径越大,微孔材料的孔径越大;随着烧结温度和烧结时间的增加,微孔材料的孔径变小,孔径分布变宽。     

超高相对分子质量聚乙烯/聚丙烯共混物研究进展

回顾了超高相对分子质量聚乙烯(PE-UHMW)与聚丙烯(PP)共混物的研究进展.介绍了PE-UHMW/PP共混物的制备方法,性能(加工流变性能、力学性能、摩擦磨损性能)及结晶和微观形态的研究现状,并展望了PE-UHMW/PP共混物的研究方向.     

高生产效率全电动注射成型机

正(日)《プラスチックスェ-ヅ》第61卷第2期第56-58页2015年日本东芝机械公司为了满足生产超小型精密制品的需求,成功开发了全电动注射成型机"EC30S"系列并推向市场。全电动"EC30S"注射成型机的特点:1)生产效率高,由于该机定模板和动模板采用优质的高刚性金属材料,注射成型时模具受力均匀、开模闭模时模具不会产生振动、开闭模速度快、成型周期时间短、生产效率高、产品合格率高、产品附加值高;2)成型稳定,该机生产使用LCP树     

超高分子量聚乙烯注射成型技术的研制及应用

分析了超高分子量聚乙烯(UHMW-PE)的口模流动特性,论述了UHMW-PE专用注射机及注射成型工艺的特点,并探讨了UHMW-PE注射制品的应用领域.研制的UZ300型注射机的参数为:螺杆直径45,注射量300g.结果表明,在低温、低压、低速条件下成功地实现了注射成型,典型制品每小时可成型27模(一模两腔),制品形状、尺寸稳定,达到了工业化水平.     

PE-UHMW异型材挤出成型有限元模拟与实验制备

根据生产需求,设计了3字形超高分子量聚乙烯(PE-UHMW)异型材挤出成型流道,并建立了该异型材挤出成型有限元模型,应用有限元软件Polyflow对挤出流道内的熔体流动情况进行了有限元模拟,分析了不同壁面滑移系数、压缩比、压缩角对成型过程的影响,预测了在成型过程中不同参数可能导致的缺陷。结果表明,当模具压缩比与压缩角分别为2.5和25°、壁面滑移系数为5×106情况下,可获得较好的压力与速度分布,应用优化后的挤出模具制备了合格的PE-UHMW异型材。     

无机填料增强改性超高相对分子质量聚乙烯的研究

采用超细白云母和针状硅灰石两种无机填料对超高相对分子质量聚乙烯(PE-UHMW)进行填充改性,并用单螺杆挤出机进行成型,研究不同用量的无机填料对PE-UHMW复合材料的力学性能、耐热性能和摩擦磨损性能等的影响。结果表明,添加适量的针状硅灰石、超细白云母均可提高PE-UHMW的拉伸强度、表面硬度、热变形温度和耐磨性,其中以超细白云母的效果最佳,针状硅灰石的效果稍差。当超细白云母的填充量为5%时,PE-UHMW的拉伸强度提高了28.7%,热变形温度提高了16℃,磨损量降低了58.3%;当云母的含量达到15%时,PE-UHMW的摩擦因数降低了26.8%。     

超高相对分子质量聚乙烯管材新型连续挤出成型技术

超高相对分子质量聚乙烯（PE-UHMW）管材连续挤出成型法有压制-烧结、柱塞推压、单螺杆挤出、双螺杆挤出和柱塞冲压挤出等几种，其中柱塞冲压挤出成型法是新开发的一种PE-UHMW管材连续挤出成型技术，该技术的突出优点表现在：能加工任意相对分子质量的PE-UHMW树脂，加工能力强；能实现连续挤出，生产效率不低于单螺杆挤出法，而制品的表面质量、力学性能（如耐磨性）则优于单螺杆挤出法；完全正位移输送机理，温度控制简单可靠（控温段只有三个），因此加工过程中的降解程度较小，能很好地保持原料固有的优良性能；主机结构简单，能耗低（约为螺杆挤出法的30％～50％），生产线造价便宜。另外，采用该技术还能挤出高质量的聚四氟乙烯（PTVE）和过氧化物交联聚乙烯（PEX-a）制品。     

聚丙烯注射成型收缩研究进展

在介绍注射成型中浇日凝固前收缩、制品模内冷却讨程收缩及脱模后制品自由收缩的收缩讨程和热收缩、结晶收缩、取向收缩、负收缩及后收缩等注射成型收缩原因的笨础}一,详细回顾了聚丙烯(PP)分子结构、共混、填充及加入成核剂等因素对注射成型收缩率的影响。同时,还讨论了注射温度、成型压力、成型时间、模具温度、冷却时间、充模辣度等注塑工艺条件以及制品厚度对PP注射成型收缩率的影响,介绍了生产中注射成型收缩的控制方法     

炭黑、微珠粉填充PE-UHMW复合材料性能比较分析

对超高相对分子质量聚乙烯(PE-UHMW)和炭黑、微珠粉填充的PE-UHMW复合材料进行了拉伸、硬度和磨损性能试验。结果表明：炭黑、微珠粉对PE-UHMW拉伸性能和摩擦磨损性能的影响不同，两种填充材料加入PE-UHMW后，复合材料的拉伸强度和断裂延伸率有不同程度的下降。炭黑的加入会使PE-UHMW的硬度下降，但可较好地改善其耐磨性，而微珠粉的加入会使PE-UHMW的耐磨性下降。     

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。