丙烯酸接枝线形低密度聚乙烯的热学行为及结晶形态

利用差示扫描量热仪研究了丙烯酸接枝线形低密度聚乙烯（PE-LLD-g-AA）的热学行为，结果表明，与纯线形低密度聚乙烯（PE—LLD）相比，PE-LLD-g-AA的熔融温度（Tm）略有增加，结晶温度（Tc）增加大约4℃，熔融焓（AHm）随AA含量的增加而降低。还利用差示扫描量热仪研究了PE—LLD和PE—LLD-g—AA的等温结晶动力学，用扫描电子显微镜观察了PE—LLD-g—AA等温结晶形态。结果表明，PE-LLD-g-AA的结晶速率大于纯PE—LLD的，随着接枝率的增加，PE-LLD的球晶半径减小，接枝到PE—LLD分子链上的AA分子起到了成核剂的作用。     

线形低密度聚乙烯粉料固相光接枝丙烯酸的研究

采用接枝率测定、红外光谱、光电子能谱、接触角、剥离强度等测试，研究了紫外线（UV）引发丙烯酸（AA）固相表面接枝线形低密度聚乙烯（PBLLD）粉料的影响因素（温度、单体浓度和反应时间），接枝PE—LLD表面结构、微观形态和性能。结果表明：UV能高效地引发AA在PE-LLD材料表面接枝聚合，随辐照时间延长、温度升高和单体浓度增大，接枝率增大，在实验条件下达到满足实际应用所需接枝率（约0．5％质量含量）的反应时问可达分钟数量级。接枝改性后，PE-LLD与水的接触角下降，亲水性增强；对钢材和聚乙烯黏接强度提高。     

反应型流滴剂接枝线性低密度聚乙烯的制备、表征及性能

对含有羟基、酯基和双键的反应型流滴剂(D)的结构进行了表征,采用预辐照和反应挤出接枝技术将D接枝到了线性低密度聚乙烯(LLDPE)分子链上,应用FTIR对纯化接枝物的结构进行了表征.研究了单体浓度和反应温度对接枝率的影响,对接枝产物膜的力学性能、透光性能及高温加速流滴性能进行了表征.在60℃时,接枝产物膜的流滴持效期为52天.     

官能化超高相对分子质量聚乙烯的制备和表征

用60Coγ射线辐照方法,将丙烯酸(AA)单体接枝到超高相对分子质量聚乙烯(PEUHMW)分子链上。提出了接枝反应的机理。研究了单体浓度、辐照剂量及辐照时间对接枝率的影响。应用FTIR和DSC对接枝共聚物的结构及热性能进行了表征,用化学滴定法测定了接枝共聚物的接枝率。结果表明:接枝物在1716cm-1处有明显的羰基峰,说明AA分子确实接枝到PEUHMW分子链上,接枝率随单体浓度、预辐照剂量及辐照时间的增加而上升。     

茂金属线形低密度聚乙烯的热降解研究

研究了光敏剂钴化合物存在时茂金属催化剂和Ziegler—Natta催化剂生产的线形低密度聚乙烯(m—PE-LLD和PE—LLD)的热降解行为，测定了降解后产品的熔体流动速率、红外光谱和氧化诱导温度。结果表明：光敏剂使得加工过程中的降解反应增强，氧化诱导温度降低，氧化曲线形状发生改变；与PE—LLD相比，光敏剂对增强m—PE—LLD的降解反应和降低加工后样品的热稳定性的作用更强。     

DCP对原位聚合改性交联PE-LLD性能的影响

研究了在线形低密度聚乙烯（PE—LLD）中原位聚合丙烯酸钠（NaAA）后，过氧化二异丙苯（DCP）用量对体系力学性能、电气性能、吸水性能的影响。在改性的PE—LLD中，DCP不仅起到交联剂的作用，还作为单体丙烯酸钠的引发剂。实验结果表明：断裂伸长率随DCP增加明显下降；DCP含量对体系电性能有较大影响；介电常数随DCP的增加明显下降，击穿场强有大幅度下降；体系的吸水性能随DCP含量的上升而下降；当DCP含量为1质量份，N如～含量为2质量份。水温为90℃时，体系吸水率达14％。     

聚丙烯／茂金属线形低密度聚乙烯的熔融行为和等温结晶动力学

用示差扫描量热仪测定了共聚聚丙烯（PP）伐金属线形低密度聚乙烯（m—PE—LLD）共混体系的熔融和等温结晶动力学。结果发现，m-PE—LLD和PP主体中PE链段之间存在相互作用。用Avrami方程对共混体系的等温结晶动力学进行了研究，m—PE—LLD的加入对PP的结晶动力学参数影响不大，说明m—PE—LLD的加入没有起到异相成核作用，而是使PP的晶体生长更加完整。由于两者的相容性，m—PE—LLD的加入明显降低了结晶温度下的过冷度，而使整体结晶速率有所下降。用Friedman方程计算了体系的结晶活化能，发现m—PE—LLD的加入提高了结晶活化能。同时还用Hoffman—Lauritzen理论计算了体系成核参数Kg。     

硅烷接枝PE-LLD结晶行为的研究

用傅里叶变换红外光谱（FT-IR）、X射线衍射仪（XRD）、差示扫描量热仪（DsC）分析了熔融接枝反应对线形低密度聚乙烯（PE—LLD）晶体结构和熔融行为的影响，并对晶体结构和熔融行为之间的关系进行了初步探索。结果表明：随着接枝率增加，晶面间距基本不变，晶粒尺寸逐渐减小；接枝后熔点降低，DSC曲线对应的高温熔融峰，即稳定的正交晶型因重排受阻，其含量逐渐减小，低温熔融峰对应的非稳定晶型逐渐增多。将XRD得到的晶粒大小代入Tbomas-Chbbs方程，求得正交晶型的理论熔融温度与DSC的高温熔融温度基本符合，表明PE-LLD接枝后熔融行为的变化是由晶粒尺寸和晶型的改变造成的。     

农膜用聚乙烯树脂分子结构与耐老化性能的关系

通过对低密度聚乙烯（PE_LD）、线形低密度聚乙烯（PE-LLD）、茂金属线形低密度聚乙烯（m-PE—LLD）、乙烯-乙酸乙烯酯共聚物（EVA）等原料直接吹塑农用棚膜进行农田扣棚试验和力学性能测试，分析了各种树脂对生产PE功能性农用棚膜的适用性，并尝试从各种树脂基础分子结构角度对农膜的耐老化性能进行解释。试验结果表明：m—PE-LLD附脂的力学性能明显优于PE-LD和EVA树脂，EVA树脂在透明性方面占有优势；在耐老化性能方面，m-PE-LLD和EVA树脂无论扣棚时间还是测试数据均比PE-LD要好，从连续取样测试数据看出PE-LD断裂伸长保留率下降趋势明显，而m-PE-LLD和EVA树脂则是拉伸强度保留率下降趋势明显。     

反应性挤出聚乙烯接枝低偶联马来酸酯

将低密度聚乙烯(LDPE)、过氧化二异丙苯(DCP)、低偶联马来酸酯(LCME)均匀混合后,在单螺杆挤出机中进行反应性挤出,得到聚乙烯接枝低偶联马来酸酯(PE-LCME)产品。红外光谱分析确证有部分LCME接枝到PE分子链上。示差扫描量热法(DSC)测定揭示了反应性挤出过程中化学反应的起始温度、峰温和终止温度,以及在静态下反应所需的时间。并且从不同升温速度的DSC曲线可以初步确定挤出温度及分布。反应性挤出得到PE—LCME的接枝率(G)随PE的型号、不同DCP的浓度而呈规律性变化。     

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.     

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。     

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.