反应条件对接枝改性PVC树脂力学性能的影响

采用熔融接枝法制备了接枝聚氯乙烯(PVC)材料,从工艺条件方面分别考察了反应温度、混炼方式、加料次序及膨润时间等因素对产物力学性能的影响。结果表明:反应温度为175℃,采用粉料直接混合,PVC先与增塑剂(DOP)混合,然后加入固体助剂,最后加入溶有引发剂(DCP)的接枝单体甲基丙烯酸甲酯(MMA)的加料顺序且膨润时间为0h的加工工艺,接枝共聚产物具有最佳的力学性能。     

苯乙烯氯化原位接枝改性氯化聚氯乙烯的研究

采用氯化原位接枝技术在聚氯乙烯（PVC）进行氯化反应的同时接枝上各种不同单体．从而制备改性的氯化聚氯乙烯（CPVC）。研究了PVC固相法氯化原位接枝St的规律，讨论了单体苯乙烯（St）加入量、氯含量对产物物理力学性能及流变性能的影响。结果表明：St的加入量为10份时，改性CPVC的屈服强度明显高于空白CPVC的屈服强度，但维卡软化点降低；改性CPVC的屈服强度和维卡软化点均随氟含量增加而增大；St的加入量适当，可以同时提高改性CPVC的屈服强度和冲击性能，降低熔体粘度。     

氯化原位接枝反应制备羟基官能化CPE力学性能研究

采用气-固相氯化原位接枝来实现对聚乙烯粉末的改性，将氯化和接枝过程合为一体，大大简化了接枝共聚物的合成过程，为含氯聚合物的改性提供了一个新的手段。以高密度聚乙烯（HDPE）为原料．采用氯化原位接枝法合成了以氯化聚乙烯（CPE）为骨架聚合物，丙烯酸-2-羟基乙酯（HEA）为支链的接枝聚合物，反应中不需要加入任何引发剂。探讨了影响接枝聚合物力学性能的因素及变化规律。实验结果表明接枝聚合物的力学性能较CPE有显著的提高。氯化接枝温度、聚合物氯含量以及HEA单体的加入量对CPE—g—HEA的力学性能有很大的影响。     

PVC氯化接枝聚合制备CPVC-g-VDF接枝共聚物的研究

通过将聚氯乙烯（PVC）氯化原位接枝共聚含氟单体生成氯化聚氯乙烯接枝偏氟乙烯（CPVC-g-VDF）,当配比为VDF占CPVC-g-VDF量的4％时,接枝聚合的效果最好,所得接枝聚合物的综合性能优于聚氯乙烯.     

MMA与CR／CPE接枝共聚合的研究

本文对氯丁胶的接枝共聚合改性进行了研究，主要考察了聚合条件、接枝单体甲基丙烯酸甲酯（ＭＭＡ）用量、第三组分氯化聚乙烯的加入对接枝型氯了胶性能的影响，研究发现引发剂用量、反应温度、时间、ＭＭＡ与氯丁胶的配比等因素对共聚体系的粘度、因含量都有较大影响，加入氯化聚乙烯进行混合接枝共聚合可以显著提高共聚体系的粘接强度。     

氯化原位接枝技术制备改性CPVC的研究

采用氯化原位接枝技术制备了改性CPVC，研究了在气固相中氯化接枝的规律，讨论了单体苯乙烯（St）和甲基丙烯酸甲酯（MMA）用量、氯含量以及氯化反应温度对产物性能的影响。结果表明，单体用量为10份左右时，改性CPVC的屈服强度高于CPVC的屈服强度；加入St改性后，氯化反应温度120℃时可得到屈服强度较高的CPVC—g—St；在135℃可得到维卡软化点较高的CPVC—g—St；单体用量适当，可同时提高改性CPVC的屈服强度和韧性。     

氯化聚丙烯／MMA／BA／MAA接枝共聚物的合成

采用溶液法用混合单体甲基丙烯酸甲酯（MMA）、丙烯酸丁酯和2-甲基丙烯酸（MAA）对氯化聚丙烯（cmm）进行接枝改性，考察了反应温度、反应时间、引发剂浓度和单体浓度等因素对接枝率的影响，并对接枝产物进行了傅立叶变换红外光谱分析。确定了理想的工艺条件：反应温度为105℃，反应时间为5h，m（CPP）／m（单体）／m（BPO）为1：0．3：0．0：3。     

氯化原位接枝反应制备酐基化HDPE

采用氯化原位接枝的方法合成了以高密度聚乙烯(HDPE)为骨架、马来酸酐(MAH)为支链的接枝聚合物,反应中不需要加入任何引发剂.傅立叶红外光谱(FTIR)分析证明了该方法对HDPE改性的可行性.探讨了影响接枝聚合物力学性能的因素及变化规律.结果表明.接枝反应温度、接枝率以及MAH单体的加入量对MAH氯化接枝HDPE(HDPE-cg-MAH)的力学性能有很大的影响.     

乙酸乙烯酯与PVC接枝共聚物的制备及其性能

以过氧化苯甲酰(BPO)为引发剂,通过接枝共聚反应制备了乙酸乙烯酯接枝PVC的共聚物,考察了脱氯时间,引发剂、分散剂和单体的用量,反应温度,接枝时间对接枝共聚的影响,以及单体用量对接枝共聚物吸油性能和压缩性能的影响。结果表明:PVC与乙酸乙烯酯适合的接枝共聚工艺条件为:PVC脱氯时间1 h,分散剂用量0.8 g,引发剂用量0.9 g,反应温度90℃,单体用量7 g,接枝时间2 h。     

低相对分子质量聚丙烯氯化原位接枝共聚物的性能

以低相对分子质量的聚丙烯为原料,采用气-固相法制备了聚丙烯的氯化原位接枝共聚物。溶解性测试发现,当氯化聚丙烯(CPP)的氯含量为50.1%时,溶解度可达到90.0%,基本可在二甲苯中完全溶解,但是CPP的附着力相当差,不能满足涂料要求。通过氯化原位接枝共聚(ISCGC)的方法向CPP大分子链引入极性基团可以提高产物的附着力。本研究讨论了单体种类及配比对产物附着力的影响,最终确定了体系为单体甲基丙烯酸缩水甘油酯/马来酸酐共聚接枝时,产物的附着力最佳,可达到0级。     

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。