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。     

PE氯化接枝St/AN共聚共混物研究

采用固相法对聚乙烯(PE)进行氯化接枝苯乙烯/丙烯腈(St/AN)单体,制得了改性氯化聚乙烯(CPE)材料。探讨了氯化反应温度、氯含量、引发剂过氧化苯甲酰(BPO)用量和单体配比对聚合物力学性能的影响,实验中还对PE接枝了不同单体,结果表明,采用二段温度(70℃,120℃)法,氯质量分数为35%,BPO加入质量为0.24g,m(St)/m(AN)为1:1时,可制得力学性能较好的CPE材料。极性单体MA、AN及St的加入提高了CPE材料的拉伸强度。     

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制备了苯乙烯(St)改性氯化聚氯乙烯(PVCC)。研究了St单体加入量、氯含量对PVCC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份左右时,改性PVCC的拉伸屈服强度达到最大值(69MPa),较未改性PVCC约提高17%,但维卡软化点降低;改性PVCC的拉伸屈服强度和维卡软化点均随氯含量的增加而提高;改性PVCC的熔体粘度较未改性PVCC的低,加工温度范围变宽。     

高强度高软化点CPVC的制备与性能

以氯化原位接枝方法制备氯化聚氯乙烯(CPVC)接枝顺丁烯二酸酐(MAH)的共聚物(CPVC-cg-MAH),初步探索了MAH的单体含量、反应温度对接枝产物的力学性能和软化点的影响.结果表明:当MAH为8份、反应温度为140 ℃时,CPVC-cg-MAH拉伸强度达到最高,为68.9 Mpa;当MAH为4份、反应温度为120 ℃时,CPVC-cg-MAH软化点达到130 ℃.     

氯化聚丙烯接枝马来酸酐的合成研究

考察了马来酸酐（MAH）用量、引发剂（BPO）用量、反应温度和反应时间对氯化聚丙烯接枝马来酸酐（CPPgMAH）中接枝率和接枝效率的影响。结果表明m（MAH）：m（CPP）=0．28时，接枝率和接枝效率较高；随着引发剂过氧化苯甲酰（BPO）用量的增大，接枝率和接枝效率也随之增大；提高反应温度，可以提高接枝效果，适宜的反应温度和反应时间分别为100℃、1．5h。     

天然橡胶/氯化聚氯乙烯热塑性弹性体的性能与结构

采用动态硫化法制备天然橡胶(NR)/氯化聚氯乙烯(CPVC)热塑性弹性体(TPV),并研究甲基丙烯酸缩水甘油酯(GMA)/苯乙烯(St)双单体熔融接枝NR[NR-g-(GMA-co-St)]与白炭黑复配增容补强NR/CPVC TPV的物理性能、耐溶剂性能和微观形态结构。结果表明:当NR-g-(GMA-co-St)和白炭黑的用量分别为7和3份时,交联NR分散相在CPVC基体中的分散度和均一性得到明显改善,相界面的结合强度显著提高,达到良好的复配增容补强效果。与未改性NR/CPVC TPV相比,改性NR/CPVC TPV的拉伸强度、拉断伸长率和撕裂强度增大,耐溶剂性能明显改善。     

丙烯酸改性氯化聚丙烯的合成和粘接性能的研究

氯化聚丙烯是聚丙烯的氯化改性产物，通过改性，其硬度、耐磨性、耐酸性、耐盐水性能比聚丙烯都好，耐热、耐老化性也优于聚丙烯。但其性能尤其是粘接性能还不能满足其在胶粘刺等方面的需要，为了进一步提高氯化聚丙烯的粘接性能，拓宽其应用领域，需对氯化聚丙烯改性。接枝共聚法是一种很好的化学改性方法。本文以丙烯酸(AA)作为接枝单体，以过氧化苯甲酰(BPO)为引发剂，以甲苯为溶刺，采用液相接枝共聚法，将丙烯酸单体接枝到氯化聚丙烯大分子链上，得到丙烯酸改性氯化聚丙烯产物。系统研究了反应温度、反应时间、引发剂过氧化苯甲酰用量和丙烯酸单体用量等因素对丙烯酸接枝改性的氯化聚丙烯产物粘接性能的影响，得出了较佳的工艺条件是反应温度T=100℃，反应时间t=3．5h，原料质量配比为100份氯化聚丙烯、3份丙烯酸和0．3份的过氧化二苯甲酰。研究还表明，丙烯酸改性的氯化聚丙烯的粘接性能优于氯化聚丙烯的粘接性能。     

BA氯化接枝改性CPVC流变行为的研究

采用氯化原位接枝法制备改性CPVC，在氯化的同时加入丙烯酸丁酯（BA）得到CPVC-g-PBA，利用毛细管流变仪研究了CPVC和CPVC-g-PBA的流变行为，讨论了两者的剪切应力和剪切速率以及温度对熔体流变行为、熔体粘度的的的影响，并测定了其非牛顿指数。     

CPP/VTES/St接枝共聚物的合成与性能

以二甲苯为溶剂,过氧化苯甲酰(BPO)为引发剂,采用乙烯基三乙氧基硅烷(VTES)和苯乙烯(St)为接枝单体,自由基溶液聚合法改性氯化聚丙烯(CPP),制得接枝共聚胶黏剂。并考察了聚合单体用量及配比、溶剂用量、引发剂用量、反应温度和反应时间对树脂胶黏性能的影响。得到的最佳反应条件为：溶剂与CPP的质量比m(二甲苯)∶m(CPP)=2.5∶1,聚合原料配比m(CPP)∶m (VTES)∶m (St)∶m (BPO) =100∶2.4∶0.6∶0.2,反应温度95 ℃,反应时间3 h。在此条件下制备的共聚物粘接聚丙烯材料和钢的剪切强度分别达3.4 MPa和7.7 MPa。     

CPVC改性SBS接枝胶黏剂的研制

SBS接枝丙烯酸酯类能改善胶液对PVC人造革的黏合性.若在此体系中引入高氯含量的氯化聚氯乙烯CPVC与SBS并用,可进一步提高性能.以质量比为10:3.0的甲苯、丁酮混合液作溶剂,其用量为骨架聚合物(SBS CPVC)用量的4.0倍,引发剂2.0%,单体70%,温度控制在90±1 ℃.在此工艺条件下研究了CPVC、SBS与MMA的三元接枝共聚反应,并用红外光谱对接枝产物进行了表征.实验表明,CPVC和SBS必须采用分步法溶解,即待CPVC溶解完全后,再加SBS溶解.CPVC在体系中的含量不能过高,否则,胶层在拉伸时易脱离基材,放置过程中也易分层.CPVC用量为骨架聚合物总用量的20%～30%时,所制胶黏剂的贮存稳定性及耐水性能较好,对PVC材料的黏合强度亦较高.     

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。