生物可降解聚丁二酸/2,2-二甲基丁二酸丁二酯系列共聚物的合成与性能研究

合成了一系列聚丁二酸/2,2-二甲基丁二酸丁二酯共聚物(PBS-2M),利用DSC、1H-NMR和XRD等测试手段对共聚物组成、热力学性能、结晶性能、等温结晶行为进行了研究。结果表明：2,2-二甲基丁二酸共聚单元的引入显著改变了聚丁二酸丁二酯(PBS)的热力学性能,利用Hoffman-Week曲线得到的共聚物平衡熔点随共聚组分含量的增加显著降低,玻璃化转变温度亦有所降低,结晶熔点则符合无规共聚物的Flory方程。此外,利用Avrami方程对均聚物PBS以及共聚物PBS-2M-20分别进行了等温结晶行为研究。结果表明：共聚使结晶速率降低,PBS和PBS-2M-20的Avrami指数分别介于2.8~3.0和2.6~2.8之间,结晶方式为三维生长异相成核,XRD测试结果证明共聚不影响晶体结构。     

可生物降解P(BS-co-CL)的合成

将不同配比的1,4-丁二酸、1,4-丁二醇与己内酯(ε-CL)在氯化亚锡和对甲基苯磺酸的催化作用下进行熔融缩聚合,合成了可生物降解聚丁二酸丁二酯-聚己内酯共聚物[P(BS-co-CL)]。采用核磁共振波谱仪、差示扫描量热仪、广角X射线衍射仪、偏光显微镜等对P(BS-co-CL)的结构、结晶性能、晶体形态和力学性能进行了分析。结果表明:引入ε-CL降低了聚丁二酸丁二酯(PBS)的结晶能力,改变了PBS的结晶形态,但晶体结构未发生改变,仍为单斜晶系α晶型。适当含量ε-CL的引入显著提高了P(BS-co-CL)的拉伸弹性模量和断裂拉伸应变。     

1,4-环己烷二甲醇改性PBT共聚酯的热性能研究

以对苯二甲酸(PTA)、1,4-丁二醇(BD)和1,4-环己烷二甲醇(CHDM)为主要原料,制备了一系列CHDM改性聚对苯二甲酸丁二醇酯(PBT)共聚酯。采用差式扫描量热仪(DSC)和热重分析仪(TGA)等分析方法测试了共聚酯的性能,研究了不同CHDM含量对共聚酯热性能和结晶性能的影响。结果表明:随CHDM含量的增加,共聚酯玻璃化转变温度逐渐升高;共聚酯的熔点先降低后升高,CHDM/PTA摩尔比为40%时熔点最低;随CHDM含量的增加,共聚酯的结晶性能逐渐减弱。     

枝化聚丁二酸丁二醇酯共聚物的合成及结晶性能研究

采用丁二酸(SA)、1,4-丁二醇(BDO)及枝化单体正丁基缩水甘油醚(BGE)合成了不同枝化度的枝化聚丁二酸丁二醇酯(PBS)共聚物,采用核磁共振仪、X射线衍射仪、差示扫描量热仪以及偏光显微镜对枝化共聚物的化学组成及结晶性能进行了表征。结果表明,枝化单元的引入没有改变聚合物的晶型,但显著改变了其热力学性能,枝化PBS共聚物的熔点(Tm)、结晶度(Xc)均随枝化单体含量的增加逐渐降低;相比纯PBS,枝化PBS共聚物的Avrami指数n降低;高枝化度对结晶形貌,特别是环带的形貌有较大影响。     

CHDM改性PBT共聚酯的非等温结晶动力学研究

采用直接酯化熔融缩聚工艺路线,以1,4-环己烷二甲醇(CHDM)为第三单体,制备了CHDM改性聚对苯二甲酸丁二醇酯(PBT)共聚酯(PBTG),利用差示扫描量热仪测定了PBT及PBTG在不同降温速率下的降温曲线,并采用Jeziorny方法分析了PBTG的非等温结晶动力学。结果表明:随着降温速率的增加,PBT及PBTG的结晶温度降低,结晶曲线变宽;在相同降温速率下,相比PBT,加入第三单体CHDM后的PBTG的非等温结晶动力学速率常数降低,证明PBTG的非等温结晶能力降低,结晶速率变慢; CHDM的加入不利于PBT结晶。     

二酸和二醇改性聚丁二酸丁二醇酯的性能比较

采用二酸[二乙醇酸(DGA)]和二醇[1,4-环己烷二甲醇(1,4-CHDM)]分别对PBS进行共聚改性。通过热分析、WAXD、拉力试验等对共聚物的性能进行了比较研究。结果表明:相比PBS,共聚物的球晶尺寸有所减小,结晶度降低。无论是酸还是醇的改性都使共聚物的柔韧性增强,断裂伸长率提高了近两倍。热分析结果还表明:相比PBS的Tg(-34℃),具有立体构造1,4-CHDM的添加,使P(BS-co-CHDM)的Tg上升为-28℃;线性结构DGA的添加,使P(BS-co-DGA)的Tg下降到-37℃,但tanδ都是增大的。热分解温度(失重率为5%时)仍在300℃以上,说明共聚物仍具有良好的热稳定性。     

PBS/PCL共混物的增容研究

采用1,4-丁二酸、1,4-丁二醇和己内酯为共聚单体,合成丁二酸丁二酯-己内酯共聚物[P(BS-coCL)],作为聚丁二酸丁二酯(PBS)/聚己内酯(PCL)共混物的增容剂。通过将m(PBS)∶m(PCL)为80∶20的PBS/PCL共混物与增容剂熔融共混,制备不同增容剂含量的PBS/PCL共混物。结果表明:随着增容剂P(BS-co-CL)的加入,PCL相的结晶能力增强,PBS相的结晶能力减弱;增容剂的加入未改变共混物中PBS及PCL相的晶体结构;当增容剂用量为5 phr时,共混物两相的界面相容性提高,共混物晶体生长受到抑制,晶体尺寸变小,共混物的拉伸形变显著增大。     

PBS-PTMO嵌段共聚物的合成及其结晶动力学北大核心

以丁二酸、丁二醇以及聚四氢呋喃醚(PTMO)为原料制备了w(PTMO)为50%的可生物降解聚丁二酸丁二酯(PBS)-PTMO嵌段共聚物(记作PBSPTMO50)。采用核磁共振氢谱仪,凝胶渗透色谱仪对共聚物进行了表征,利用差示扫描量热仪研究了PBS硬段和软段的非等温结晶动力学。结果表明:PBSPTMO50的数均分子量和重均分子量分别为53 083,152 407,相对分子质量分布指数为2.87;PBSPTMO50有两个结晶峰;Ozawa方程能拟合PBS硬段的非等温结晶过程,但不适合PTMO软段;而莫志深方程能拟合PBS硬段和PTMO软段的非等温结晶过程。     

乙烯-四氟乙烯共聚物非等温结晶行为

采用差示扫描量热仪(DSC)和偏光显微镜(PLM)对乙烯-四氟乙烯共聚物(ETFE)的非等温结晶行为进行了研究,并用莫志深法和Kissinger法对结晶动力学进行处理。结果表明,随着降温速率增大,ETFE的结晶温度逐渐下降,结晶温度范围变宽;ETFE的结晶过程分三阶段进行,分别为成核阶段、由晶核生成球晶阶段和球晶碰撞并生长阶段;ETFE的非等温结晶活化能随着共聚物中C2F4组分的增加而增加。     

含侧甲基可生物降解P(BS-co-NPG)的合成

采用熔融聚合法将不同比例的1,4-丁二酸、1,4-丁二醇与季戊二醇(NPG)在氯化亚锡和对甲基苯磺酸的催化作用下进行缩聚合,合成了可生物降解聚(丁二酸丁二醇-丁二酸季戊二醇)酯共聚物[P(BS-co-NPG)],并分析了P(BS-co-NPG)的化学结构、结晶性能、结晶形态和拉伸性能。结果表明:随着NPG含量的增加,P(BSco-NPG)的熔融温度、结晶温度逐渐降低,结晶能力逐渐下降,当y(NPG)为40%时,P(BS-co-NPG)呈非晶态;引入NPG并未改变P(BS-co-NPG)的晶体结构,仍为单斜晶系α晶型;NPG的引入改变了P(BS-co-NPG)的晶体形态,提高了其拉伸性能。     

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.