淀粉/聚乳酸共混材料的性能研究

对比研究了淀粉/聚乳酸(starch/PLA)和淀粉/聚乳酸接枝马来酸酐(starch/PLA-gMAH)共混体系的主要性能。结果表明:淀粉与聚乳酸直接共混时相容性较差,而将聚乳酸接枝马来酸酐则实现了对共混物的增容,使starch/PLA-g-MAH体系的力学性能和耐水性能显著提高。同时,不同配比的starch/PLA-g-MAH共混物仍具备良好的可生物降解性能。     

聚乙烯醇共混薄膜研究进展

从近年来聚乙烯醇（PVA）与天然高分子［淀粉、壳聚糖（CS）及蛋白质］、合成型生物降解高分子［聚乳酸（PLA）、聚己内酯（PCL）及聚乙二醇（PEG）］以及合成型不可生物降解高分子［聚苯胺（PANI）、低密度聚乙烯（PE⁃LD）及聚氨酯（PU）］进行共混研究角度进行分析,总结了共混薄膜的制备方法及结构性能,并介绍了PVA共混膜材料在医疗、分离、食品包装及农业领域的应用情况,最后对PVA共混薄膜未来的研究方向进行了展望。     

增塑剂对聚乳酸/热塑性淀粉共混物结构与性能的影响

采用柠檬酸三丁酯(TBC)、聚乙二醇(PEG)增塑聚乳酸(PLA)/热塑性淀粉(TPS)共混体系,调节PLA的流变性能,改善PLA与TPS相容性、熔融共混特性和共混物的微观结构和力学性能.结果表明:TBC的改性效果比PEG更佳;TBC能增加TPS分散均匀性,相分散尺寸明显变小;TBC改性PLA/TPS的拉伸强度和断裂伸长率明显提高.吸水率较小.     

聚乳酸/热塑性淀粉多组分生物可降解共混物研究进展

全生物基聚乳酸/淀粉生物可降解材料,同时具有聚乳酸(PLA)的高性能和淀粉(TPS)的低成本,是近年来受到广泛关注的全生物降解高分子体系。由于淀粉具有较强的亲水性,与PLA基体难以相容,使界面的黏附性较差,导致材料的性能恶化; PLA/TPS共混物体系研究的焦点主要是通过改善组分的界面相容性,提高共混物的力学性能。文章对聚乳酸/热塑性淀粉(PLA/TPS)共混物的制备和性能进行介绍,对PLA/TPS二元共混物的力学性能进行了概述,主要总结了增塑剂、无机粒子对PLA/TPS共混物界面结构和力学性能的影响,详细阐述了接枝(嵌段)共聚物、小分子化合物增容PLA/TPS共混物多组分体系的研究进展。高性能聚乳酸/淀粉生物可降解多组分共混物是一种极具开发前景的新型生物可降解塑料。     

淀粉/聚乳酸/聚己内酯共混材料的性能研究

研究了淀粉/聚乳酸接枝马来酸酐/聚己内酯接枝马来酸酐(starch/PLA-g-MAH/PCL-g-MAH)共混材料的主要性能。结果表明:PCL-g-MAH的加入有效增强了共混物的韧性,且将两聚酯接枝马来酸酐实现了对共混物的增容,使starch/PLA-g-MAH/PCL-g-MAH共混体系的力学性能和耐水性能比淀粉/聚乳酸/聚己内酯(starch/PLA/PCL)共混物显著提高。同时,增容后的共混物仍具备良好的可生物降解性能。     

聚乳酸复合材料增塑及增韧改性研究进展

简要介绍了聚乳酸(PLA)增塑改性的增塑机理,综述了近年来PLA增塑及增韧改性研究现状及进展,主要包括聚乙二醇、柠檬酸酯、植物油增塑改性PLA及柔性可降解树脂、弹性体、无机刚性粒子、植物纤维、淀粉等韧性材料共混增韧改性PLA,得出了PLA在增塑及增韧过程中存在的一些问题,如添加增塑剂改性或与柔性可降解树脂共混难以保证力...     

丙交酯接枝淀粉提高聚乳酸/淀粉共混物透明性的研究

合成了丙交酯接枝淀粉(STL),采用红外光谱(FTIR)和核磁共振(NMR)表征了其结构。分别制备了聚乳酸(PLA)与塑化淀粉(TPS)、马来酸酐改性淀粉(MTPS)、STL质量比为90/10、70/30、50/50的熔融共混物,通过扫描电子显微镜(SEM)、雾度、透光率和拉伸测试表征了共混物的微观形貌、透明性和力学性能。结果表明:PLA/STL共混物中淀粉分散相尺寸更小,透明性与力学性能均明显大于PLA/TPS和PLA/MTPS。PLA/STL(90/10)共混物的透光率达到72.3%,力学性能接近纯PLA。     

GMA接枝聚乳酸对聚乳酸/淀粉共混物性能的影响

首先制备了聚乳酸与甲基丙烯酸缩水甘油酯(GMA)的接枝共聚物(PLA-g-GMA)和丁二酸酐功能化改性淀粉,并利用红外光谱和核磁共振谱对二者的结构进行了表征。进一步通过熔融共混法制备了聚乳酸(PLA)/改性淀粉/PLA-g-GMA三元共混物,并利用转矩流变仪、扫描电子显微镜、差示扫描量热仪和万能拉力试验机等手段研究了接枝物对共混物的流变性能、形貌结构、热性能以及力学性能的影响。结果表明,PLA-g-GMA的加入促进了淀粉在PLA基体中的分布,淀粉粒径最小在0.5μm以下;同时也抑制了PLA的热降解,提高材料的力学性能,尤其是断裂伸长率,最高达到260%;另外也抑制了PLA的结晶。     

淀粉/PLA可降解复合材料性能研究

采用熔融共混技术制备淀粉/聚乳酸(PLA)复合材料.以制备出的复合材料力学性能、转矩流变性能和微观结构作为指标,研究了淀粉的含量、甘油的加入量对淀粉/PLA共混材料性能的影响.结果表明,以PLA为基体材料,淀粉质量分数为30％,甘油/淀粉质量分数为30/100时,制备出的淀粉/PLA复合材料有较好的性能.     

聚乳酸共混膜的制备与表征

以聚乳酸(PLA)为膜基材、动物油或植物油为添加剂、二氯甲烷为溶剂,通过流延法制备聚乳酸共混膜。考察添加剂种类、添加剂与PLA的质量比对膜的表面结构与相关性能的影响。结果表明:制备的聚乳酸共混膜具有"海岛"结构;随着添加剂与PLA质量比值的增大,共混膜的"岛径"、接触角、弹性模量、渗析系数和铵根离子的累积渗透量均呈现有规律性的变化,具有良好的可调节性,在包膜缓控释肥料领域具有发展潜力。     

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。