PHBV增韧PLA的结晶及力学性能研究

采用熔融共混法,以聚(3-羟基丁酸-co-3-羟基戊酸酯)(PHBV)为增韧剂对聚乳酸(PLA)进行改性,得到PLA/PHBV复合材料。研究了PHBV用量对PLA/PHBV复合材料结晶性能和力学性能的影响。结果表明:随着PHBV用量的增加,PLA/PHBV复合材料的结晶度逐渐减小,拉伸强度和弯曲强度逐渐降低,而断裂伸长率则逐渐增大(当PHBV用量为50%时,复合材料的断裂伸长率比纯PLA提高了1.72倍),同时复合材料的冲击强度亦有所提高。由此可见,在不明显降低拉伸强度和弯曲强度的前提下,适量PHBV的添加能够改善PLA/PHBV复合材料的韧性。     

丙烯酸酯接枝改性天然橡胶增韧聚乳酸

通过在天然橡胶(NR)分子链上接枝甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA),制备了三种丙烯酸酯接枝改性NR:NR-g-PMMA,NR-g-PBA和NR-g-(PMMA,PBA)。采用核磁共振氢谱对三种接枝物进行了化学结构鉴定。将接枝改性后的NR和未改性的NR与PLA采用哈克密炼机熔融共混,分别制备了PLA/NR,PLA/NR-gPMMA,PLA/NR-g-PBA和PLA/NR-g-(PMMA,PBA)共混物,研究了接枝改性NR和未改性NR含量对共混物力学性能和热性能的影响。各共混物的拉伸弹性模量和拉伸强度均随接枝改性NR和未改性NR含量的增加而降低,断裂伸长率和缺口冲击强度随接枝改性NR和未改性NR含量的增加而提高。其中,PLA/NR-g-PBA共混物的断裂伸长率和缺口冲击强度比其它共混物提高的幅度大,当NR-g-PBA的质量分数为5%时,PLA/NR-g-PBA共混物的断裂伸长率达到78%,缺口冲击强度为5.2 k J/m2,而纯PLA的断裂伸长率仅为7.7%,缺口冲击强度为2.5 k J/m2,说明NR接枝分子柔顺性较高的BA更有利于促进其与PLA共混物的韧性提高。热分析结果表明,PLA/NR-gPBA共混物的热稳定性相比于纯PLA也有所提高。     

扩链剂KL-E4370对PLA/PBAT复合材料结构与性能的影响

选用扩链剂KL-E4370与聚乳酸(PLA)和己二酸-对苯二甲酸-丁二酯共聚物(PBAT)熔融共混,制备出增容改性的PLA/PBAT复合材料。通过万能拉伸试验机、转矩流变仪、凝胶渗透色谱仪(GPC)、差热扫描量热仪(DSC)和动态热机械分析仪(DMA)研究了KL-E4370对PLA/PBAT复合材料结构与性能的影响。结果表明:随着KL-E4370用量的增加,PLA/PBAT复合材料的拉伸强度和断裂伸长率持续增大,平衡扭矩和非牛顿指数不断升高,冷结晶能力减弱,初始储能模量提高,分子链段的松弛转变更加容易;当KL-E4370的加入量超过0.2 phr时,复合材料中出现明显的支化结构。     

有机硅改性聚氨酯增韧聚乳酸的研究

针对聚乳酸(PLA)韧性差的特点,采用有机硅改性热塑性聚氨酯(TPSiU)对PLA通过熔融共混进行增韧改性,考察了TPSiU含量对PLA/TPSiU共混物微观结构、热性能及力学性能等的影响。研究结果表明,TPSiU的加入,使PLA由脆性材料转变为韧性材料,共混物的拉伸强度、弹性模量,冲击强度均随TPSiU含量的增加呈先增大后减小的趋势,当TPSiU的质量分数为20%时,PLA/TPSiU共混物的断裂伸长率提高约8倍。PLA/TPSiU共混物中两相呈海-岛结构,相容性欠佳,而且随着TPSiU含量的增加,"岛"相尺寸逐渐增大。另外,TPSiU的加入对PLA的热性能稍有影响,当TPSiU质量分数为10%时,共混体系的耐热性与纯PLA相当。     

不同己烯含量对PBH性能及其改性聚丙烯性能影响的研究

采用本实验室自制的负载钛催化剂[TiC l4/MgC l2-A l(i-Bu)3]体系,合成了不同己烯初始摩尔含量1-丁烯-1-己烯共聚物(PBH)热塑性弹性体,研究其结构与性能的关系;并用不同己烯初始摩尔含量的PBH对聚丙烯(PP)进行共混改性,研究了共混物的力学性能和热性能。结果表明,随着共聚物中己烯初始摩尔含量的增加,共聚物的拉伸强度、撕裂强度和硬度均下降;而断裂伸长率明显增大。当共混物中PBH含量一定(10%)时,随着共聚物中己烯初始摩尔含量的增加,共混物的冲击强度和断裂伸长率均明显增大,而拉伸强度、硬度和耐热温度有一定的下降。     

聚己内酯/聚乳酸/竹纤维复合材料制备及性能

以聚己内酯（PCL）和聚乳酸（PLA）共混物为基材,竹纤维（BF）作为增强材料,硅烷偶联剂为改性剂,通过模压成型制备了PCL/PLA/BF复合材料。研究了PCL和PLA质量比、BF质量分数、硅烷偶联剂用量以及模压温度对复合材料性能影响。结果表明,适宜的PCL/PLA质量比为1∶1,BF质量分数为40 %时BF/PCL/PLA复合材料的冲击强度、拉伸强度和断裂伸长率分别达到最大值11.26 kJ/m2,12.68 MPa和5.2 %;硅烷偶联剂用量为1 %时复合材料的冲击强度、拉伸强度和断裂伸长率分别达到最大值15.11 kJ/m2、13.15 MPa和5.8 %;模压温度为150 ℃时,复合材料的冲击强度、拉伸强度和断裂伸长率分别达到最大值14.51 kJ/m2、13.75 MPa和5.8 %。     

聚乳酸/改性甘蔗纤维复合材料的制备与性能分析

以低分子量聚乙二醇(PEG)为增塑剂,马来酸酐改性的甘蔗纤维(MSF)为成核剂,采用熔融共混的方式制备PLA/MSF/PEG复合材料,并对复合材料的结晶行为、晶体形貌、力学和表面亲水性进行研究。结果表明:表面改性的MSF可作为异相成核剂,显著提高PLA的结晶能力;增塑剂PEG和成核剂MSF的协同加入,能够进一步提高PLA的结晶速率,并增大球晶尺寸。增塑剂PEG的加入,能够明显提高PLA/MSF/PEG的断裂伸长率,但使复合材料的拉伸强度和模量下降。与PLA/PEG共混物相比,PLA/MSF/PEG共混物具有更高的拉伸强度和模量。PLA/MSF(3%)/PEG(10%)的综合性能较好,与纯PLA相比断裂伸长率提高468.7%,拉伸强度降低48.7%左右。因此,增塑剂PEG与改性纤维MSF协同改性,使PLA/MSF/PEG共混物具有更优异的力学性能和结晶性能,能够进一步扩大PLA材料的应用范围。     

生物可降解聚乳酸的无卤阻燃与增韧改性研究

选用次磷酸铝(AHP)与聚乳酸(PLA)熔融挤出共混制备无卤阻燃PLA复合材料,采用氮系阻燃剂(MCA)与次磷酸铝进行复配,并通过添加增韧剂乙烯-甲基丙烯酸酯-甲基丙烯酸缩水甘油酯共聚物(EMA-GMA)改善阻燃PLA的冲击性能。研究结果表明,随着磷系阻燃剂AHP用量的增加,聚乳酸的阻燃性能提高;当AHP添加量为20%时,阻燃PLA复合材料的氧指数为29.0%,UL94测试达到V-0级,AHP与MCA有一定的阻燃协同作用。随增韧剂EMA-GMA用量的增大,阻燃聚乳酸复合材料的韧性较未改性的阻燃聚乳酸材料有明显增加。当EMA-GMA质量分数为15%时,改性聚乳酸复合材料的断裂伸长率比PLA阻燃复合材料提高5倍;缺口冲击强度增加了54.8%,无缺口冲击强度增加了230%。     

PBAT/PLA复合材料的制备及其微球发泡行为研究

采用熔融共混法制备了聚(己二酸丁二醇酯-对苯二甲酸丁二醇酯)/聚乳酸(PBAT/PLA)共混复合材料,并对PBAT/PLA共混体系的流变性能、结晶性能、力学性能、微观形貌以及发泡行为(热膨胀微球作为发泡剂)进行了表征。结果表明:随着PLA含量的增加,PBAT/PLA共混体系的非牛顿指数先减小后增大,其中当PLA含量为30%时达到最小值;PLA的引入改善了PBAT的结晶性能,且PBAT与PLA对彼此的晶型均无影响;随PLA含量的增加,PBAT/PLA共混体系的拉伸强度增大、断裂伸长率降低,其中当PLA含量为50%时,拉伸强度和断裂伸长率分别达到25.3 MPa和422.2%;PLA与PBAT的相容性差,当PLA含量为30%时,PLA/PBAT共混体系发生相分离;此外,当PLA含量为10%时,PBAT/PLA复合发泡材料的密度达到最小值0.34 g/cm~3。     

聚酰胺弹性体增韧聚乳酸改性研究

选用聚酰胺弹性体(聚酰胺和聚氧乙烯的共聚物,PAE)与聚乳酸(PLA)熔融共混进行增韧改性。结果表明,当PAE弹性体含量在20%～30%(质量分数,下同)之间时,共混体系发生脆韧转变,最大冲击强度达到67.6J/m,但拉伸强度和模量大幅度下降;PAE弹性体含量为5%～10%时共混体系的拉伸强度保持率最高,而且断裂伸长率提高近40倍,综合性能较好;虽然扫描电子显微镜照片显示共混体系为两相分离,但是差示扫描量热分析数据均表明,随着PAE弹性体含量的增加,共混体系的玻璃化转变温度和熔点发生相应变化,证明该共混体系为半溶混性,即两相间存在一定的相互作用;热失重分析数据显示,PAE弹性体在一定程度上提高了PLA的热降解温度。     

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.     

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.     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Some Large Wood-Boring Beetles in Southeastern USA

Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002–2004. Multiple-funnel traps baited with (−)-α-pinene (released at about 2 g/d at 25–28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (−)-α-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (−)-α-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (−)-α-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (−)-α-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.