表面处理对剑麻纤维性能及与淀粉相容性的影响

采用碱处理、硅烷偶联剂处理以及两者复合的处理方法对剑麻纤维进行表面改性,研究了不同处理方法对剑麻纤维的性能以及剑麻纤维/淀粉复合材料界面粘结性能的影响。通过傅立叶变换红外光谱仪、热重分析仪、扫描电子显微镜和万能试验机对不同处理的剑麻纤维进行表征,使用拔出实验测试剑麻/淀粉复合材料的界面粘结情况,并采用二参数威布尔模型计算拉伸强度和界面剪切强度。结果表明,所有处理方法都能提高剑麻纤维的热稳定性和界面剪切强度。与未处理纤维相比,碱处理后的剑麻纤维与淀粉的界面剪切强度最高,为2.011 MPa,提高了19%。     

剑麻纤维／酚醛树脂复合材料研究

本文采用碱处理、硅烷偶联剂处理、化学接枝和热处理等物理化学方法，对剑麻纤维进行改性。研究了改性后短剑麻纤维／酚醛树脂复合材料的弯曲性能、无缺口冲击强度和布氏硬度，借助扫描电子显微镜观察了复合材料的弯曲断口形貌，并研究了剑麻纤维的不同处理方法对复合材料耐水浸泡性的影响。结果表明：剑麻纤维经硅烷偶联剂处理后，能有效改善刚性的剑麻纤维与脆性的酚醛树脂基体之间的粘结，从而提高了复合材料的综合力学性能，剑麻     

基于非连续碱处理的剑麻纤维增强聚乳酸复合材料的制备和力学性能

提出了一种新的纤维表面处理方法———不完全化学处理法。以该方法制备的非连续碱处理剑麻纤维(DASF)作为增强纤维,通过开炼压制制备了DASF/聚乳酸(PLA)复合材料。对比了未处理剑麻纤维(SF)、连续碱处理剑麻纤维(CASF)以及DASF制得的PLA复合材料力学性能,并通过扫描电镜(SEM)、体视显微镜对试样进行观察分析。研究了DASF长度与直径的变化,以及非连续碱处理方法、DASF质量分数对复合材料结构和性能的影响。结果表明,DASF/PLA复合材料中,纤维的长度多分布在1.6～3.1 mm范围内,直径小于SF而大于CASF。相比于连续碱处理,非连续碱处理可以进一步提高复合材料力学性能。纤维质量分数会影响DASF/PLA复合材料的力学性能,当纤维质量分数为30%时,DASF/PLA复合材料的力学性能最优。     

协同改性处理对剑麻增强HDPE复合材料力学性能的影响

植物纤维和树脂的界面相容性差一直制约着天然纤维复合材料的发展和应用。分别对剑麻纤维(SF)进行了碱-偶联协同处理和碱-接枝协同处理,并利用双螺杆挤出机制备了SF/高密度聚乙烯(HDPE)复合材料。观察了剑麻纤维表面以及复合材料断面的微观形貌,表征了改性前后纤维基团的变化,研究了协同改性处理对剑麻纤维及其复合材料力学性能的影响。结果表明,碱-偶联协同处理的改性效果更好,剑麻纤维与HDPE的相容性得到明显改善,复合材料最大拉伸强度和弯曲强度相对于未改性纤维复合材料分别提高18.64%和20.25%。     

剑麻纤维增强聚乳酸复合材料酶降解研究

通过热压成型的方式制备了剑麻纤维增强聚乳酸（PLA/SF）复合材料,并通过K蛋白酶降解方式研究了该复合材料的生物降解性能,利用差热扫描量热仪测试分析了复合材料在酶降解过程中的非等温结晶性能。研究发现,剑麻纤维的加入加快了聚乳酸及其复合材料的降解速率,且随着剑麻纤维含量的增加,其降解速率提高;剑麻纤维的加入对聚乳酸的结晶性能有一定的影响,进而也影响了复合材料的酶水解速度。     

剑麻纤维的表面改性及其复合材料的研究进展

简述了剑麻纤维的组成、结构及力学性能,并总结了剑麻纤维表面改性的几种方法,包括物理方法：热处理、酸碱处理、有机溶剂处理;化学方法：改变表面张力、界面偶合、表面接枝聚合。同时论述了剑麻纤维的表面改性对复合材料力学性能的影响。     

表面处理对剑麻纤维布/不饱和树脂材料性能影响

采用碱、高锰酸钾及热对剑麻纤维布进行了表面处理,并由真空辅助树脂传递模塑成型(VARTM)工艺制备了剑麻纤维布增强不饱和聚酯树脂复合材料。通过对复合材料的力学性能及吸水性的测试,研究了不同剑麻纤维布表面处理对其不饱和聚酯树脂复合材料性能的影响。结果表明:经过碱处理,复合材料的拉伸、弯曲,冲击强度提高最大,可分别提高26.5%,16.5%和22.6%,吸水率降低了47.5%。对剑麻纤维布进行表面处理可使复合材料的界面性能得到改善,力学性能提高,吸水性降低。     

剑麻柄处理方法对剑麻纤维／脲醛树脂复合材料的性能影响

采用碱处理、偶联剂处理、醋酸处理等方法，对剑麻柄进行处理，再与自行合成的脲醛树脂(UF)进行捏合、模压，制成剑麻纤维／脲醛树脂共混复合材料。研究了碱处理最佳工艺以及不同处理方法对复合材料的力学性能、耐磨性、耐水性、电性能和热性能的影响，并与木粉／UF复合材料的性能进行了对比。结果表明：剑麻柄的处理方法对复合材料的电性能、热性能和吸水性影响不大；采用乙酰化处理剑麻柄时，复合材料强度较高。耐磨性好，此时剑麻纤维／UF复合材料的各项性能接近木粉／UF复合材料的性能     

改性处理对聚乳酸/废旧报纸回收纤维复合材料性能的影响

采用注射成型的方法制备了聚乳酸/废旧报纸回收纤维复合材料,探讨了马来酸酐接枝聚丙烯改性处理和1 %的NaOH改性处理对复合材料性能的影响。结果表明,在复合材料中加入2 %的马来酸酐接枝聚丙烯后,聚乳酸与废旧报纸回收纤维的相容性得到改善,复合材料的力学性能得到提高。废旧报纸回收纤维经1 %的NaOH处理后,与聚乳酸的界面被优化,纤维的相对结晶度增大,二者的黏结性能得到改善,复合材料的力学性能也会得到提高。     

碱处理对剑麻纤维增强聚乳酸可降解复合材料性能的影响

以剑麻纤维(SF)和聚乳酸(PLA)为原料,通过注塑成型工艺制备了剑麻纤维增强聚乳酸可降解复合材料。研究了连续碱处理剑麻纤维(CASF)和未改性处理剑麻纤维(USF)在不同含量时对复合材料力学性能、吸水性及可降解性能的影响。结果表明:剑麻纤维的质量分数会显著影响复合材料的力学性能、吸水性和降解性能。相较于未改性处理剑麻纤维(USF),碱处理剑麻纤维(CASF)可以进一步提高复合材料的力学性能,降低复合材料的吸水率,延缓剑麻纤维增强可降解树脂基复合材料的降解速率,且酶降解法相较于土埋法降解能够显著加快复合材料的降解速率。当剑麻纤维含量为20%时,CASF/PLA复合材料的拉伸强度、弯曲强度和弯曲模量相较于纯PLA和USF/PLA分别提高了32.71%、10.08%;19.63%、12.11%;97.33%、12.40%;其冲击强度相较于纯PLA提高了71.19%。     

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。