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1.
西佛碱/尼龙6原位聚合复合材料的合成与表征   总被引:1,自引:0,他引:1  
采用原位聚合方法制备了西佛碱(SD)刚性链/尼龙6(PA6)复合材料,并对其结构和热性能进行了表征。红外光谱和紫外光谱分析结果表明,SD刚性链已在PA6基体中生成;DSC和TGA热分析结果表明,SD的加人,对PA6的结晶有诱导作用,但没有改变铸型尼龙的α晶型结构;SD(5%)/PA6的动态力学谱图上,只出现一个玻璃化转变温度,较PA6提高了9℃。  相似文献   

2.
根据碱催化阴离子聚合原理制备了单体浇铸(MC)尼龙6(PA6)、长碳纤维增强尼龙6(PA6/CL)复合材料和三维编织碳纤维增强尼龙6(PA6/C3D)复合材料,分析了工艺影响因素,并通过动态热机械分析仪对材料的热机械性能进行了研究。结果表明,PA6/C3D复合材料比PA6的热强度高4.37倍,而玻璃化转变温度却基本未发生变化,PA6/C3D复合材料的综合性能优于PA6/CL复合材料。  相似文献   

3.
MC尼龙6/TiO2原位纳米复合材料的制备及表征   总被引:10,自引:0,他引:10  
利用阴离子原位聚合法制备了铸型尼龙6(MC尼龙6)/TiO2原位纳米复合材料,并对其结构与性能进行了表征。透射电子显微镜观察表明,TiO2以纳米级均匀分散于MC尼龙6中,其含量小于1份时近乎单分散,大于1份时则开始团聚。差示扫描量热法和X射线衍射法分析结果表明,纳米TiO2对MC尼龙6的结晶起到了异相成核作用,提高了MC尼龙6的结晶温度,但不改变MC尼龙6的α晶型结构;退火处理结果表明,高温退火或加入纳米TiO2,都有利于MC尼龙6基体中α晶型的生成,加快γ晶向α晶的转变。热重分析和力学性能测试表明,纳米TiO2提高了复合材料的热稳定性,其拉伸强度、冲击强度等也得到了不同程度的提高。  相似文献   

4.
尼龙6/粘土纳米复合材料的性能   总被引:6,自引:1,他引:5  
对尼龙6/粘土纳米复合材料(PA6CN)的力学性能、结晶性能、流变性能、热稳定性、阻隔性能、阻燃性能、各向异性和可纺性进行了综述。加入粘土后,基体尼龙6的晶型变为γ型,改善了尼龙6的力学性能,提高了热变形温度,降低了吸水率,改善了气体阻隔性和材料的阻燃性,拓宽了复合材料的应用范围。  相似文献   

5.
采用溶液共混法制备了聚酰胺6(PA 6)/聚酰胺66(PA 66)/热致聚酰胺液晶(TLCPa)共混物,分析了TLCPa对PA 6/PA 66相容性及结晶行为的影响。差示扫描量热法分析表明,TLCPa的加入改善了PA 6和PA 66之间的相容性,PA 6/PA 66共混物结晶受到抑制;傅里叶变换红外光谱研究表明,TLCPa和PA 6、PA 66分子间形成了大量的分子间氢键,是TLCPa改善共混物相容性的主要原因;广角X射线衍射分析表明,TLCPa的加入没有影响共混物的晶型结构,当w(TLCPa)大于10%时,共混物的结晶度明显下降。  相似文献   

6.
利用反应挤出的方法,制备了尼龙6/乙烯-辛烯共聚物(PA6/POE)热塑性弹性体(TPE)。采用差示扫描量热法(DSC)研究了TPE中PA6相的非等温结晶行为。结果表明,POE降低了TPE中PA6的结晶热,相容剂的加入使TPE中PA6的γ结晶减少以及降低了PA6的结晶速度。  相似文献   

7.
采用挤出方式分别制备尼龙6/氯化钙(PA6/Ca Cl_2)、尼龙6/氯化钙/玻璃纤维(PA6/Ca Cl_2/GF)复合材料。利用差示扫描量热仪(DSC)研究了氯化钙和玻璃纤维对两种复合材料非等温结晶行为的影响,并用Jeziorny法、Mo法对复合材料结晶动力学进行研究。结果表明,Ca Cl_2的络合作用使PA6/Ca Cl_2复合材料起始结晶温度、结晶速率降低;而GF提高了PA6/Ca Cl_2结晶的起始温度,减小其总结晶时间,对于PA6/Ca Cl_2/GF复合材料,GF起到了成核作用。X射线衍射仪(XRD)研究表明,与金属离子诱导PA6生成α晶型不同,GF诱导其生成γ晶型。  相似文献   

8.
通过熔融共混方法成功制备了尼龙-6(PA6)/埃洛石纳米管(HNTs)二元复合材料和PA6/碳纤维(CF)/HNTs三元复合材料,并研究了HNTs对PA6力学性能及热性能的影响,以及HNTs和CF协同增韧增强PA6的效果。结果表明,HNTs的加入能够显著提高PA6的刚性和韧性,在质量分数10%的添加量下,可将PA6冲击强度提高56.4%,弯曲模量提高50%。另外,HNTs能够有效诱导PA6结晶形态从α晶型向γ晶型转变,降低了结晶度,有利于降低材料的成型收缩率。同时,HNTs和CF在增韧增强PA6方面显示出了良好的协同作用。  相似文献   

9.
采用广角X射线衍射仪(WAXD)、偏光显微镜和差示扫描量热仪(DSC)等手段研究尼龙6(PA6)/高岭土纳米复合材料的结晶行为.结果表明:高岭土的加入起到成核剂的作用,影响到PA6成核机理和结晶的生长,且改变了PA6的晶型,使PA6结晶温度略有升高,结晶速率增加,更易于结晶.同时从Avrami方程出发,得出纳米高岭土的存在可以明显改变PA6的结晶行为.  相似文献   

10.
通过熔融共混法制备了不同配比的尼龙6(PA6)/磷酸三苯酯(TPP)/三聚氰胺氰尿酸盐(MCA)粒料,采用垂直水平燃烧仪、万能材料试验机、摆锤冲击试验机,研究了阻燃 PA6粒料的组成对其阻燃和力学性能的影响。通过熔融纺丝技术证明了 PA6阻燃粒料的可纺性,研究了材料组成对其纺丝性能的影响。使用纤维强伸度仪、热重分析仪研究了 PA6纤维的组成对纤维力学性能和热性能的影响与规律。研究结果表明,TPP 含量的增加能够提高阻燃PA6粒料的阻燃等级,并且当 PA6∶MCA∶TPP 质量比为90∶9∶0.3时,PA6具有较好的阻燃和力学性能。  相似文献   

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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.  相似文献   

13.
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.  相似文献   

14.
A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by 1H MAS NMR. For direct comparison purposes, an SiO2 coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N2 absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.  相似文献   

15.
Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.  相似文献   

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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.  相似文献   

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