首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
纳米SiO_(2-x)改性环氧复合材料研究   总被引:9,自引:0,他引:9  
采用偶联剂表面处理同时通过超声波震荡的方法使纳米SiO2 x粒子在环氧树脂中充分分散,制得了纳米SiO2 x环氧E-51/MeTHPA复合材料。利用INSTRON试验机、TEM、TG等方法对该复合材料的性能进行了研究,结果表明,纳米SiO2 x粒子能够以纳米级分散到环氧树脂基体中,较大地提高了环氧树脂的拉伸强度、冲击强度、断裂伸长率、热稳定性等性能。  相似文献   

2.
LLDPE/纳米SiO2复合材料的制备与性能研究   总被引:14,自引:1,他引:13  
利用超声波分散,偶联剂对纳米SiO2进行了表面改性,用共混法制备了LLDPE/纳米SiO2复合材料,系统研究了该种新型复合材料的静态,动态力学性能和红外吸收性能,并与球磨机分散,偶联剂表面处理的纳米SiO2制备的LLDPE/纳米SiO2复合材料进行了对比。结果表明,纳米SiO2对LLDPE具有一定的增强,增韧作用;复合材料的贮能模量和损耗模量随SiO2含量的增加而增大,阻尼在-15-30℃范围内逐渐降低;复合材料的红外吸收能力较LLDPE明显提高,不同的分散,表面处理方法对纳米SiO2在基体中的分散性能影响不同。仅填加3份纳米SiO2时,常规分散,表面处理方法比基体树脂的红外吸收性能提高了42.5%。超声波分散,偶联剂表面处理方法比基体树脂提高了106.7%。  相似文献   

3.
纳米粒子增韧环氧树脂的研究   总被引:1,自引:1,他引:0  
本文主要探讨了纳米SiO2对环氧树脂韧性的影响。通过用偶联剂对纳米粒子表面改性处理,再辅助以超声波振动,使纳米粒子在环氧树脂中分散均匀、稳定,增强了纳米粒子与环氧树脂之间的粘结力,从而使复合材料的冲击强度得到了较大的提高,增韧效果较为明显。  相似文献   

4.
纳米SiO2/双马来酰亚胺复合材料的性能研究   总被引:2,自引:0,他引:2  
采用浇铸成型法制备了纳米SiO2粒子填充双马来酰亚胺(BMI-BA)复合材料,研究了纳米SiO2的填充量对复合材料滑动磨损性能的影响。在磨损机上测试该复合材料的摩擦和磨损性能,利用扫描电镜(SEM)观察了复合材料的磨损表面和对磨环的表面形貌。结果表明,纳米SiO2能够有效地提高复合材料的力学性能和摩擦学性能。当纳米SiO2粒子的添加量为0.75%(质量含量,下同)时,复合材料的综合力学性能最好;当纳米SiO2粒子的的添加量为1.0%时,复合材料的耐磨性能最好。SEM显示复合材料主要是黏着磨损,能在对磨环上形成薄而连续的均匀转移膜,而BMI-BA树脂主要发生的是疲劳磨损,并伴有塑性变形。  相似文献   

5.
粒子分散性对环氧树脂/纳米SiO2材料性能的影响   总被引:9,自引:0,他引:9  
通过原位分散聚合法制得了环氧树脂/纳米SiO2复合材料。采用超声波和偶联剂改善了纳米SiO2在基体中的分散性,利用拉伸实验、冲击实验、扫描电子显微镜、热重法等方法研究了粒子分散性对复合材料结构和性能的影响。结果表明:超声波和偶联剂都能使纳米SiO2均匀地分散在环氧树脂基体中,有效地增加复合材料的力学强度及韧性,并能提高材料的耐热性。对于提高纳米SiO2在环氧树脂中的分散均匀性,超声波的作用优于偶联剂。  相似文献   

6.
原位聚合法制备钼酚醛树脂纳米复合材料的研究   总被引:1,自引:0,他引:1  
刘晓洪  胡银霞 《塑料工业》2004,32(7):18-19,50
采用原位聚合法,用表面处理过的二氧化硅(SiO2)纳米粒子对钼酚醛树脂进行填充改性,制备了钼酚醛脂/SiO2纳米复合材料,研究了SiO2纳米粒子填充改性对复合材料耐热性和力学性能的影响。实验结果表明,SiO2质量分数为2%时,材料的耐热性和冲击强度达到最大值,分别为105℃和4.3kd/m^2;SiO2质量分数为4%时,材料的拉伸模量和拉伸强度达到最大值,分别为1288MPa和30.3MPa。  相似文献   

7.
纳米SiO2粒子对PP结晶行为的影响   总被引:7,自引:1,他引:6  
通过X-射线光电子能谱(XPS)对经偶联剂处理的纳米SiO2粒子(简称烷基化SiO2纳米粒子)和聚甲基丙烯酸甲酯(PMMA)接枝包覆SiO2纳米粒子(简称SiO2-g-PMMA复合纳米粒子)的表面组成进行分析。将纳米SiO2粒子,烷基化SiO2纳米粒子,复合纳米粒子分别与基体PP复合制备复合材料,通过DSC,WAXD和TEM等测试方法详细研究了PP/SiO2复合材料的结晶行为与力学性能,结果发现:纳米SiO2粒子与烷基化SiO2纳米粒子并不改变基体PP的结晶形态,而复合纳米粒子诱发了基体PP的β晶型结晶,复合纳米粒子比较均匀地分散于PP基体中,对复合材料的力学性能有较大的改善。  相似文献   

8.
聚氨酯弹性体/纳米SiO2复合材料的力学性能研究   总被引:2,自引:0,他引:2  
刘少兵  程绍娟  张颖  贾林才 《塑料工业》2008,36(2):38-40,50
采用预聚体的方法制备了聚氨酯弹性体(PUE)/纳米SiO2复合材料,通过AJ(OH)3对纳米SiO2表面改性以及超声波分散的方法来提高纳米SiO2在PUE基体中的分散性,并考查了表面处理前后的纳米SiO2对PUE/纳米SiO2复合材料力学性能的影响.结果表明:改性后的纳米SiO2能均匀分散于PUE基体中,复合材料的力学性能明显提高;纳米SiO2的用量对PUE/纳米SiO2复合材料的力学性能影响较大,并且当纳米SiO2的质量分数为2%和3%时,复合材料的拉伸强度和撕裂强度分别达到最大.  相似文献   

9.
利用表面原位接枝聚合在纳米二氧化硅颗粒表面引入聚甲基丙烯酸甲酯(PMMA)高分子链段,用共混法制备了nano-SiO2/PVC复合材料,研究了不同界面特性时SiO2/PVC复合材料的力学性能.研究结果表明通过表面原位接枝聚合反应可以在纳米二氧化硅颗粒表面接枝聚甲基丙烯酸甲酯;表面接枝PMMA的nano-SiO2/PVC复合材料在力学和加工性能等方面都优于偶联剂处理和表面未处理样品.在纳米二氧化硅颗粒填充量为0%~8%(wt)时,复合材料的拉伸强度和冲击强度随着填充量的提高先上升后下降,并在4%~6%(wt)达到最大值.经PMMA表面接枝后SiO2/PVC具有更强的界面作用,偶联剂KH570处理的次之,表面未处理样品的最差.  相似文献   

10.
采用正硅酸乙酯(TEOS)水解生成的SiO2对纳米ZnO进行表面包覆,制备了ZnO—SiO2纳米复合粒子,并用该复合粒子对聚碳酸酯(PC)进行改性处理。考察了纳米ZnO的表面包覆改性效果,研究了不同纳米复合粒子用量时复合材料的耐光氧老化性能,并探讨了纳米复合粒子对复合材料注塑工艺的影响。结果表明,SiO2成功包覆在纳米ZnO的表面,纳米复合粒子为球形,大小均匀,且在PC基体中分散均匀;纳米复合粒子的加入使复合材料的耐光氧老化性能明显提高,而加热温度、注塑压力和保压压力降低。  相似文献   

11.
12.
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.
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   

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   

16.
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   

17.
18.
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号