三维编织碳纤维增强尼龙6热机械性能研究

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。     

三维编织芳纶纤维增强尼龙复合材料性能研究术

研究了纤维体积比对三维编织芳纶纤维增强尼龙(简称K3D／PA)复合材料力学性能的影响。同时，研究了γ射线辐照处理对K3D／PA的影响。研究发现，随着芳纶纤维体积比的增大，K3D／PA的力学性能提高；芳纶纤维经γ射线辐照处理后，表面含氧量有所提高，并出现新的官能团。纤维经表面处理后，K3D／PA的弯曲强度、弯曲弹性模量及剪切强度均比未处理的高，但冲击强度较低。     

PA6/SANMAH/GF复合材料的制备及其性能研究

采用双螺杆挤出机通过熔融共混制备了尼龙6／（苯乙烯／丙烯腈／顺丁烯二酸酐）共聚物／玻璃纤维（PA6／SANMAH／GF）复合材料，测试了材料的拉伸强度、弯曲强度、弯曲弹性模量、缺口冲击强度、热变形温度、吸水率、熔点和熔融焓，并与GF增强PA6（PA6／GF）复合材料和GF增强PA6／（苯乙烯／丙烯腈）共聚物（PA6／SAN／GF）复合材料进行了性能对比。结果表明，在PA6与SANMAH的质量比为100：3—30时，PA6／SANMAH／GF复合材料的拉伸强度与PA6／GF复合材料相当，但高于PA6／SAN／GF复合材料，弯曲强度和弯曲弹性模量高于PA6／GF和PA6／SAN／GF复合材料．缺口冲击强度高于PA6／GF复合材料，但低于PA6／SAN／GF复合材料；在PA6与SANMAH的质量比为100：40时，PA6／SANMAH／GF复合材料的拉伸强度、弯曲强度和缺口冲击强度明显降低；在整个试验范围内，PA6／SANMAH／GF复合材料的热变形温度比PA6／GF和PA6／SAN／GF复合材料低4～7℃；吸水率随着SAN-MAH用量的增加而逐渐减小。     

马来酸酐接枝POE对PA6/OMMT性能的影响

用熔融共混法制备了尼龙6（PA6）／马来酸酐接枝乙烯-辛烯-1共聚物（MAH-g-POE）／有机蒙脱土（OMMT）复合材料，研究了MAH-g-POE用量对PA6／OMMT复合材料力学性能的影响。结果表明，随着MAH-g-POE用量增加，复合材料的冲击强度显著提高，而拉伸强度和弯曲强度则呈现下降的趋势。     

碳纤维增强尼龙复合材料的摩察性能研究

根据碱催化阴离子聚合原理，制备了连续长碳纤维增强单体浇铸尼龙复合材料（简称CL/PA）。在MM-200型磨损试验机上考察了碳纤维含量和试验条件对其摩擦性能的影响，并利用扫描电子显微镜对其摩擦性能和磨损机制进行了考察。分析结果表明：碳纤维的体积分数在35%左右时增强效果最好，CL/PA复合材料的摩擦系数和磨损率随着载荷的增加而减小。其磨损机制主要表现为粘着磨损和碳纤维的破碎和磨平的特征。     

表面处理对PA6/CF复合材料力学性能与破坏形态的影响

通过碳纤维(CF)表面官能团的酰氯化,利用酰氯作为己内酰胺阴离子聚合的活化剂,成功地制备了表面接枝尼龙6(PA6)的CF。研究了表面己内酰胺稳定化并阴离子接枝PA6的CF对PA6／CF复合材料力争性能与破坏形态的影响。结果表明,表面接枝PA6后的PA6／CF复合材料界面相互匹配,改善了复合材料界面的相互作用,提高了复合材料的剪切强度,复合材料剪切破坏呈部分非界面脱粘破坏。     

浸润剂对短切玻纤增强尼龙66性能影响的研究

利用双螺杆挤出机制备短玻纤增强尼龙66（GF／PA66）复合材料,采用不同组成的浸润剂处理玻璃纤维,研究其对GF／PA66的微观结构及性能的影响。结果表明,在T435D中加入乙烯基树脂或三聚氰胺后,玻纤增强尼龙66复合材料的拉伸强度、弯曲强度、简支梁冲击强度均有不同程度的提高,并通过扫描电镜观察到PA66基体与玻纤相界面的微观结构在一定程度上得到了改善,但在T435D中加入三聚氰胺在三种浸润剂配方中效果最佳。     

PA6／OMMT／SiO2纳米复合材料的制备及力学性能研究

以天然蒙脱土为原料，11-氨基酸作为有机插层剂与蒙脱土层间的阳离子进行交换制备OMMT，用原位聚合法制备PA6／OMMT／SiO2纳米复合材料，用X射线衍射仪、FT-IR光谱仪、差示扫描量热仪等对OMMT、纳米复合材料的结构及力学性能进行表征。结果发现，添加3％（质量含量，下同）OMMT的PA6／OMMT复合材料的拉伸强度、弯曲强度和弯曲模量较纯PA6分别提高了19％、13．8％、14％；而纳米SiO2的加入使纳米复合材料的拉伸和弯曲强度、刚性和韧性得到提高的同时，明显改善了蒙脱土使纳米复合材料缺口冲击强度下降的趋势，当纳米SiO2含量为1％时，缺口冲击强度提高了近33．5％。     

碳纤维表面处理对液体成型碳纤维增强MC尼龙复合材料力学性能的影响

本论文采用真空辅助树脂灌注成型工艺(VARI),通过己内酰胺原位阴离子聚合的方法制备了连续碳纤维增强浇铸(MC)尼龙的复合材料,并系统研究了丙酮去浆处理、气相氧化处理、偶联剂处理和火焰处理四种不同碳纤维织物表面处理方式的碳纤维表面的O/C比和微观形貌以及复合材料的力学性能、表面形貌和碳纤维体积分数。结果表明:对碳纤维表面进行偶联剂涂层处理,此碳纤维制备的复合材料的力学性能较其他处理方式的碳纤维制备的复合材料而言力学性能最优,其拉伸强度达到595.5 MPa,弯曲强度达到330.7 MPa,层间剪切强度达到30.6 MPa;此条件下碳纤维表面的O/C比达到44.51%,复合材料的碳纤维体积分数达到51.4%。     

原位插层聚合PA6／OMMT的性能

以自行合成的NJ-I型插层剂对蒙托土进行改性，并以X射线衍射、傅立叶变换红外光谱及热重分析表征了改性蒙脱土（OMMT）的性能。采用单体熔体插层-原位本体聚合的方法，制备了PA6／OMMT纳米复合材料，测定了该材料的热稳定性能及力学性能。结果表明，含1.2％OMMT的PA6／OMMT纳米复合材料的拉伸强度、弯曲强度及弯曲弹性模量较PA6分别提高14％、16．2％及38.1％，断裂伸长率及冲击强度则分别下降37．7％及4.5％。     

三维编织碳纤维尼龙复合材料的探索性研究

本文论述了根据碱催化阴离子聚合原理、用液态原位聚合方法制备三维编织碳纤维尼龙复合材料的成型工艺过程,测试并分析了其力学性能及其成型过程中的主要影响因素.结果表明,该复合材料的性能明显优于长碳纤维尼龙复合材料.     

Biopolyamide hybrid composites for high performance applications

This study focuses on the performance characteristics of wood/short carbon fiber hybrid biopolyamide11 (PA11) composites. The composites were produced by melt‐compounding of the fibers with the polyamide via extrusion and injection molding. The results showed that mechanical properties, such as tensile and flexural strength and modulus of the wood fiber composites were significantly higher than the PA11 and hybridization with carbon fiber further enhanced the performance properties, as well as the thermal resistance of the composites. Compared to wood fiber composites (30% wood fiber), hybridization with carbon fiber (10% wood fiber and 20% carbon fiber) increased the tensile and flexural modulus by 168% and 142%, respectively. Izod impact strength of the hybrid composites exhibited a good improvement compared to wood fiber composites. Thermal properties and resistance to water absorption of the composites were improved by hybridization with carbon fiber. In overall, the study indicated that the developed hybrid composites are promising candidates for high performance applications, where high stiffness and thermal resistance are required. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43595.     

注塑工艺参数对长玻纤增强PA66复合材料力学性能的影响

研究了注塑工艺参数对长玻纤增强PA66(LGF-PA66)复合材料力学性能和玻纤残余长度的影响。运用非连续纤维增强复合材料的拉伸强度和冲击强度模型来解释实验结果,并建立了工艺参数与LGF-PA66力学性能的关系曲线。结果表明:注塑工艺参数决定了玻纤的残余长度和取向,进而影响了LGF-PA66复合材料的力学性能。     

Preparation and Mechanical Properties of Long Glass Fiber Reinforced PA6 Composites Prepared by a Novel Process

Summary: Long glass fiber reinforced PA6 (LGF/PA6) prepregs were prepared by impregnating PA6 oligomer melt into reinforcing glass fiber followed by subsequent solid‐state polymerization (SSP) to obtain LGF/PA6 composite pellets. A conventional injection‐molding machine suitable for short glass fiber reinforced composites was applied to the processing of the prepared composites, which reduced the fiber length in the final products. Mechanical properties, thermal property, and fiber length distribution of injection molding bars were investigated. Scanning electron microscopy (SEM) was used to observe the impact fracture surfaces and the surfaces of glass fiber after the SSP. It was found that the LGF/PA6 composites were of favorable mechanical properties, especially the impact strength, although the average length of glass fiber was rather short. By this novel process, the content of glass fiber in composite could be high up to 60 wt.‐% and the maximum level of heat distortion temperature (HDT) was close to the melting temperature of PA6. SEM images indicated the favorable interfacial properties between the glass fiber and matrix. The glass fiber surfaces were further observed by SEM after removing the matrix PA6 with a solvent, the results showed that PA6 macromolecules were grafted onto the surface. Furthermore, the grafting amount of PA6 was increased with SSP time.

SEM images of impact fracture surfaces of LGF/PA6 composites (left) and of glass fiber surfaces after removing PA6 with 5 h SSP (right).     

Microstructure and fracture behavior of (co)injection‐molded polyamide 6 composites with short glass/carbon fiber hybrid reinforcement

The mechanical and fracture properties of injection molded short glass fiber)/short carbon fiber reinforced polyamide 6 (PA 6) hybrid composites were studied. The short fiber composites of PA 6 glass fiber, carbon fiber, and the hybrid blend were injection molded using a conventional machine whereas the two types of sandwich skin–core hybrids were coinjection molded. The fiber volume fraction for all formulations was fixed at 0.07. The overall composite density, volume, and weight fraction for each formulation was calculated after composite pyrolysis in a furnace at 600°C under nitrogen atmosphere. The tensile, flexural, and single‐edge notch‐bending tests were performed on all formulations. Microstructural characterizations involved the determination of thermal properties, skin–core thickness, and fiber length distributions. The carbon fiber/PA 6 (CF/PA 6) formulation exhibits the highest values for most tests. The sandwich skin‐core hybrid composites exhibit values lower than the CF/PA 6 and hybrid composite blends for the mechanical and fracture tests. The behaviors of all composite formulations are explained in terms of mechanical and fracture properties and its proportion to the composite strength, fiber orientation, interfacial bonding between fibers and matrix, nucleating ability of carbon fibers, and the effects of the skin and core structures. Failure mechanisms of both the matrix and the composites, assessed by fractographic studies in a scanning electron microscope, are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 957–967, 2005     

注射成型短碳纤维增强聚乙烯复合材料力学性能的研究

研究了碳纤维含量对注射成型高密度聚乙烯/碳纤维复合材料拉伸强度、硬度和弹性模量的影响。结果表明,随着碳纤维含量的增加,复合材料的硬度、弹性模量和拉伸强度逐渐增大;当碳纤维含量小于3.3 %时,复合材料的硬度、弹性模量和拉伸强度成线性增加趋势;当碳纤维含量大于3.3 %时,复合材料的硬度、弹性模量和拉伸强度的上升趋势增大。     

连续碳纤维增强热固性酚醛树脂复合材料的3D打印工艺及性能研究

针对连续碳纤维增强热固性酚醛树脂复合材料3D打印成型工艺的技术难题,本文提出了浸渍-原位预固化-后固化的3D打印成型方案,实现了连续碳纤维增强热固性酚醛树脂复合材料的3D打印成型,并研究浸渍温度对酚醛树脂接触角与表面张力,以及打印工艺对样件形貌和力学性能的影响规律。结果表明:当浸渍温度为40 ℃,预固化温度为180 ℃时,纤维-树脂界面结合效果最佳,原料具备成型条件;当打印间距为0.5 mm时,样件的弯曲强度及模量达到最大值,分别为660.00 MPa和57.99 GPa,层间剪切强度达到20.14 MPa。此连续碳纤维增强热固性酚醛树脂复合材料一体化制备工艺解决了3D打印热固性树脂原位成型难的问题,为制备具有复杂结构的连续纤维增强热固性树脂复合材料提供了参考。     

碳纤维三维网络体增强环氧树脂复合材料的性能

以酚醛树脂粘结短切碳纤维(SCF)并炭化制得碳纤维三维网络增强体(CFNR),再采用真空袋成型法浸入环氧树脂(EP)制得新型EP/CFNR复合材料。通过显微镜观察CFNR和复合材料的微观结构,采用万能试验机测试力学性能,以及用电阻仪测定导电性能等方法对复合材料进行了评价。结果表明,炭化后的酚醛树脂将SCF粘结成连续的三维网络结构,EP/CFNR复合材料中SCF间有明显可见的炭质粘结点;当SCF质量分数为7.3%时,EP/CFNR复合材料较纯EP,EP/SCF复合材料的弯曲强度分别提高33%,29%,压缩强度分别提高23%,10%,同时,其体积电阻率是EP/SCF复合材料的1/45。     

Properties of anionic polymerized ε‐caprolactam in the presence of carbon nanotubes

The results of the investigations of the relations between structure, physical and usage properties of polyamide 6 (PA6) reinforced with multiwall carbon nanotubes (MWNTs) are presented. A method of in situ anionic bulk polymerization of ε‐caprolactam in the presence of MWNTs was used for the preparation of reinforced PA6. The polymerization product was crushed, and the pellets of PA6 and PA6/MWNTs composites were injection molded to produce the standard test specimens for various measurements. The surface morphology (SEM), thermal (DSC, TGA, DMTA), and mechanical properties (tensile strength, Charpy's notched impact strength) of these materials were examined. Some differences between our specimens and those obtained by hydrolytic polymerization of ε‐caprolactam (CL) were found. It was found that a small amount of carbon nanotube decreases the crystallinity degree of PA6 matrix in the composites. The thermal stability was higher than that for neat PA6. DMTA results showed that the magnitudes of the storage modulus are higher for the PA6/MWNTs composites than for the unmodified PA6 in the temperature range between ?90 and 200°C. The tensile strength and tensile modulus are higher compared with the neat PA6. The elongation at break showed no noticeable change in the range of MWNTs loading considered, while the Charpy's notched impact strength slightly decreased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007