玻璃纤维增强聚丙烯复合材料制孔损伤

为抑制玻璃纤维增强聚丙烯复合材料（GF/PP）制孔损伤并提高其制孔效率,本文通过钻削实验获得多种进给速度下的GF/PP复合材料钻削轴向力和出口温度,使用高速摄影设备对刀具钻出过程进行在线观测,研究出口材料去除过程及其损伤成因,分析进给速度对GF/PP复合材料制孔损伤的影响规律。结果表明：GF/PP复合材料的钻削出口温度在低速进给时显著升高,在高速进给时基本趋于稳定;出口撕裂是重要的出口损伤形式,成因是大片毛刺受副切削刃的撞击和撕挤,进给速度过高或过低均会加剧损伤; 0°毛刺在低速进给时较严重,入口撕裂在高速进给时较严重。     

长玻璃纤维增强聚丙烯复合材料的研究

选用无碱玻璃纤维 ,采用特殊方法使长纤维与基体聚丙烯树脂有序复合 ,制备了一系列不同纤维长度、含量以及采用不同表面处理的玻纤 /PP复合材料 ,并测定了材料的力学性能 ,通过SEM观察了复合体系的界面 ,从微观上验证了材料力学性能的变化规律。实验表明 ,所采用的复合材料制备方法可使纤维的排布更加有序 ,并可改进材料的力学性能。     

Modeling and analysis for surface roughness in machining glass fibre reinforced plastics using response surface methodology

Now a days glass fiber reinforced plastic (GFRP) composite materials are a feasible alternative to engineering materials. They have excellent properties and are being extensively used in variety of engineering applications. However, the users of FRP are facing difficulties to machine it, because of its anistropic properties. In this paper, an attempt has been made to model the surface roughness through response surface method (RSM) in machining GFRP composites. Four factors five level central composite, rotatable design matrix is employed to carryout the experimental investigation. Analysis of variance (ANOVA) is used to check the validity of the model. For finding the significant parameters student’s t-test is used. Also, an analysis of the influences of the entire individual input machining parameters on the response has been carried out and presented in this study.     

Assessment of factors influencing surface roughness on the machining of glass fiber-reinforced polymer composites

In recent years, the utilization of glass fiber-reinforced polymers (GFRP) composite materials in many different engineering fields has undergone a tremendous increase. Accordingly, the need for accurate machining of composites has increased enormously. In the present work, an attempt has been made to assess the influence of machining parameters on the machining of GFRP composites. Design of experiments (full factorial design) concept has been used for experimentation. The machining experiments were conducted on all geared lathe using coated cermet tool inserts with two level of factors. The factors considered were cutting speed, work piece fiber orientation angle, depth of cut and feed rate. A procedure has been developed to assess and optimize the chosen factors to attain minimum surface roughness by incorporating: (i) response table and response graph; (ii) normal probability plot; (iii) interaction graphs; (iv) analysis of variance (ANOVA) technique.     

MCA-MMT的制备及其对玻璃纤维增强聚丙烯复合材料阻燃性能的影响

为了提高玻璃纤维(GF)增强聚丙烯(PP)复合材料(GF/PP)的阻燃性能,通过在蒙脱土(MMT)悬浮液中进行三聚氰胺氰尿酸盐(MCA)分子自组装制备了新型协效成炭剂MCA-MMT,并采用FTIR、XRD、SEM和TGA对MCA-MMT的结构及热性能进行了表征;将MCA-MMT、无卤膨胀型阻燃剂与GF/PP熔融共混制备了阻燃复合材料MCA-MMT/(GF/PP),通过极限氧指数(LOI)测试、垂直燃烧试验和锥形量热测试研究了MCAMMT对GF/PP的阻燃效果和阻燃机制,并测试了复合材料的力学性能。结果表明:MMT的加入会影响氰尿酸和三聚氰胺在MCA合成过程中的氢键作用,干扰和抑制大平面氢键网络的形成,减少MCA氢键复合体的分子体积,使颗粒变小。MCA-MMT/(GF/PP)的UL-94防火等级达到V-0级,LOI为31.3%。MCA-MMT的阻燃效率高于传统MCA的,可降低材料燃烧的热释放程度和总烟释放量,使复合材料的阻燃性能提高,其阻燃机制为片层结构的MMT可提高MCA的成炭量,使MCA-MMT/(GF/PP)燃烧后能形成致密的残留炭层。MCA-MMT/(GF/PP)的拉伸、冲击强度与MCA/(GF/PP)的相比并未下降。     

甘蔗渣纤维增强聚丙烯复合材料的制备和力学性能

利用注射成型制备了甘蔗渣纤维增强聚丙烯复合材料, 分析了纤维质量分数、 注射成型条件以及添加物对复合材料力学性能的影响。结果表明, 随着纤维质量分数的增加, 材料的弯曲模量呈递增趋势。由于甘蔗渣纤维热降解的发生, 材料的力学性能随筒体温度的增加呈下降趋势。在模具温度90℃、 注射间隔时间30s、 不同的筒体温度185℃和165℃的成型条件下, 材料的弯曲性能和冲击强度分别呈现最大值。添加了马来酸酐改性聚丙烯后, 材料的弯曲强度和冲击强度得到了提高。      

The influence of sizing conditions on bending properties of continuous glass fiber reinforced polypropylene composites

In this study, the interphase construction by using binding agents was proposed in continuous glass fiber reinforced polypropylene composites. Two types of binding agents modified with maleic anhydride, i.e. low- and high-molecular-weight PP binders were employed. Amino silane coupling agent was also used for the sizing of the glass fibers. In the first step, the sizing conditions with non-binding, low- and high-molecular-weight PP binders were compared for bending properties. According to the near infra-red (NIR) analysis of the sized glass fibers, the glass fiber finished with the low-molecular-weight PP binders greatly indicated the existence of the amide bond between the PP binder and the silane coupling agent. This result implies that the matrix PP chain tends to entwine with the PP binder chain. As a consequence, low-molecular-weight PP binder specimens gave the highest bending strength. Furthermore, the concentration ratio of the low-molecular-weight PP binder was varied with three steps. Matrix PP modified with maleic anhydride was also used in order to investigate the effect of matrix modification on bending properties. The interphase structure formed by a binder agent and a silane coupling agent in the continuous glass fiber reinforced polypropylene composites was discussed in detail.     

碱处理对竹纤维及竹纤维增强聚丙烯复合材料性能的影响

为探究竹纤维表面能对纤维与树脂的粘附功及复合材料界面的影响,采用碱处理对竹纤维进行表面改性,通过模压工艺制备了竹纤维增强聚丙烯(PP)复合材料。研究了碱处理对竹纤维性能、竹纤维与PP间的粘附功及对竹纤维/PP复合材料力学性能的影响,采用SEM研究了不同浓度碱处理后竹纤维表面形貌的变化。结果表明:随着碱浓度的增加,竹纤维断裂强度呈现一定波动,当碱浓度为1wt%时竹纤维断裂强度达到最大值;竹纤维与PP的粘附功与竹纤维极性比密切相关,竹纤维极性比越小,粘附功越大;随着碱浓度增大,竹纤维与PP间粘附功与竹纤维/PP复合材料剪切性能呈现相同的趋势,并且都在碱浓度为20wt%时达到最大值,此时竹纤维与PP的粘附功较未处理时提高了67.18%;竹纤维/PP复合材料剪切性能较未处理时提高了23.29%;复合材料弯曲强度在碱浓度为5wt%时达到最大值,相比未处理时提高了23.13%。     

Expanded graphite nanoplatelets as coupling agents in glass fiber reinforced polypropylene composites

The interfacial adhesion between E-glass fibers and various types of nanomodified polypropylene (PP) matrices have been investigated on single-fiber model composites. In particular, an evaluation of the fiber–matrix interfacial shear strength was performed by the fragmentation tests on model composites prepared by using PP matrices containing various amounts (up to 7 wt%) of expanded graphite nanoplatelets (xGnP).The presence of xGnP in the polymer matrix resulted in a remarkable increase of the interfacial shear strength values (up to a factor of about 6 for a 7 wt% content of xGnP) if compared to neat PP. Moreover, wettability measurements in various liquids evidenced that the work of adhesion of the polymer matrix with respect to glass fiber, was improved by the presence of xGnP.     

超声振动对玻纤增强聚丙烯复合材料注射成型特性的影响

为了研究超声振动对纤维增强复合材料注射成型特性的影响,利用自行开发的超声辅助可视化注射成型实验装置对不同玻纤(GF)含量的GF增强聚丙烯(PP)复合材料进行了超声外场作用下的可视化实验,观测分析了超声功率对复合熔体充填流动行为的影响。此外,通过对试样不同部位的金相观察,分析了超声功率对复合材料纤维取向的影响。结果表明:超声功率会对复合材料注射成型的充填流动行为及制品的纤维取向产生影响,而复合材料纤维含量对超声振动的效果也有直接影响。在纤维含量较低时,超声振动对基体材料微观形态的作用为影响复合材料充填流动性及纤维取向的主因;在纤维含量较高时,超声振动对纤维的作用为影响复合材料充填流动性及纤维取向的主因。研究结果为复合材料超声辅助成型技术的发展提供了依据。     

The influence of surface diffusion on surface roughness and component distribution profiles during deposition of multilayers

The kinetic processes taking place on the surface and influencing the depth distribution of components during deposition of multilayers are considered by proposed kinetic model. The depth distribution of components in growing structure, broadening of interfaces between layers and shape of concentration peaks of multilayers are analyzed with respect of evolution of surface roughness during deposition. Surface roughness depends on adsorption rate and on surface diffusion. In presented model, the process of surface diffusion is subdivided into up-diffusion and down-diffusion. It is shown that atomic fluxes of up-diffusion and down-diffusion do not compensate each other even in the case of equal diffusion coefficients as they depend on coverage of different monolayers. Down-diffusion results in smoother surface, in contrary, up-diffusion makes it rougher. It is quantitatively shown by kinetic modeling that with increase of down-diffusion the amplitude of concentration peaks of components increases, the broadening of interface between layers decreases and concentration peaks become asymmetrical. The asymmetry of concentration peaks is found even in the case of equal diffusion coefficients of different components. At different diffusivity of components, the asymmetry is following: the concentration peaks of heavy-component (less diffusivity) show enhanced trailing tails on the back profile side (for light-component on the contrary). Up-diffusion results in increase of surface roughness and broadening of interface between layers. The quantitative functions of surface roughness on ratio of up- and down- diffusion coefficients are calculated and analyzed.     

汉麻纤维表面改性对其增强聚丙烯复合材料性能及挥发性有机化合物释放影响

通过非织造-热压工艺制备了汉麻纤维增强聚丙烯（HF/PP）复合材料。采用热重-质谱联用仪（TG-MS）研究了HF/PP复合材料的挥发性有机化合物（Volatile organic compounds,VOC）释放来源及汉麻经聚乙烯醇（PVA）改性和尿素改性对HF/PP复合材料VOC释放的影响,同时研究了两种改性方法对HF/PP复合材料热学性能和力学性能的影响。结果表明：HF/PP复合材料中的VOC主要来源于汉麻纤维,改性后的HF/PP复合材料力学性能相比未处理的均有不同程度的提升,尿素改性后,HF/PP复合材料的拉伸强度和弯曲强度达到最大值,较未处理时分别提升了19.32%和15.04%。PVA改性后,HF/PP复合材料的拉伸模量、弯曲模量和剪切强度达到最大值,相比未改性时分别提升了17.72%、15.94%和24.72%。改性后HF/PP复合材料热稳定性能和VOC释放相较未处理时均得到了优化：PVA改性后HF/PP复合材料热稳定性最优,三个阶段总活化能较未处理时提高了121.99%,达到了392.56 kJ·mol^-1,并且HF/PP复合材料热稳定性与界面性能密切相关;尿素及PVA改性后HF/PP复合材料的总VOC（TVOC）释放量相较未处理时均降低。     

Influence of process parameters on cutting force and torque during drilling of glass–fiber polyester reinforced composites

This research outlines the Taguchi optimization methodology, which is applied to optimize cutting parameters in drilling of glass fiber reinforced composite (GFRC) material. Analysis of variance (ANOVA) is used to study the effect of process parameters on machining process. This procedure eliminates the need for repeated experiments, time and conserves the material by the conventional procedure. The drilling parameters and specimen parameters evaluated are speed, feed rate, drill size and specimen thickness. A series of experiments are conducted using TRIAC VMC CNC machining center to relate the cutting parameters and material parameters on the cutting thrust and torque. The measured results were collected and analyzed with the help of the commercial software package MINITAB14. An orthogonal array, signal-to-noise ratio are employed to analyze the influence of these parameters on cutting force and torque during drilling. The method could be useful in predicting thrust and torque parameters as a function of cutting parameters and specimen parameters. The main objective is to find the important factors and combination of factors influence the machining process to achieve low cutting low cutting thrust and torque. From the analysis of the Taguchi method indicates that among the all-significant parameters, speed and drill size are more significant influence on cutting thrust than the specimen thickness and the feed rate. Study of response table indicates that the specimen thickness, and drill size are the significant parameters of torque. From the interaction among process parameters, thickness and drill size together is more dominant factor than any other combination for the torque characteristic.     

Experimental investigation and optimization of machining parameters in drilling of fly ash-filled carbon fiber reinforced composites

Particle-filled polymer composites have become attractive because of their wide applications and low cost. Carbon fiber reinforced polymer (CFRP) is well known as a difficult-to-cut material, which has very strong physical and mechanical characteristics. Machining of carbon fiber reinforced composites is essential to have functional upshots, out of which drilling is the key operation needed for fabrication. In this paper Taguchi L₂₇ experimental design is coupled with grey relational analysis (GRA) to optimize the multiple performance characteristics in the drilling of fly ash-filled carbon fiber reinforced composites. Experiments were conducted on a vertical machining center, and Taguchi L₂₇ experimental design was chosen for the experiments. The drilling parameters, namely spindle speed, feed rate, drill diameter and wt% of fly ash, have been optimized based on the multiple performance characteristics including thrust force, surface roughness, and delamination. The GRA with multiple performance characteristics indicates that the wt% of fly ash and drill diameter are the most significant factors that affect the performance. Experimental results have shown that the performance in the drilling process can be improved effectively by using this approach.     

Effect of fiber surface modification on the lifetime of glass fiber reinforced polymerized cyclic butylene terephthalate composites in hygrothermal conditions

Mechanical performances of polymerized cyclic butylene terephthalate (pCBT) matrix, glass fiber reinforced pCBT (GF/pCBT), and nano-silica modified glass fiber/pCBT composites (nano-GF/pCBT) in hygrothermal condition were investigated. All the materials were aged in hygrothermal environments for up to three months, and then their mechanical strength degeneration ratio (SDR) was calculated. To study the aging effect of temperature, specimens with and without nano-silica modification were tested in temperatures ranging from 298 to 500 K. Differential scanning calorimeter (DSC) test, dynamic mechanical analysis (DMA), and fiber pull-out test were adopted to complement the experimental results. It is found that all the SDR-time curves follow the linear relationship in hygrothermal environment, while SDR-temperature curves follow a bilinear relationship due to the effect of glass transition temperature (T_g) of the matrix. Fibers modified by coating nano-silica on the surface could decrease SDR of the composites. This is due to the fact that the fillers on the fiber surface could resist the movement of pCBT molecular chain and diffusion of water molecules in aging conditions. The fiber pull-out test verifies that the interface strength between fiber and matrix is enhanced by the modification.     

Influence of additive materials on the roughness of AISI D2 steel in electrical discharge machining (EDM) environment

The quality of the machined surface resulted from the electrical discharge machining (EDM) environment is not efficient according to the previous studies. One of the significant problems is the impedance of dielectric fluid, where it is contributing to focusing the plasma channel in a limited area. Hence, this behavior leads to appearing deep craters on the machined zone. The researchers have attempted to enhance the average of surface roughness by employing powder particles or surfactant as the additive materials in the dielectric fluid. Unfortunately, these studies did not present a comparison between these additive materials in this environment. Therefore, the present study aims to compare the performance of the average of surface roughness (R_a) for AISI D2 steel by utilizing Nano chromium powder (NCP) and Span-20. The present work has proved that the behavior of the average of surface roughness for this steel is dropping at the maximum level of Nano chromium powder concentration and pulse duration as compared to the behavior with the Span-20. Moreover, the best roughness was produced by this steel with Nano chromium powder at 2 g/L and 20 μs for this powder and the pulse duration.     

苯基膦酸铈与十溴二苯醚阻燃玻璃纤维增强聚对苯二甲酸乙二醇酯复合材料

通过熔融共混方法制备苯基膦酸铈（CeHPP）与十溴二苯醚（DBDPO）复配阻燃玻璃纤维增强聚对苯二甲酸乙二醇酯（GF/PET）复合材料。采用热失重分析（TGA）测试研究了DBDPO-CeHPP对GF/PET复合材料热稳定性的影响。同时利用垂直燃烧（UL-94）、极限氧指数（LOI）及微型锥形量热（MCC）测试表征DBDPO-CeHPP-GF/PET复合材料的阻燃性能。使用SEM对DBDPO-CeHPP-GF/PET复合材料的残炭表面形貌进行观察分析。结果表明,DBDPO与CeHPP复配后对DBDPO-CeHPP-GF/PET体系的热性能和阻燃性能都有很大的影响。其中,GF/PET复合材料与DBDPO和CeHPP质量比为91:6:3时,DBDPO-CeHPP-GF/PET复合材料的LOI高达29.5%,可以通过UL-94 V-0级。在MCC测试中,与纯GF/PET复合材料相比,该配比的DBDPO-CeHPP-GF/PET复合材料总热释放（THR）、热释放速率峰值（PHRR）及热熔（HRC）分别下降了10.2%、13.1%和12.8%。结合残炭形貌的测试结果,对DBDPO-CeHPP-GF/PET复合材料的阻燃机制进行了适当的解释分析。      

Control of interfacial adhesion in continuous carbon and kevlar fiber reinforced polymer composites

Carbon fiber surfaces were treated by cold plasmas of oxygen, nitrogen, argon, ammonia, and propylene. A two-component bismaleimide, an epoxy, and a model thermoplastic resin polypropylene were used as the matrices for composites. The effectiveness of various plasmas in improving the interfacial adhesion between carbon fibers and matrix resins was demonstrated. Predominant adhesion promotion mechanisms as influenced by various plasma treatments were determined. Oxygen and argon plasmas were found to promote mechanical keying by increasing the level of fiber surface roughness and porosity. The wettability of carbon fiber surface by the matrix resin was also enhanced by oxygen plasmas and argon plasmas (to a lesser extent), as evidenced by the increased total surface energies and their polar components. These surface energy increases are mainly due to the various oxygen-containing functional groups observed on the oxygen plasma-treated surface. For the cases of ammonia and combined ammonia/argon plasma treatments, possible chemical bonding between bismaleimide and the plasma-deposited amine groups is one important promoter of interfacial bonding. In these cases increased wettability was also observed. Ammonia and ammonia/argon plasmas appear to be the more appropriate treatments for carbon-fiber/thermoset resin composites considering that they generally do not induce any appreciable reduction in fiber strength. In contrast, excessively prolonged exposure of carbon fibers to oxygen, nitrogen or argon plasma could lead to a significant reduction in fiber strength. The plasma-polymerized polypropylene deposited on the fiber surface was capable of improving the compatibility and adhesion between the fiber and the polypropylene matrix.     

The influence of nanosized precipitates on Portevin-Le Chatelier bands and surface roughness in AlMgScZr alloy

The influence of different precipitate-dislocation interactions,namely dislocation shearing and bypass-ing mechanisms,on PLC bands and the resultant surface roughness in AlMgScZr alloy was investigated.Three-dimensional surface roughness was quantitatively measured by confocal microscopy.We find that the introduction of shearable precipitates increases the stress amplitude,decreases the PLC bands number and surface roughness.However,the stress amplitude decreases,the PLC bands number and sur-face roughness increase with shearable precipitates turning to nonshearable precipitates.By analyzing the precipitation strengthening mechanisms quantitatively,the influence of precipitates on PLC bands and the resultant surface roughness was explored.Furthermore,our study demonstrates that the shear-able precipitates can decrease the surface roughness by decreasing the number of PLC bands,which is instructive for designing structural materials with desirable mechanical property and surface quality.     

Effect of machining parameters on surface roughness and material removal rate in finish turning of ±30° glass fibre reinforced polymer pipes

This paper studies the effect of varying machining parameters in turning on surface roughness and material removal rate (m.r.r.) for ±30° filament wound glass fibre reinforced polymers (GFRP) in turning operations using coated tungsten carbide inserts under dry cutting conditions. The paper describes the development of an empirical model for turning GFRP utilising factorial experiments. Second order predictive model covering speed, feed, depth of cut and tool nose radius has been developed at 95% confidence interval for surface roughness and material removal rate. Contour plots of the surface roughness and m.r.r. for different machining conditions have been generated from the empirical equations. Overlaid contour graph help in obtaining iso-value of roughness for different values of m.r.r.