Durability Testing of Composite Aerospace Materials Based on a New Polymer Carbon Fiber-Reinforced Epoxy Resin

In this study,the durability of a new polymer carbonfiber-reinforced epoxy resin used to produce composite material in the aerospacefield is investigated through analysis of the corrosion phenomena occurring at the microscopic scale,and the related infrared spectra and thermal properties.It is found that light and heat can con-tribute to the aging process.In particular,the longitudinal tensile strength displays a non-monotonic trend,i.e.,itfirst increases and then decreases over time.By contrast,the longitudinal compressive and inter-laminar shear strengths do not show significant changes.It is also shown that the inter-laminar shear strength of carbonfiber/epoxy resin composites with inter-laminar hybrid structure is better than that of pure carbonfiber materials.The related resistance to corrosion can be improved by more than 41%.

Effect of Resin Composite Materials Containing Tourmaline Powders Modified with Lanthanum Element on Diesel Oil Combustion

The resin composite materials (RCM) were prepared by the method of doping resin with tourmaline powders modified with lanthanum element. It was characterized by scanning electron microscope (SEM), IR radiation determination, X-ray diffraction (XRD), and fourier transform infrared spectroscope (FTIR). The results showed that the RCM could radiate higher intensity of far infrared. The molecular movement was strengthened and the inter-molecular contacts were easily reduced when the diesel oil was dealt with the RCM. The effects of the RCM on the oil consumption and air pollutant emissions of oil-burning boiler were investigated. The oil-saving rate of the RBS·VH-1.5 boiler dealt with the RCM was 2.76%, and the reducing rates of CO and NO in the exhaust gas were 32.9% and 15.8%, respectively.

The Effect of the Light Intensity and Light Distances of LED and QTH Curing Devices on the Hardness of Two Light-Cured Nano-Resin Composites

Background: Effective polymerization of the composite resin is essential to obtain long term clinical success and has a great importance obtaining improved mechanical properties. The purpose of this study was to measure the effect of the light intensity of LED and QTH curing devices in relation to the light distances, on the hardness (KHN) of two light cure nano-resin composite. Material and Methods: The top and bottom surfaces of the two nanofill composite specimens were evaluated. Two LED and two QTH light curing devices were used at nine different distances. Light intensity was measured with two radiometers placed at these same distances from the curing tip. 360 pvc dies were prepared with circular cavity 3 mm in diameter and 2 mm thick. The tested materials were placed in each cavity. The different light curing distances were standardized by adding pvc spacers dies at different height matching the different distances. Top and bottom surface microhardness were evaluated with a Micro Hardness Tester in knoop hardness numbers (Kg/mm2). Data were statistically analyzed using: Three-way ANOVA, Tukey and Pearsons test. Results: It was revealed that there was a statistically significant difference in microhardness between the composites (p < 0.001), between the nine distances (p < 0.001) and between the four light curing devices (p < 0.001). Increasing the distance of the light source from composite resin, the light intensity and the microhardness values at the top and bottom surface decrease. LED light curing devices produced a greater microhardness results at the bottom surface of the specimens. The Filtek Ultimate nanocomposite (3 m) showed highest microhardness values on the top and bottom surfaces, polymerized with all four curing devices and all nine distances compared to Empress Direct nano composite (Ivoclar vivadent). Clinical significant: Even with high power LED curing light, the distance between the tip of the light source and the restoration surface should be as close as possible. In this study, Filtek Ultimate showed better results (highest microhardness values) than Empress Direct.

Fracture and Tribological Evaluation of Dental Composite Resins Containing Pre-polymerized Particle Fillers

The fracture and tribological evaluation of dental composite resin containing pre-polymerized particle fillers were investigated. Composite resins, e.g. metafil, silux plus, heliomolar and palfique estelite were selected as specimens in order to evaluate the effects of pre-polymerized particle filler on the fracture and wear characteristics of composite resins. In the wear tests, a ball-on-flat wear test method was used. The friction coefficient of metafil was quite high. The wear resistance of silux plus and palfique estelite was better than that of metafil and heliomolar under the same experimental condition. The main wear mechanism of composite resins containing pre-polymerized particle fillers was an abrasive wear by brittle fracture of pre-polymerized particles and by debonding of fillers and matrix.

Ablation Property of Ceramics/Carbon Fibers/Resin Novel Super-hybrid Composite

A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.

Mechanical Properties of Glass Fiber/Unsaturated Polyester Resin Composite Water Collector

The water collector is operated in the humid and hot environment of the cooling tower all the year round.It also needs to carry part of the weight of water and silt.Therefore,it is particularly critical to optimize the material of the water collector and improve its mechanical properties.Polyester,a general term of polymer obtained from polyols and polyacids,is a kind of engineering plastics with excellent properties and wide applications.Glass fiber is a reinforced plastic reinforcement material,and the biggest characteristic of it is the high tensile strength and good heat resistance.In this paper,glass fiber reinforced polyester resin composite material is prepared,its tensile properties and bending properties are tested,and the performance of the imported material JK2020B is compared and analyzed.The results show that the elastic modulus along the fiber direction is relatively high,but the interlayer force in the direction of thickness and width is very small.This review provides a guidance for production process.

Development of a Composite Material Based on Wood Waste Stabilized with Recycled Expanded Polystyrene

Environmental pollution is a whole world concern. One of the causes of that pollution is the proliferation of plastic waste. Among these wastes there is expanded polystyrene (EPS), mainly from packaging. This study aims to valorize EPS waste by developing a composite material from EPS waste and wood waste. For this purpose, a resin made of EPS has been elaborated by dissolving EPS in acetone. That resin was used as a binder in volume proportions of 15%, 20%, 25% and 30% to stabilize the samples. Some of them were thermoformed. The method of elaboration was based on a device consisting of an extruder for mixing the constituents, and a manual press for shaping and compacting the samples. Analyses show that the drying time depends on the composition of the mixture. Increasing the resin content leads to reduce water absorption and porosity of the samples;it also contributes to homogenize the internal structure of the samples. However, for the same resin contents, the thermoformed samples are less porous;they have more homogeneous internal structure;and absorb less water than non-thermoformed samples.

Study of Physical, Chemical and Thermo-Mechanical Properties of Talc Filled Polyester Resin Composite Using Styrene Monomer

Fiber Reinforced Thermoplastic (FRTP) composites are emerging as potential materials in many engineering fields. In this research, the compression-molding process was used as the fabrication technique for producing talc-filled reinforced polyester composite. The weight percentage of these composites was varied, like 30 wt%, 40 wt%, 45 wt%, and 50 wt% talc, respectively. Besides, different percentages of styrene monomer, such as 0 wt%, 20 wt%, and 30 wt%, were also used in this study. Different types of physical, chemical, mechanical, and thermal properties were investigated. The water absorption percentage is increased for composites having a higher percentage of talc filler, while the elasticity of the composites shows a decreasing nature with the increase of talc content. Compressive strength is increased with higher talc content. After a certain limit, with the increase of talc content, it decreases and remains more or less constant. The flexural properties (flexural strength, tangent modulus, and flexural strain) of polyester-talc composites are higher initially, and as the percentage of talc increases, the flexural properties decrease or remain constant. The rate of water absorption is very low with the increase in soaking time. The thermal analysis of polyester-talc composites shows that the thermal stability of the composites is better than that of polyester.

Preparation and Properties of Y_(2)O_(3)-PF Alternating Coating on Polymer Matrix Composite Material Surface

High-performance yttrium oxide-phenolic resin(Y_(2)O_(3)-PF)alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique.Y_(2)O_(3)-coated PF(Y_(2)O_(3)/PF)powder was firstly sprayed onto the substrate,forming a transition layer,and then the spherical Y_(2)O_(3) powder and Y_(2)O_(3)/PF powder were alternately deposited to form the composite alternating coating.Results show that the alternating coating is mainly composed of deposited Y_(2)O_(3)/PF powder.The bonding strength between coating and substrate is as high as 26.48 MPa with the single-test maximum bonding strength of 28.10 MPa,and shear strength reaches 24.30 MPa.Additionally,the heat transfer effect caused by external Y_(2)O_(3) particles gradually softens and even melts PF,thus effectively avoiding the damage of high temperature to molecular structure and thereby promoting the crosslinking and curing effects of resin during the deposition process.In the meantime,the unmelted Y_(2)O_(3) powder results in the shot peening effect,which washes out and eliminates the powder particles with inferior deposition effect,ultimately improving the physical and chemical properties of the alternating coating.

Ablation Performance of a Novel Super-hybrid Composite

A novel super-hybrid composite (NSHC) was boron-modified phenolic resin (BPR) with three-dimensional reticulated SiC ceramic (3DRC) and high silica fibers. Ablation performance of the NSHC was studied. The results show that the linear ablation rate of NSHC was lower than that of pure BPR and the high silica/BPR composite. Its linear ablation rate is 1/17 of the high silica/BPR. Mass ablation rate of the NSHC is very close to that of the pure BPR and the high silica/BPR composite. Scanning electron microscope (SEM) analysis indicates that 3DRC has scarcely changed its shape at the ablation temperature. Its special reticulated structure can restrict the materials deformation and prevent high velocity heat flow from eroding the surface of the materials largely and thus increase ablation resistance of the NSHC.

环氧树脂/石墨烯复合材料的制备及其性能

为提高环氧树脂的导电性能和电磁屏蔽性能,将石墨烯作为导电填料添加到环氧树脂中制备了环氧树脂/石墨烯复合材料,并研究了石墨烯含量对复合材料力学性能及微观形貌的影响。结果表明:添加石墨烯使复合材料的电导率和电磁屏蔽效率显著提高。石墨烯含量为10.0%(w)时,复合材料的电导率和电磁屏蔽效率分别为1.34×10^(-3)S/m,2.95 dB;石墨烯含量为7.5%(w)时,复合材料的冲击强度为1.67 kJ/m^(2),较纯环氧树脂提高了50%。

麻纤维增强改性环氧树脂复合材料声学性能研究

为验证麻纤维增强改性环氧树脂复合材料的声学性能,探讨植物纤维改性材料制备某类乐器的可行性,以亚麻、黄麻、苎麻等麻纤维材料为例,制备了几种不同麻纤维增强改性环氧树脂材料,以增强改性环氧树脂材料代替木材制作打击乐器,采用自由振动方法对打击乐器的声学性能进行测试。结果表明:黄麻、苎麻增强改性后的环氧树脂基复合材料声学性能各占优势,与一般的枫木相比力学性能更好,但综合声学性能尚无法达到天然枫木的水平。

聚合物基陶瓷化复合材料的研究进展

聚合物基陶瓷化复合材料具有有机高分子材料和无机陶瓷的优异性能,可在高温下变成多孔结构和冲击陶瓷层,陶瓷层可阻碍热量传递,隔离可燃物与氧气的接触,因此具有很好的阻燃和耐火作用,是一种新型耐火和耐高温材料。介绍了聚合物基陶瓷化复合材料的组成及其陶瓷化机理,综述了聚合物基陶瓷化复合材料的分类,包括橡胶类陶瓷化复合材料、乙烯聚合物基陶瓷化复合材料、环氧树脂基陶瓷化复合材料、酚醛树脂基陶瓷化复合材料等。未来的研究重点主要集中在提高陶瓷填料与树脂基体的相容性、制备高效阻燃剂和高效陶瓷化体系的设计上。

生物油-树脂复合调优技术研究进展与性能评价

梳理和总结生物油-树脂复合调优技术的研究进展,探索生物油-树脂复合材料的性能评价方法,为该材料的进一步应用和发展提供基础知识和借鉴方法。分析生物油-树脂复合材料的材料组成及基本性质,明确生物油-树脂复合材料的分类及相应制备工艺,评价不同类型生物油-树脂复合材料的基本性能及力学性能,从微细观角度阐释生物油-树脂复合机理。根据调优目标及材料配比,生物油-树脂复合材料分为生物油改性树脂及树脂改性生物油两类。现阶段研究聚焦于生物油改性树脂,其中以生物油代替苯酚合成改性酚醛树脂研究为主。生物油与树脂经复合调优既可补强生物油的高温性能,亦可改善树脂的柔韧性。但随着生物油掺量提高,复合材料的拉伸强度、黏结强度均不断降低。基于综合性能考虑,推荐复合材料中的生物油掺量为10%~30%。本研究为生物油-树脂复合材料的合成体系优化、制备工艺更新等深度研发与进一步推广拓展新思路。

提升杂环芳纶复合性能的研究进展

杂环芳纶是指主链中含有芳杂环(通常为苯并咪唑)的一类对位芳纶,其具有轻质、高强高模、高耐热、耐溶剂等优异性能。相比典型的芳纶Ⅱ纤维,杂环芳纶具有更加优异的力学性能,目前在我国的航空航天和防弹防护等领域得到了实际的应用。然而,与其他有机纤维类似,杂环芳纶由于表面惰性,其与树脂的复合性能相对较低,限制了其在先进复合材料领域的应用。本文从杂环芳纶表面改性和结构设计两方面出发,总结近年来提高杂环芳纶复合性能的设计思路、技术手段和研究成果,展望其在先进复合材料应用领域的发展趋势,为有机纤维的界面设计及改善界面粘接性提供帮助和参考。

基于机器学习预测环氧树脂复合材料抗冲击性能

剩余压缩强度(RCS)是评价复合材料受到冲击损伤后力学性能的重要指标。采用声发射技术(AE)对玻璃纤维增强环氧树脂复合材料冲击载荷进行了在线监测,分析了振铃计数、峰值计数、信号强度和信号均方根值4种冲击载荷参数,采用人工神经元网络(ANN)和径向基网络(RBF)基于冲击载荷参数预测了试件RCS。结果表明,高冲击能量造成了试件分层、玻璃纤维断裂、环氧树脂基体开裂、纤维脱黏,当冲击能量为10、15、20和30 J时,冲击3 ms后冲击能量达到最大值,分别为10.53、16.67、21.77和27.13 J,随后冲击能量不断下降。随着冲击能量的增加,试件冲击深度从0.18 mm增加到3.35 mm,RCS从56.87 MPa降低到20.45 MPa。最优ANN模型结构为4-48-1,预测和实验RCS的均方误差(MSE)最低为0.03 MPa,最优RBF模型结构为4-21-1,MSE最低为0.01。RBF模型的局部响应特性使得其对输入数据中的噪声具有较好的鲁棒性,预测与实验RCS数据的相关系数(R2)为0.9863,而ANN模型预测结果为0.9514。

BPA可逆热敏变色复合材料制备方法及其应用研究进展

综述了BPA可逆热敏变色材料的制备及其应用,以及复配法、无机包覆法、微胶囊法、湿成膜法和近年来的2,6-单取代双酚A复合膜新方法,并分析了2,6-单取代法中膜结晶相变与二醛、酚醛树脂及胶种的关系。2,6-单取代双酚A线型或芳香酚醛树脂及其复合膜有机体系的设计与研究将进一步推动该类材料在具有可调的迟滞响应相变智能窗口,超低温变色敏感性、变色深度、稳定性,环境友好型合成树脂及塑料及实验教学等方面的应用。

纤维增强树脂矿物复合材料的细观力学特性及损伤机理

纤维增强树脂矿物复合材料因优异的力学性能得到广泛应用,但有关材料损伤机理的研究仅停留在宏观层面,较少关注损伤过程中材料的细观力学特性和微裂纹演化规律。针对这一问题,基于颗粒流离散元技术建立了纤维树脂矿物复合材料的细观模型,分析了材料应力-应变曲线的变化规律,揭示了材料的微裂纹萌生扩展机制和其破坏失效形式。结果表明,相比于树脂矿物复合材料,纤维增强树脂矿物复合材料的抗压强度更高,起裂应力和损伤应力更大;骨料颗粒形状对纤维的增强增韧作用影响较小;纤维对树脂矿物复合材料具有增韧阻裂的作用。研究从细观角度揭示了纤维增强树脂矿物复合材料的损伤性能,能够为该材料的推广应用提供指导。

铁粉/碳纤维增强树脂复合材料的制备 及脆化损伤研究

将偶联剂改性纳米铁(Fe)粉与预处理后的碳纤维混合,浸润于环氧树脂基料中,经过搅拌混合制备纳米Fe粉/碳纤维增强树脂复合材料,研究了复合材料在高温老化、水浸老化环境下的脆化损伤行为。结果表明:树脂受到高温老化和水浸泡老化后会出现脆化损伤,碳纤维和纳米Fe粉加入会对该损伤有一定抑制;加入质量分数为4.0%的纳米Fe粉后,随着高温老化时间延长,碳纤维质量分数为3.0%的纳米Fe粉/碳纤维增强复合材料的拉伸强度、断裂韧性下降幅度较小,同时脆化损伤后树脂与纳米Fe粉、碳纤维仍结合紧密;碳纤维质量分数为3.0%、纳米Fe粉质量分数为4.0%的纳米Fe粉/碳纤维增强复合材料经水浸老化后,断裂韧性仍旧保持较高水平。