原位复合成纤增强技术

介绍了2类原位复合成纤增强体系，分别讨论了它们的成纤机理，影响成纤的条件及组分间的相互影响；并概要地叙述了目前国内外在这些领域内所取得的进展。     

原位成纤技术研究进展

描述了原位成纤技术的增强机理,综述了影响原位成纤的主要因素,指出原位成纤技术现存的问题,并对原位成纤技术的发展进行了展望。     

原位成纤复合材料研究进展

综述了近年来利用原位成纤技术增强复合材料的研究现状,介绍了原位成纤技术的增强机理和影响因素,总结了不同体系原位增强复合材料的性能特点和最优的成纤加工条件。最后对原位成纤复合材料的发展进行了展望。     

聚合物共混体系原位增强机制的形成与强化

简述了热塑性聚合物共混物原位复合材料的研究进展及意义，总结了如原位复合材料的化学组成、物理特性及成型工艺对分散相“原位”成纤及其性能的影响，重点叙述了相容性对材料力学性能及拉伸、剪切作用对分散相原位成纤的影响．并提出了，磁场作用促进共混体系中分散相聚合物分子链取向及与流场协同作用的思路。     

原位成纤复合法改善聚丙烯的力学性能

采用原位成纤复合法制备了均聚聚丙烯(PP-H)/聚对苯二甲酸乙二酯(PET)原位成纤复合材料,研究了PET原位微纤化对PP-H力学性能的影响.实验采用的设计工艺可实现PET在PP-H基体中原位微纤化;原位生成的PET纤维对PP-H力学性能的影响呈各向异性,表现为拉伸及弯曲强度提高,冲击强度下降,改善效果受PET微观形态...     

具有原位导电微纤网络的CB／PET／PE复合材料的力学性能

在前期热塑性塑料原位成纤研究的基础上，尝试利用原位成纤方法制备炭黑(CB)／聚对苯二甲酸乙二醇酯(PET)／高密度聚乙烯(HDPE)原位导电微纤网络复合材料(CEMN)，以期增强复合体系的力学强度。通过对CEMN体系与CB／PE体系的力学性能测试发现，CEMN体系的拉伸强度低于普通CB／PE复合物。为增强复合体系的力学性能，应改变加工过程及降低体系中CB的用量。     

HDPE/r-PET原位微纤物微观形态与力学性能

以高密度聚乙烯(HDPE)和回收聚对苯二甲酸乙二醇酯(r-PET)为原料,通过反应挤出、冷拉伸、退火工艺制备了HDPE/r-PET原位微纤物。研究了扫描电镜(SEM)的制样方法即用液氮冷冻、脆断样品、聚四氟乙烯带包覆、在沸腾的二甲苯中刻蚀7～10min和不同r-PET用量、不同拉伸比制备出的系列HDPE/r-PET原位微纤物的力学性能。结果表明,通过SEM可清晰地看到形成的微纤,原位微纤物的拉伸强度和冲击强度都随拉伸比的增大而增大;r-PET质量分数为15%时,原位微纤物的拉伸强度和无缺口冲击强度达到最大值;HDPE/r-PET原位微纤物的适宜注塑温度为210℃。     

TP／TP原位微纤化共混物的研究进展

简要介绍了热塑性聚合物(TP)／热塑性聚合物原位微纤化共混物的产生、制备方法,并着重讨论了原位成纤的机理、影响微纤化共混物材料特性(形态、流变性、结晶性、力学性能等)的因素,对该材料的发展进行了展望。     

聚合物原位成纤方法及其在PP共混体系中的应用

介绍了聚合物共混体系原位成纤原理、影响因素、制备方法及聚丙烯(PP)与其他聚合物原位成纤共混体系研究进展,包括PP/聚酰胺(PA)、PP/聚对苯二甲酸乙二醇酯(PET)原位成纤共混体系等.重点阐述了不同共混比、相容性、黏度比和加工参数(如拉伸速率、螺杆转速、加工温度等)等对PA或PET在PP中的成纤形态和PP力学性能、...     

原位成纤复合材料研究进展

综述了近年原位成纤技术在热致性液晶聚合物(TLCP)/热塑性聚合物(TP)、TP/TP体系中的应用研究进展,提出目前研究过程中存在的问题及解决方法构想,展望原位成纤技术在新的复合体系中的的应用.     

普通热塑性树脂的原位成纤技术进展

通过与热液晶原位复合材料的对比,系统阐述了具有柔性分子链的普通热塑性树脂就地成纤增强增韧高聚物的国仙外研究进展,着重对近几年来该技术在成纤机理、控制因素以及结构与性能等方面的研究成果作了初步总结。     

PP／UHMWPE原位成纤复合材料的混炼及成型工艺研究

采用超高分子量聚乙烯（ＵＨＭＷＰＥ）原位成纤增强、增韧聚丙烯（ＰＰ）。讨论了混炼剪切力、成型冷却方式和ＵＨＭＷＰＥ熔体熔点粘度对材料力学性能的影响。发现提高剪切力,加快冷却速度均有利于力学性能的提高,配比为９０／１０的ＰＰ／ＵＨＭＷＰＥ的缺口冲击强度、拉伸强度和断裂伸长率可达８８．６ｋＪ／ｍ＾２、４５．１ＭＰａ和５７０％,分别是ＰＰ－１３３０的３．５倍、１．５倍和２．５倍;而ＵＨＭＷＰＥ相对分子擀     

In situ modulus and strength of carbon fibers in C/SiC composites

The in situ elastic modulus and strength distribution of carbon fibers in C/SiC composites were studied. To obtain the in situ property data, fibers were heat treated according to the fabrication process of C/SiC composites. Tensile tests were performed on the single fibers and fiber bundles. The equivalent in situ modulus and strength were proposed considering the loose and unparallel fibers in the composites. The experimental and numerical results showed that the equivalent elastic modulus and average strength of in situ fibers are much lower than that of the original fibers. In addition, the equivalent strength distribution of in situ fibers is more dispersive.     

改性方法对PP/纳米CaCO3复合材料性能的影响

分别采用熔融共混法和原位聚合法制备了聚丙烯(PP)／纳米CaCO3复合材料，比较了用两种方法制备的PP／纳米CaCO3复合材料的力学性能及纳米CaCO3的分散状况。结果表明：当纳米CaCO3质量分数分别为5％和0．73％时，两种方法制备的复合材料的冲击强度达到最大值，分别为纯PP的2．2倍和2倍；两种方法中CaCO3均可达到纳米级分散；原位聚合法制备的复合材料的韧性断裂比熔融共混法更为明显，且综合性能与共混法相近，并有工艺上的优越性。     

Effects of fiber contents on the mechanical and microwave absorbent properties of carbon fiber felt reinforced geopolymer composites

In this paper, phosphate-based geopolymer composites are studied and the effects of different carbon fiber felt contents (from 20?vol% to 40?vol%) on the phase composition, microstructure, mechanical properties and microwave absorbent properties from 2?GHz to 18?GHz frequency band of the composites were systematically investigated. The results indicate that with the increase in carbon fiber felt contents, flexural strength and Young's modulus of the composites gradually increased. The fracture mode of the composite changed from brittle failure to ductile failure with the presence of carbon fiber felt. It was mainly due to the micropore deformation as well as fibers pulling-out and the crack deflection, which consumed most fracture energy. However, microwave absorbent performance tended to increase at first and then decreased as the carbon fiber felt content ramping up. When the content of carbon fiber felt in the composite was 26.7?vol%, the composite showed the best microwave absorbent performance and the reflection loss reached to ??59.3?dB. It is mainly attributed to the Debye polarization of the carbon fibers and the interface polarization between fibers and the matrix.     

Stress field and damage evolution in C/SiC woven composites: Image-based finite element analysis and in situ X-ray computed tomography tests

The construction and examination of meso-structural finite element models of a Chemical-Vapor-Infiltrated (CVI) C/SiC composite is carried out based on X-ray microtomography digital images (IB-FEM). The accurate meso-structural features of the C/SiC composites, which are consisted of carbon fiber tows and CVI-SiC matrix, in particular the cavity defects, are reconstructed. With the IB-FEM, the damage evolution and fracture behaviors of the C/SiC composite are investigated. At the same time, an in situ tensile test is applied to the C/SiC composite under a CT real-time quantitative imaging system, aiming to investigate the damage and failure features of the material as well as to verify the IB-FEM. The IB-FEM results indicate that material damage initially occur at the defects, followed by propagating toward the fiber-tow/SiC-matrix interfaces, ultimately, combined into macro-cracks, which is in good agreement with the in situ CT experiment results.     

High dielectric constant polyaniline/epoxy composites via in situ polymerization for embedded capacitor applications

Polyaniline (PANI)/epoxy composites with different polyaniline (PANI) contents were successfully developed by in situ polymerization of aniline salt protonated with camphorsulfonic acid within epoxy matrices and fully characterized. The influence of PANI loading levels on various properties was also explored. Dielectric and electrical properties of PANI/epoxy composites were studied for samples in parallel plate configuration. A PANI/epoxy composite prepared in this fashion reached a high dielectric constant close to 3000, a dielectric loss tangent less than 0.5 at room temperature and 10 kHz. The hardener type was also found as a critical parameter for the dielectric properties of PANI/epoxy composites. The distribution of the conductive element clusters within the polymer matrix was studied by SEM and correlated to the dielectric behavior of the composite films.     

Interfacial in situ polymerization of single wall carbon nanotube/nylon 6,6 nanocomposites

An interfacial polymerization method for nylon 6,6 was adapted to produce nanocomposites with single wall carbon nanotubes (SWNT) via in situ polymerization. SWNT were incorporated in purified, functionalized or surfactant stabilized forms. The functionalization of SWNT was characterized by FTIR, Raman spectroscopy and TGA and the SWNT dispersion was characterized by optical microscopy before and after the in situ polymerization. SWNT functionalization and surfactant stabilization improved the nanotube dispersion in solvents but only functionalized SWNT showed a good dispersion in composites, whereas purified and surfactant stabilized SWNT resulted in poor dispersion and nanotube agglomeration. Weak shear flow induced SWNT flocculation in these nanocomposites. The electrical and mechanical properties of the SWNT/nylon nanocomposites are briefly discussed in terms of SWNT loading, dispersion, length and type of functionalization.     

Modified Nonconventional Synthesis of New Terpoly(Aniline,o-Anthranilic Acid and o-Phenylenediamine)/Bentonite Composites

Terpolymers of aniline, anthranilic acid and o-phenylenediamine/Hydrophilic bentonite composites were synthesized using a 1:1:1 molar ratio of the respective monomers with different percentages of clay via modified in situ chemical terpolymerization. The spectral characteristics upon incorporation of anthranilic acid units into the copoly(aniline o-phenylenediamine) backbone in absence and in presence of bentonite nanoparticles were investigated. Moreover, terpolymer/bentonite composites were thermally more stable than pure terpolymer under nonoxidative condition. On the basis of surface morphological studies of terpolymer composites, a platy network texture can be explained, and it can be clearly seen in the SEM photomicrographs.