复合材料用预浸料

３预浸料的质量控制预浸料的一些性能将直接带入复合材料 ,复合材料的性能取决于预浸料的性能。对于热固性树脂预浸料而言 ,在制造过程中 ,运输、储存期间均会发生化学变化。热塑性树脂预浸料在上述情况下虽不发生化学变化 ,但聚合物分子量、分子量分布、纯度、结晶形态等对预浸料和复合材料性能及成型工艺均有很大影响 ,如树脂体系组成的微小变化、工艺过程控制不当或偶然失误 ,都会对复合材料带来无法挽回的损害 ,因此 ,对预浸料必须进行严格的质量控制。国外已形成一整套严密地质量控制程序和方法 ,建立了保证预浸料制备过程各阶段性能的…     

预浸料技术的新进展

本文根据复合材料低成本制造技术，介绍了预浸料技术的新进展，包括可常温储存的预浸料；低温固化温使用的预浸料；大丝束碳纤维预浸料和快速固化预浸料。     

国外FRP预浸料发展概况

预浸料是用树脂预先浸渍,可以储存的纤维增强塑料（FRP）半成品,随时可以用来制造复合材料制品。预浸料有热固性和热塑性预浸料之分。因它们容易使用、性能稳定、空隙率低、模塑过程清洁等诸多优点,预浸料在复合材料工业中日趋普遍,前景甚好。     

预浸料技术的新进展

本文根据复合材料低成本制造技术，介绍了预浸料技术的新进展，包括可常温储存的预浸料；低温固化高温使用的预浸料；大丝束碳纤维预浸料和快速固化预浸料。     

复合材料预浸料的粘性及其表征方法

粘性是决定复合材料预浸料是否适合铺贴的一个关键因素。本文对预浸料的粘性及其物理意义进行了讨论，重点介绍了目前的几种预浸粒粘性测试方法，认为建立最化的预浸粘性测试方法对预浸料制造中的工艺参数控制及树脂配方研究有重要意义。     

复合材料用预浸料

１预浸料的基本概念预浸料是用树脂基体在严格控制的条件下浸渍连续纤维或织物,制成树脂基体与增强体的组合物,是制造复合材料的中间材料。它的一些性质直接带入复合材料中,是复合材料的基础。复合材料的性能在很大程度上取决于预浸料的性能。对于复合材料设计师来说,预浸料是具有一定力学性能的结构单元,可用以进行结构设计。对于复合材料工艺工程师而言,预浸料是制造结构的原料,可直接用以制造各种复合材料构件。预浸料的优劣关系到复合材料的质量。因此,预浸料对复合材料的应用和发展具有重要意义。预浸料从４０年代末期开始采用…     

复合材料用预浸料

(续 5)4　预浸料的类型和性能4 1　预浸料的类型随着复合材料研究和开发的不断进步 ,使用领域日渐扩大 ,复合材料构件不同制造工艺、不同工作条件对预浸料也提出了不同要求。为了适应来自多方面的需要 ,新的预浸料不断出现 ,预浸料的类型不断增加。按物理状态分类 ,预浸料分成单向预浸料、单向织物预浸料、织物预浸料 ;按树脂基体不同 ,预浸料分成热固性树脂预浸料和热塑性树脂预浸料 ;按增强材料不同 ,分成碳纤维 (织物 )预浸料、玻璃纤维 (织物 )预浸料、芳纶 (织物 )预浸料 ;根据纤维长度不同 ,分成短纤维 (4 76ｍｍ以下 )预浸料、长纤…     

芳纶预浸料的研究

介绍了芳纶预浸料及其与碳纤、玻纤混杂预浸料的研制状况。探讨了不同因素对预浸料及其复合材料的性能影响。叙述该预浸料的性能和特点。     

热熔预浸料预浸工艺研究

采用幅宽300mm热熔预浸机,对碳纤维/环氧树脂热熔预浸料制作过程中预浸温度、平压辊间隙、预浸速度等影响预浸料质量的主要工艺参数进行研究。对含浸过程中出现的问题进行了分析,得到适合该设备型号制作碳纤维/环氧树脂热熔预浸料的工艺参数优化值:预浸温度控制为100~105℃,预浸速度控制为4~5m/min,间隙为380~400μm之间,冷却板温度控制在16℃左右,收卷张力控制为300N/m。     

环氧树脂/芳纶纤维预浸料的质量控制试验方法研究

测定了环氧树脂／芳纶纤维预浸料的固化度（红外法）、不可溶分含量及其复合材料的力学性能与储存时间的关系。结果表明,固化度、不可溶分含量与储存时间之间在９５％的置信条件下呈显著的线性关系。固化度、不可溶分含量可以作为预浸料的质量控制参数,其试验方法可用于预浸料的质量控制。     

Preparation of AgNPs/PS composite via reverse microemulsion polymerization

Silver nanoparticles (AgNPs) were synthesized in reverse microemulsions using silver nitrate as silver source, hydrazine hydrate as reducing agent, n‐heptane as oil phase, cetyl trimethyl ammonium bromide (CTAB) as surfactant, and isoamyl alcohol as cosurfactant. A uniform silver nanoparticles/polystyrene (AgNPs/PS) composite was further prepared by a reverse microemulsion polymerization method. The morphologies and structures of the AgNPs and the AgNPs/PS composite were characterized by UV‐visible spectroscopy (UV–vis), X‐ray diffraction (XRD), fourier transform infrared spectra (FTIR), and transmission electron microscopy (TEM). Furthermore, the molecular weight of the AgNPs/PS composite was measured by gel permeation chromatography (GPC), and the thermal stability of the AgNPs/PS composite was determined by thermal gravimetric (TG) analysis. Results show that the AgNPs have a particle size of 3–10 nm, and are almost spherical, uniform, and monodisperse both in a AgNPs colloid and in the AgNPs/PS composite. There are no characteristic peaks of silver oxide in the synthetic AgNPs and AgNPs/PS composite. The AgNPs/PS composite has a better thermal stability and a higher molecular weight than virgin PS. POLYM. COMPOS., 35:1325–1329, 2014. © 2013 Society of Plastics Engineers     

应用于聚丙烯塑料的水性复合涂层的制备及性能研究

为了解决聚丙烯材料上水性涂料附着力较差的技术难题,首先合成一种丙烯酸酯单体改性水性氯化聚丙烯树脂,采用该树脂制备聚丙烯塑料水性底漆,并研制配套的水性面漆和罩光清漆,制备得到成套水性复合涂层体系。使用傅里叶变换红外光谱仪(FT-IR)、动态光散射(DLS)、凝胶渗透色谱(GPC)和差示扫描量热法(DSC)对所制备丙烯酸改性水性氯化聚丙烯树脂进行结构表征。重点考察了水性底漆的附着力、复合涂层的附着力以及复合涂层的耐热水煮性能,结果表明:水性底漆和复合涂层均表现出优异的附着力,涂层耐热水煮性能较好。最后,对水性复合涂层的性能进行测试,结果表明:复合涂层综合性能优异,在汽车内外饰及各类聚丙烯材料领域具有较大的应用前景。     

复合硫化物近常温热催化降解低密度聚乙烯薄膜

采用回流法合成新型热敏催化剂,将其与低密度聚乙烯(LDPE)熔融共混制得复合薄膜,并置于近常温黑暗烘箱中热催化降解。通过扫瞄式电子显微镜(SEM)、X射线能量色散光谱分析(EDX)、力学性能、原子力显微镜(AFM)、热重分析(TG)、凝胶渗透色谱(GPC)和傅里叶变换红外光谱(FT-IR)等表征手段对研究复合薄膜的热降解性能进行了研究。结果表明：纯聚乙烯薄膜在黑暗近常温条件下亦能发生热降解,但效果甚微;而复合薄膜的降解效果明显优于纯聚乙烯薄膜。在55℃下热降解45 d后,复合薄膜力学性能明显下降,粗糙度明显增加且周围出现了不同程度的褶皱与鳞片状结构,甚至于剥落现象,热分解温度下降13℃,分子量亦明显减小,同时出现了羧基和羟基等特征吸收峰。     

Effects of mesoporous SBA-15 contents on the properties of polystyrene composites via in-situ emulsion polymerization

Different loading of mesoporous molecular sieve SBA-15 was used to prepare polystyrene (PS)/SBA-15 composite materials via in-situ emulsion polymerization. The influence of SBA-15 silica on the styrene emulsion polymerization was studied regarding to the monomer conversion, particle size and particle size distribution, stability and viscosity of the resulting emulsion. The structure and properties of the composites were investigated by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and gel permeation chromatography (GPC). In addition, the glass transition temperature (T_g), thermal mechanical property and thermal stability of the composite film were measured by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. The results indicated that the composite emulsion showed high monomer conversion, thick viscosity, low coagulum, uniform particle size and broad size distribution. Molecular weight of the polymer decreased with the increase of mesoporous silica. SBA-15 silica was dispersed evenly in PS matrix at a loading of 5 %. The PS/SBA-15 composite material containing 10 % silica maintained a certain ordered structure. DMA results demonstrated that PS/SBA-15 composite exhibited greater storage modulus and high T_g compared to pure PS. The improved thermal stability and T_g of the composite were also confirmed by the TGA and DSC.     

Inverse gas chromatography for the determination of the dispersive surface free energy and acid–base interactions of a sheet molding compound. I. Matrix material and glass

Sheet molding compound is a material composed of a polyester thermosetting matrix with a thermoplastic, an inorganic filler, a metal oxide, reinforcement fibers, and material performance enhancers embedded in the crosslinked matrix. To achieve the optimum mechanical properties required for the composite material, the surface free energy of the polyester composite needs to be understood. In this study, the composite matrix and glass reinforcement fibers are compared with respect to their surface free energy and acid–base characteristics on the basis of inverse gas chromatography measurements. The inverse gas chromatography results for the matrix and glass are compared to previous results found for sized and unsized cellulosic fibers. The inverse gas chromatography data are used to assess chemical modifications performed on the biobased fibers to predict improvements in the fiber/matrix interaction, and this provides inferences on the overall composite cohesion. Our results show first that any fiber reinforcement system for the polyester composite material has to be acidic to promote good adhesion as the matrix system is very basic and second that the individual dispersive surface energies of the components of the matrix interact in a weighted average to determine the overall surface energy of the composite. Also, a commercial glass reinforcement sized for polyester has been found to have a lower interaction parameter than literature values for cellulosic fibers. This finding suggests that cellulosic fibers might have an advantage in competing with a conventional glass‐fiber reinforcement system in fiber/matrix bonding for sheet molding compound composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Development of polystyrene composites based on blue agave bagasse by in situ RAFT polymerization

A new approach for the production of polystyrene-blue agave bagasse (BAB) composite materials is presented. In this approach, dried powdered raw BAB is press molded in the presence of a coupling agent based on glycidyl methacrylate (GMA), producing a hybrid material of poly(GMA) grafted onto BAB. The in situ reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene in presence of this poly(GMA)-graft-BAB hybrid material results in a reinforced composite material. These composites are characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, scanning electron microscopy, impact test analyses, and dynamic mechanical analysis. The characterization results show that the amount of GMA coupling agent plays a key role in the efficiency of the process, manifested as improvement of the mechanical properties of polystyrene. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47089.     

Intraparticle diffusion coefficients in packed columns: Measurement by arrested-flow gas chromatography

Arrested-flow chromatography was used to determine intraparticle diffusivities of large-pore particles packed in columns. Particle and column tortuosity factors were determined for helium tracer in nitrogen carrier gas at 40°C and atmospheric pressure. Semiempirical modifications of Maxwell's, Burger's, Jeffrey's, and Rayleigh's relations for the composite diffusivity of spherical particles in a stationary medium are proposed for the effective composite diffusion coefficient for a packed bed of porous particles. The equations, modified to represent accurately the extraparticle void diffusion based on measurements for beds of nonporous particles, are used to evaluate intraparticle diffusivities from experimental data obtained by arrested-flow chromatography.     

Synthesis,Characterization of a Novel Light Stable Cross-Linker—Isophorone Diisocyanate Terpolymer Composite

Isophorone diisocyanate (IPDI) is an alicyclic isocyanate, in which the outcomes always possess good light and heat stability. A novel IPDI terpolymer composite were synthesized and characterized using Fourier transform infrared (FTIR), Nuclear magnetic resonance (NMR), gas permeation chromatography (GPC), and the chemical analysis method. The result showed that IPDI terpolymer composite could be prepared in the presence of Cat-5 catalyst and under the reaction temperature between 70 ～ 90°C. The colorless or pale yellow liquid products without solvent could be obtained in a short time under optimized reaction conditions. In addition, the IPDI trimer/monomer mixture having an NCO content ranging from 25.0% to 28.0% and average nominal functionality of from 2.5 to 2.8 could be compatible with sufficient reactivity and liquidity.     

Analysis of interfacial action of rectorite/thermoplastic polyurethane nanocomposites by inverse gas chromatography and molecular simulation

The compatibility of surface properties and the degree of interfacial action between filler and base directly affect the structure of their composites and make great contribution to a series of properties of composite materials. Interactions among rectorite (REC), quaternary ammonium salt and polymer are investigated via molecular simulation. Inverse gas chromatography (IGC) has been used to investigate the surface properties of REC, organic-modified rectorite with dodecyl benzyl dimethyl ammonium bromide (12-OREC) and hexadecyl trimethyl ammonium bromide (16-OREC), and thermoplastic polyurethane (TPUR). The correlation of the surface properties and the interfacial action between REC and TPUR and the structure of composite were analyzed. The results indicate that the modification of REC lowers its surface energy, and changes the surface from being acidic to being predominantly basic and increased the binding energy hence improving the dispersibility of 12-OREC and 16-OREC in TPUR; 12-OREC was found to be the best dispersibility in TPUR because the dispersive energy is approached to TPUR, the acid-base property is most comparable with TPUR and the binding energy between 12-OREC and TPUR is larger, which can yield higher interfacial strength.     

Morphology and failure in nanocomposites. Part II: surface investigation

Polymer composites filled with calcium carbonate (CaCO₃) nanofillers (<100 nm), and kaolin filler of layered structure, both well suited to create nanocomposites, were analysed. The aim of this study was to investigate the influence of surface properties of the filler and matrix on the adhesion parameters at the interface in composites. The inverse gas chromatography, contact angle and capillary measurements were used for the surface characterization of filler and matrix. Although these methods are based on different assumptions, we found the same trends in the effects of filler surface treatment and/or matrix chemical structure on the changes in the dispersive and polar components of the surface energy. The energetics of the filler and matrix was varied in order to investigate the work of adhesion, interfacial energy and coefficient of spreading, and their influence on the composite properties. We found that the surface treatment of calcium carbonate filler lowered the filler surface energy and the work of adhesion in the composite with poly (vinyl acetate) matrix. The mechanical, thermal and morphological properties of the composite with treated CaCO₃, measured in the first part of this paper, indicated a weak and thin interphase. In the composite with kaolin filler the higher interaction with the polyacrylate copolymer matrix based on styrene as compared to the one based on methyl methacrylate, was confirmed by the higher work of adhesion in the interphase, resulting in a stronger reinforcing of the composite.