纤维增强环氧发泡复合材料的研究

研究制备纤维增强环氧发泡复合材料的方法，对影响材料性能的因素进行了分析。结果表明：采用纤维增强环氧发泡复合材料，有效地提高了环氧发泡材料的拉伸强度和弯曲强度。与未经纤维增强的环氧树脂固化后相比，密度下降了一半而强度基本相当，具有轻质、高强的特点     

环氧树脂基发泡材料的制备及力学性能研究

主要研究了发泡剂、发泡助剂及纤维增强对一种可诱导骨再生的环氧发泡材料力学性能的影响。结果表明:孔隙率是影响发泡材料力学性能的最重要因素,且存在一临界值;发泡剂及助剂都是通过改变孔隙率从而影响材料的力学性能。随发泡剂用量的增加,环氧基发泡材料的力学性能存在临界转变点。发泡助剂如氧化锌和硬脂酸锌的加入能有效地降低偶氮二甲酰胺(简称AC)的分解温度,改善发泡效果。纤维增强相的加入能明显地提高发泡材料的力学性能。     

纤维增强聚合物发泡体的研究进展

纤维增强聚合物发泡体是一种新型的三相复合材料，纤维增强发泡体可以大大提高发泡体的弹性模量和压缩模量，提高材料的破坏强度，也显著地降低了材料的收缩率，因而可用于结构性材料。纤维增强发泡体中纤维特性，长径比，用量，与基体的粘合状态，泡孔的大小，形状，发泡密度等因素对发泡体系的性能均有影响，其中粘合是非常生要的。过长的纤维由于结构缠结对聚合物发泡体的增强并不理想。     

环氧基纤维增强复合材料应用面面观

进行了环氧基玻璃纤维覆铜箔板(电子玻璃纤维基板)、环氧基纤维增强复合材料用于航天航空结构材料、环氧基纤维复合材料在运动器材方面应用、环氧基纤维增强复合材料高压管道和压力容器、环氧乙烯基酯树脂在化工防腐中运用及环氧树脂运用于建筑结构工程补强等方面的调查。报告了环氧基纤维增强复合材料应用的情况。     

阳离子淀粉增强剂对纤维发泡缓冲材料性能的影响

以阳离子淀粉为主体配以一定比例的水性环氧树脂和固化剂作为增强剂,提升植物纤维发泡缓冲材料的强度和回弹性;优化增强剂配比,分析该增强剂对纤维发泡缓冲材料性能的影响。以2.5%的阳离子淀粉溶液和1.5%的水性环氧树脂溶液在一定的配比下,添加适量的固化剂,得到较优的纤维发泡缓冲材料增强剂。植物纤维发泡材料成型选用的是一次发泡成型,成型前添加20%的增强剂,成型后得到的发泡材料的回弹性、应力变化等物理性能提升显著。     

硬质泡沫橡胶浮子的试制

针对泡沫浮子的使用要求，筛选出了用于制备泡沫橡胶浮子的配方体系，通过实验确定出了3种不同发泡剂的泡沫橡胶浮子的配方，比较了垂直自由发泡法、垂直加压发泡法和水平加压发泡法的优缺点。     

轨道车辆用纤维增强酚醛发泡材料研制

为提高酚醛发泡材料的力学性能、阻燃性能,满足轨道车辆地板产品应用需求.采用微球发泡及纤维增强技术通过热压成型研制了轨道车辆用高阻燃酚醛发泡材料板材,采用单因素试验方法,研究了初始固化温度、发泡剂、阻燃剂以及发泡材料密度等对材料性能的影响.结果表明,初始固化温度在140℃左右时能使发泡剂球体保留完好,含水率得到有效控制,...     

KH-560对硬质聚氨酯发泡材料阻水机理的研究

为降低水对聚氨酯发泡材料性能的影响,向聚氨酯发泡材料中添加了γ-(2,3-环氧丙氧)丙基三甲氧基硅烷(KH-560).并利用TG、SEM、IR研究了添加硅烷偶联剂前后聚氨酯发泡材料吸水情况,最终研究出发泡材料阻水的机理.TG的结果表明,加入KH-560后,聚氨酯发泡材料的吸水性大大降低.在偶联剂的添加量为3%时,泡孔结...     

纤维增强发泡复合材料中纤维与发泡关系的研究进展

介绍了挤出发泡法、注塑发泡法这两种生产效率较高的发泡成型方法,对纤维在复合材料中所起的作用以及发泡对纤维的影响进行了详细的介绍,最后对纤维增强发泡复合材料的未来发展趋势进行了展望。     

短纤维/橡胶发泡复合材料的微观结构及拉伸破坏机理

对锦纶短纤维增强的NR发泡材料的微观结构及拉伸破坏行为进行了研究，并分析了其破坏机理。采用未处理短纤维增强的NR发泡材料中短纤维成为泡孔的成核点，并大部分悬空在泡孔中，拉伸破坏时泡壁与短纤维结合处容易出现应力集中，成为裂纹的起始点，失效时短纤维大部分被抽出；预处理短纤维能与橡胶基体之间产生良好的粘合，从而处于橡胶基体中。其短纤维增强的NR发泡体拉伸产生的裂纹扩展时遇到纤维，纤维能起到承载应力、使应力转向、阻止裂纹扩展的作用，一定程度上改善了复合材料的拉伸强度等物理性。     

环氧树脂/空心玻璃微珠泡沫材料性能研究

以高强度环氧树脂为基体,表面改性处理的空心玻璃微珠(HGB)为填料,经高温固化制备了环氧树脂/HGB泡沫材料,并研究了HGB类型、HGB含量和固化剂用量对泡沫材料压缩性能的影响。研究发现,随着HGB填充量的增大,泡沫材料的密度和压缩强度均下降。当固化剂与环氧树脂物质的量比为0.85时,泡沫材料的抗压性能最好,压缩强度为40.19 MPa。偶联剂改性HGB可以有效改善HGB和基体树脂的粘合效果。当改性HGB质量分数为80%时,与未改性环氧树脂相比,环氧树脂/改性HGB泡沫材料压缩强度提高了5.0%,吸水率下降40.6%。     

A study on the compressive characteristics of co‐cured foam‐composite sandwich structures according to the crimp angle variations

A foam‐composite sandwich column composed of two‐ply carbon/epoxy fabric prepreg as a skin and PVC foam for a core material was investigated to determine the effect of crimp angle variations of the fabric prepreg on the compressive characteristics of the sandwich column. The crimp angle of the composite skin was observed and measured in terms of the forming pressure and the foam density as correlated with the foam deformation regimes. End compression tests for the foam‐composite sandwich columns were carried out to obtain the values of the compressive modulus and strength depending on the crimp angle variations. From the tests and observation results, it was found that the crimp angle and compressive strength were highly correlated; as the crimp angle increased, the compressive strength decreased as a large‐crimp angle caused the composite skin to fail due to simple microbuckling of the longitudinal tows. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

腰果酚醛胺固化环氧树脂泡沫塑料性能研究

以双酚A型环氧树脂(EP)为基体树脂、自制的腰果酚醛胺(PCT)为固化剂、正戊烷(N-PT)为发泡剂、吐温-80和二甲基硅油为稳泡剂室温发泡制备新型环氧树脂泡沫塑料。研究了PCT用量对发泡时间和泡沫性能的影响,通过扫描电子显微镜和热失重分析对泡沫塑料的微观形貌和热性能进行了表征。结果表明,随着PCT用量增加,发泡时间逐渐缩短;环氧树脂泡沫塑料的密度、压缩强度、吸水率和热导率均随PCT用量的增加呈现先减小后增大趋势;当PCT加入量为30 %(相对于纯EP)时,发泡时间降至5 min;泡沫塑料的综合性能较佳,密度为0.0467 g/cm^3、压缩强度为276 kPa、吸水率为2.9 %、热导率为0.037 W/m·K,此时泡孔大小均匀,不良泡孔少;泡沫初始失重温度为248.4 ℃,最大失重速率温度为362.3 ℃,耐热性最佳。     

电子束辐射接枝对PAN基碳纤维的表面改性

采用电子束加速器辐射接枝方法对聚丙烯腈(PAN)基碳纤维进行表面改性,研究了接枝单体种类对接枝率及其环氧树脂基复合材料力学性能的影响,分析了辐射接枝前后PAN基碳纤维的表面形貌与化学结构以及其复合材料界面断口的形貌变化。结果表明:电子束辐射接枝改性的PAN基碳纤维表面粗糙度增加,表面活性官能团增多,与树脂的机械锲合作用增强,其树脂基复合材料断口表而较为平整;乙二胺/水溶液体系是辐射接枝改性的理想溶液,在200 kGy的电子束辐射下,PAN基碳纤维表面的接枝率为6.66%,复合材料的层间剪切强度提高了45.1%。     

轻质环氧树脂微孔发泡材料的力学及隔热性能

通过添加不同含量的化学发泡剂,制备了较小密度(0.5 g/cm~3)的环氧树脂基微孔发泡材料,研究了发泡剂含量(0.25%~2%)对环氧复合发泡材料发泡行为的影响,并讨论了材料的力学性能及隔热性能的变化规律。结果表明,随着发泡剂含量的增加,材料的表观密度不断降低,但泡孔尺寸不断增大,泡孔密度则不断降低。力学性能及隔热性能测试表明,随发泡剂含量的增加,材料的压缩屈服强度和压缩弹性模量不断降低,但是材料的隔热性能不断提高。     

Effect of Acetic Acid as Catalyst on the Properties of Epoxy Foam

In this study, the effect of acetic acid used as catalyst in promoting the decomposition rate of blowing agent (sodium bicarbonate) in epoxy foam was done. Hard epoxy foam was produced using mechanical mixing technique. Epoxy foam has been tested with adding acetic acid at 5 phr and different content of sodium bicarbonate which are 0, 5, 10, 15, and 20 phr, respectively. The effect of acetic acid on the viscosity, density, mechanical properties, and dielectric constant has been studied. The results were compared between with and without acetic acid in the system. Viscosity reading was increased with increasing the content of sodium bicarbonate due to the rapid production of bubbles that created porosity in the structure of epoxy foam. The addition of acetic acid is able to reduce the dielectric constant. In overall, the density, flexural strength and modulus dropped for the epoxy foam with acetic acid as compared to that of without acetic acid.     

Evaluation of fiber surfaces treatment and sizing on the shear and transverse tensile strengths of carbon fiber-reinforced thermoset and thermoplastic matrix composites

The mechanical performance of advanced composite materials depends to a large extent on the adhesion between the fiber and matrix. This is especially true for maximizing the strength of unidirectional composites in off-axis directions. The materials of interest in this study were PAN-based carbon fibers (XA and A4) used in combination with a thermoset (EPON 828 epoxy) and a thermoplastic (liquid crystal poymer) matrix. The effect of surface treatment and sizing were evaluated by measuring the short-beam shear (SBS) and transverse flexural (TF) tensile strengths of unidirectional composites. Results indicated that fiber surface treatment improves the shear and trasverse tensile strengths for both thermosetting and thermoplastic matrix/carbon fiber-reinforced unidirectional composites. A small additional improvement in strengths was observed as the result of sizing treated fibers for the epoxy composites. Scanning electron microscope photomicrographs were used to determine the location of composite failure, relative to the fiber-matrix interface. Finally, the epoxy composites SBS and TF strengths appear to be limited to the maximum transeverse tensile strength of the epoxy matrix, while the thermoplastic composite SBS and TF strengths are limited by the LCP matrix shear and transverse tensile strengths, respectively.     

PVC/WF复合发泡材料的研究

采用一步模压法制备聚氯乙烯/木粉(PVC/WF)复合发泡材料,研究木粉(WF)的预处理、用量及粒径对PVC/WF复合发泡材料力学性能、尺寸稳定性、密度、吸水性及吸油性能的影响,并通过扫描电镜(SEM)对其泡孔结构进行分析.结果表明:WF经预处理,PVC/WF复合发泡材料拉伸强度有所增强,密度和吸水率略有减小,吸油性尤明显变化,耐热性稍有降低;随着WF粒径的增加,PVC/WF复合发泡材料的密度、吸水率、吸油率和线性收缩率均增大,拉伸强度从1.25MPa增大到1.78 MPa,断裂伸长率随之减小;随着WF含量增加,PVC/WF复合发泡材料密度和吸油率均明显增加,拉伸强度也随之增大,线性收缩率减小,吸水率先增大后减小,WF质量分数10%时吸水率最大.     

Improvement of Interfacial Adhesion of Glass Fiber/Epoxy Composite by Using Plasma Polymerized Glass Fibers

This study intends to produce plasma polymer thin films of γ-glycidoxypropyltrimethoxysilane (γ-GPS) on glass fibers in order to improve interfacial adhesion of glass fiber-reinforced epoxy composites. A low frequency (LF) plasma generator was used for the plasma polymerization of γ-GPS on the surface of glass fibers at different plasma powers and exposure times. X-ray photoelectron spectroscopy (XPS) and SEM analyses of plasma polymerized glass fibers were conducted to obtain some information about surface properties of glass fibers. Interlaminar shear strength (ILSS) values and interfacial shear strength (IFSS) of composites reinforced with plasma polymerized glass fiber were evaluated. The ILSS and IFSS values of non-plasma polymerized glass fiber-reinforced epoxy composite were increased 110 and 53%, respectively, after plasma polymerization of γ-GPS at a plasma power of 60 W for 30 min. The improvement of interfacial adhesion was also confirmed by SEM observations of fractured surface of the composites.