玻璃纤维增强热塑性树脂复合材料界面表征方法的研究

玻璃纤维复合材料的界面性能是影响复合材料整体力学性能的关键因素。本文提出利用剥离试验表征玻璃纤维增强热塑性树脂复合材料界面粘结强度,并结合红外光谱、接触角、扫描电镜进行表征的方法。结果表明:实验室制备的玻璃片与玻璃纤维原丝浸润剂处理前后红外图谱对比发现,红外特征峰硅羟基峰位、定量分析结果基本一致;浸润剂处理前后的玻璃片接触角分别为41.01°、52.71°,表面疏水性明显增大,可以更好地被树脂浸润;剥离试验曲线与其他界面表征试验的脱粘趋势相似,亦符合剥离曲线的基本趋势,浸润剂处理前后玻璃片与聚乙烯树脂间的平均剥离力增大84.67%,浸润剂处理表面后,复合材料界面的粘结力明显增大。因此,将剥离试验用于探究玻璃纤维热塑性复合材料的界面粘结性能具有一定的可行性。     

硅烷偶联剂改性芳纶的性能测试

采用硅烷偶联剂对芳纶进行改性,然后用傅里叶红外光谱仪、单一纤维接触角测试仪和X射线衍射仪对改性前后的芳纶进行测试、观察并分析。结果显示:红外光谱分析表明芳纶的改性发生在纤维的表面,并没有对纤维大分子产生明显破坏;接触角测试表明改性后芳纶的接触角变小,说明KH550硅烷偶联剂可改善芳纶的亲水性;X射线衍射测试表明芳纶结晶度有所下降,可以更好地与树脂黏结。     

碳纳米管改性环氧树脂/碳纤维复合材料的界面性能

采用碳纳米管对环氧树脂体系以及碳纤维进行改性处理,得到四种试样,即CNTs-00 (不添加碳纳米管)、CNTs-01 (碳纳米管与活性分子预反应)、CNTs-02 (碳纳米管与树脂体系直接混合)、CNTs-03 (碳纤维表面生长碳纳米管)。采用视频接触角测量仪以及界面性能测试仪对树脂浸渍国产T800S碳纤维单丝形成的微球形态、微球与纤维的界面接触角及界面剪切强度(IFSS)等进行了分析表征;同时采用模压法制备了复合材料单向板,从宏观尺度表征了其层间剪切强度(ILSS)。结果表明,与CNTs-00相比,CNTs-01的树脂界面浸润性以及复合材料IFSS有了较大提高,接触角减小了3.1°,IFSS提高了12.7%,ILSS提高了9%;CNTs-02的树脂界面浸润性略有降低,接触角增大了0.9°,IFSS降低了8.6%,ILSS与CNT–00基本相同;CNTs-03的界面浸润性降低,浸润角增大了4.5°,IFSS降低了5.7%,ILSS降低了11.5%。     

SB-j增强型玻璃纤维浸润剂的使用

玻璃纤维增强材料和树脂基体是玻璃钢的主要原材料。为了获得性能好、质量高的玻璃钢,除提高玻璃纤维和树脂性能外,还需改善树脂与纤维之间的界面状况。界面状况受着保留在玻璃纤维表面上浸润剂的影响。通常的做法是对玻璃纤维表面进行化学处理或使用增强型浸润剂。本文较系统的介绍了一种新型增强型玻璃纤维浸润剂SB-j浸润剂的使用情况。     

基于Wilhelmy法的单一炭纤维/环氧树脂动态接触角测量及表面能表征

基于Wilhelmy法对日本东丽T700炭纤维/BA202环氧树脂体系动态接触角的测量方法进行研究,利用测试得到的"润湿回线"分析探讨炭纤维与树脂间的浸润过程,并基于此"润湿回线"进行测试条件优化,得到最佳测试条件为纤维伸出测量夹具4 mm、纤维浸入树脂深度2 mm、检测速度1 mm/min、检测阈值0.0002 g和炭纤维单丝根数6根。最后通过测试炭纤维上浆前后与树脂的接触角变化及计算对应的纤维表面能及其组成的变化,得出该表面上浆剂能够提高T700炭纤维的表面能,降低纤维接触角,增强纤维与基体树脂间的结合力,提高其浸润性能的结论。     

连续毡对风电叶片界面性能的影响分析

依据风电叶片主梁界面形成过程,采用真空辅助树脂灌注工艺制备层合板,选用层合板T剥离测试方法测试复合材料的界面性能。根据T剥离测试方法得到:真空辅助树脂灌注成型技术中,脱模布形成的界面上铺放连续毡,能够提高复合材料界面结合性能。最后,通过试样失效模式及显微结构分析得到与T剥离测试结果一致的结论,为连续毡在复合材料界面应用提供了参考。     

碳纤维不同表面处理及其对聚三唑基复合材料界面性能的影响

采用高温处理、硝酸氧化、丙酮抽提上浆剂和氨水处理等方法对碳纤维(CF)进行表面处理,采用热压成型制备了CF增强聚三唑树脂(PTA)基复合材料,分析了CF表面处理前后的变化并研究了其对PTA/CF复合材料界面性能的影响。单丝拉伸强度测试结果表明,表面处理后的CF单丝拉伸强度均出现不同程度的下降;接触角测试结果表明,CF与水及PTA丙酮溶液的浸润性均变好;原子力显微镜分析表明,经丙酮抽提后CF表面粗糙度略有下降,而其它几种方法处理后的CF表面粗糙度均有不同程度的提高;X射线光电子能谱揭示高温处理主要是氧化去除CF表面上浆剂,硝酸主要是氧化CF,丙酮主要是物理抽提CF表面上浆剂,而氨水与CF表面发生了化学键合。不同的表面处理均可增加CF的极性,提高CF在PTA胶液中的浸润性能,增强与PTA基体的氢键合,改善CF与PTA基体的界面性能。与未表面处理CF相比,以上4种表面处理的CF增强PTA基复合材料的层间剪切强度均得到提高,提高幅度分别为47.0%,36.7%,63.3%和45.3%,其中氨水处理效果虽然低于丙酮抽提,但其条件温和,操作简便,是一种较好的CF表面处理方法。     

在湿态条件下玻璃钢的增强机理(提要)

研究玻璃钢在湿态条件下的增强机理,需着重于玻璃/基体界面的分子结构,包括对玻璃表面、玻璃/耦联剂界面、玻璃表面上的硅烷耦联剂,耦联剂/基体界面,并一直扩展到充满了粒子的复合物内部状态以及树脂基体的研究。为了更好地了解玻璃钢的湿态强度,还     

浓强碱溶液处理对不饱和聚酯树脂/苎麻布复合材料界面性能的影响

利用不同质量分数的NaOH溶液处理苎麻布,并与不饱和聚酯树脂形成复合材料。研究了碱的质量分数及碱处理时间对树脂与苎麻布之间的接触角的影响;观察了碱处理前后苎麻布的表面形貌及复合材料的冲击断面形貌;探讨了碱处理可提高麻塑复合材料力学性能的机理。结果表明：NaOH溶液处理可降低树脂在苎麻布上的接触角,苎麻布表面因碱处理而变得更加光滑蓬松,复合材料的冲击断面上,纤维被树脂紧紧包裹着,说明碱处理可改善纤维与树脂之间的界面结合。     

ESPCEG对玻璃纤维表面的润湿及其润湿表面的特性

本文测定了玻璃纤维表面对双[γ—(三乙氧基硅基)丙基碳酰氧基]二甘醇(ESPCEG)的吸附热;测定了ESPCEG/乙醇/水溶液对玻璃的前进接触角θ及浸润功,表明该溶液对玻璃表面具有良好的润湿能力。玻璃表面经ESPCEG处理后,对不饱和聚酯树脂的接触角由未处理表面的54.5°降低到38.8°,对水的接触角由23.8°提高到52°,改善了对树脂的浸润性,提高了憎水性。     

Mechanical properties of particulate composites

The mechanical properties of glass bead (30 micron diameter glass spheres) filled epoxy and polyester resins have been studied as a function of volume fraction of filler and the strength of the interfacial bond. The bonding between glass and resin was varied by chemically surface treating the glass using a silicone mold release to prevent chemical bonding at one extreme and a silane coupling agent to maximize bonding at the other extreme. Theoretical predictions of the elastic modulus and tensile strength have been made utilizing a finite element method. Excellent agreement is obtained with the experimental results. Izod impact energies have been measured for these composites as a function of filler content and interface treatment.     

Modification of a nitrile-phenolic bonding agent by addition of an interfacial agent: effect on the practical adhesion between nitrile rubber and metal

—The mechanism of vulcanization bonding of a nitrile rubber (NBR) elastomer to metal with a single-coat nitrile-phenolic bonding agent is discussed. A nitrile-phenolic bonding agent consisting of NBR, phenol formaldehyde (PF) resin, and vulcanizing agents was modified with an interfacial agent (p-cresol formaldehyde resin) and the effect of interfacial agent addition on the practical adhesion between metal and the NBR elastomer after vulcanization was investigated. The adhesion strength was measured in terms of the metal-to-NBR elastomer peel strength using the bonding agent. The addition of p-cresol formaldehyde (PCF) resin to the bonding agent with a proportionate reduction of PF resin initially improved the peel strength; a maximum was reached at about 20% PCF content and then decreased with a further increase in the PCF content. The improvement in peel strength produced by the addition of PCF resin is attributed to the increased chemical bonding between NBR and the phenolic resin. The drop in peel strength above 20% PCF content is explained by the increased diffusion of the bonding agent into the NBR elastomer, away from the bond line, leading to a starved glue line. The mechanism for the optimum performance at about 20% PCF resin content is believed to be due to the balance of diffusion and chemical crosslinking.     

树脂-水泥界面改性的多尺度表征

为从多尺度层次探明水泥基体与透明树脂界面以及偶联剂对界面的改性作用,利用硅烷偶联剂A-151和液体铝酸酯偶联剂处理水泥与树脂界面,采用抗拉和斜剪、显微硬度、FTIR和ESEM等测试手段从宏观、细观、微观尺度来表征界面的粘结强度、显微硬度、微观形貌和化学反应.结果表明:在宏观方面,硅烷偶联剂A-151和液体铝酸酯偶联剂能大幅提高树脂-水泥界面抗拉和斜剪强度,28 d强度至少提高73%和40%.在细观方面,偶联剂改善了透明树脂与水泥基体界面显微硬度,特别是在界面-10~10 μm区间内,且降低透明树脂"性能减弱区域"厚度达100 μm.在微观方面,硅烷偶联剂A-151、液体铝酸酯偶联剂与水化硅酸钙CSH中羟基OH反应分别生成Si-O-Si键和Al-O-Si键,偶联剂促使水泥净浆与透明树脂更好地融合,极大地改善了界面粘结情况.     

Release Mechanisms for Pressure Sensitive Adhesive Tape on Silicone-Coated Glass

Regarding the function of the silicone release agent, the following two mechanisms, that is, the low energy surface of a cross-linked methyl hydrogen polysiloxane (MHPS) resin and the separation of a non-cross-linkable dimethyl polysiloxane (DMPS) oil itself have been compared. The 180° peel strength of the glass plate/silicone release agent/pressure sensitive adhesive (PSA) tape laminates decreased in the following order: un-coated > MHPS-coated > DMPS-coated glasses. ATR, ESCA and SEM observations of the PSA and glass surfaces after the peel test showed that no MHPS transferred from the glass surface to the PSA but a part of the DMPS transferred. From these results, it was concluded that, for decreasing peel strength, the separation of silicone oil (DMPS) itself is more effective than the low energy surface of the silicone resin (cross-linked MHPS).     

淀粉纳米晶对玻璃纤维的表面改性研究

采用自制的淀粉纳米晶(SNC)对玻璃纤维进行表面处理,增加其与环氧树脂基体的界面剪切强度(IFSS)。研究了处理方式、处理时间、SNC乙醇分散液浓度、热处理温度等工艺参数对SNC在玻璃纤维表面沉积情况的影响,以及对改性玻璃纤维与环氧树脂的界面性能的影响规律。采用扫描电子显微镜、单纤维强力仪对处理前后玻璃纤维进行表征,并采用微脱粘法测试玻璃纤维与环氧树脂的界面粘结情况。结果表明,当重力静置处理时间24 h,SNC乙醇分散液浓度为1 g/100 m L时,SNC在玻璃纤维表面均匀沉积,且能显著提高玻璃纤维与环氧树脂的IFSS,为27.29 MPa,较未处理的纤维增加29.3%。150℃热处理4 h后,X射线光电子能谱结果显示SNC与玻璃纤维形成化学键合,进一步增加纤维与环氧树脂的界面粘结,IFSS值达到32.30 MPa,较未处理的纤维增加53%,且纤维的拉伸强度得到较好的维持。     

Shear bond strength of bis-acryl resin provisional material repaired using a flowable composite

This study investigated the shear bond strength of a bis-acryl composite repaired with a flowable composite after different surface treatments. Sixty standardized cylindrical silicone molds were filled with bis-acryl resin provisional material and then divided into six groups (n = 10 per group) to undergo different surface treatments. After a surface treatment had been performed, the flowable composite was injected directly into the cylinder of each specimen, and the specimens were then cured over a 10-mm-thick glass slide for 20 s. The shear bond strength was determined using a universal testing machine at a crosshead speed of 1.0 mm/min by placing a knife-edged blade immediately adjacent and parallel to the adhesive interface between the repair material (flowable composite) and the bis-acryl resin provisional material. The mean shear bond strengths ranged from 8.98 to 17.14 MPa. The highest mean shear bond strength corresponded to the bonding group (17.14 MPa), whereas the air-particle abrasion group exhibited the lowest mean shear bond strength (8.98 MPa). Surface treatment of bis-acryl resins with bonding appears to be a promising approach for improving repair bond strength, and the bonding group exhibited the highest levels of bond strength.     

The Use of Peel Ply as a Method to Create Reproduceable But Contaminated Surfaces for Structural Adhesive Bonding of Carbon Fiber Reinforced Plastics

In the fabrication of fiber-reinforced plastics materials peel plies are commonly used as an additional layer on top of the laminates to sponge up the surplus resin and to create an activated surface for adhesive bonding or coating by peel ply removal. In theory, the peel ply removal results in a new and uncontaminated fracture surface that is activated by polymer chain scission. The peel ply method is often presented as being a good surface treatment for structural bonding.

In this study carbon fiber-reinforced plastics (Hexcel® 8552/ IM7) were produced by the use of five different peel plies and a release foil made of polytetrafluorethylene (PTFE). The peel plies themselves and the surfaces on the CFRP created by peeling were examined by scanning electron microscopy (SEM), x-ray photo electron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDX), infrared (IR) spectroscopy, atomic force microscopy (AFM), and contact angle measurements to characterize the surfaces produced. Furthermore, the bond strength of lap shear and floating roller peel samples was determined with and without additional plasma treatment. For bonding, a room temperature-curing two-component-epoxy adhesive (Hysol® 9395) was used to prove the applicability of different peel plies for structural adhesive bonding under repair conditions.     

GF处理工艺及熔体流动场对PET/GF复合材料微观结构的影响

采用不同玻纤(GF)处理工艺,改变制备聚对苯二甲酸乙二酯(PET)/GF复合材料试样过程中熔体流动场剪切速率,通过红外光谱(IR)仪、差示扫描量热(DSC)仪分析和扫描电镜(SEM)观察,研究GF处理工艺和熔体流动场对PET/GF复合材料微观结构的影响。结果表明,硅烷偶联剂与聚合物成膜剂并用处理GF,不仅能增强GF与树脂基体之间的化学键合,提高树脂的结晶度,形成不易发生界面脱粘的稳定界面层,并且使GF沿树脂流动方向取向变得容易,其中A1100硅烷偶联剂与低分子量PET成膜剂并用处理的GF增强PET复合材料的界面粘着状态最佳。     

The effect of nano-structured alumina coating on the bond strength of resin-modified glass ionomer cements to zirconia ceramics

The purpose of this study was to evaluate the effect of Y-TZP ceramic surface functionalization with a nano-structured alumina coating on bond strength of the resin modified glass ionomer dental cement. A total of 160 disc-shaped specimens were produced and randomly divided into two groups of 80. Half of the discs in each group received an alumina coating which was fabricated by exploiting the hydrolysis of aluminum nitride (AlN) powder. The shear bond strengths of the resin-modified glass ionomer cement FUJI+ (GC Japan) and the composite resin luting agent RelyX Unicem (3M ESPE, USA) were then studied for the coated and uncoated surfaces The SEM analyses revealed that the application of an alumina coating to the Y-TZP ceramics created a highly retentive surface for bonding. The bond strengths for the coated groups in both cements were significantly higher than the uncoated groups.     

Prevention of Hydrosilation Cure Inhibition in a Polysiloxane Adhesive by Surface Oxidation

For a variety of reasons epichlorohydrin-ethylene oxide (ECO)-based compounds, in the form of rain erosion boots or sleeves, are bonded to aircraft radomes using a hydrosilation-cured RTV polysiloxane adhesive. Unfortunately, cure of the adhesive can be completely inhibited by unreacted vulcanizing agent and/or ECO cure by-products. We have earlier shown that this inhibition can be prevented by treating the ECO surface with hydrogen peroxide to oxidize the hydrosilation catalyst poisons to a harmless state. In this study we have used spectroscopic techniques to monitor the hydrosilation reaction kinetics and in turn to identify the poison, define the poisoning level and monitor the poison removal by hydrogen peroxide treatment. The degree of poison removal is also correlated with adhesive bond strength using a 180°; peel test. The critical poison in the system was excess ECO vulcanizing agent which can be completely removed from the surface using a 30 vol. % H₂O₂ treatment for 30 minutes as long as the initial vulcanizing agent concentration is 1 p.p.h. or less.