PBO纤维表面空气冷等离子体改性

采用等离子体处理方法对PBO(聚对苯撑苯并二 口 恶 唑)纤维表面进行改性。用XPS和AFM测试分析等离子处理时间对PBO纤维表面组成和表面形貌的影响规律;首次采用浸润性测试和IR测试分析等离子体处理前后纤维浸润性和表面官能团的变化。用Microbond测试方法表征了纤维与树脂基体的界面剪切强度,并用SEM观察微复合材料破坏形貌。结果表明:等离子体处理后纤维浸润性得到改善,纤维表面苯环上引入了很多羟基。等离子体处理最佳条件下(170 W,10 min),纤维表面粗糙度最大,纤维表面O元素含量最大, O/C比率提高了50.5 %, IFSS值提高了64.7 %。     

氩气低温等离子体处理对PBO纤维的表面改性

采用低温等离子体表面处理技术对聚苯撑苯并二口恶唑(PBO)纤维表面进行改性.选用氩气作为处理气氛,研究了气压、功率和处理时间等参数对纤维表面性质的影响.采用FT-IR和SEM等方法对处理前后纤维表面化学结构及形态结构进行了表征,并通过单丝拔出试验测定了改性前后PBO纤维与环氧树脂基体的界面剪切强度(IFSS),对纤维与树脂的界面粘结性进行了初步评价.同时,采用液滴形状法对纤维表面亲水性进行了表征.通过研究发现,经低温氩气等离子处理后,PBO纤维表面亲水性增强,PBO纤维/环氧树脂的IFSS较未处理样品提高了42%.     

用常压空气等离子体对PBO纤维表面接枝改性

用常压空气介质阻挡放电等离子体在PBO纤维表面接枝聚氨酯,研究了上浆剂对接枝反应的影响。对接枝改性后的PBO纤维的XPS分析结果表明,等离子体接枝聚氨酯改性使PBO纤维表面的化学组成发生了很大的变化。与DBD单独处理相比,接枝改性后的PBO纤维出现了更多的羧基,其提高值为64%~189%(不含上浆剂时)、102%~184%(含上浆剂时),为其与其它材料之间的化学键合提供了条件。接枝反应不受上浆剂的影响,等离子体接枝反应破坏了表面PBO分子的噁唑环。通过ATR-FTIR发现,带上浆剂的PBO纤维接枝前后噁唑环的特征峰没有变化,因此在近表面尺度的PBO分子没有破坏的依据;而在不含上浆剂的接枝改性PBO纤维上能检测到噁唑环的破坏,表明上浆剂能阻止等离子体对纤维近表面层的破坏。     

NiTi纤维表面处理及其树脂基复合材料的界面特性

NiTi纤维表面呈惰性,表面能低,NiTi纤维与树脂间界面粘结性差.为了提高界面性能,采用硅烷偶联剂、表面涂层和低温冷等离子体技术等方法对NiTi纤维表面进行处理,改善纤维表面的浸润性,达到纤维与树脂界面良好的粘结.对复合材料进行界面剪切强度的测定,并利用扫描电镜观察拔脱纤维表面形貌的变化.研究表明:NiTi纤维经不同方法处理后,纤维的浸润性和界面的粘结强度均有不同程度的改变,其中冷等离子体处理的纤维再经硅烷处理,其复合材料IFSS提高2.94倍,ILSS提高1.45倍,且纤维与树脂粘合较好.     

连续玄武岩纤维冷等离子改性处理性能研究

采用低温等离子体表面改性处理仪对玄武岩纤维等离子改性,对玄武岩纤维改性前后表面形貌SEM、表面浸润性以及回潮率等的变化进行测试、表征分析。结果表明,未处理的玄武岩纤维表面较为光滑,接触角滞后现象不明显,与树脂基体界面粘结效果不理想,回潮率为0.12%。比较处理时间5min、12min,等离子体改性处理15min刻蚀程度最大,表面最粗糙,回潮率增加到0.83%,而接触角差异达到37.57°,与树脂基体界面粘结效果最好。     

氟橡胶表面接枝丙烯酸/丙烯酰胺的表征与表面性能

在常压条件下采用空气介质阻挡等离子体处理氟橡胶表面,使之表面活化,进而在氟橡胶表面分别接枝丙烯酸和丙烯酰胺单体,研究表明,接枝改性能显著改善氟橡胶表面的浸润性.采用表面水接触角的变化表征了改性氟橡胶表面的浸润性,结果表明接枝丙烯酸的最佳条件为接枝时间60 min、温度60℃,其最小水接触角为40°;接枝丙烯酰胺的最佳条...     

冷等离子体处理对涤纶纤维表面性能的影响

采用冷等离子体技术处理涂纶纤维,利用ESCA分析了冷等离子体处理前后的纤维表面元素组成,官能团类型的变化,通过比较处理前后浸润性,涂纶纤维／环氧复合材料的层间剪切强度,研究了冷等离子处理对涤纶纤维表面性质的影响,结果表明：绦纶纤维经冷等离子处理后表面含氧的极性基团增加,纤维表面的浸润性显著改善,涤纶纤维／环氧复合材料界面性能增强。     

接枝偶联剂对F-12 纤维/环氧复合材料界面改性的研究

采用一种大分子接枝偶联剂对F-12 纤维表面进行等离子体接枝改性, 并采用ESCA 对改性后的纤维表面进行分析, 研究了接枝偶联剂的分子量和浓度对F-12/环氧复合材料横向拉伸强度的影响, 并结合横向拉伸的断口对改性机理进行了分析。实验结果表明: 接枝偶联剂接枝改性以后, 能够有效地改善F-12/环氧复合材料的界面结合状态, 从而提高复合材料的横向拉伸强度。      

聚酯纳米纤维改性膜的制备及对Cu(Ⅱ)的吸附

采用低温等离子体处理技术将丙烯酰胺(AM)接枝到聚对苯二甲酸乙二醇酯(PET)静电纺丝膜上,实现了对PET纳米纤维膜的表面改性。用电子扫描显微镜(SEM)观察了纤维的形貌,红外(FT-IR)分析了纤维膜改性前后表面性质,通过铜离子吸附试验考察了纤维改性膜对Cu2+的吸附效果。结果表明:成功的将PET纳米纤维膜表面接枝上了AM,且该膜吸附水溶液中的Cu2+效果显著,适用于水中Cu2+的去除。     

合成纤维界面改性研究进展

合成纤维增强高分子复合材料的性能以及纤维良好性能的发挥很大程度上由复合物界面作用来决定,好的界面粘合可以带来复合物良好的性能。文章总结了实用的纤维界面改性的方法,如电化学改性、氧化刻蚀、表面涂覆、化学接枝、等离子体接枝等。这些方法有效地改善了纤维与聚合物机体的界面黏合力,提高了复合材料的力学性能。     

Hierarchical poly(p-phenylene benzobisoxazole)/graphene oxide reinforcement with multifunctional and biomimic middle layer

A new hierarchical reinforcement developed by coating biomimic polydopamine (PDA) on the surface of poly(p-phenylene benzobisoxazole) (PBO) fibers, which served as a platform for the graphene oxide (GO) grafting, using branched polyethyleneimine (b-PEI) as a bridging agent. The surface morphologies and chemical structures of PBO fibers were characterized for confirming the formation of covalent bond between GO and PBO fibers. The surface roughness (R_a) and wettability of the obtained fibers, denoted as PBO@PDA-PEI-GO, were obviously increased in comparison with those of untreated one. The reinforcement offered a 68.8% enhancement in the interfacial shear strength (IFSS) without degrading the base fiber. The PDA layer on the PBO fiber surface led to improved UV resistance. The hydrothermal aging resistance of PBO/epoxy composite was also greatly improved. This biomimic surface modification approach is facile to prepare, highly efficient to enhance interface, adaptable to all high-performance fibers, and meaningful in multifunctional applications.     

高性能有机纤维单丝复合体系界面粘结性能实验研究

采用单丝复合体系多次断裂法,通过对纤维单丝断点数的统计及其断点形貌的分析,考察了PBO纤维、芳纶Twaron纤维、超高分子量聚乙烯纤维(UHMWPE)3种高性能有机纤维与韧性环氧基体的界面剪切强度;并对比考察了界面剪切强度与对应复合材料单向板层间剪切强度之间的关系;结合XPS、SEM等手段分析了有机纤维表面物理化学特性对界面剪切强度的影响。结果表明,Twaron/环氧的界面剪切强度高于PBO/环氧,UHMWPE/环氧的界面粘结弱,该方法不能测试;上述体系界面剪切强度与对应的复合材料单向板层间剪切强度变化趋势是一致的;表面化学活性高的纤维对应的界面剪切强度高。     

离子基团对PBO 纤维的表面性能及其界面粘结性能的影响

PBO 作为增强纤维存在与环氧树脂基体界面粘结性能差的问题。通过在聚合过程中添加少量5-磺酸钠2间苯二甲酸部分替代对苯二甲酸与4 , 6-二氨基间苯二酚盐酸盐进行共聚, 合成了大分子链上含有离子基团的SPBO 共聚物, 并制得SPBO 初生纤维。通过接触角测试和XPS 研究了纤维的表面性能, 通过微脱粘实验和SEM评价了纤维与环氧树脂基体的界面粘结性能。结果表明: 与PBO 纤维相比, SPBO 纤维表面浸润性能提高, 表面含氮、氧量均增加, 与环氧树脂的界面剪切强度从8. 2 MPa 提高到10. 1 MPa , 提高了23 %。      

甲基丙烯酰氧基倍半硅氧烷改性碳纤维/聚芳基乙炔复合材料界面性能

利用微脱粘法、三点弯曲法、扫描电镜（SEM）、力调制模式原子力显微镜（AFM）和动态力学热分析（DMTA）研究了甲基丙烯酰氧基倍半硅氧烷（Methacryl-POSS）涂层改性前后的碳纤维增强的聚芳基乙炔（PAA）复合材料的界面性能。用Wilhelmy法研究了处理前后的碳纤维与PAA树脂的浸润性。结果表明: POSS涂层处理后的碳纤维表面粗糙度增大,与PAA树脂的浸润性提高;复合材料的界面剪切强度提高了36%,层间剪切强度提高了50%。DMTA图谱表明, POSS涂层改性后,复合材料的玻璃化转变温度提高了12℃,损耗因子降低了53%,表明复合材料的界面粘接性能得到大幅度的改善。      

Atmospheric air plasma treated PBO fibers: Wettability,adhesion and aging behaviors

Poly (p–phenylene-2, 6-benzobisoxazole) (or PBO) fibers were modified by air dielectric barrier discharge plasma (air-DBD) with different treatment time. The wettability of the PBO fibers were enhanced evidently, which was proved by dynamic contact angle analysis (DCAA), the contact angle in water of the fibers treated by air-DBD plasma decreased from 77.52° to 34.05°, while the surface free energy increased from 44.73 mJ/m² to 64.04 mJ/m². The surface morphology changes and variations of chemical components of PBO fibers were detected by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the fiber surface morphology became rougher and some newly polar groups were introduced onto the fiber surfaces. They contributed to the enhancement of the wettability. Furthermore, the interfacial adhesion between PBO fibers and bismaleimide (BMI) resin was improved obviously, which revealed by the increased ILSS of the PBO/BMI composites. Nevertheless, the ILSS of PBO/BMI composites decreased to 47.0 MPa after PBO fibers were stored in air for 7 days and there were little changes for 7–30 days.     

Optimum dispersion conditions and interfacial modification of carbon fiber and CNT–phenolic composites by atmospheric pressure plasma treatment

Electric resistance measurements were used to determine the optimal dispersion conditions for carbon nanotubes (CNTs) in phenolic resins. Plasma treatment is frequently used to modify carbon fiber surfaces to improve adhesion of the fibers to matrices. Such treatment might also influence carbon fiber tensile strength. In order to determine the effect of atmospheric pressure plasma treatment on carbon fiber tensile strength and interfacial bonding strength, change in tensile strength of the fiber was studied at different gage lengths before and after the plasma treatment. The wettability of carbon fibers was improved significantly after only 10 s of plasma treatment. Such plasma treatment resulted in a decrease in the advancing contact angle from 65° to 28°. Surface energies of carbon fiber and CNT–phenolic composites were measured using the Wilhelmy plate technique, indicating that the work of adhesion between plasma treated carbon fibers and CNT–phenolic composites was higher than it before plasma modification. The interfacial shear strength (IFSS) and apparent modulus were also increased by plasma treatment of the carbon fibers.     

Surface treatment of coir (Cocos nucifera) fibers and its influence on the fibers’ physico-mechanical properties

Coir, an important lignocellulosic fiber, can be incorporated in polymers like polyacrylate in different ways for achieving desired properties and texture. But its high level of moisture absorption, poor wettability and insufficient adhesion between untreated fiber and the polymer matrix lead to debonding with age. In order to improve the above qualities, adequate surface modification is required. In our present work, fiber surface modification by ethylene dimethylacrylate (EMA) and cured under UV radiation. Pretreatment with UV radiation and mercerization were done before grafting with a view to improve the physico-mechanical performance of coir fibers’. The effects of mercerization on shrinkage and fiber weight losses were monitored at different temperature and alkali concentration. We observed that, fiber shrinkage is higher at low temperature and 20% alkali treated coir fibers yielded maximum shrinkage and weight losses. It was found that higher shrinkage of the polymer grafted fiber showed enhanced physico-mechanical properties. The grafting of alkali treated fiber shows an increase of polymer loading (about 56% higher) and tensile strength (about 27%) than 50% EMA grafted fiber. The fiber surface topology and the tensile fracture surfaces were characterized by scanning electron microscopy and were found improved interfacial bonding to the modified fiber–matrix interface.