基体性质对GMT-PP复合材料力学性能的影响

研究了基体树脂的性质及基体配方中炭黑、结晶成核剂、接枝极性基团的功能化聚丙烯（ＰＰ）等对玻璃纤维毡增强ＰＰ复合材料力学性能的影响。结果表明：提高基体树脂熔体的流动性,有利于复合体系的浸渍过程;复合材料的弯曲强度及模量随基体树脂强度及模量的增大而提高;采用韧性较好的ＰＰ或ＰＰ增韧体系作为基体,可获得抗冲性能较好的复合材料;随着炭黑加入,复合体系的弯曲及冲击强度有所下降;结局成核剂的加入,可改善复合体     

硅灰石与连续玻璃纤维毡组合增强聚丙烯的力学性能

采用硅灰石与连续玻璃纤维毡组合增强聚丙烯,研究了硅灰石的含量,玻璃纤维毡的面密度、基体树脂的性质及界面改性等对材料力学性能的影响。结果表明：采用硅灰石与连续玻璃纤维毡组合增强,可提高复合材料的拉伸、弯曲强度及模量,但过高的硅灰石含量,会导致拉伸及弯曲强度下降,材料的力学性能随着所用玻璃纤维毡面密度的增大而显著提高,采用偶联剂对硅灰石进行处理及在基体聚丙烯中添加功能化聚丙烯,可改善界面结合、提高材料性能,随着功能化聚丙烯含量的增加,材料的拉伸、弯曲强度及模量有所提高,但含量过高时,会引起材料冲击强度的下降;组合增强材料的性能与基体树脂本身的力学性能密切相关,同时还受基体树脂熔体流动性的影响。     

连续玻璃纤维毡增强聚丙烯的研究

对影响连续玻璃纤维毡增强聚丙烯复合材料的主要因素进行了系统研究,探讨了偶联剂种类,玻纤含量,基体分子量及接枝聚丙烯种类和用量等对ＣＦＲＰＰ的力学性能的影响。     

增强阻燃聚丙烯的研制

研究了玻璃纤维增强剂、ＭＦ８２／ＰＰ膨胀型阻燃剂对聚丙烯（ＰＰ）的力学性能，阻燃性能的影响。结果表明，加入适量的添加剂后能得到综合性能良好的改性ＰＰ。     

废弃木粉与短切玻璃纤维组合增强聚丙烯的力学性能

用废弃木粉与短切玻璃纤维作为增强材料，制得了组合增强的聚丙烯复合材料，研究了制备工艺及设备、材料配方及界面改性方法等对材料力学性能的影响。结果表明，用单螺杆挤出机制备组合增强材料，可减少对玻璃纤维的损伤，保持较长的玻璃纤维，有利于其增强作用的发挥；随着玻璃纤维含量的增加，体系的力学性能提高，而木粉含量对材料力学性能的影响与玻璃纤维的含量相关；采用硅烷偶联剂对木粉进行表面处理，在基体中添加接枝极性基团的改性聚丙烯，可改善体系的界面结合，提高力学性能。     

风机叶片用玻璃纤维连续毡对比分析

针对兆瓦风机叶片用玻璃纤维连续毡,将国产连续毡与进口连续毡进行了同等实验条件下的对比分析,分别考察了两种玻璃纤维连续毡的均匀性、导流性能、力学性能以及对玻璃纤维复合材料性能的影响等。结果表明,国产连续毡力学性能和对玻璃纤维复合材料力学性能影响均相当于进口连续毡,可以适用于制造兆瓦级风机叶片,但是需要在成型的稳定性上做进一步改进。     

玻纤增强PP热塑性片材的制备及力学性能研究

采用熔融浸渍法制备了玻璃纤维毡增强聚丙烯（PP）热塑性复合片材；通过在PP中加入复合改性PP改善了基体与增强纤维间的相容性；考察了相容剂、PP种类及玻纤毡种类对复合片材的影响。结果表明，相容剂的加入可使复合片材的拉伸强度提高29％、拉伸模量提高23％、弯曲强度提高42％、弯曲模量提高25％；高熔体质量流动速率PP可使片材的弯曲与冲击性能进一步改善。连续玻纤毡和长玻纤毡增强PP复合片材，前者综合力学性能良好，而后者则冲击强度较弱、弯曲性能加强。     

改性炭黑对天然橡胶/顺丁橡胶并用胶性能的影响

采用3种方法对传统炭黑进行表面改性,考察了改性前后炭黑表面形貌及结构的变化,并采用改性炭黑填充天然橡胶（NR）/顺丁橡胶（BR）并用胶,考察了改性炭黑对并用胶力学性能、硫化特性及动态力学性能等的影响。结果表明,与未改性炭黑相比,细化粒径、调高pH值及木质素改性处理后,炭黑表面的粗糙程度增加;且细化改性炭黑具有更高的比表面积,调高pH值改性炭黑具有更多疏松的二次结构,木质素改性炭黑粒径略有增加。对于炭黑填充NR/BR,用细化粒径及调高pH值方法处理的炭黑进行填充,NR/BR硫化胶的力学性能、耐磨性能及抗湿滑性均得到明显改善,但硫化延迟效应明显;木质素改性后,炭黑填充胶的力学性能、耐磨性能均出现不同程度的降低。     

木粉增强聚丙烯力学性能的改善方法

以废弃木粉为增强材料,制备了木粉增强聚丙烯复合材料,研究了改善废弃木粉增强聚丙烯复合材料力学性能的途径。结果表明,通过适当的处理方法对木粉进行表面处理、对基体树脂进行改性,可以有效地提高复合体系的界面粘接强度,能大幅度改善复合体系的力学性能;采用短切玻璃纤维及玻璃纤维毡与废弃木粉组合,可以获得力学性能很高、能作为结构材料使用的复合材料。     

浸润剂对玻璃纤维湿法毡工艺及性能的影响

考察了浸润剂对玻璃纤维拉丝工艺、玻璃纤维湿法毡工艺及力学性能的影响。研究结果表明：使用浸润剂后玻璃纤维拉丝工艺得到改善;湿法毡力学性能提高,其中使用偶联剂（A-174）处理的湿法毡拉伸强度为213,N/5cm、撕裂强度为2.1,N。经甲酸萃取湿法毡剩余玻璃纤维IR分析可知,使用偶联剂后,玻璃纤维与粘结剂有良好的作用,从微观上解释了湿法毡使用浸润剂后力学性能提高的原因。     

New GMT material suitable for various polymers and high glass fibre content

Abstract

As a kind of long fibre reinforced thermoplastic, a new glass mat thermoplastic (GMT)-like material is introduced. It is designed to be suitable for various polymers and high glass fibre (GF) content, which might be a promising attempt to overcome the limit of conventional GMT material (PP matrix and maximum 40 wt-% GF). The concept is based on a multi-layered hybrid structure consisting of several thin GF sub-layers and polymer films having an inherently high viscosity. They are then needle-matted all together. The capability of higher GF content was derived from the porosity changes under pressure and the cross-sectional view after impregnation. It was finally confirmed by measurement of flexural properties up to 70 wt-% of GF content in PP grade. Moreover, PA6 grade was investigated to show the other capability of multi-layered hybrid mat for various polymers.     

玻纤毡增强聚丙烯复合材料的增容及力学性能

通过玻璃纤维(GF)毡与双螺杆挤出相容剂改性聚丙烯(PP)膜的多层叠合,以熔融浸渍法制得PP基GF毡增强热塑性塑料(GMT)复合材料,研究了相容剂PP接枝马来酸酐(PP-g-MAH)和PP接枝丙烯酸(PP-g-AA)的用量(为PP基体质量的百分数)及其复配改性,以及相容剂改性PP基体分布和毡体种类对GMT力学性能的影响。结果表明,PPg-MAH可明显提高GMT的拉伸与弯曲性能,但降低了冲击性能;PP-g-AA可明显提高GMT的冲击性能,但不利于拉伸与弯曲性能的提高,只有当PP-g-AA用量超过5%后,拉伸性能才有所提升。在PP-g-MAH用量为3%的条件下,将其与不同用量的PP-g-AA进行复配改性没有对GMT力学性能产生协同作用。在各相容剂用量相近(3%~3.5%)的情况下,与相容剂复配改性GMT相比,以两层PP-g-AA改性PP为芯层、PP-g-MAH改性PP为上下表面层作为改性基体分布时,GMT拉伸与弯曲强度分别提高17%和27%、缺口冲击强度提高48%;而以两层PP-g-MAH改性PP为芯层、PP-g-AA改性PP为上下表面层作为改性基体分布时,在不损失强度与刚性的同时,缺口冲击强度提高了88%。采用连续GF毡的GMT力学性能比采用短切GF毡的GMT高,尤其是缺口冲击强度提高了89.6%。     

高性能玻璃纤维增强材料

本文简要评述了国内外高性能玻纤增强材料如高强度、高模量、高硅氧、抗辐照、抗碱、空心玻璃纤维等的研究进展与现状；同时评述了高新玻纤制品的现状及其应用，如连续原丝毡、针织缝编毡、３Ｄ织物、复铜板薄毡、膨体纱系列产品、增强热塑性塑料玻纤基材等。     

Effect of the microstructure of GMT on its mechanical properties

The effect of microstructure of GMT on its mechanical properties was investigated. The studied microstructure includes the fiber mat structure, the through-thickness glass fiber content-distribution of GMT sheets and the void content. The fiber bundle GMT (FB-GMT) and the single fiber GMT (SF-GMT) were prepared by the impregnation process using continuous fiber bundle mats and continuous single fiber mats as reinforcement, respectively. The mechanical properties of the two GMTs were compared to reveal the difference in reinforcing effect between the fiber bundle and the single fiber. The effect of needle density of the fiber mat on the mechanical properties of GMT was also studied, which indicated that needle-punching improves the mechanical properties of GMT, and that the optimal needle density is 40∼60 needles/cm². The through-thickness glass fiber content-distribution, which is inhomogeneous and can be modified by the film-stacking method, significantly affects the mechanical properties of GMT. Finally, the study of the effect of void content indicated that with increasing void content, the strength and modulus of GMT decrease, but the impact property increases slightly.     

Flax fibre physical structure and its effect on composite properties: Impact strength and thermo-mechanical properties

Earlier investigations by the authors showed that the tensile modulus of flax fibre mat polypropylene composites (NMT) could surpass the values of glass mat reinforced thermoplastic (GMT) on fibre weight basis. The tensile and flexural strength could reach values of up to 65% of the GMT strength values, however, very much dependent on the fibre physical structure. This study deals with the Charpy impact and the thermo-mechanical properties of flax NMT materials. The trend is that the Charpy impact strength decreases with increasing fibre internal bonding and enhanced fibre-matrix adhesion, which is opposite to the trend for the tensile and flexural properties. The impact strength of the NMT materials is lower than generally reported for GMT materials. Dynamic mechanical thermal analysis reveals that with increasing temperature the storage modulus of the NMT materials reduces more slowly when the fibre internal bonding and the fibre-matrix adhesion are improved. In order to approach the tensile, flexural and impact strength of GMT materials, composites should be based on the strong elementary flax fibres. The axial tensile strength of elementary fibres approaches the strength of glass fibres and the lateral strength of the elementary fibres is higher than the technical flax fibres lateral strength. The thermo-mechanical properties can probably be improved when non-cellulosic material can be removed from the flax fibre surface without damaging the fibre.     

Flow induced fiber orientation in compression molded glass mat thermoplastics

This study examines how the mechanical properties in GMT are affected by axisymmetric flow during compression molding. Two types of GMT with different architecture are used, swirled mat and short fiber GMT. Tree different grades are tested for each fiber architecture 20, 30, and 40% fiber content by weight. These are in principle the grades of GMT commercially available today. It is found that the flow reduced the tensile strength by 30 to 50% and the tensile modulus up to 30% in the flow direction. The reduction in mechanical properties, which is mainly caused by flow‐induced fiber orientation, is larger at high fiber contents. The study also showed that there is no major difference in behavior between swirled mat and short fiber GMT regarding flow induced fiber orientation.     

玻璃纤维毡增强热塑性复合材料废弃制品回收利用技术的研究

对废弃玻璃纤维毡增强热塑性复合材料（ＧＭＴ）制品回收利用技术进行了研究,针对制品的特点,研究了回炉预热升温过程,提出了较为合理的升温序列,使弃弃制品得到完全回收利用;探索了回收利用的次数对制品弯曲性能的影响,经过９次回炉加工的废弃制品的性能仍满足使用要求。     

Welding of thermoplastics reinforced with random glass mat

Thermoplastics reinforced with random glass mat have high strength and stiffness; the fibers dominate the mechanical behavior of these composites. The results of this investigation have shown that fibers are ineffective for reinforcing hot-tool and vibration welded butt welds. The maximum weld strengths attained with GMT are comparable to the strengths of good welds of the unfilled material. The optimum hot-tool welding parameters for the reinforced materials are different from those for the unfilled material. Unfilled polypropylene is easier to weld than unfilled polyamide. This characteristic is also true of the reinforced materials. In vibration welding, high welding pressures and high amplitudes result in lower mechanical properties. The optimum penetration depends on the fiber content of the bulk material. This penetration dependence is different from that for unfilled thermoplastic, for which the mechanical properties are independent of the penetration once a steady state has been attained.     

操作参数对玻纤毡增强复合材料流动成型的影响

研究了玻纤毡增强热塑性复合材料(GMT)流动成型过程中模腔压力和材料流动方向对制品力学性能和纤维取向的影响。研究表明：随着压力提高，弯曲强度和模量同步增加；但压力超过18MPa后，性能变化不明显。随布料面积分数减小，单轴拉伸流动成型将导致沿流动方向和垂直流动方向强度及模量差异变大，纤维取向严重；但双轴拉伸流动成型得到的制品各方向性能较均匀，基本呈现各向同性。