EFFECT OF INTERFACIAL PROPERTIES ON STATIC AND FATIGUE OF SHORT GLASS FIBER REINFORCED THERMOPLASTICS

首先，研究了纤维与热塑性塑料基体（主要是聚丙烯）之间的界面性能对注射成型和冲压成型的短玻璃纤维增强热塑性塑料的静态和疲劳破坏的影响。试验结果表明，采用长纤维球团法制备的frp试样的静强度高于采用短纤维球团常规注塑法制备的frp试样。使用长纤维球团也能提高屈服应力。然而，纵向模量不会因长纤维球团而增加。由于球团中的纤维在注射成型过程中断裂，对于长纤维球团，8 ~ 10mm的球团长度足以提高其静强度。另一方面，长纤维球团的使用对高周疲劳没有显著影响，尽管长纤维球团可以有效提高低周疲劳寿命。在低周疲劳状态下，使用长纤维球团可使疲劳寿命延长30 ~ 80%。长纤维的加入也大大改善了纤维的蠕变性能。虽然PP基本身不吸水，但PP基短玻璃纤维复合材料（FRTP）吸水明显。水通过玻璃纤维和基质之间的界面渗透到内部。由于吸水，不仅静强度降低，疲劳强度也降低。而在静载荷作用下，强度降低幅度仅为20%左右。利用低温等离子体制备性能优异但价格低廉的pp基FRTP是可行的。在这种方法中，表面已经过处理的PP片材与玻璃织物堆叠并压制形成FRTP。由于这种表面处理，剥离强度提高高达50%。静强度提高约20%。最后，研究了交联丁腈橡胶亚微米球改性环氧基对CFRP的静态强度和疲劳强度的影响。由于橡胶改性，碳纤维与环氧基之间的界面强度得到了提高。少

Firstly, the effect of interfacial properties between fibers and thermoplastic matrix (mainly Polypropylene) on static and fatigue failure of short glass fiber reinforced thermoplastics fabricated by injection molding and stamping was studied. From the test results it was revealed that the static strength of the FRTP sample fabricated using long fiber pellets was higher than that of the sample fabricated by conventional injection molding using short fiber pellets. The yielding stres was also increased by using long fiber pellets. However, the longitudinal modulus does not increase due to long fiber pellets. As fibers in the pellets are broken during injeciton molding process, 8 to 10 mm in length in pellets is enough to improve the static strength for long fiber pellets. On the other hand, no significant effect of usage of long fiber pellets on high cycle fatigue is found although long fiber pellets are effective to increase the fatigue life at low cycle fatigue. The fatigue life is in … More creased 30-80% longer by using long fiber pellets at low cycle fatigue. The creep behavior is also improved much due to long fibers.Although PP matrix itself does not absorb water, PP matrix short glass fiber composites (FRTP) absorbs appreciable water. Water penetrates inside through the interface between blass fibers and the matrix. Due to water absorption, not only static strength but also fatigue strength decrease. However, the strength reduction under static loading is only about 20%.A possibility for fabricating PP-based FRTP which have high performance but being not expensive was shown by using low temperature plasma. In this method, PP sheets whose surfaces have been previously treated are stacked with glass fabrics and pressed to form FRTP.Due to this surface treatment, peeling strength increases as high as 50%. The static strength increases about 20%.Lastly, the effect of rubber modification of epoxy matrix using cross-linked NBR submicron spheres on both static and fatigue strengths of CFRP were shown. Due to rubber modification, the interfacial strength between carbon fibers and epoxy matrix is improved. Less