玻纤增强基材的创新与发展

分析了当今下游复合材料工业的发展对玻纤增强基材发展的需要。重点介绍了风电叶片用玻纤纱、技术织物、复合织物、预浸渍制品、预成型增强体等各类玻纤增强基材以及增强热塑性塑料用的短切纤维、混合纱、LFT、GMT、GMT-D、LFT—D、增强热塑性片材等各类玻纤增强基材。并为玻纤增强基材如何促进这两类复合材料产品的发展提出建议。     

LFT技术发展概况

定义 长纤维增强热塑性塑料简称LFT或LFRT,是用长玻璃纤维代替原来的短切纤维与PP、PA、PET等热塑性塑料通过挤出、造粒或造片等方法制得的复合材料,可以用玻璃纤维和塑料造粒制成半成品后再经注射或模压成型为最终制品,也可以在同一生产线上把玻璃纤维、塑料混合挤出后直接模压或注射成型为最终制品.前者称为L胛粒料(LFT-G或LFT-P),后者称为直接LFT(LFT-D或D-LFT).     

玻璃纤维增强热塑性复合材料的研究进展

综述了LFT和GMT加工工艺的进展，介绍了最新的两种GMT材料，提出了玻璃纤维增强热塑性复合材料的发展方向，并对未来趋势作出预测。     

长玻纤增强复合材料的浸渍技术的发展研究

概述了国内外长纤维增强热塑性复合材料(LFT)的主要浸渍技术(包括:原位聚合技术、粉末浸渍、熔体浸渍等),展望了连续玻璃纤维增强热塑性塑料发展前景.     

GMT制品加强筋表面缩痕成因分析

对GMT(玻璃纤维毡增强热塑性复合材料)模压制件加强筋缩痕的大小进行定量表征,并对加强筋缩痕的成因进行分析。采用电子数显百分表等距离测量深度的方法,对加强筋缩痕进行了较准确的测量和数字化表征。在此基础上,考察了材料性质、成型工艺、布料方式等对加强筋缩痕大小的影响。研究表明:加强筋内的纤维取向是影响表面缩痕大小的主要因素,树脂基体和成型工艺条件对表面缩痕的影响很小。加强筋内的纤维取向与GMT片材本身的流动性能密切相关,增强GMT片材的流动性能,是改善其制品表面缩痕的有效方法。     

玻璃纤维增强热塑性塑料在航空航天领域中的应用

研究了玻璃纤维增强热塑性塑料（GRTP）的分类,短玻纤增强热塑性塑料（SFT）,玻纤毡增强热塑性塑料（GMT）,长纤维增强热塑性塑料（LFT）3种类型的特性和制备方法。介绍GRTP在军用飞机和民用飞机等航空航天领域的应用情况。总结了未来纤维增强热塑性复合材料的发展方向。     

热塑性预浸带模压成型工艺研究

本文针对热塑性预浸带的模压成型工艺进行了探索研究，为成型连续纤维增强热塑性复合材料模压制品提供了简单，实用的工艺方法。     

2007年我国热塑性增强塑料用纱量突破十四万吨

据第五届中国（上海）国际工程塑料工业展览会传来信息，我国用于工程塑料PP、PA、PBT、PET、TPU、ABS、以及GMT、LFT等热塑性增强玻纤用量达到十四万吨。以纤维含量20—25％测算，全年玻纤增强塑料产量达到了60万吨。     

欧文斯科宁在中国国际复合材料展上阐述长纤维热塑性塑料产品和应用的最新进展

2009年9月2日，中国上海，作为世界玻璃增强纤维，住宅和商业建筑材料的领军企业，欧文斯科宁在中国国际复合材料展期间举办的技术研讨会上介绍了长纤维热塑性塑料（LFT）产品和应用的最新进展和优点。与金属相比，LFT复合材料能明显降低产品重量，提高燃油效率及减少废气排放。     

纤维增强热塑性复合材料新动向--从GMT-LFT到All-PP

随着人们环保意识的增强，对材料的开发研究提出了一些新的要求。All-PP复合材料可全部回收利用，低密、高强，低温下良好的耐冲击性，可替代GMT和LFT，有很大发展前景。本文将介绍热压法和共挤带法两种All-PP生产工艺，并对GMT、Twintex、All-PP的性能进行了比较。     

长纤维增强热塑性复合材料模塑技术新动向

近年来,长纤维/热塑性树脂在线复合直接模塑制作热塑性复合材料(LFT-D)在欧洲和美国发展很快.本文介绍了LFT-D的模压工艺和注塑工艺及最新应用情况,并对LFT-D工艺与GMT/预制粒料模塑工艺进行了比较.     

Swirl mat– and long discontinuous fiber mat–reinforced polypropylene composites—status and future trends

Polypropylene (PP) composites with glass and natural fiber mat reinforcement (GMT‐PP and NMT‐PP, respectively) are widely used in different applications, competing with metallic sheets and thermoset polymer composites. Their production occurs via melt impregnation, slurry deposition and various textile architecturing processes that lead to either consolidated or non‐consolidated preforms. These preforms are then converted into final parts by hot pressing. The “traditional” GMT‐PP composites are nowadays faced with a great challenge because of the introduction of long fiber reinforced thermoplastic (LFT) composites produced on‐ or off‐line. This paper gives a brief survey on the manufacturing, processing, properties and application of GMT and GMT‐like systems and it concludes by describing some of the future trends, especially in the fields of material and process developments.     

汽车内饰用酚醛树脂/黄麻纤维复合材料的拉伸性能

采用正交试验方法,用5%Na OH溶液对黄麻毡进行预处理,利用模压成型工艺制备酚醛树脂/黄麻纤维复合材料,通过对正交试验结果进行极差分析和方差分析,研究树脂含量、模具温度、模具压力和保压时间4个工艺参数对复合材料拉伸性能的影响程度和显著性水平,并通过多指标综合评分法对材料的拉伸性能综合评价,分析各个工艺参数对材料拉伸性能的影响规律。结果显示,树脂含量和模具压力对复合材料的拉伸性能影响非常显著,当树脂含量为20%、模具温度为180℃、模具压力为10 MPa、模压时间为6 min时,复合材料的拉伸性能最好,此时拉伸强度为24.06 MPa,拉伸弹性模量为113.17 MPa。     

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.     

玻璃纤维毡增强聚丙烯在冲压成型中的纤维分布研究

本文研究了玻璃纤维毡增强聚丙烯(GMT)复合材料在流动态冲压成型中玻璃纤维的分布情况,分析了温度、压力等工艺参数对纤维分布的影响,为GMT片材冲压成型复杂形状的产品提供理论指导.     

Effects of preferential encapsulation of glass fiber on the properties of ternary GF/PA/PP blends

Long fiber molding materials are expected to play an important role in the near future. This paper describes a series of experiments performed to examine properties of ternary blends containing glass fiber (GF), polyamide (PA), and polypropylene (PP). The continuous glass fiber was impregnated with one of the blend constituent polymers by our specially designed impregnation apparatus and cut into chips of 6 mm length. These chips and the other polymer were used to produce various testing specimens in a twin screw extruder or in injection molding machine. The results indicated that the effect of fiber addition on the mechanical and rheological properties is clearly dependent on the order of impregnation process. In the blends containing the GF/PA + PP, the GFs are preferentially encapsulated with PA, and therefore the mechanical properties are superior to the blends with the GF/PP + PA in which the PP phase is located surrounding the GFs. This improved wetting of fibers by sequential impregnation not only resulted in better properties but also protected the fibers from shear action of the screw, thereby allowing significant increase in average fiber length to be achieved in the injection molding process.     

缓释碳源材料的选择与制备探究

固体缓释碳材料可在地下水异氧反硝化过程中作为电子供体。目前,所研究的缓释碳源主要分为两大类:一类为天然释碳材料;另一类为人工合成释碳材料。复合释碳材料的制备工艺主要为挤出成型法、注塑成型法和压膜成型法3类。     

Effects of A,B, and S components on fiber length distribution,mechanical, and impact properties of carbon fiber/ABS composites produced by different processing methods

Carbon fiber/ABS composites with different acrylonitrile, butadiene, and styrene components were produced via extrusion/injection and long fiber thermoplastic (LFT)/injection molding processes, respectively. The effect of the components on fiber length distribution, tensile, flexural, impact, and dynamic mechanical properties of the composites was investigated. The properties of carbon fiber/ABS composites produced using 12 mm-long LFT pellets were markedly higher than those produced using extruded pellets made with 12 mm-long chopped carbon fibers. Uses of LFT pellets were preferable to enhancing the mechanical properties of carbon fiber/ABS composites. The tensile, flexural, and dynamic mechanical properties were increased in order of ABS750sw > ABS720 ≥ ABS780 > ABS740, whereas the impact strength was increased in order of ABS740 > ABS780 > ABS720 ≈ ABS750sw. Less carbon fiber damages and less carbon fiber length degradation upon LFT processing resulted in longer fiber length distribution and higher fiber aspect ratio in the composites with LFT pellets, indicating a beneficial reinforcing effect, which was responsible for the increased mechanical properties of ABS composites, particularly with ABS750sw. The results were agreed with each other, significantly depending on the A, B, and S components, being supported by fiber length distribution, fiber aspect ratio, and fracture surfaces.     

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.     

Numerical modeling of injection/compression molding for center-gated disk: Part II. Effect of compression stage

In the accompanying paper, Part I, we have presented a physical modeling and the associated numerical analysis of the injection molding process with a compressible viscoelastic fluid model. In Part II, effects of the compression stage in the injection/compression molding process are presented. Numerical results showed that the injection/compression molding process reduced birefringence as compared with the injection molding process. In this respect, the injection/compression molding process seems to be more suitable for manufacturing precise optical products of good optical quality than the injection molding process. Effects of the packing stage on the birefringence distribution in the injection/compression molding process were found to be similar to those in the injection molding process. Our numerical results show that the birefringence becomes smaller as the melt temperature gets higher and the closing velocity of the mold gets smaller with the flow rate and the mold temperature affecting the birefringence insignificantly. As far as the density distribution is concerned, the flow rate, melt temperature, and mold closing velocity have insignificant effects on the density distribution in comparison with the mold temperature.