GMT制品流动成型研究

本文主要研究以GMT材料流动成型脚踏板支架,考察了流劝成型所得制品纤维分布、力学性能、收缩性和纤维取向分布,并与包覆成型法作了对比,研究表明,对于复杂曲面形状、有高筋的制品,流动成型法成型率高,制品性能均匀,收缩率较小,纤维仍呈随机取向。     

高稠度陶瓷结合剂悬浮液材料——二氧化硅陶瓷浇注料成型方法的研究与比较评估

结合石英砂高调度陶瓷结合剂悬浮液材料以及加入5％耐火粘土的二氧化硅陶瓷浇注料的工艺探讨了振动冲压成型方法(P=0.3MPa)及静力冲压成型方法(P达500MPa)。对于上述成型方法来说,半成品气孔率的最低值分别为11.5％～12％及15％～16％。在配料组成及水份均处在可比条件下时,采用加入粘土的配料以静力冲压成型,则在成型压力比不加入粘土的配料低三分之二至四分之三时即可使气孔率达到相同的值。     

汽车顶棚用轻质GMT吸音性能的研究

研究了轻质玻璃纤维毡增强热塑性复合材料(GMT)板材的面密度、成型厚度、透气率以及GMT汽车内饰顶棚与钣金间隙4个因素与顶棚吸音性能的关系。结果表明,GMT汽车内饰顶棚的吸音系数受GMT板材面密度的影响不大,但随成型厚度的增加而增大;高透气率的顶棚的吸音系数在高频区最大;增加GMT汽车内饰顶棚与钣金之间的间隙可以显著提高顶棚在低频和中频区的吸音系数。     

FRTP片材冲压成型技术的近况及市场预测

冲压成型工艺是利用FRTP片材为原科(坯料)加工制品的高速压模工艺,也是熔融流动成型工艺(a melt forming process)——熔融状片材投入模内,在高压下快速闭合上下模具,使物料充满模腔,最终制成制品。其坯料利用率为100％,系净模塑工艺(a net molding process)。分析一下当今FRTP工艺,可初步看出该冲压工艺较为先进,因而前景广阔。一、冲压系统冲压系统(见图1)的主要设备有片材加热炉冲压模具、冲压机和模温控制仪。     

玻璃纤维毡增强聚丙烯复合薄板的热冲压成形

通过ABAQUS有限元模拟及热冲压成形实验,研究了不同温度下玻璃纤维毡增强聚丙烯复合材料(GMT–PP)的冲压成形性。结果表明,在可成形范围内,温度越高,可成形的深度越大,所需要的冲压力越小,越有利于材料成形,在测试的范围内,GMT–PP的适宜成形温度为160,200℃;结合冲压成形实验的结果与模拟结果可得出,冲压成形时最容易出现损伤和断裂的部分为冲压件底部;冲压成形实验的曲线与模拟曲线的变化趋势基本吻合,实验中冲压压力的大小与模拟值的大小在误差允许范围内保持一致,验证了所选黏弹性本构模型的合理性,为类似材料的成形研究提供参考。     

玻璃钢法兰的结构设计及成型工艺

根据玻璃纤维增强塑料的性能特点，结合实际经验，探讨了玻璃纤维增强塑料法兰的结构及成型工艺。结果表明，此种法兰的结构设计及其成型方法可行，已获得应用。     

中长纤维增强热塑性复合材料制品的成型技术

本文重点介绍用中长纤维增强热塑性复合材料片材,如GMT片材加工成型制品的技术,所用设备以及模具设计。     

GMT片材发展概况

<正>1简介GMT是玻纤毡增强热塑性塑料片材的英文缩写。它于上世纪60年代中期问世,是用玻璃纤维毡和一种热塑性塑料用干法(熔体浸渍法)或湿法(抄纸法)制成的轻质复合片材。这种中间材料可通过模压、冲压或流动模塑法成型为最终制品。GMT兼具材料和工艺性能     

聚四氟乙烯成型加工新技术

介绍了聚四氟乙烯(PTFE)成型的特殊性,并对现有各种加工方法的优缺点进行了比较.为了弥补现有各种加工方法的不足,设计了新型聚四氟乙烯加工设备--柱塞冲压式挤出机,并阐述了它的加工工艺过程和成型原理.     

长纤维增强热塑性复合材料的浸渍技术与成型工艺

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：溶液浸渍、粉体浸渍、熔体浸渍等）与成型工艺（传统的注射成型、模压成型，挤出成型以及在线混炼模压及注塑成型等）；对LFT和GMT进行了比较，分析了LFT优势；通过一些特殊的技术处理，LFT材料在力学性能方面已与GMT不相上下，由于优异的成型加工性能及相对低廉的成本，LFT必将在汽车、建材等领域获得更为广泛的应用。     

Mechanism of fiber–matrix separation in ribbed compression molded parts

This paper presents a model that predicts fiber–matrix separation in ribbed sections of compression molded parts. The model combines a mechanical analysis of compression molding with some experimentally measured variables. It is shown that with a higher closing speed, the viscosity of the material will increase and fiber–matrix separation can be reduced. Specific applications for this method are compression molding of sheet molding compounds and glass mat‐reinforced thermoplastics. POLYM. COMPOS., 28:451–457, 2007. © 2007 Society of Plastics Engineers     

Recyclability of a continuous e-glass fiber reinforced polycarbonate composite

Fiber reinforced plastics are multi-component materials for which physical properties are strongly dependent on fiber and resin structure. Despite the disruptive nature of recycling methods on such structures, these materials nevertheless can be recycled. In this report, the recyclability of a fiber-reinforced cyclic BPA polycarbonate has been studied. It is found that ground up composite is recyclable and possesses properties as good as or better than a comparable commercial composite. The processing techniques investigated herein are injection, extrusion compression, and compression molding. As expected, processing technique and parameters are important in determining the mechanical properties of the molded regrind. Our results show that injection and extrusion compression molding yield recycled composites with good tensile properties, though the impact strengths are relatively low. This is due to high fiber orientation and fiber bundle dispersion. On the other hand, compression molded samples, which show random fiber orientation and low fiber bundles dispersion have relatively low tensile properties, but excellent impact strength. Results are discussed in terms of microstructural details, which include resin molecular weight and fiber length and orientation.     

Studies in the properties of nylon 6–glass fiber composites

Caprolactam has been anionically polymerized within the planar-random continuous glass mat reinforcement using a technique similar to reaction injection molding and up to 55% (w/w) [i.e., 33% (v/v)] glass fiber loading was achieved. The fiber volume fraction distribution across the diameter of the composite was observed to be reasonably uniform. The tensile stress–strain properties were determined. Composite modulus and strength appeared to be linearly dependent on the fiber volume fraction and increase with fiber volume content. The type of composite material studied has been used for compression molding of articles. Therefore, some tensile data were redetermined after compression molding and possible changes in degree of crystallinity resulting from the change in the thermal history monitored by differential scanning calorimetry. A 50% drop in the percent degree of crystallinity (monoclinic modification) of the as-polymerized composite and a deterioration in the tensile properties of the composite were observed after compression molding. On compression molding the mold surface needs to be completely covered with the composite sheet material; otherwise, matrix polymer flows out of the composite, and areas deficient in reinforcement result.     

Linear viscoelastic and morphological description of multiphase systems affected by processing parameters

Influence of processing methods, in terms of comparing compression and injection moldings, on the rheological behavior of polycarbonate (PC)/acrylonitrile‐butadiene‐styrene (ABS) blends and PC/ABS/glass fibers composites is presented. Blend compositions and fiber content are considered as material variables. For blends, the effect of the processing route on the viscoelastic functions is evident only for low shearing frequencies. Injection molding created morphology with cocontinuous character, while compression molded blends have “relaxed” structure, where dispersed phase domains are several times larger than in injection molded ones. The glass fiber reinforcement led to the significant differences in viscoelastic properties of composites processed by injection and compression molding. Injected composites have both moduli always higher than compression molded. Also, fiber lengths are reduced more for compressing molding. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

玻璃纤维/聚丙烯复合纤维的应用

玻璃纤维/聚丙烯复合纤维材料织物剪裁性好,可用低压力模塑迅速成型为均质的结构,热塑性纤维分布紧密且均匀,玻璃丝能得到非常迅速的浸渍和浸透,用它制作的产品的玻纤含量可达45%～75%,可采用各种成型工艺,例如模压、缠绕、拉挤、真空模压等。它具有韧性高,使用温度高,可回收,质轻,力学性能优异等特点,具有一定的社会效益和经济效益。     

短纤维增强PVC的力学性能研究

本文讨论了模压成型制成的短纤维增强PVC的制备方法和力学性能,主要探讨了纤维含量、纤维长度、混杂纤维效应等对复合材料拉伸、弯曲和冲击性能的影响。     

Investigation of fiber orientation states in injection‐compression molded short‐fiber‐reinforced thermoplastics

Injection‐compression molding (ICM) has received increased attention because of its advantages over conventional injection molding (CIM). This article aims to investigate the effects of five dominating ICM processing parameters on fiber orientation in short‐fiber‐reinforced polypropylene (SFR‐PP) parts. A five‐layer structure of fiber orientation is found across the thickness under most conditions in ICM parts. This is quite different from the fiber orientation patterns in CIM parts. The fibers orient orderly along the flow direction in the shell region, whereas most fibers arrange randomly in the skin and the core regions. Additionally, the fiber orientation changes in the width direction, with most fibers arranging orderly along the flow direction at positions near the mold cavity wall. The results also show that the compression force, compression distance, and compression speed play important roles in determining the fiber states. Thicker shell regions, in which most fibers orient remarkably along the flow direction, can be obtained under larger compression force or compression speed. Moreover, the delay time has an obvious effect on the fiber orientation at positions far from the gate. However, the effect of compression time is found to be negligible. POLYM. COMPOS., 31:1899–1908, 2010. © 2010 Society of Plastics Engineers.     

新酚树脂的改性研究

对烯丙基新酚／ＢＭＩ树脂体系以及用它制成的玻璃纤维压塑料和炭黑增强压塑粉的性能进行了讨论，结果表明，烯丙基新酚／ＢＭＩ树脂体系具有良好的工艺性和反应性，压塑料和压塑粉的力学性能，韧性，耐热性和电气绝缘性能优良。     

Recyclability of a glass fiber poly(butylene terephthalate) composite

The recyclability of a fiber-reinforced poly(butylene terephthalate) (PET) composite has been studied. After treatment with a suitable silane, processed regrind composites are successfully recycled, with mechanical properties as good as a comparable, commercial composite. The three processing techniques investigated are injection molding, extrusion compression molding and compression molding. As expected, processing technique and processing parameters are important in determining the mechanical properties of the molded regrind. Our results show that injection- and extrusion-compression-molded regrind composites have good fiber bundle dispersion and fiber alignment, resulting in tensile properties better than the compression-molded samples. On the other hand, compression-molded samples, which show random fiber orientation and low fiber bundle dispersion, have lower tensile properties, but better impact strength than injection- and extrusioncompression-molded composites.