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.     

改性芳纶纬编增强体复合材料力学性能的研究

为探讨芳纶纬编增强体复合材料的力学性能,以对位芳纶为原料,采用LiCl/无水乙醇溶液对芳纶表面进行改性处理,设计并编织1+1满针罗纹和罗纹空气层2种组织织物增强体,以E-51环氧树脂为基体,应用手糊成型技术制备芳纶纬编增强体平板复合材料。采用YG026D型电子织物强力机对制备的芳纶纬编增强体复合平板材料的经纬向拉伸、弯曲、压缩以及层间剪切性能进行测定。结果显示:经LiCl/无水乙醇络合溶液处理的芳纶纬编增强体复合材料的各项力学性能均有所提高,且经向的各项力学性能优于纬向。在拉伸、弯曲性能方面,罗纹空气层芳纶纬编增强体平板复合材料优于1+1满针罗纹芳纶纬编增强体复合材料。     

Mechanical Properties of Compression Molded Banana Pseudo-stem Filled Unplasticized Polyvinyl Chloride (UPVC) Composites

Mechanical strengths of a banana pseudo-stem (BPS) fiber and unplasticized polyvinyl chloride (UPVC) composite were evaluated to assess the possibility of using it as a new material in engineering applications. Samples were fabricated by the compression molding process with reference to the effect of filler loading. The samples were submitted to mechanical tests to measure tensile, flexural, and impact properties of the composites. The nature of adhesion between the matrix and the reinforcement and information relating the structure of mechanical properties can be obtained by scanning electron microscopy (SEM) assessment of the composite fracture surface. The mechanical properties show that the composites did not have good adhesion between filler and matrix; on the other hand, the filler insertion improved the flexural modulus and the material rigidity.     

动态注射成型短玻纤增强高密度聚乙烯力学性能的研究

在不同的振动条件下注射成型短玻纤增强高密度聚乙烯复合材料。实验表明,振动可以有效地改善玻纤在树脂基体中的分散取向状况,提高复合材料的力学性能。与稳态注射成型的复合材料相比,动态注射成型复合材料的拉伸强度最大可提高11.1%,冲击强度最大可提高11.4%。     

Processing and physical properties of native grass-reinforced biocomposites

Big blue stem grass fiber-reinforced high density polyethylene powder biocomposites were fabricated using two separate processing schemes: (1) by compounding biofiber with the thermoplastic powder in an extruder and subsequently injection molding the extrusion pellets and (2) by combining biofiber and the powder thermoplastic powder using a modified sheet molding compounding (SMC) line and subsequently compression molding the sheet material. The physical properties including storage modulus, heat deflection temperature (HDT), notched Izod impact strength, and morphology were evaluated with dynamic mechanical analysis, Izod impact strength measurement, and microscopy observation. It was found that compression-molded specimens achieved similar modulus values to injection molded specimens for grass-reinforced high density polyethylene (HDPE) composites. The stiffness of the compression-molded specimens is related to the consolidation state of the samples, which depends on compression molding conditions such as temperature, pressure, and mold type. Compression-molded specimens exhibited a higher HDT and notched Izod impact strength compared to injection-molded samples. Grass fiber-reinforced cellulose acetate butyrate (CAB) biocomposites made with SMC processing had similar physical properties with grass fiber-reinforced HDPE composites, which indicates that natural fiber-reinforced CAB biocomposites have the potential to replace polyolefin-based composites for automotive applications. POLYM. ENG. SCI. 47:969–976, 2007. © 2007 Society of Plastics Engineers.     

连续碳纤维增强聚醚醚酮复合材料的制备及力学性能

采用自主研发的连续碳纤维/聚醚醚酮热熔法预浸料(HC2110),通过热压成型工艺制备了复合材料层合板。测试了复合材料的力学性能,表征了微观形貌和破坏模式。预浸料热性能测试表明,HC2110预浸料较国外材料(TC1200)的耐热性及成型工艺性较优。微观形貌分析表明,复合材料层合板中纤维分布均匀性对0°拉伸性能影响较小;而纤维和树脂的界面结合较差是导致90°拉伸强度明显偏低的主要原因。     

A Comparative Study on the Mechanical Properties of Jute and Sisal Fiber Reinforced Polymer Composites

The aim of the present study is to investigate and compare the mechanical properties of raw jute and sisal fiber reinforced epoxy composites with sodium hydroxide treated jute and sisal fiber reinforced epoxy composites. This is followed by comparisons of the sodium hydroxide treated jute and sisal fiber reinforced composites. The jute and sisal fibers were treated with 20% sodium hydroxide for 2 h and then incorporated into the epoxy matrix by a molding technique to form the composites. Similar techniques have been adopted for the fabrication of raw jute and sisal fiber reinforced epoxy composites. The raw jute and sisal fiber reinforced epoxy composites and the sodium hydroxide treated jute and sisal fiber reinforced epoxy composites were characterized by FTIR. The mechanical properties (tensile and flexural strength), water absorption and morphological changes were investigated for the composite samples. It was found that the sodium hydroxide treated jute and sisal fiber reinforced epoxy composites exhibited better mechanical properties than the raw jute and raw sisal fiber reinforced composites. When comparing the sodium hydroxide treated jute and sisal fiber reinforced epoxy composites, the sodium hydroxide treated jute fiber reinforced composites exhibited better mechanical properties than the latter.     

Natural fiber hybrid composites—A comparison between compression molding and resin transfer molding

Short randomly oriented intimately mixed banana and sisal hybrid fiber‐reinforced polyester composites having varying volume fraction of fiber were fabricated by compression molding (CM) and resin transfer molding (RTM) techniques by keeping the volume ratio of banana and sisal, 1:1. The static mechanical properties such as tensile, flexural, and impact behavior were studied. The dynamic mechanical properties were also evaluated. Resin transfer molded composites showed enhanced static and dynamic mechanical properties, compared with the compression molded samples. To analyze the fracture surface morphology of the composites, scanning electron microscopy (SEM) was also performed. Water sorption studies revealed that the water uptake of RTM fabricated composites was lower than that of the compression molded composites. The void content of the RTM composites was also found to be lower than that of the other one. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers     

Pultruded fiber reinforced thermoplastic poly(methyl methacrylate) composites. Part II: Mechanical and thermal properties

A novel process has been developed to manufacture poly(methyl methacrylate) (PMMA) pultruded parts. The mechanical and dynamic mechanical properties, environmental effects, postformability of pultruded composites and properties of various fiber (glass, carbon and Kevlar 49 aramid fiber) reinforced PMMA composites have been studied. Results show that the mechanical and thermal properties (i.e. tensile strength, flexural strength and modulus, impact strength and HDT) increase with fiber content. Kevlar fiber/PMMA composites possess the highest impact strength and HDT, while carbon fiber/PMMA composites show the highest tensile strength, tensile and flexural modulus, and glass fiber/PMMA composites show the highest flexural strength. Experimental tensile strengths of all composites except carbon fiber/PMMA composites follow the rule of mixtures. The deviation of carbon fiber/PMMA composite is due to the fiber breakage during processing. Pultruded glass fiber reinforced PMMA composites exhibit good weather resistance. They can be postformed by thermoforming, and mechanical properties can be improved by postforming. The dynamic shear storage modulus (G′) of pultruded glass fiber reinforced PMMA composites increased with decreasing pulling rate, and G′ was higher than that of pultruded Nylon 6 and polyester composites.     

Feasibility of foam forming technology for producing wood plastic composites

Cellulose fiber-containing thermoplastic composite materials are being used in an increasing number of applications produced typically by injection molding and extrusion processing methods. One potential way to manufacture thermoplastic cellulosic fiber composites is foam forming technology developed originally for paper manufacturing. This article compares the low-density polyethylene (LDPE) and unrefined northern bleached softwood kraft pulp (NBSKP) composite materials prepared with foam forming, extrusion, and injection molding. The results show that the foam forming enabled three times higher Charpy impact strength properties and 68% higher tensile modulus compared to injection molded 30% NBSKP fiber-containing LDPE composites without changes in composite color. Foam forming is a potential large-scale manufacturing method for thermoplastic composite sheets used, for example, in compression molding or thermoforming.     

Preparation of polypropylene fiber/banana fiber composites by novel commingling method

Short natural fiber thermoplastic composites are usually fabricated by melt mixing or solution mixing followed by conventional methods like injection molding or compression molding. In melt mixing, the fibers are subjected to high shear and this damage the natural fiber. In solution mixing, the use of the organic solvent is essential and its use is hazardous. Development of a novel method commingling to prepare polypropylene (PP)/short natural fiber composite is the main objective of this study. The influence of fiber loading on the mechanical properties of the composites prepared by the above method has been evaluated. The applications and limitations of several equations to predict physical properties such as tensile strength and modulus of the composites have been described. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

黄麻纤维增强聚丙烯的力学性能

本文讨论了注塑成型黄麻纤维增强聚丙烯的制备方法和力学性能.将纤维重量含量分别为10%、20%和30%的复合材料进行比较,分析纤维含量对复合材料拉伸、弯曲和冲击性能的影响;将纤维分别切成约3mm、5mm和10mm长制成复合材料进行比较,分析纤维长度对复合材料拉伸、弯曲和冲击性能的影响.掺入黄麻纤维能使聚丙烯的拉伸和弯曲性能提高,但使其冲击强度降低;随纤维含量的增加或纤维长度的增加,复合材料的强度和模量是递增的,而冲击强度是递减的.     

加工方式对PP/EAA/LDH复合材料性能影响

进行了聚丙烯(PP)、乙烯–丙烯酸共聚物(EAA)及水滑石(LDH)复合材料改性一体化研究,并研究了一次熔融挤出加工法和二次熔融挤出加工法对PP复合材料性能的影响。X射线多晶衍射、透射电子显微镜分析表明:两种加工方法制备的复合材料中EAA均插层和剥离了LDH,改善了LDH在PP基体中分散性,并且一次挤出加工效果优于二次挤出加工效果;热失重分析表明,两种加工方式均提高了复合材料的热稳定性能;静态力学性能测试表明:一次挤出加工制备的复合材料PP1的拉伸强度、拉伸弹性模量和缺口冲击强度均高于二次挤出加工制备的复合材料PP2。实验表明一次熔融挤出加工方法对复合材料中LDH插层和剥离效果以及LDH在PP基体中分散效果优于二次熔融挤出加工。     

Pultruded fiber-reinforced poly(methyl methacrylate) composites. II. Static and dynamic mechanical properties,environmental effect,and postformability

This paper presents a novel process developed to manufacture poly(methyl methacrylate) (PMMA) pultruded composite. The mechanical, thermal, and dynamic mechanical properties, environmental effect, postformability of various fiber (glass, carbon, and Kevlar 49 aramid fiber) reinforced pultruded PMMA composites have been studied. Results show mechanical properties (i.e., tensile strength, specific tensile strength, tensile modulus, and specific flexural strength) and thermal properties (HDT) increase with fiber content. Kevlar fiber/PMMA composites possess the highest specific tensile strength and HDT, carbon fiber/PMMA composites show the highest tensile strength and tensile modulus, and glass fiber/PMMA composites show the highest specific flexural strength. Pultruded glass-fiber-reinforced PMMA composites exhibit good weather resistance. These composite materials can be postformed by thermoforming under pressure, and mechanical properties of postformed products can be improved. The dynamic shear storage and loss modulus (G′, G″) of pultruded glass-fiber-reinforced PMMA composites increased with decreasing pulling rate, and their shear storage moduli are higher than those of pultruded Nylon 6 and polyester composites.     

碳纤维布表面处理对酚醛树脂复合材料力学性能的影响

以碳纤维布(CB)为增强相,丁苯橡胶为增韧剂,酚醛树脂(PF)为基体,通过模压成型工艺制得了PF/CB复合材料,研究了CB表面处理方式、丁苯橡胶含量及加工成型温度对PF/CB复合材料的界面结合及力学性能的影响。结果表明,丙酮处理CB、氧化处理CB及加工成型温度的提高都能改善纤维与基体的结合程度,提高界面结合力。但氧化处理CB随着加工成型温度的提高,易断裂,对复合材料的增强作用有所减弱。丁苯橡胶加入量为12%时PF的加工及冲击性能为最佳。     

Study on the mechanical and thermal properties of poly(lactic acid)/office waste paper fiber composites

Environment friendly composites with favorable mechanical properties and low water absorption performance were successfully produced from poly(lactic acid) (PLA), office waste paper fiber (OWF), and coupling agents. The perfect sample was easily manufactured by melting–blending and injection molding. The PLA/OWF composites were comparable with other PLA/plant fiber composites, and the results indicated that the PLA/OWF composites show better performance than PLA/wheat straw fiber composites and PLA/bamboo fiber composites. On this basis, influence of modification of OWF on the properties of composites was investigated. The infrared results show that the OWF modification by different coupling agents was successful, and the scanning electron microscopy indicates that prepared composites exhibit good interfacial compatibility due to preferable binding force between fiber and matrix. With addition of 2 wt% γ-(2,3-propylene oxides)propyl trimethylsilane, the composite exhibits high tensile strength of 58.96 MPa, reflecting increase of 14% than the pure PLA. According to the crystallization and melting performance table, OWF can act as nucleating agent to promote the crystallization properties on composites, while the coupling agents have little effect on thermal stability. This article confirmed that the OWF has appropriate properties and is suitable for preparing composite materials and this work provides a novel idea for the utilization of office waste paper.     

短纤维在氯丁橡胶中的应用

研究了短纤维种类、用量及长度对短纤维/氯丁橡胶复合材料的纤维取向、纤维分散、力学性能、耐热性能以及溶胀性能的影响。结果表明,复合材料呈现明显的各向异性;3mm短纤维/氯丁橡胶(CR)复合材料的纤维取向度、拉伸强度、撕裂强度和耐溶胀性能均优于1mm复合材料,短纤维分散性对复合材料耐热性的影响较小。     

Tensile properties,morphology, and thermal behavior of PVC composites containing pine flour and bamboo flour

Composites of unplasticized poly(vinyl chloride) (PVC) blended with bamboo flour and pine flour, respectively, were prepared in a batch mixer followed by compression molding. The effects of wood flour fillers on the morphology, static mechanical properties, and thermal properties of the composites were investigated. Compared with neat PVC resin, the introduction of both bamboo flour and pine flour significantly improved the stiffness of the composites, while decreasing the tensile strength to some extent. Tensile tests showed that pine flour–filled composites exhibited better mechanical properties than those filled with bamboo flour with the same particle size at the same loading level. Scanning electron microscopic examination revealed good dispersion and alignment tendency of short pine fiber within the composites at a lower loading level. Moreover, experimental results indicated that both bamboo flour and pine flour additions showed no obviously adverse effect on the thermal stabilities of these composites. Based on the comprehensive properties, these composites meet the need of woodlike material for use as wood structures. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1804–1811, 2004     

成型工艺对碳纤维增强热塑性聚酰亚胺复合材料性能的影响

采用双螺杆挤出共混的方法,制备了热塑性聚酰亚胺(TPI)/碳纤维(CF)复合材料,考察了注射和热模压两种成型工艺对 TPI/CF 复合材料力学性能、应力-应变曲线、线性膨胀系数以及摩擦磨损性能的影响。结果表明,注射成型试样的各项力学性能均比模压成型的高,达到1.5～2.0倍;相比模压成型,注射成型试样具有较高的断裂强度和断裂伸长率,其应力-应变曲线斜率也较大;由于纤维在注射流动方向上高度取向,注射成型试样具有最佳的高温尺寸稳定性;注射成型试样的摩擦系数和磨损率为模压成型的1.7倍和1.5倍;扫描电镜分析表明,纤维在注射流动方向上高度取向,模压成型试样呈现黏着磨损,注射成型试样以磨粒磨损为主。     

Thermotropic polyester amide-carbon fiber composites

Liquid crystal polymers (LCP) have been developed for the first time as a thermoplastic matrix for high-performance composites. A successful melt impregnation method has been developed that results in the production of continuous carbon fiber (CF)-reinforced LCP prepreg tape. Subsequent layup and molding of prepreg into laminates has yielded composites of good quality. Tensile and flexural properties of LCP-CF composites are comparable to those of epoxy-CF composites. LCP-CF composites have better impact resistance than the latter, although epoxy-CF composites possess superior compression and shear strength. LCP-CF composites have good property retention until 200°F (67% of room temperature value). Above 200°F, mechanical properties are found to decrease significantly. Experimental results indicate that the poor compression and shear strength may be due to the poor interfacial adhesion between the matrix and carbon fiber.