Influence of fly ash cenospheres on performance of coir fiber‐reinforced recycled high‐density polyethylene biocomposites

Recycled high‐density polyethylene (RHDPE)/coir fiber (CF)‐reinforced biocomposites were fabricated using melt blending technique in a twin‐screw extruder and the test specimens were prepared in an automatic injection molding machine. Variation in mechanical properties, crystallization behavior, water absorption, and thermal stability with the addition of fly ash cenospheres (FACS) in RHDPE/CF composites were investigated. It was observed that the tensile modulus, flexural strength, flexural modulus, and hardness properties of RHDPE increase with an increase in fiber loading from 10 to 30 wt %. Composites prepared using 30 wt % CF and 1 wt % MA‐g‐HDPE exhibited optimum mechanical performance with an increase in tensile modulus to 217%, flexural strength to 30%, flexural modulus to 97%, and hardness to 27% when compared with the RHDPE matrix. Addition of FACS results in a significant increase in the flexural modulus and hardness of the RHDPE/CF composites. Dynamic mechanical analysis tests of the RHDPE/CF/FACS biocomposites in presence of MA‐g‐HDPE revealed an increase in storage (E′) and loss (E″) modulus with reduction in damping factor (tan δ), confirming a strong influence between the fiber/FACS and MA‐g‐HDPE in the RHDPE matrix. Differential scanning calorimetry, thermogravimetric analysis thermograms also showed improved thermal properties in the composites when compared with RHDPE matrix. The main motivation of this study was to prepare a value added and low‐cost composite material with optimum properties from consumer and industrial wastes as matrix and filler. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42237.     

Effect of surface modification of fly ash reinforced in polyetheretherketone composites

Fly ash reinforced polyetheretherketone (PEEK) composites were fabricated using compression molding technique. The fly ash surface was chemically modified using vinyltrimethoxy silane and 3‐aminopropyltriethoxy silane. The properties of treated fly ash PEEK composites were examined in terms of scanning electron microscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, and thermo gravimetric analysis. The modified fly ash was observed to disperse more uniformly than the unmodified counterpart. The tensile strength and modulus also improved with treated fly ash filled PEEK composites. The increment of the dynamic modulus for the PEEK/treated fly ash composites is 32% at 250°C, indicating apparent improvement of high temperature mechanical properties. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers.     

Modification of polypropylene composites containing potassium titanate whisker and talcum

Modified polypropylene was prepared by blending with potassium titanate whisker (PTW) and 10 w/w% talc via Haake extruder followed by injection molding. Reinforced with both PTW and talc, the PP composites exhibited better mechanical properties. The tensile modulus and flexural modulus of PP composites tend to increase with the increasing of whisker concentrations. The talc plays a synergistic role in improving the mechanical properties of composites and reducing cost. Torque measurement shows the PP composites has a good processing condition due to lubrication of PTW. TGA test shows PP composites containing 20 w/w% PTW and 10 w/w% talc is useful for improving PP composite's thermo oxidative stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of steel and PP fibers on mechanical and microstructural properties of fly ash-GGBFS based geopolymer composites

In this study, experimental investigations were carried out to estimate the mechanical and microstructural properties of polypropylene (PP) and steel fiber reinforced geopolymer mortar. Two industrial by-products are used as binders to produce the geopolymer composites, i.e., fly ash (FA) and ground granulated blast furnace slag (GGBFS). Different percentages of PP and steel fibers are used in geopolymer mortars to find the mechanical properties such as compressive, splitting tensile and flexural strengths were investigated to understand the strength behavior. However, the compressive elastic modulus values were estimated through the proposed equation based on the compressive strength of the fiber reinforced geopolymer composite samples. Moreover, to understand the geopolymeic reaction, microstructural studies, i.e., scanning electron microscopy (SEM), were conducted. The experimental results revealed that the addition of PP fibers up to 2.0% (volume fraction) enhanced the flexural properties of geopolymer mortar samples. The compressive strength of the steel fiber-reinforced geopolymer composite reached a maximum of 2.5% volume fraction, being a 13.26% improvement over the control mix. The flexural toughness index of the PP and steel fiber reinforced composites improved with increasing the fraction. However, steel fiber reinforced geopolymer samples are shown better flexural toughness compared to PP fibers. The SEM analysis of the geopolymer control mix achieved a good degree of geopolymerization and both the fibers yielded a considerable interfacial bonding with the geopolymer paste.     

Fibre-reinforced boroaluminosilicate geopolymers: A comparative study

This paper investigates the effect of fibres on the physical and mechanical behaviour of boroaluminosilicate geopolymers (BASG) compared to conventional aluminosilicate binders. The use of various types of fibres by the means of reinforcing geopolymers against flexural loads is very common. In this work, fly ash and ground granulated blast furnace slag (GGBS) are utilised as raw materials to generate geopolymer specimens. Different alkaline solutions comprising sodium hydroxide, sodium silicate, and borax are prepared to activate precursors. The sodium silicate solution is substituted with borax by 30?wt% and 70?wt% in order to produce fly ash and slag-based BASG respectively. Steel and polymer fibres are employed in the mixtures for reinforcement. Three-point bending and mini slump tests are conducted for assessing the flexural strength, elastic modulus, toughness, and flow of geopolymer specimens. A pair plotting interpretation is also used in order to illustrate the patterns. The obtained results indicate that the fly ash-based BASG mortar shows superior flexural strength to the GGBS-based BASG mortar. The flexural strength of fly ash-made aluminosilicate geopolymer declines from 7.3?MPa to 6.4?MPa with an increase in the content of steel fibres from 1% to 2%. Inversely, raising the percentage of steel fibres in the fly ash-based BASG mortar caused a slight growth in the flexural strength of specimens. The polypropylene fibres, when added sufficiently, play a significant role in improving the toughness of fly ash-based BASG and slag-based aluminosilicate mixtures, more than 0.8 and 0.7?J surge in the toughness respectively. In addition, the polypropylene and steel fibres perform well in improving the elastic modulus of slag-based BASG and fly ash-based aluminosilicate binders. While keeping the water to binder ratio constant, introducing the steel fibre increased the flow of fly ash-based geopolymers. Nonetheless, the polymer fibres declined the flow of mortars.     

玻璃微珠改性PP和LLDPE力学性能的比较研究

采用玻璃微珠(GB)改性聚丙烯(PP)和线性低密度聚乙烯(LLDPE)，对玻璃微珠的用量、粒径和复合材料加工方法对材料的力学性能的影响进行了比较研究。结果表明：随着GB用量的增加，单、双螺杆挤出GB／PP复合材料的拉伸模量、弯曲强度和弯曲模量均呈线性增长的趋势，而屈服强度则有小幅下降；断裂应变在低含量时有所提高，然后迅速下降；单双螺杆挤出材料的冲击强度均有所提高，并在一定范围内随GB用量的提高而增大，且单螺杆挤出材料的冲击强度略高于双螺杆挤出材料。而GB／LLDPE中，随着GB用量的增加，单螺杆挤出复合材料的拉伸模量、弯曲模量均呈线性增长趋势，而屈服强度和弯曲强度在含量较高时略有上升；双螺杆挤出复合材料的拉伸模量、屈服应力、弯曲强度和弯曲模量均呈线性增长的趋势，两者的断裂应变都有所降低，但没有严重劣化LLDPE复合材料的冲击特性。GB的粒径对两种复合材料的力学性能影响不大，但对GB／PP复合材料的韧性有较大影响。单、双螺杆挤出GB／PP复合材料的冲击强度在一定范围内较纯料有一定提高；同样的，双螺杆挤出复合材料的冲击强度低于单螺杆挤出材料。     

Thermomechanical and Interfacial Properties of Calcium Alginate Fiber-Reinforced Polypropylene Composites

Polypropylene (PP) matrix calcium alginate fiber reinforced unidirectional composites (10% fiber by weight) were fabricated by compression molding. Tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM), and impact strength (IS) were found to be 26 MPa, 950 MPa, 38 MPa, 1320 MPa, and 20 kJ/m², respectively. Degradation tests of composites were performed for 6 weeks in soil and it was found that composites retained almost 75% of its original strength. The interfacial properties of the composite were investigated by using single fiber fragmentation test (SFFT) and by scanning electron microscope (SEM).     

Behavior of low-calcium fly and bottom ash-based geopolymer concrete cured at ambient temperature

This paper presents the results of an experimental study on the behavior of fly ash-, bottom ash- and blended fly and bottom ash-based geopolymer concrete (GPC) cured at ambient temperature. A total of 10 bathes of GPC and a single batch of ordinary Portland cement concrete (OPC) were manufactured. The tests of compressive strength, elastic modulus, flexural strength, workability, drying shrinkage and absorption capacity were carried out to determine the properties of fresh concrete and mechanical and durability-related properties of hardened concrete. Test parameters included the mass ratio of fly ash-to-bottom ash, liquid alkaline-to-coal ash binder ratio, coal ash content and concrete type. The results indicate that the selected parameters significantly affect the microstructure and the behavior of GPCs. It is seen that bottom ash-based GPCs exhibited significantly lower geopolymerization than that of the fly ash-based GPCs, resulting in the inferior behavior of the former compared to the latter.     

A comparative analysis of woven jute/glass hybrid polymer composite with and without reinforcing of fly ash particles

The objective of this research article is to compare the mechanical and tribological properties of jute‐glass‐fiber‐reinforced epoxy (J‐G‐E) hybrid composites with and without fly ash particulate filler. A dry hand lay‐up technique is used to fabricate all the laminates. The properties including flexural strength, tensile strength, flexural modulus, and erosion behavior of all the composites are evaluated as per American Society for Testing and Materials (ASTM) standards. The fly ash particulate‐filled hybrid composite shows a better mechanical and tribological property. The maximum flexural strength and flexural modulus are obtained for GJGJ+ 5 wt% fly ash filler epoxy composites. Whereas the maximum tensile strength is obtained for GJJG+ 10 wt% fly ash filler epoxy composites. Scanning Electron Microscopy (SEM) analysis also has been carried out to categorize mechanical and tribological behavior of composites. POLYM. COMPOS. 37:658–665, 2016. © 2014 Society of Plastics Engineers     

Reinforcement of polypropylene by cellulose microfibers modified with polydopamine and octadecylamine

Cellulose microfibers (CMFs) having surfaces modified with polydopamine (PDPA) and octadecylamine (ODA) were prepared, and their reinforcing abilities for polypropylene (PP) were investigated. The PDPA coating was made via self-polymerization of dopamine (P-CMF), and subsequent alkylation was conducted by the reaction with ODA (OP-CMF). The modified CMFs exhibited improved dispersibility in the PP matrix due to the reduced hydrophilicity. The OP-CMF/PP composite prepared by batch mixing had a higher tensile modulus compared to that for the pure PP and composites with unmodified CMFs. However, excess alkylation lowered the tensile modulus, and the presence of an optimal degree of alkylation was demonstrated. The CMF/PP-IM composites fabricated by injection molding exhibited improved tensile properties compared to those prepared by batch mixing. Both the tensile modulus and yield stress were increased by increasing the CMF content and improved by the surface modification of the CMFs.     

Static and Dynamic Mechanical Properties of Vinylester Resin Matrix Composites Filled with Fly Ash

Summary: Vinylester resin matrix composites were prepared with a fly ash loading of 30, 40, 50 and 60 wt.‐%. Flexural properties of the composites were investigated. It was found that the flexural strength was lowered in all the filled composites, but the flexural modulus showed a significant increase of 10, 57, 112% in case of 30, 40 and 50 wt.‐% fly‐ash‐loaded composites respectively, compared to the neat resin. However, there was a decrease in the mechanical properties in case of 60 wt.‐% fly‐ash‐filled composites. The dynamic mechanical analysis was carried out to obtain information about the matrix‐filler interaction at the interface. The storage modulus value at room temperature was highest for the 50 wt.‐% fly‐ash‐filled composites, corroborating with the observed flexural modulus value. The fractured surfaces were examined under SEM and were correlated with the mechanical properties.

Large voids evident in the 60 wt.‐% fly‐ash‐filled composites.     

聚氯乙烯/粉煤灰复合材料的制备与性能研究

制备了聚氯乙烯/粉煤灰复合材料,研究了粉煤灰的不同表面处理方式对共混物的力学性能和耐温性能的影响。结果表明:湿法处理粉煤灰的效果最好,不做处理的效果最差;粉煤灰会降低PVC材料的缺口冲击强度;添加5份处理过的粉煤灰可以提高PVC材料的拉伸强度;添加粉煤灰可以提高PVC材料的弯曲强度和弯曲模量,同时,耐温性也有一定的提高。     

注塑压力对粉煤灰微珠改性PP综合性能的影响

叙述了粉煤灰空心微珠改性PP注塑件在加工过程中注塑压力对体系综合性能的影响，分析了注塑压力与有关性能(冲击强度、拉伸强度、断裂伸长率、成型收缩率)之间的关系，指出了采用合适的注塑压力有助于提高体系的综合性能。     

Processing and properties of polypropylene‐based composites containing inertized fly ash from municipal solid waste incineration

This article reports for the first time the results about the use of inertized fly ash from municipal solid waste incineration as a filler for polypropylene (PP). An innovative process based on the stabilization with colloidal silica has been used for fly ash inertization. Polymer–filler composites containing different filler amounts up to 30 wt % have then been formulated and prepared by means of melt compounding process. Structural, morphological, mechanical, and thermal characterization of their properties has been performed and discussed in detail. Remarkable enhancements of tensile (+ 93%) and flexural (+ 107%) elastic moduli if compared to pristine PP, together with enhancements of flexural resistance (+ 36%) and deflection temperature under load (+ 50%), have been observed when adding filler 30 wt % in suitable processing conditions. Moreover the filler has been shown to interact with polymer crystalline structure and positively influence the thermal‐oxidative stability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4157–4164, 2013     

Use of preimpregnated sisal yarn in woven reinforced polypropylene sheets: Thermoformability and mechanical properties

Thermoplastic composites were made from polypropylene (PP) and long sisal fibers (SF) by using different processing techniques. Four sets of composites specimens were made with a 60/40 (wt/wt) SF/PP ratio: the first set was made by melt‐blending PP and SF and compression molding 2‐mm‐thick flat sheets; a second set was made by melt‐blending PP, SF, and maleic anhydride grafted polypropylene (MA‐g‐PP); the third set was made by compression molding knitted SF yarns, preimpregnated with PP, between PP sheets; the fourth set was also made by compression molding knitted SF yarns, preimpregnated with diluted MA‐g‐PP, between PP sheets. The bidirectional array of fibers, containing 60% of SF well‐impregnated with a small quantity of MA‐g‐PP, increases the flexural modulus by 600%, the tensile modulus by 475%, and the tensile strength by 300% compared with unfilled PP. The composites sheets were successfully thermoformed with small wall thickness reductions to obtain a three‐dimensional (3D) shape with very low forming energy, outstanding mechanical properties, and excellent surface finish. POLYM. ENG. SCI., 45:976–983, 2005. © 2005 Society of Plastics Engineers     

玻纤增强聚丙烯木塑复合材料的性能研究

分别以聚丙烯(PP)、聚乙烯(PE)、玻纤增强PP/PE为基体材料,通过挤出成型制备了木塑复合材料(WPC)。研究表明,玻纤能够有效地提高WPC的性能,以玻纤增强PP/PE为基体制备的WPC的冲击强度、拉伸强度、弯曲强度、弯曲弹性模量分别达到4.58 kJ/m2,19 MPa,30.8 MPa,3520 MPa,性能优于以PP或PE为基体制备的WPC。     

Injection molding of polypropylene reinforced with short jute fibers

Composites with polypropylene (PP) and jute fiber were prepared by injection molding technique. Maleic anhydride-grafted polypropylene was added as coupling agent to improve the adhesion between jute fiber and PP. A high fiber attrition was noted during injection molding, which had negative effects on the mechanical properties of the composites. The coupling agent improved the tensile and bending strengths, however the elastic and bending moduli were found not to be influenced by the coupling agent. The role of the average fiber length in strengthening of the composites was interpreted with help of the critical fiber length. Fracture surfaces of the composites, and the fiber orientations, were investigated by scanning electron microscopy and light microscopy, respectively. © 1996 John Wiley & Sons, Inc.     

The influence of addition of carbon nanotube and graphene platelets on characteristics of carbon/basalt fiber reinforced intra-ply hybrid composites

In this study, effects of addition of carbon nanotubes (CNTs) and graphene platelets (GPLs) on characteristics of carbon/basalt fiber reinforced intra-ply hybrid composites were investigated. The composites were fabricated using vacuum assisted resin infusion molding (VARIM) method in two types including bare and 0.1, 0.5 wt.% of GPL and CNT nanoparticles filled hybrid composites. Fabricated normal and multiscale composites were cut by water jet and mechanical properties of specimens were examined by tensile, flexural, SBS experiments. Therefore, the modulus of elasticity, flexural modulus, tensile and flexural strength and ILSS of bare and multiscale composites were compared. Thermomechanical properties of fabricated composites were evaluated by dynamic mechanic analyze (DMA), thermogravimetric analyze ( TGA) and thermal conductivity (TC) tests and storage modulus, loss modulus, damping ratio, glass transition temperature, weight loss and derivative weight loss were compared in fabricated normal and multiscale composites. Similarly, modal properties of fabricated composites such as natural frequency and damping factor were obtained by vibrational tests and compared in fabricated composites. According to the results, the addition of carbon-based nanoparticles improved the characteristics of carbon/basalt fiber intra-ply hybrid composites. The response of composites was directly proportional to the addition ratio of the carbon-based nanoparticles.     

Development and Characterization of Grain Husks Derived Lignocellulose Filler Containing Polypropylene Composites

Oat and spelt husks (OH and SH, respectively) lignocellulosic biomass derived fillers have been compared with commercial wood flour (WF) in respects to their morphology, chemical composition, bulk density, aspect ratio, and thermal stability. OH and SH have been obtained by both mechanical milling and steam explosion auto‐hydrolysis treatment at various processing conditions. Reinforcement efficiency of OH and SH derived lignocellulosic biomass fillers on the flexural properties of maleic acid‐grafted polypropylene (PPgMA) compatibilized polypropylene (PP) composites is compared with that of WF. The compatibilized PP composites have been manufactured by melt compounding. Flexural test specimens of the compatibilized PP composites have been manufactured by injection molding. It has been demonstrated that both the husks derived lignocellulose fillers can be used to improve flexural modulus and maximal flexural strength of PP, although its modifying effect is somewhat smaller in comparison to WF reinforcement, most probably due to higher cellulose content of the latter. Husks derived lignocellulose filler‐reinforced PP composites, however, demonstrate increased flexibility in comparison to WF‐filled systems. POLYM. ENG. SCI., 59:2467–2473, 2019. © 2019 Society of Plastics Engineers     

Study of the flexural modulus of natural fiber/polypropylene composites by injection molding

Effect of fiber compression on flexural modulus of the natural fiber composites was examined. The kenaf, bagasse, and polypropylene were mixed into pellets, and composites were fabricated by injection molding. To predict flexural modulus of the composites, the Young's modulus of kenaf and bagasse fiber were measured. Using the obtained Young's modulus, the flexural modulus of the composites was predicted by Cox's model that incorporates the effect of fiber compression. It was found that those fibers with high Young's modulus were more compressed than that with low Young's modulus. Moreover, the distribution of fiber length and orientation in the composites were also investigated. To calculate the orientation factor for the prediction model, the distribution function of fiber orientation was determined to a triangular function. The flexural modulus of the composites increased with increase of volume fraction. The predicted values were in good agreement with the experimental values. Furthermore, it was revealed by SEM that the porous structure of the natural fibers was compressed. The fiber compression ratio (3.6) in bagasse was higher than that in kenaf (1.4) due to the difference in porous structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 911–917, 2006