Mechanical and thermal properties of talc and calcium carbonate filled polypropylene hybrid composites

The main aim of this work was to study and compare the mechanical and thermal properties of hybrid polypropylene (PP) composites and single‐filler PP composites. With two main types of mineral fillers—calcium carbonate (CaCO₃) and talc—PP composites of different filler weight ratios (talc/CaCO₃) were compounded with a twin‐screw extruder and then injection‐molded into dumbbell specimens with an injection‐molding machine. Tensile, flexural, and impact tests were performed to determine and compare the mechanical properties of the hybrid and single‐filler PP composites. A synergistic hybridization effect was successfully achieved; the flexural strength and impact strength were highest among the hybrids when the PP/talc/CaCO₃ weight ratio was 70:15:15. The nucleating ability of the fillers and its effects on the mechanical properties were also studied with differential scanning calorimetry. Because of the influence of talc as the main nucleating agent, the hybrid fillers showed significant improvements in terms of the nucleating ability, and this contributed to the increase in or retention of the mechanical properties of the hybrid composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3327–3336, 2004     

The effect of multiscale hybridization on the mechanical properties of natural fiber-reinforced composites

The main objective of this work was to investigate the effect of reinforcements at different scales on the mechanical properties of natural fiber-reinforced composites. Pure jute and interlaminar hybrid jute/glass fiber-reinforced polymer composites were fabricated. Different types of fillers in two weight fractions (1 and 3 wt. %) were used as second reinforcements in the hybrid jute/glass composites. Tensile, flexural, and impact tests were performed. It was found that the macroscale inter-play hybridization significantly improved the mechanical properties of the pure jute fiber based composites. When the fillers are used as second hybridization, the modified composites presented higher mechanical properties when compared to pure jute composites. However, the effect of fillers on the mechanical properties of the hybrid composites presented various trends due to the interaction between several factors (i.e., particle scale, content, and nature), which cannot always be separated. Increasing the synthetic filler content improved the tensile properties of the filled hybrid composites, while increasing the natural filler content worsen the tensile properties. The flexural strength of the multiscale hybrid composites was improved, while the impact properties were negatively affected.     

Study of plastic compounds containing polypropylene and wood derived fillers from waste of different origin

The scope of the article was to study the perspectives of the using of wood derived fillers (WDF) from waste of different origin as fillers of polypropylene. The WDF used in this study was hard wood flour (HW), birch veneer polishing dust (VD) and tetra‐pack carton cellulose fiber (TC). Some mechanical strength parameters, water uptake in the static and cyclic test and resistance to fungal decay of polypropylene (PP) composites containing these three types of WDF were studied and compared with similar loading (40 wt %) talc‐filled PP. Composites containing TC and VD fibers as filler showed the highest flexural strength at three test temperatures (?40, +20, and +40°C) and flexural modulus and tensile strength at plus temperatures. On the other hand talc‐filled PP exhibited greatest flexural modulus at minus temperature, greatest impact strength at room temperature and best flow ability. Significant difference was observed between PP composites with HW and VD fillers regarding water uptake in cyclic tests, however flexural strength and modulus change of composites were reversible after drying. No weight loss of WDF/PP composites was observed after 6 week exposure to brown‐ and white‐rot fungi, however, degradation of the surface of samples was detected by SEM. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Mechanical properties and morphology of nylon‐6 hybrid composites

In this investigation, the influence of filler type and filler content on the mechanical properties of nylon‐6 is investigated. The mineral fillers were selected on the basis of their shape and size: flake‐like kaolin and talc, spherical glass beads or fibrous wollastonite. These fillers were added to nylon‐6 individually or in mixed combinations. They were added at different percentages varying between 10 and 30% w/w. Samples of the composites were prepared by the injection moulding process. Uniaxial tensile, Izod impact and flexural tests were carried out. Tensile strength, elongation at break, modulus of elasticity and impact energy were obtained and compared. In case of single fillers the results showed that the tensile strength, modulus of elasticity and their flexural values for nylon‐6 composite improve with the increase in filler content while mixed compounds showed no significant changes above 15% + 15% w/w filler. However, for single and mixed filler up to 10% w/w, the impact strength and maximum elongation at break showed significant decrease. In general, the maximum improvement in mechanical the addition of 10–15% w/w filler. Copyright © 2003 Society of Chemical Industry     

Effect of single‐mineral filler and hybrid‐mineral filler additives on the properties of polypropylene composites

The present study was carried out to determine the filler characteristics and to investigate the effects of three types of mineral fillers (CaCO₃, silica, and mica) and filler loadings (10–40 wt%) on the properties of polypropylene (PP) composites. The characteristics of the particulate fillers, such as mean particle size, particle size distribution, aspect ratio, shape, and degree of crystallinity were identified. In terms of mechanical properties, for all of the filled PP composites, Young's modulus increased, whereas tensile strength and strain at break decreased as the filler loading increased. However, 10 wt% of mica in a PP composite showed a tensile strength comparable with that of unfilled PP. Greater tensile strength of mica/PP composites compared to that of the other composites was observed because of lower percentages of voids and a higher aspect ratio of the filler. Mica/PP also exhibited a lower coefficient of thermal expansion (CTE) compared to that of the other composites. This difference was due to a lower degree of crystallinity of the filler and the CTE value of the mica filler. Scanning electron microscopy was used to examine the structure of fracture surfaces, and there was a gradual change in tensile fracture behavior from ductile to brittle as the filler loading increased. The nucleating ability of the fillers was studied with differential scanning calorimetry, and a drop in crystallinity of the composites was observed with the addition of mineral filler. Studies on the hybridization effect of different (silica and mica) filler ratios on the properties of PP hybrid composites showed that the addition of mica to silica‐PP composites enhanced their tensile strength and modulus. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Biopolymers as effective fillers in natural rubber: Composites versus biocomposites

Biocomposites of natural rubber (NR) blends were prepared with a variety of fillers obtained from renewable resources by a mastication technique. They were characterized for their mechanical properties and morphologies and compared with composites of the conventional filler carbon black (c‐black). The biopolymers exhibited an interesting trend and imparted strength to NR that was quite comparable to c‐black. Up to 30 phr of the fillers could be successfully incorporated; this led to enhancements in the mechanical strength. The properties were found to vary with the type and ratio of filler, namely, starch, cellulose, and chitin. The optimum mechanical strength of the biocomposites was observed at 10 phr. The results were interpreted on the basis of the morphology by scanning electron microscopy, which revealed strong filler–polymer interactions. The moisture‐uptake characteristics of the composites were studied. It was found that addition of biofillers did not lead to a significant increase in the moisture absorption. Furthermore, as the adhesion between the polymer matrix and fillers increased, the water uptake decreased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Comparison of the mechanical properties and interfacial interactions between talc,kaolin, and calcium carbonate filled polypropylene composites

Three types of mineral fillers—talc, calcium carbonate (CaCO₃), and kaolin (10–40 wt % filler loadings)—were compounded with polypropylene (PP) with a twin‐screw extruder. The composites were injection‐molded, and the effects of the filler loading on the mechanical, flow, and thermal properties for the three different types of filled composites were investigated. The aim was to compare their properties and to deduce prospective filler combinations that would yield hybrid PP composites in following studies. The results showed that in most cases, the strength and stiffness of the talc‐filled PP composites was significantly higher than those of the CaCO₃‐ and kaolin‐filled PP composites. However, CaCO₃, being a nonreactive filler, increased the toughness of PP. The kaolin‐filled PP composites also showed some improvement in terms of strength and stiffness, although the increases in these properties were not as significant as those of the talc‐filled PP composites. The effects of interfacial interactions between the fillers and PP on the mechanical properties were also evaluated with semiempirical equations. The nucleating ability of all three fillers was studied with differential scanning calorimetry, and the strongest nucleating agent of the three was talc, followed by CaCO₃ and kaolin. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3315–3326, 2004     

Agrofillers in polypropylene composites: A relationship between the density and the mechanical properties

One of the most interesting properties of agrofilled polymer composites is their light weight. Polypropylene composites containing six different agrofillers were prepared in a mixer, and their properties were examined in terms of the density of the fillers and composites. The densities of the composites increased with the level of filler but did not show a direct relationship with the density of the fillers used. This probably happened because of the different degrees of filler densification during processing. The composites showed decreased tensile strength and increased elastic modulus with filler loads, and the specific mechanical properties showed similar trends. However, the addition of maleated polypropylene improved the tensile strength and decreased the density; this improved the specific properties of the composites filled with cane, wood, and bamboo. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comparative study of maleated polyolefins as compatibilizers for polyethylene/wood flour composites

The effects of various types of compatibilizers on the mechanical properties of high‐density polyethylene/wood flour composites were investigated. Functionalized polyolefins, including maleated polyethylenes, polypropylene, and styrene–ethylene/butylene–styrene copolymer, were incorporated to reduce the interfacial tension between the polyethylene matrix and wood filler. Of these, maleated linear low‐density and high‐density polyethylenes gave higher tensile and impact strengths for the composites, presumably because of their better compatibility with the high‐density polyethylene matrix. Similar but less enhanced improvements in the mechanical properties, depending on the compatibilizer loading, were seen for a maleated styrene–ethylene/butylene–styrene triblock copolymer, whereas maleated polypropylene only slightly improved the tensile modulus and tensile strength, which increased with increasing compatibilizer loadings. Scanning electron microscopy was used to reveal the interfacial region and confirm these findings. Dynamic mechanical thermal measurements showed the interaction between the filler and the matrix. Fourier transform infrared spectroscopy was used to assign the chemical fixation and the various chemical species involved on the surfaces of the fillers before and after surface treatment. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 487–496, 2003     

Use of construction and demolition wastes as mineral fillers in hybrid wood–polymer composites

The recycling of construction materials has been the subject of much research in past years. In this study, the use of construction and demolition wastes (CDWs) as mineral fillers in hybrid wood–polymer composites was studied. Two types of waste materials were used as fillers in the composites: (1) a mixture consisting of waste mineral wool (MW) and plasterboard (PB) and (2) mixed CDWs. The performance of the composites was evaluated from their mechanical properties and water‐absorption behavior. We found in the study that the addition of mineral fillers decreased the flexural strength and modulus values of the wood–polypropylene (PP) composites. On the other hand, the exchange of part of the wood with a mineral filler resulted in an increase in the impact strength of the composite. The composite manufactured with the combination of MW and PB had the lowest water absorption. The decrease in wood loading resulted in improved dimensional stability in the hybrid wood–mineral filler–PP composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43412.     

Effect of γ-Radiation on the Mechanical Performance of Hybrid Rice Straw/Seaweed-Polypropylene Composites

Hybrid composites of rice straw (Rs)/seaweed (Sw) and polypropylene (PP) were prepared at a fixed filler ratio of 30:70 and variable ratio of the two reinforcements, viz. 30:0, 25:5, 20:10, 10:20, 0:30 by weight. Mechanical properties of the composites such as tensile strength (TS), bending strength (BS), impact strength (IS) and elongation at break (Eb%) were investigated and the composite formulation of 20:10:70 (Rs:Sw:PP) was found to be optimum that showed TS = 2.8 MPa, BS = 68 N/mm², IS = 2.5 kJ/mm² and Eb = 50%. For better compatibility, Rs and Sw were subjected to surface treatment using various intensities of γ-radiation to prepare improved hybrid composites. γ-irradiated filler hybrid composites significantly enhanced mechanical properties and the composite in which fillers were irradiated at 100 krad achieved maximum enhancement with TS = 35 MPa, BS = 75 N/mm², IS = 2.7 kJ/mm² and Eb = 68%. Water absorption capacity of the different composites was also studied and irradiated filler composites showed less water uptake.     

Degree of conversion and mechanical properties studies of UDMA based materials for producing dental posts

Nanocomposites are a relatively new material in producing fiber re‐enforced dental posts. The mechanical properties of nanocomposites, which strongly associate with the resin matrix, nanoparticles, and the interface between inorganic fillers and organic matrix, play an important role in determining the quality of dental posts. This work was to investigate the effect of degree of conversion (DC) and silanization of fillers on the mechanical properties of nanocomposties. Experimental Urethane dimethacrylate (UDMA) based dental composites containing unsilanized and silanized SiO₂ filler and various amount of triethylene glycol dimethacrylate (TEGDMA) were prepared at the first step. The DC of composites at different ratios of UDMA/TEGDMA, cure temperature and cure time was measured by Fourier transform infrared spectroscopy. The results showed that DC increases with the increase of TEGDMA content in resin matrix. Both increase of the cure temperature and cure time can cause the increase of DC. The incorporation of fillers, either silanized, or unsilanized filler, caused the decrease of DC. However, composites reinforced with silanized silica showed relatively lower DC, and DC decreased with the increase of silanized filler content. The effect of incorporation of fillers on the mechanical properties was investigated. Silanized silica can effectively improved the flexural strength and flexural modulus of material, and these properties increased with the increase of silica content. Thermomechanical analysis (DMA) provided the similar results to the static property measurements. SEM images of fracture surfaces of specimens from flexural testing revealed the surface morphology is strongly related to the quality of interface between inorganic fillers and organic matrix. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Investigation on flammability of rigid polyurethane foam‐mineral fillers composite

This study investigates the incorporation of castor oil–based rigid polyurethane foam with mineral fillers feldspar or kaolinite clay in order to enhance the mechanical, thermal, and flame retardant properties. Influence of mineral fillers on the mechanical strength was characterized by compressive strength and flexural strength measurement. Thermogravimetric analysis (TGA) was performed to diagnose the changes in thermal properties, while cone calorimeter test was performed to ascertain the flame retardancy of the mineral filler–incorporated rigid polyurethane foam composites. Results showed that the foams incorporated with mineral filler demonstrated up to 182% increase in compressive strength and 351% increase in flexural strength. Thermal stability of these composite foams was also found to be enhanced on the incorporation of kaolinite clay filler with an increase in 5% weight loss temperature (T_5%) from 192°C to 260°C. Furthermore, peak heat release rate (PHRR), total heat release (THR), smoke production rate (SPR), and total smoke release (TSR) were also found to decreased on the incorporation of mineral filler in the rigid polyurethane foam. So mineral fillers are ascertained as a potential filler to enhance the mechanical, thermal, and flame retardant behaviors of bio‐based rigid polyurethane foam composites.     

Correlation of the material properties of calcium carbonate filled polypropylene with the filler surface energies

The physical and mechanical properties of polypropylene (PP) were measured and compared with those of PP composites filled with calcium carbonate modified with sodium polyacrylate, stearic acid, or both. The variations in the mechanical properties showed a high degree of correlation with the surface energies of the fillers, as determined by inverse gas chromatography. The results confirmed the usefulness of inverse gas chromatography for characterizing the compatibility of polymer–filler combinations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1951–1955, 2003     

Effect of chemical treatments on the mechanical,flow, and morphological properties of talc‐ and kaolin‐filled polypropylene hybrid composites

This study was performed with commercially available phenyl trimethoxysilane (PTMS) and neoalkoxytitanate [i.e., neopentyl(diallyl)oxytri(dioctyl)phosphato titanate (LICA 12)] as coupling agents. PTMS and LICA 12 were used to treat talc and kaolin to compare their effects with untreated fillers upon incorporation into polypropylene (PP). Single‐filler PP composites (containing either talc or kaolin) and hybrid‐filler composites (containing a mix of both talc and kaolin) were compounded in a twin‐screw extruder and subsequently injection‐molded into dumbbells. The incorporation of PTMS and LICA 12 slightly decreased the tensile and flexural properties in terms of modulus and strength but increased the elongation at break for both single‐filler and hybrid‐filler composites. There was also a significant improvement in the impact strength of the composites, particularly those treated with LICA 12. The hybrid composites, through the synergistic coalescence of positive characteristics from talc and kaolin with the aid from chemical treatment provided an economically advantageous material with mechanical properties comparable to those of the single‐filler‐filled PP composites. Further investigations on flow and morphological properties were also done to correlate the mechanical properties of the single‐ and hybrid‐filler‐filled PP composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The comparison of properties of (rubber tree seed shell flour)‐filled polypropylene and high‐density polyethylene composites

The effect of varied rubber tree seed shell flour (RSSF) filler loadings on processing torque, mechanical, thermal, water absorption, and morphological properties of polypropylene (PP) and high‐density polyethylene (HDPE) composites has been studied. The addition of RSSF in the composites increased the stabilization torque in both PP‐ and HDPE‐based composites. Tensile strength, elongation at break, flexural strength, and impact strength show significant reduction when higher loading of RSSF was incorporated, while tensile modulus and flexural modulus were improved. The phenomenon was noted for both matrices, PP and HDPE, but HDPE‐based composites showed clear effects on the reduction of the mechanical properties compared with RSSF‐filled PP. Scanning electron microscopy of tensile fracture specimens revealed the degree of dispersion of RSSF filler in the matrices. At higher filler loadings, agglomerations and poor dispersion of RSSF particles were spotted, which induce the debonding mechanism of the system. Thermogravimetric analysis thermograms showed that both PP‐ and HDPE‐based composite systems with higher RSSF content have higher thermal stability, initial degradation temperature, degradation temperature, and total weight loss. Water absorption ability of the composites increases as the filler loading increases for both matrices. J. VINYL ADDIT. TECHNOL., 22:91–99, 2016. © 2014 Society of Plastics Engineers     

Mechanical properties of particulate‐filler/woven‐glass‐fabric‐filled vinyl ester composites

Studies of the effect of particulate fillers on specific mechanical properties of vinyl ester epoxy (VE) reinforced with woven glass fiber composites were carried out with different filler types and particulate filler contents (1%, 3%, and 5% by weight). Two types of particulate filler were used, i.e., calcium carbonate (CC) and phenolic hollow microspheres (PHMS). The composites were prepared by using a hand lay‐up and vacuum bagging method. Woven glass fabric composites filled with particulate PHMS were observed to have better specific flexural strength and specific impact strength, as well as lower density, than those filled with particulate CC. Morphological features determined by scanning electron microscope (SEM) proved that the PHMS filler experienced good bonding in the VE matrix, a feature which contributed to the improvement in the properties of the composites. The incorporation of particulate fillers into the composites also influenced the storage modulus with a minimal effect on T_g. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

Mechanical behavior of nylon composites containing talc and kaolin

Particulate reinforced thermoplastic composites are designed to improve the properties and to lower the overall cost of engineering plastics. In this study, the influence of adding talc and kaolin fillers on the mechanical properties of nylon 6 was investigated. Fillers, either singly or mixed by various weight ratios between 10 and 30 wt %, were added to nylon 6. Test samples of the composite material were prepared by the injection‐molding process. Uniaxial tensile and Izod impact tests were carried out. Tensile strength, elongation at break, modulus of elasticity, and impact energy were obtained. The results showed that the tensile strength and modulus of elasticity of nylon 6 composite increased with the increase in filler ratio, whereas the impact strength and maximum elongation decreased with the increase in filler ratio. The optimal nylon composite was determined with the addition of a 10 to 15 wt % filler ratio. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1694–1697, 2003     

β成核剂与无机填料对聚丙烯力学性能的影响

无机填料可以提高聚丙烯的刚性、硬度、抗化学性、尺寸稳定性和气体阻隔性,同时减少聚合物的用量,降低产品成本。滑石粉和碳酸钙是聚丙烯复合材料中大量使用的两种填料。主要研究β成核剂和无机填料对聚丙烯成核效应的协同作用,考察经β成核剂FB-1分别与无机填料滑石粉和碳酸钙共同改性的聚丙烯力学性能。     

Dielectric and mechanical properties of natural nanofibers‐reinforced ethylene propylene diene rubber: Carrot foliage and corn gluten

A study has been carried out to investigate the dielectric and mechanical properties of composites based on reinforcing carrot foliage (CF) and corn gluten meal (CGM) as by‐products of food processing units into ethylene propylene diene rubber matrix. Transmission electron microscope micrographs indicate that both types of fillers are in the nanoscale. The permittivity ε′ and dielectric loss ε″ were measured in the frequency domain and at room temperature ～ 25°C. The increase in ε′ and ε″ by increasing filler content is due to its reinforcing nature which was found to be more pronounced in case of CF than CGM. The mechanical properties are found to increase in the same manner. The values obtained for ε′ and ε″recommend such composites to be used in the electrical insulation purposes. The analysis of composite morphology indicated that at low concentration both types of fillers are fine distributed in the EPDM matrix, whereas at higher filler loading aggregation of filler is clearly appeared. The composites under investigation are found to be highly thermal aging resistant as both electrical and mechanical properties are slightly affected by such aging. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers