Modification of polyethylene and incorporation of fillers for effective reinforcement of mechanical and better flame retardant properties

The effect of incorporation of the two different fillers, i.e. calcium carbonate and magnesium hydroxide, over a concentration range of 0–35% w/w on mechanical and burning properties and hot set test of polyethylene (PE) has been studied. The incorporation of either of these fillers deteriorates mechanical properties such as percent elongation at break and tensile strength of PE. However, modification of PE not only mitigates the reduction in these properties, but brings enhancement in all the aforementioned properties. A clear difference in these properties for the incorporation of each of these fillers to just PE, silane‐grafted but uncured PE, and silane cross‐linked PE has been found. These properties follow the order of superiority as: cross‐linked PE > silane‐grafted uncured PE > physically filled PE. The different properties due to physical bonding of filler, physical bonding in the presence of polar silane grafted onto PE, and that of chemical bonding of filler in cross‐linked PE has been discussed and analyzed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1928–1933, 2006     

Toughening of recycled poly(ethylene terephthalate)/glass fiber blends with ethylene–butyl acrylate–glycidyl methacrylate copolymer and maleic anhydride grafted polyethylene–octene rubber

The aim of this study was to improve the toughness of recycled poly(ethylene terephthalate) (PET)/glass fiber (GF) blends through the addition of ethylene–butyl acrylate–glycidyl methacrylate copolymer (EBAGMA) and maleic anhydride grafted polyethylene–octene (POE‐g‐MAH) individually. The morphology and mechanical properties of the ternary blend were also examined in this study. EBAGMA was more effective in toughening recycled PET/GF blends than POE‐g‐MAH; this resulted from its better compatibility with PET and stronger fiber/matrix bonding, as indicated by scanning electron microscopy images. The PET/GF/EBAGMA ternary blend had improved impact strength and well‐balanced mechanical properties at a loading of 8 wt % EBAGMA. The addition of POE‐g‐MAH weakened the fiber/matrix bonding due to more POE‐g‐MAH coated on the GF, which led to weakened impact strength, tensile strength, and flexural modulus. According to dynamic rheometer testing, the use of both EBAGMA and POE‐g‐MAH remarkably increased the melt storage modulus and dynamic viscosity. Differential scanning calorimetry analysis showed that the addition of EBAGMA lowered the crystallization rate of the PET/GF blend, whereas POE‐g‐MAH increased it. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of silicone oil and polymeric modifiers on the mechanical properties of highly filled LLDPE

The effects of coupling agents, silicone oil, and three types of polymeric modifiers on the mechanical properties of linear low density polyethylene (LLDPE) composites highly filled with aluminium hydroxide [Al(OH)₃] were studied. Polymeric modifiers that contain polar groups, such as silane‐grafted polyethylene (Si‐g‐PE) and acrylic‐acid‐grafted ethylene‐vinyl acetate copolymer (AA‐g‐EVA), improve the mechanical properties dramatically, while nonpolar modifiers improve them to some extent. When Al(OH)₃ was treated using a titanate coupling agent, the silicone oil increased the impact strength and elongation at break of the LLDPE/Al(OH)₃ composites. Introduction of a polymeric modifier containing polar groups destroys the beneficial effects of silicone oil on film mechanical properties, while the introduction of a nonpolar elastomeric polymeric modifier retains the high impact strength and elongation at break. SEM analyses provide the indirect evidence of the encapsulation of silicone oil around the filler. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 121–128, 2002     

Recycling of commingled plastics by cellulosic reinforcement

In this article, a model study was conducted on the effect of combining cellulose on the properties of virgin and/or recycled commingled plastics with a simulated waste‐plastics fraction composed of high‐density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), and poly(vinyl chloride) (PVC) (PE/PP/PS/PVC = 7/1/1/1 by weight ratio). The compatibilizing effect of maleic anhydride‐grafted styrene–ethylene/butylene–styrene block copolymer (SEBS‐g‐MAH) for the cellulose‐reinforced commingled blends was also investigated. Commingled blends were prepared in a table kneader internal mixer. Mechanical properties were measured by using a universal testing machine. Thermal stability was measured by a thermogravimetric analyzer. It was found that the addition of more than 12.5% cellulose into the commingled blends was effective to enhance the mechanical properties of the virgin and recycled blends. The thermal stability as well as the mechanical properties of the commingled blends were much improved by the reactive blending of cellulose with the commingled blends by peroxide and maleic anhydride. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1531–1538, 1999     

Flour rice husk as filler in block copolymer polypropylene: Effect of different coupling agents

Flour rice husk (FRH) was employed as a filler in block copolymer polypropylene (PPB) in order to prepare polymer‐based reinforced composites. Four coupling agents were selected to modify the surface of the rice husk in the composite materials, including two types of functionalized polymers [PP homopolymer grafted with maleic anhydride (MA‐PP) and an elastomer styrene–ethylene–butadiene–styrene triblock copolymer grafted with MA (MA‐SEBS)] and two bifunctional organometallic coupling agents (silane and titanate with linear low‐density polyethylene as a carrier). The influence of each type of coupling agent on the interfacial bonding strength was studied by dynamic mechanical analysis, scanning electronic microscopy, and rheological tests. The results showed that strong interactions were formed between the coupling agents and the filler surface. The addition of a coupling agent with an elastomeric carrier (MA‐SEBS) increased the loss tangent and reduced the storage modulus of the composite. A similar but less intense effect was observed for the titanate coupling agent. However, an antagonistic performance was obtained when MA‐PP and silane were employed as coupling agents. In addition, when the percentage of MA‐SEBS was increased, the impact properties of FRH/PPB blends were improved and the strength was reduced. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1823–1831, 2006     

Synthesis and evaluation of compatibilizer based on interpenetrating polymer networks (IPN) for PET/LDPE blends

The present work considers the evaluation of recycled polymers, which are generally incompatible and are degraded during recycling with fatal consequences to their thermal and mechanical properties. Regarding this subject, the synthesis of a new compatibilizer in network form was carried out in order to counter such incompatibility. In this sense, low density polyethylene (LDPE) and poly(ethylene terephthalate) (PET) were compatibilized via the implementation of an interpenetrating polymer network (IPN), which was specifically synthesized to possess chemical groups that are akin to both plastics, PET and LDPE. The effects of the relative amount of poly(acrylic acid) (PAA) in the compatibilizer and the amount in the blends of PET/LDPE were evaluated. The results show that mechanical properties and interfacial adhesion of PET/LDPE blends were modified and improved with the addition of the synthesized compatibilizer compared with a commercial compatibilizer (polyethylene grafted with maleic anhydride, PE‐g‐AA). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43704.     

Effectiveness of functionalized 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 (HDPE/WF) composite were investigated. Functionalized polyolefins such as maleated and acrylic acid grafted polyethylenes, maleated polypropylene (PPgMA) and styrene‐ethylene/butylene‐styrene triblock copolymer (SEBSgMA) were incorporated to reduce the interfacial tension between the polyethylene matrix and the wood filler. Among them, it was found that maleated linear low‐density polyethylene (LLDPEgMA) gave maximum tensile and impact strength of the composites, presumably because of better compatibility with the HDPE matrix. Similar but less enhanced improvements in the mechanical properties, depending on the compatibilizer loading, were seen for the SEBSgMA system. Whereas acrylic acid grafted high‐density polyethylene (HDPEgAA) and maleated polypropylene (PPgMA) only slightly improved tensile modulus and tensile strength; and they both increased with increasing loadings of compatibilizers. A scanning electron microscopic study was employed to reveal the interfacial region and confirm these findings. In addition, dynamical mechanical thermal measurements also revealed the interaction between filler and matrix, and FTIR spectroscopy was used to assign the chemical fixation and the various chemical species involved at the surface of the wood fillers before and after surface treatment.     

Modification of the polarity and adhesive properties of polyolefins through blending with maleic anhydride grafted Fischer–Tropsch paraffin wax

The modification of the polarity and adhesive properties of linear low‐density polyethylene, low‐density polyethylene, and isotactic polypropylene through blending with paraffin wax (Fischer–Tropsch synthesis), grafted by maleic anhydride, was investigated. Maleic anhydride grafted paraffin wax significantly increased the polar component of the total surface free energy of polyolefins. Modified polyolefins also had significantly higher adhesion to the polar substrate, a crosslinked, epoxy‐based resin. The conservation of the good mechanical properties of the blends was observed up to 10 wt % wax, except for isotactic polypropylene blends, for which there was a reduction in the stress and strain at break at wax concentrations higher than 5%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3069–3074, 2006     

Rice husk/poly(propylene‐co‐ethylene) composites: Effect of different coupling agents on mechanical,thermal, and morphological properties

Poly(propylene‐co‐ethylene) composites with rice husk were prepared in a corotating intermeshing twin‐screw extruder using four different coupling agents. While modified maleic anhydrides such as maleated polypropylene (MAPP) and maleated polyethylene (MAPE) are commonly used as compatibilizers to improve interfacial adhesion between lignocellulosic filler and matrix, in this study, polypropylene grafted with acid comonomer (CAPP) and high‐density polyethylene grafted with acid comonomer (CAPE) were also used. The morphologies and the thermal and mechanical properties of the composites were characterized using scanning electron microscopy, thermogravimetric analysis, differential scanning analysis, tensile and impact tests. The results indicate that the base resin of the compatibilizer is an important factor in determining the effectiveness of compatibilizers for composites. Composites with PP‐based compatibilizers are more effective than PE‐based compatibilizers due to the improved wetting of the former compatibilizer in the matrix polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Composite of low‐density polyethylene and aluminum obtained from the recycling of postconsumer aseptic packaging

The recycling process of postconsumer aseptic packaging composed of paper, low‐density polyethylene (LDPE), and aluminum consists of recovering paper, the major component, through centrifugation. The remaining mixture of LDPE and aluminum, a recycled composite called PEAL, offers an interesting combination of properties, especially because of the presence of a small amount of poly(ethylene‐co‐methacrylic acid (EMAA). In this work, this composite is characterized, and the properties are compared with those of pure LDPE and EMAA, the polymers that constitute the recycled material. PEAL is around 15% aluminum particles with different shapes and sizes. The composite presents higher thermooxidative stability, higher crystallinity, lower impact resistance, and higher tensile strength than the other olefin polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3183–3191, 2006     

Mechanical and morphological properties of recycled high‐density polyethylene,filled with calcium carbonate and fly ash

In this study, mechanical and morphological properties of composites made up of recycled high‐density polyethylene (HDPE) filled with calcium carbonate and fly ash (FA) were studied. Interfacial interactions were modified to improve the filler compatibility and mechanical properties of the composites by surface treatment of the FA filler with 3‐amino propyl triethoxy silane. The composites were prepared by using a Thermo Haake Rheomixer. Effect of filler loading and treatment of FA with silane coupling agent on mechanical and morphological properties were investigated and it was found that silane treatment indicated significant improvements on the mechanical properties of the HDPE‐FA composites. The improvement with silane treatment of FA was also confirmed by applying the Pukanszky model. Scanning electron microscopy on the fracture surface of composites had given direct evidence of better interfacial adhesion via silane treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4460–4467, 2006     

Compatibility of HDPE/postconsumer HDPE blends using compatibilizing agents

Mechanical properties, molecular weight, X‐ray diffraction, and differential scanning calorimetry (DSC) characterization of blends of virgin high‐density polyethylene (HDPE) with two types of recycled material were investigated. The recycled came from urban plastic waste; one kind was only washed and grounded and the other was extruded and pelletized to remove most of contaminant particles. Starting with the 30/70 virgin/grounded recycled and 50/50 virgin/pelletized recycled blends the recycled content was increased in both blends and compatibilizing agents were used to increase the blend performance. A mixture of phenolic antioxidants and phosphite costabilizers under the name of Recycloblend?, ethylene vinyl acetate (EVA) copolymer, low‐density polyethylene (LDPE), and linear low density polyethylene (LLDPE) were used as compatibilizers. The effect of these additives and the recycled content on the performance of extrusion blow‐molded bottles was determined. The results suggest that blends of virgin/grounded recycled and virgin/pelletized recycled HDPE, in general, were not significantly different among each other and both had a quite similar behavior than the virgin HDPE when compatibilizing agents were used. The addition of compatibilizing agents yielded a material with properties similar to those for the virgin HDPE, helping to reduce the effect of polymers degradation on the rheological and mechanical behavior, with Recycloblend and LLDPE being the most effective for the blends with grounded recycled material, and LLDPE y EVA, for the blends with pelletized recycled. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3696–3706, 2006     

A compatibilized composite of recycled polypropylene filled with cellulosic fiber from recycled corrugated paper board: Mechanical properties,morphology, and thermal behavior

This article deals with the feasibility of using recycled corrugated paper board (rPF) as the reinforcing material for recycled plastics. The composites of recycled polypropylene (rPP) and rPF were prepared by extrusion compounding and injection molding, and the rPP/rPF composites compatibilized by maleic anhydride grafted PP (PP‐g‐MA), maleic anhydride grafted ethylene‐1‐octene copolymer (POE‐g‐MA), and maleic anhydride grafted styrene‐ethylene‐butylene‐styrene copolymer (SEBS‐g‐MA) were also prepared. The crystallization and melting behavior, mechanical properties, thermal stability, and morphology of these composites were studied. The results indicated that rPF promoted the crystallization, enhanced the strength and toughness of rPP/rPF composites to some extent while decreased thermal stability at the same time. PP‐g‐MA and POE‐g‐MA improved the dispersion and interface adhesion of rPF, and further upgraded the mechanical properties and vicat softening temperatures. Among these compatibilizers, PP‐g‐MA was most favorable to the strength improvement while POE‐g‐MA was most favorable to the toughness improvement. As for SEBS‐g‐MA, it had no obvious modification effect. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Compatibility effect of reactive copolymers on polypropylene/polyamide 6 blends from commingled plastic wastes

We report the compatibility effect on a recycled polypropylene/nylon (75/25) blend processed with reactive copolymers on the basis of morphological, mechanical, and rheological characteristics. Via a scanning electron microscopy investigation, we found improved surface morphologies with regular and fine domains in a recycled polypropylene/nylon (75/25) blend compatibilized with copolymers containing maleic anhydride as a reactive functional group [styrene–(ethylene/butylene)–styrene‐graft‐maleic anhydride copolymer and polypropylene‐graft‐maleic anhydride]. Large increases in both the mechanical and rheological properties with the addition of the styrene–(ethylene/butylene)–styrene‐graft‐maleic anhydride copolymer could be interpreted with respect to a specific structure at the interface, showing a strong interfacial adhesion between recycled polypropylene and nylon. To confirm the existence of this structure, we used various dynamic rheological parameters: the Cox–Merz rule, storage modulus, and phase angle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1188–1193, 2006     

Green composites based on high‐density polyethylene and Saccharum spontaneum: Effect of filler content on morphology,thermal, and mechanical properties

Here we report the preparation and characterization of a green composite based on high‐density polyethylene and Kaans grass (Saccharum spontaneum). The composites were prepared by conventional melt‐mixing method, using maximum loading of Kaans grass in powder form (KG‐filler) to achieve acceptable range of required properties. Maleic anhydride grafted polyethylene was used as compatibilizer to achieve effective interaction for improved surface adhesion which was confirmed by FT‐IR spectroscopy. Morphological studies revealed good interaction between the base polymer matrices and the KG‐fillers that improved the mechanical and thermal properties of the composites up to certain (10 phr) KG‐filler loading. Study on water absorption property revealed moderate increase in weight at higher KG‐filler loadings. Thermogravimetric analysis (TGA) and melt flow index (MFI) studies indicated retention of thermal stability and flow property of the HDPE/KG‐filler composite at lower filler loadings. POLYM. COMPOS., 36:2157–2166, 2015. © 2014 Society of Plastics Engineers     

Maleated Natural Rubber as a Coupling Agent for Recycled High Density Polyethylene/Natural Rubber/Kenaf Powder Biocomposites

Kenaf powder (KP) was incorporated into recycled high density polyethylene (rHDPE)/natural rubber (NR) blend using an internal mixer at 165°C and rotor speed of 50 rpm. The tensile strength and elongation at break of the composites decreased, while the tensile modulus increased with increasing filler loading. The water absorption was found to increase as the filler content increased. The maleic anhydride grafted natural rubber was prepared and used to enhance the composites performance. The addition of MANR as a coupling agent improved the tensile properties of rHDPE/NR/KP biocomposites. The water absorption was also reduced with the addition of MANR.     

Dynamic mechanical properties and morphology of high‐density polyethylene/CaCO3 blends with and without an impact modifier

Dynamic mechanical analysis and differential scanning calorimetry were used to investigate the relaxations and crystallization of high‐density polyethylene (HDPE) reinforced with calcium carbonate (CaCO₃) particles and an elastomer. Five series of blends were designed and manufactured, including one series of binary blends composed of HDPE and amino acid treated CaCO₃ and four series of ternary blends composed of HDPE, treated or untreated CaCO₃, and a polyolefin elastomer [poly(ethylene‐co‐octene) (POE)] grafted with maleic anhydride. The analysis of the tan δ diagrams indicated that the ternary blends exhibited phase separation. The modulus increased significantly with the CaCO₃ content, and the glass‐transition temperature of POE was the leading parameter that controlled the mechanical properties of the ternary blends. The dynamic mechanical properties and crystallization of the blends were controlled by the synergistic effect of CaCO₃ and maleic anhydride grafted POE, which was favored by the core–shell structure of the inclusions. The treatment of the CaCO₃ filler had little influence on the mechanical properties and morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3907–3914, 2007     

Toughening and compatibilization of polypropylene/polyamide‐6 blends with a maleated–grafted ethylene‐co‐vinyl acetate

In this article, maleated–grafted ethylene‐co‐vinyl acetate (EVA‐g‐MA) was used as the interfacial modifier for polypropylene/polyamide‐6 (PP/PA6) blends, and effects of its concentration on the mechanical properties and the morphology of blends were investigated. It was found that the addition of EVA‐g‐MA improved the compatibility between PP and PA6 and resulted in a finer dispersion of dispersed PA6 phase. In comparison with uncompatibilized PP/PA6 blend, a significant reduction in the size of dispersed PA6 domain was observed. Toluene‐etched micrographs confirmed the formation of interfacial copolymers. Mechanical measurement revealed that the addition of EVA‐g‐MA markedly improved the impact toughness of PP/PA6 blend. Fractograph micrographs revealed that matrix shear yielding began to occur when EVA‐g‐MA concentration was increased upto 18 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99:3300–3307, 2006     

Blends of poly(ethylene terephthalate) and low density polyethylene containing aluminium: A material obtained from packaging recycling

Composites of polyethylene and aluminium (PEAL) may be obtained from the recycling of postconsumed Tetra Pak aseptic packaging. The components of the composite are low density polyethylene (LDPE), aluminium and an ethylene‐methacrylic acid random copolymer (EMAA). The presence of metallic filler and a functionalized copolymer, which may act as a compatibilizer, suggests that blending PEAL with other thermoplastic would be a way to obtain reinforced and compatibilized blends from recycled materials. Blends of PEAL and recycled poly(ethylene terephthalate) (PET) were prepared in the compositions of 30, 50, and 70 wt % of PET in a twin‐screw extruder. Blends of PET/LDPE and PET/EMAA were also prepared for comparison. The morphological analysis showed that the PET/PEAL blends present an excellent interfacial adhesion, similar to the PET/EMAA blend. The improvement of adhesion in comparison with the PET/LDPE blend is a result of the interaction between polar groups of PET and EMAA. PET/PEAL blends presented lower elongation at break and impact strength than the other blends whereas Young modulus was higher. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

The Use of Ethylene/Propylene Copolymers as Compatibilizers for Recycled Polyolefin Blends

Compatibilizing effects of ethylene/propylene (EPR) diblock copolymers on the morphology and mechanical properties of immiscible blends produced from recycled low‐density polyethylene (PE‐LD) and high‐density polyethylene (PE‐HD) with 20 wt.‐% of recycled poly(propylene) (PP) were investigated. Two different EPR block copolymers which differ in ethylene monomer unit content were applied to act as interfacial agents. The morphology of the studied blends was observed by scanning‐ (SEM) and transmission electron microscopy (TEM). It was found that both EPR copolymers were efficient in reducing the size of the dispersed phase and improving adhesion between PE and PP phases. Addition of 10 wt.‐% of EPR caused the formation of the interfacial layer surrounding dispersed PP particles with the occurrence of PE‐LD lamellae interpenetration into the layer. Tensile properties (elongation at yield, yield stress, elongation at break, Young's modulus) and notched impact strength were measured as a function of blend composition and chemical structure of EPR. It was found that the EPR with a higher content of ethylene monomer units was a more efficient compatibilizer, especially for the modification of PE‐LD/PP 80/20 blend. Notched impact strength and ductility were greatly improved due to the morphological changes and increased interfacial adhesion as a result of the EPR localization between the phases. No significant improvements of mechanical properties for recycled PE‐HD/PP 80/20 blend were observed by the addition of selected block copolymers.