Preparation and characterisation of polyethylene-octene grafted maleic anhydride-toughened 70:30 PA6/PP/MMT nanocomposites

A series of nanocomposites consisting of a polyamide 6 (PA6) and polypropylene (PP) matrix (70:30) with a maleated polyethylene-octene elastomer (POEgMAH) and organophilic modified montmorillonite (MMT) were prepared by melt compounding in a co-rotating twin-screw extruder followed by injection moulding. The weight fraction of organoclay was adjusted from 2 - 10 wt% by increments of 2 wt% and the weight fraction of POEgMAH was fixed at 10 wt%. POEgMAH was used as an impact modifier as well as compatibiliser in the nanocomposites. Mechanical properties of the blends were investigated by tensile, flexural and impact testing. X-ray diffraction (XRD) was used to characterise the nanocomposites. The thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Addition of 4 wt% organoclay showed the highest tensile and flexural strengths for the blends. The Young's and flexural moduli were also improved with increasing the organoclay concentration but with a corresponding reduction in impact strength and elongation at break. XRD result revealed that the organoclay was dispersed uniformly (exfoliated) although the degree of exfoliation decreased with increasing organoclay content. The DSC analysis showed that the crystallinity of the blends decreased with increasing organoclay concentration. It was shown from the TGA analysis that the thermal stability of the PA6/PP nanocomposites was significantly improved in the presence of impermeable silicate layers in the blends

Toughening polyamide 6 nanocomposites with maleic anhydride grafted polyethylene octene

Rubber toughened nanocomposites consisting of ternary blends of polyamide 6 (PA 6), maleic anhydride grafted polyethylene octene (POEgMAH) and organoclay montmorillonite (MMT) were prepared by melt compounding followed by injection moulding. The organoclay content was kept constant at 4 wt% while the POEgMAH content was varied between 5 to 20 wt%. The mechanical properties were studied through tensile, flexural and impact properties. The scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to examine the morphology of the nanocomposties. The results showed that, the incorporation of 4 wt% organoclay significantly increased the stiffness and strength but at the expense of the toughness. Izod impact measurement indicated that the addition of POEgMAH led to a significant improvement in the impact strength of the nanocomposites. X-ray diffraction analysis (XRD) revealed that an intercalation organoclay silicate layer structure was formed in rubber-toughened PA6 nanocomposites. SEM study revealed a two-phase morphology where POE, as droplets was dispersed finely and uniformly in the PA6 matrix

Morphology and chemical resistance of poly(ethylene terephthalate)/ polycarbonate blends: effect of blend compositions

Blends of poly(ethylene terephthalate) (PET) and polycarbonate (PC) were prepared in different ratios by melt blending technique. The process was carried out through a twin extruder followed by injection molding. The morphological and chemical resistance of the PET/PC blends were studied. The scanning electron microscopy showed that the interfacial adhesion for 70PET/30PC blends has improved as indicated by the partial miscibility between the PET and PC. The chemical resistance of PET/PC blends to acetone increased with increasing PET content

Thermal and flexural properties of regenerated cellulose(RC)/poly(3- hydroxybutyrate)(PHB)biocomposites

Regenerated cellulose (RC)/ poly(3-hydroxybutyrate) (PHB) composite was prepared via melt compounding with different RC contents from 1 to 7 wt.%. Regenerated cellulose fiber was prepared in NaOH/urea aqueous solution. The properties of the cellulose and the regenerated cellulose were compared using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). The results of TGA and DSC revealed that the regenerated cellulose had lower thermal properties than cellulose. Meanwhile, the FTIR of regenerated cellulose showed that the intensity portrayed by a few peaks had reduced or disappeared as compared to cellulose. Besides, PHB composites were characterized using TGA and flexural testing. Moreover, thermal stability of the composites insignificantly changed with the incorporation of RC. Improvement in flexural strength and modulus were observed, whereas 3 wt.% was found to be the optimum RC content

Mechanical, thermal and flammability properties of dolomite filled polypropylene composites

In this project, the composites of polypropylene (PP)/dolomite were prepared via extrusion and injection moulding. Dolomite mineral was used as reinforcement in PP matrix. PP reinforced dolomite composites with various concentrations of dolomite (5, 10 and 15 wt%) were characterized by mechanical properties through tensile, impact and flexural test, morphological analysis by scanning electron microscope (SEM), thermal analysis by differential scanning calorimeter (DSC) and flammability analysis by the limiting oxygen index (LOI). The incorporation of dolomite into PP had improved Young's modulus while flexural modulus, tensile, flexural and impact strengths were decreased. The incorporation of dolomite up to 15 wt% increased the stiffness of the composites in tensile mode while in three point bending mode, 10 wt% dolomite was the optimum concentration. Tensile and flexural strength showed a slight reduction in the values while impact strength was continuously decreased with the addition of dolomite. SEM images showed poor interfacial adhesion between PP and dolomite, thus supported the decreased of tensile, flexural and impact strengths. The melting and crystallization temperatures (Tm and Tc) of the composites slightly increased with the addition of dolomite. LOI test showed that flammability of the composites decreased with the increasing content of dolomite

Kenaf fibers reinforced unsaturated polyester composites:A review

Recently development of high-performance polymer composites made from natural resources in the various sectors is increasing tremendously due to the environmental issues and health hazard possessed by the synthetic fibers during disposal and manufacturing. Among the many different types of natural resources, kenaf fibers have been extensively investigated as an alternative reinforcement for polymer composites over the past few years due to their low cost, good mechanical properties, high specific strength, nonabrasive, eco-friendly, and biodegradability characteristics. Kenaf is regarded as an industrial crop in Malaysia and grown commercially in other parts of the world for different applications. It is certainly one of the important plants cultivated for natural fibers globally which has great potential to use as automotive and construction materials. In many research studies, kenaf fibers have been used as reinforcement in unsaturated polyester (UPE) which perfectly improved the features of the polyester resin. The tensile properties of kenaf fiber reinforced UPE are mainly influenced by the interfacial adhesion between the fibers and the polyester resin. Several chemical modifications are employed to improve the interfacial bonding between kenaf fibers and polyester, resulting in the enhancement of mechanical properties of the composites. Therefore, this paper explores and highlights of the previous studies around kenaf fiber reinforced UPE composites, in terms of processing methods, mechanical, water absorption, and morphological properties to provide a perfect source of literature for doing further research in this topic

Mechanical, thermal, tribological, and flammability properties of polybutylene terephthalate composites: Comparing the effects of synthetic wollastonite nanofibers, natural wollastonite, and graphene oxide

Abstract Polybutylene terephthalate (PBT) composites were prepared with 1.0 phr synthetic :wollastonite nanofibers (SWN), natural wollastonite (NW) and graphene :oxide (GO) to study the effect of different fillers on mechanical, thermal, tribological,and flammability properties. The properties of PBT composites arerelated to the size, structure, and interfacial adhesion of the fillers in PBT matrix. PBT/SWN demonstrated the highest tensile strength and Young's modulus (6% and 9% increment), followed by PBT/NW (1.3% and 7% increment) and PBT/GO (2% decrement and 4% increment). PBT/SWN gave the highest degradation temperature (409�C), followed by PBT/GO (404.7�C). The maximum enhancement in wear resistance (73%) by PBT/SWN and anti-friction performance (26%) by PBT/GO evinced the excellent load-bearing ability of SWN and the great lubricating effect of GO. PBT/NW had the lowest peak heat release rate, smoke, and carbon dioxide production rate. This study shows that :PBT composites have great potential in different automotive applications. :KEYWORDS :flame retardance, friction and wear, mechanical properties, polymer-matrix composites,thermal properties Received: 24 August 2022 Revised: 28 October 2022 Accepted: 15 November 2022 DOI: 10.1002/app.53463 J Appl Polym Sci. 2022;e53463. wileyonlinelibrary.com/journal/app © 2022 Wiley Periodicals LLC. 1 of 1

Rheology and processing of poly(lactides) and their enantiomeric copolymers and blends

Poly(lactide) PLA, a biodegradable thermoplastic produced from corn and other renewable agricultural resources, has received a large share of the interest in biodegradable materials due to environmental concerns and desire to reduce dependence on finite petroleum reserves. In this study, nearly monodisperse controlled microstructure PLA samples synthesized using a novel chiral dinuclear indium catalyst; and studied thermorheologically. Specifically, the effects of molecular structural parameters (i.e. weight-average molecular weight (Mw) and different ratios of lactides) on solution and melt rheological properties under shear and extension were studied. The solution properties and linear viscoelasticity (LVE) of melts indicated linear structure behavior. The zero-shear viscosity and relaxation time of PLAs showed a power law scaling of 3.4 with Mw. The K-BKZ constitutive equation was used and proved that strain hardening occurs at low temperatures, which is due to the dynamics of molecular relaxation, when the longest relaxation time exceeded the characteristic time for deformation. In an attempt to reduce PLA brittleness, copolymers of L-lactide with its enantiomer D-lactide or racemic mixture DL-lactide were synthesized. The effects of Mw and block length ratio on the thermal, rheological and mechanical behavior of the diblock copolymers were investigated. For comparison, blends of PDLLA and PLLA homopolymers of equivalent Mw to the diblock copolymers were prepared. Despite different thermal behavior, the linear viscoelasticity of block copolymers and blends in disordered state are relatively similar. Improvement in elongation at break and tensile strength were observed as compared to their counterpart homopolymer blends. Furthermore, the wall slip and melt fracture behaviors of four commercial PLAs with Mw in the range of 10⁴ to 10⁵ g/mol were investigated. PLAs with Mw greater than a certain value slipped. The slip velocity increased with decrease of Mw. The onset of melt fracture for the high Mw PLAs occurred at about 0.2 to 0.3 MPa, depending on the geometrical characteristics of the dies and independent of temperature. Addition of 0.5 wt% of a poly(ε-caprolactone) (PCL) into the PLA that exhibits melt fracture was effective in eliminating and delaying its onset to higher shear rates.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat

Preliminary studies on maleated polyethylene-octene elastomer modified polyamide 6 / polypropylene (70:30) nanocomposites

Rubber toughened nanocomposites consisting of polyamide 6 (PA6) and polypropylene (PP) matrix (70:30) with a maleated polyethylene-octene elastomer (POEgMAH) and organophilic modified montmorillonite (MMT) were prepared by melt compounding in a co-rotating twin-screw extruder followed by injection moulding. The POEgMAH content was varied in the range of 0 wt% - 20 wt% and the weight fraction of organoclay was fixed at 4 wt %. Mechanical properties of the blends were investigated by tensile, flexural and Izod impact testing. X-ray diffraction (XRD) was used to characterise the nanocomposites. Izod impact measurements indicated that the addition of POEgMAH led to a significant improvement in the impact strength of the PA6/PP nanocomposites. The impact strength increased up to more than twice enhancement after addition of 15wt% POEgMAH into PA6/PP nanocomposites. However, the tensile and flexural properties were found to decrease with increasing concentration of POEgMAH. XRD revealed that an intercalation organoclay silicate layer structure was formed in rubber toughened PA6/PP nanocomposites