Effects of injection moulding induced morphology on the fracture behaviour of virgin and recycled polypropylene

Aurrekoetxea, J.; Sarrionandia, M.; Urrutibeascoa, I.; Maspoch, M. Ll.

doi:10.1016/s0032-3861(03)00493-2

Cited by 31 publications

(24 citation statements)

References 9 publications

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“…In addition, samples with no incorporated chitin whiskers were tested as a reference. To simulate the behavior of a reprocessed material under controlled conditions, ABS was subjected to six extrusion cycles in a single‐screw extruder at 30 rpm and a temperature of 150°C …”

Section: Methodsmentioning

confidence: 99%

Surface‐pegylated chitin whiskers as an effective additive to enhance the mechanical properties of recycled ABS

Mol

Martins

Oréfice

2015

J of Applied Polymer Sci

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The recyclability of materials is a key issue related to the use of polymers in the automotive and electronic industries, among others. The multiple thermal and mechanical operations used in recycling can cause severe damage to the molecular architecture and microstructure of polymers that frequently leads to a reduction in their mechanical properties, which restricts their recyclability. In this work, nanocomponents (whiskers) derived from chitin were surface‐modified by grafting different molar masses of methoxylated poly(ethylene glycol) (mPEG). The modified chitin whiskers were then incorporated into reprocessed ABS (acrylonitrile–butadiene–styrene) to yield nanocomposites with 0.5% (mass/mass) whiskers. The obtained whiskers and nanocomposites were investigated using techniques such as transmission electron microscopy, atomic force microscopy, scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. The properties of the nanocomposites were also investigated using tensile tests and dynamic mechanical tests. The results show that the surface‐modified chitin whiskers with high molar mass mPEG grafts increased the strength, elongation at break, and stiffness of the reprocessed ABS over virgin and reprocessed ABS and reprocessed ABS nanocomposites with unmodified whiskers. This indicates that the use of surface‐modified chitin whiskers can be valuable in improving the mechanical properties of recycled polymers and, consequently, enhancing their recyclability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42463.

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Section: Methodsmentioning

confidence: 99%

Surface‐pegylated chitin whiskers as an effective additive to enhance the mechanical properties of recycled ABS

Mol

Martins

Oréfice

2015

J of Applied Polymer Sci

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“…Variations in the mechanical properties are related to the degradation processes undergone by polymers during life cycle; however, the utilisation of mechanical properties as the only parameter to evaluate the degree of degradation for recycled polymers may be misleading, since the degradation at a molecular level may occur before any signs of change at a macroscopic scale are detected,26 and some observed changes in the mechanical properties may be due to physical factors and are hence reversible 12. Tensile, impact, and flexural properties are often evaluated for recycled plastics; deeper studies of the fracture behaviour and micromechanical properties offer interesting information about the mechanical performance and failure mechanisms in recycled materials 27. As mentioned earlier, previous degradation causes a deterioration of the molecular structure, resulting in recycled plastics with poorer mechanical properties than the virgin ones.…”

Section: Quality Analysis Of Recycled Plastics For Improved Use In Nementioning

confidence: 99%

Quality Concepts for the Improved Use of Recycled Polymeric Materials: A Review

Vilaplana

Karlsson

2008

Macro Materials & Eng

292

158

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Polymeric waste materials should be considered resources for the manufacture of new products through recycling processes, with a similar status to virgin fossil‐based plastics and biopolymers from renewable resources. Several efforts can be made to achieve this qualitative quantum leap in plastics recycling, and consequently introduce recycled products, with competitive performance, to the market. Scientific knowledge about the degradation processes during the life cycle and the development of fast and reliable analytical methods for the quality assessment of recycled plastics are fundamental to guarantee their performance in new applications. Different strategies—restabilisation, rebuilding, compatibilisation, and addition of elastomers and fillers—can be used to upgrade the structure and properties of polymeric waste streams. This review discusses recent developments in the mechanical recycling of plastics, focusing on how to produce quality materials from waste streams and, thus, contribute to a sustainable management of resources and energy.magnified image

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“…The maximum orientation value is usually obtained in the transition zone, being almost zero in the center of the molded sample, as a result of the shear rates, which are maximum near the wall and zero in the center. This molecular orientation gradient is responsible for the improved properties in the orientation direction; on the other hand, the properties along the perpendicular direction usually are worse [22][23][24][25] . The parameters that affect the molecular orientation are: shear and elongation tensions imposed to the molten polymer during their solidification, processing conditions (injection and mold temperatures, packing pressure and flow rate, among others) and intrinsic characteristics of the polymer (relaxation time, crystallization kinetics and chains rigidity, for example [22][23][24][25][26][27][28][29][30][31][32][33] ).…”

Section: Introductionmentioning

confidence: 99%

A X-ray study of β-phase and molecular orientation in nucleated and non-nucleated injection molded polypropylene resins

2009

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The development of α and β-phases and the molecular orientation of injection molded disks of two isotactic polypropylene (i-PP) resins were studied by wide angle X-ray diffraction (WAXD) and pole figures. A nucleated (NPP) and non-nucleated (HPP) polymers were analyzed. The main proposal of this article was the comprehensive study of the interrelations between the processing conditions, phase contents and PP α-phase molecular orientation of injection molded PP resins. In both resins, it was observed that the α-phase was present in all regions along the thickness while the β-phase was present mainly in the external layers, decreasing from the surface to the core; however this last phase was present in a very small amount in the NPP resin. For both polymers, the orientation of the macromolecules c-axis was higher along the flow direction (RD) than along the transverse direction (TD). The b-axis of the PP α-phase molecules was oriented to the thickness direction (ND). The orientation of the c-axis along RD and b-axis along ND of the NPP samples was considerably higher than of the HPP samples, due to the NPP faster crystallization kinetics. For both polymers, the most influential processing parameters on the molecular orientation were the mold temperature and flow rate. The results indicate that, as the mold temperature increased, the characteristic molecular orientation of PP α-phase, with c-axis along RD and b-axis along ND, decreased. With increase in the flow rate an increase of the c-axis molecular orientation of the samples along RD was observed.

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Effects of injection moulding induced morphology on the fracture behaviour of virgin and recycled polypropylene

Cited by 31 publications

References 9 publications

Surface‐pegylated chitin whiskers as an effective additive to enhance the mechanical properties of recycled ABS

Surface‐pegylated chitin whiskers as an effective additive to enhance the mechanical properties of recycled ABS

Quality Concepts for the Improved Use of Recycled Polymeric Materials: A Review

A X-ray study of β-phase and molecular orientation in nucleated and non-nucleated injection molded polypropylene resins

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