Kim Pickering - Academia.edu (original) (raw)

Papers by Kim Pickering

Chars and Carbonised Chars • Mostly (sp 2) carbon in aromatic (and/or graphene-like) structures. ... more Chars and Carbonised Chars • Mostly (sp 2) carbon in aromatic (and/or graphene-like) structures. Most of the major chemical changes and mass loss occur early (HTT < 400°C). • Product properties change drastically when the heat treatment temperature (HTT) used in the production process is increased.

Composites Part A: Applied Science and Manufacturing

Biology

Collagen is the most abundant structural protein in animals. It is the major component of skin. I... more Collagen is the most abundant structural protein in animals. It is the major component of skin. It finds uses in cosmetics, medicine, yarn production and packaging. This paper reviews the extraction of collagen from hides of most consumed animals for meat with the focus on literature published since 2000. The different pretreatment and extraction techniques that have been investigated for producing collagen from animal skins are reviewed. Pretreatment by enzymatic, acid or alkaline methods have been used. Extraction by chemical hydrolysis, salt solubilization, enzymatic hydrolysis, ultrasound assisted extraction and other methods are described. Post-extraction purification methods are also explained. This compilation will be useful for anyone wishing to use collagen as a resource and wanting to further improve the extraction and purification methods.

Composites Part C: Open Access

Journal of Materials Research and Technology, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Composites Science, 2021

The main objective of this study was to improve the orientation of fibres within the mats produce... more The main objective of this study was to improve the orientation of fibres within the mats produced using dynamic sheet forming (DSF). DSF is used to make fibre mats by forcing a fibre suspension through a nozzle onto a rotating drum. In this research, the effect of nozzle geometry on the orientation of hemp fibres within DSF mats was investigated. The orientation of fibres within the mats produced was assessed using ImageJ (OrientationJ) and X-ray diffraction. It was found that, as the contraction ratio of the nozzle increased, the orientation of fibres within the fibre mats increased. It was also found that the composite tensile strength increased with increased fibre orientation.

Composites Part C: Open Access, 2021

Cellulose is one of the most versatile biopolymers found in nature. Its use is now transitioning ... more Cellulose is one of the most versatile biopolymers found in nature. Its use is now transitioning from sustainabilityfocused development to provide technical solutions across a wide range of applications. This review paper describes the use of cellulose as reinforcement in biocomposites and recent related advances in 3D printing technologies, including 4D (responsive/smart) printing and current/future applications. Relevant aspects such as the origin and intrinsic/structural properties of cellulose and cellulose/matrix interaction during processing are discussed. A particular focus is directed to identify opportunities for the development of new cellulose-based composites, formulation requirements for 3D/4D printing, and comprehension of the interplay between rheology, chemistry, and processing. Overall, new materials and technologies based on cellulose have shown promising results for real-life applications, opening new scientific development opportunities and a new generation of sustainable and advanced materials.

Journal of Biobased Materials and Bioenergy, 2007

Increasing worldwide environmental awareness is encouraging scientific research into developing c... more Increasing worldwide environmental awareness is encouraging scientific research into developing cheaper, more sustainable materials. Industrial hemp fiber is one of the strongest and stiffest available natural fibers [K. L. Pickering, M. Priest, T. Watts, G. Beckermann, and S. N. Alam, J. Adv. Mater. 37, 15 (2005)] and therefore has great potential in composite materials. Incorporated into a thermoplastic matrix, it gives a structural material that is cheap, lightweight, and recyclable. However, natural fibers are commonly incompatible with common molding thermoplastics such as polypropylene, which limits the performance of the composites produced. The main objective of the current work was to investigate the use of fungi to treat hemp fiber to create better bonding characteristics in natural fiber reinforced polypropylene composites. X-ray diffraction (XRD), ζ-potential, lignin testing, thermal analysis, and scanning electron microscopy (SEM) were used to characterize the effect of...

Advanced Materials Research, 2007

This study investigates the effect weathering on composites made from fibre subjected to various ... more This study investigates the effect weathering on composites made from fibre subjected to various stages of a standard Kraft pulping process. Pre-washed, washed and bleached Kraft wood fibre of kappa numbers 27, 17, and 1 was assessed in terms of its surface potential using the streaming potential method and combined with polypropylene (PP) to produce composites. Composites were prepared using a twin screw extruder followed by pelletising and injection moulding. Tensile testing, hardness testing and impact testing were carried out to evaluate the composite mechanical properties. It was found that fibre with higher amounts of residual lignin content led to composites with lower tensile and impact strengths and increased degradability when subjected to accelerated weathering testing.

Polymers and Polymer Composites, 2019

Guar gum hydrogels may be dried to form polymer films which have the potential for use as biodegr... more Guar gum hydrogels may be dried to form polymer films which have the potential for use as biodegradable alternatives to polymers such as low-density polyethylene. In this study, the tensile strength and tensile modulus of guar gel films having moisture contents ranging between 15% and 18% (wet basis) were measured at a strain rate of 1 mm min−1. Mean tensile strengths of the films ranged between 25 MPa and 40 MPa (dependent on composition) which is of similar magnitude to the tensile strength data for polyethylene and cellophane that are reported in the literature. The mean tensile modulus of the films (1.5–2.5 GPa) was higher than the tensile modulus values reported for low-density polyethylene but comparable to those for cellophane (3 GPa).

Surface and Coatings Technology, 2018

The structural and chemical changes occurring during low energy ion implantation of Argon Nitroge... more The structural and chemical changes occurring during low energy ion implantation of Argon Nitrogen and Oxygen in cellulose materials are reported. The samples were treated to three different ions at various fluences and energies. The ion beam modification of the samples showed significant structural and chemical changes at the surface as investigated with scanning electron microscopy and Raman spectroscopy. Results found a threshold and beyond this threshold various microscopic changes were seen at surface including discolouration, pitting and fusing of fibres. These changes were consistent with ion beam damage of the polymer chain and later show molecular changes consistent with mild pyrolysis of the fibres. However, the calculated temperature rise from the implantation process is insufficient to explain such pyrolysis to occur. A mechanism is proposed for the observed structural and chemical changes.

Journal of Composites Science, 2018

The goal of this study was to investigate if it is possible to recycle chromated copper arsenate ... more The goal of this study was to investigate if it is possible to recycle chromated copper arsenate (CCA)-treated wood for use in wood polymer composites. This was done by soda pulping wood chips of CCA-treated lumber in a laboratory-scale digester. Composites of 10-30 weight percentage of filler in polypropylene were produced with and without the addition of maleic anhydride grafted polypropylene (MAPP) as a coupling agent. These composites were produced using extrusion compounding and injection moulding. The mechanical properties were determined using tensile testing; the properties examined in this study are the ultimate tensile strength, Young's modulus and strain at break. The effect of the CCA-treated filler on the dimensional stability was investigated by comparing the moisture absorption with virgin wood-filled composites. It was found that ultimate tensile strength improves with increasing filler percentage for the compositions with MAPP. The Young's modulus increases with increasing filler percentage for all compositions, and failure strain decreases with increasing filler percentage for all compositions. Moisture absorption studies show that the moisture absorption decreases when MAPP is added to the composite, and a slight decrease in moisture uptake is observed for the CCA-treated wood composites with respect to the virgin wood composites.

Journal of Polymers and the Environment, 2019

In this work, injection moulded hemp fibre reinforced polylactide bio-composites of different fib... more In this work, injection moulded hemp fibre reinforced polylactide bio-composites of different fibre contents (0, 10, 20 and 30 wt%) were subjected to accelerated weathering of 12 h cyclic exposures of UVlight at 60 o C, water spray and condensation at 50 o C for 8, 16, 32, 48 and 64 cycles to study the changes in properties such as crystallinity, tensile, flexural, plane-strain fracture toughness () and strain energy release rate (). The crystallinity of neat polylactide (PLA) was found to increase up to 50.6% after 64 cycles, whereas the crystallinity of composites of different fibre contents was found to increase in the range of 30.6 to 34.5% for 8 to 64 cycles. The overall mechanical properties (tensile, flexural, and) of the composites decreased as the number of cycles increased from 8 to 64. The crystallinity and the residual tensile strength, tensile modulus, tensile strain, and of the composites of 20 wt% fibres were found to be the highest after 64 cycles. In contrast, the residual flexural strength and flexural modulus of the composites of 30 wt% fibres were found to be the maximum after 64 cycles. Absorption of water, destruction of fibre integrity, degradation of PLA matrix, formation of cracks and pores were found to be the main causes of reduction in the mechanical properties of PLA bio-composites.

Materials (Basel, Switzerland), Jan 24, 2018

Biomedical materials constitute a vast scientific research field, which is devoted to producing m... more Biomedical materials constitute a vast scientific research field, which is devoted to producing medical devices which aid in enhancing human life. In this field, there is an enormous demand for long-lasting implants and bone substitutes that avoid rejection issues whilst providing favourable bioactivity, osteoconductivity and robust mechanical properties. Hydroxyapatite (HAp)-based biomaterials possess a close chemical resemblance to the mineral phase of bone, which give rise to their excellent biocompatibility, so allowing for them to serve the purpose of a bone-substituting and osteoconductive scaffold. The biodegradability of HAp is low (Ksp ≈ 6.62 × 10) as compared to other calcium phosphates materials, however they are known for their ability to develop bone-like apatite coatings on their surface for enhanced bone bonding. Despite its favourable bone regeneration properties, restrictions on the use of pure HAp ceramics in high load-bearing applications exist due to its inherent...

High temperature creep and mechanosorptive behaviour for any wood species is scarce and difficult... more High temperature creep and mechanosorptive behaviour for any wood species is scarce and difficult to obtain.This is mainly due to equipment design challenges and experimental constraints. This paper outlines the designand scope of a project to collect and model the creep and mechanosorption of tangential grain radiata pine athigh temperatures. The progress and challenges encountered, particularly the control of humidity, the ability tomeasure it at temperatures up to 150°C, the design of a purpose built relative humidity sensor and the issue ofhow to obtain a range of equilibrium moisture contents in order to simulate conditions encountered during wooddrying, are described.

The aim of the study reported in this paper was to improve the short beam shear strength of glass... more The aim of the study reported in this paper was to improve the short beam shear strength of glass fiber reinforced polyester rod, manufactured by Pultron Composites Limited, and used for stabilizing concrete retaining wall systems. The study illustrated how statistical experimental design can facilitate the investigation and optimization of a large number of variables in a production based process. The use of the screening experiment was instrumental in identifying the key variables which were expected to exhibit significant interactions to be investigated in the traditional one-at-a-time experimental method while minimizing the potential for missing the optimum variable setting.

Polymer Engineering & Science, 2015

Nanosized cuprous oxide filler particles (nCOP) with octahedral morphology were synthesized throu... more Nanosized cuprous oxide filler particles (nCOP) with octahedral morphology were synthesized through hydrazine reduction method and were used to develop a novel nanocomposites based on epoxy resin. The morphology of epoxy-nCOP nanocomposites were analyzed using transmission electron microscopy and scanning electron microscopy. Differential scanning calorimetry analysis showed that the cure reaction rate of epoxy was found to increase with the addition of the nCOP and a plausible cure reaction mechanism was suggested. The activation energy required for the cure reaction reduced by 22% and 13% at the initial (E 1) and final stage (E 2) of the cure, respectively, by the incorporation of 3 phr nCOP. It was also shown that the kinetically controlled parts of reaction could be expressed well by Kamal's phenomenological model while end of curing process could not be completely expressed by this model as there it was diffusion controlled. The influence of nCOP on glass transition temperature (T g), mechanical properties, and thermal stability of epoxy matrix was also investigated and the results showed that better characteristics were observed in presence of 3 phr nCOP loading.

Composites Part A: Applied Science and Manufacturing, 2015

Mechanical properties of aligned long harakeke fibre reinforced epoxy with different fibre conten... more Mechanical properties of aligned long harakeke fibre reinforced epoxy with different fibre contents were evaluated. Addition of fibre was found to enhance tensile properties of epoxy; tensile strength and Young's modulus increased with increasing content of harakeke fibre up to 223 MPa at a fibre content of 55wt% and 17 GPa at a fibre content of 63wt%, respectively. The flexural strength and flexural modulus increased to a maximum of 223 MPa and 14 GPa, respectively, as the fibre content increased up to 49wt% with no further increase with increased fibre content. The Rule of Mixtures based model for estimating tensile strength of aligned long fibre composites was also developed assuming composite failure occurred as a consequence of the fracture of the lowest failure strain fibres taking account porosity of composites. The model was shown to have good accuracy for predicting the strength of aligned long natural fibre composites.

Journal of Applied Polymer Science, 2014

In this study, magnetorheological elastomers (MREs) based on iron sand and natural rubber were pr... more In this study, magnetorheological elastomers (MREs) based on iron sand and natural rubber were prepared. The Taguchi method was employed to investigate the effect of a number of factors, namely, iron sand content, iron sand particle size and applied magnetic field during curing on tan δ and energy dissipated during cyclic loading. Tan δ was measured through dynamic mechanical analysis (DMA) over a range of frequency (0.01-130Hz), strain amplitude (0.1-4.5%), and temperature (-100-50 °C). Energy dissipated was measured using a universal tester under cyclic tensile loading. The data were then statistically analysed to predict the optimal combination of factors and finally experiments were conducted for verification. It was found that the iron sand content had the greatest influence on tan δ when measured over a range of frequency as well as energy dissipated during hysteresis tests. However, none of the factors showed significant influence on tan δ when measured over a range of strain amplitude. Furthermore, the iron sand content and magnetic field were also found to influence the width of the peak in tan δ as a function of temperature. The morphological characteristics of the MREs were also examined using scanning electron microscopy (SEM).