Marlene Cran | Victoria University (original) (raw)
Papers by Marlene Cran
... Doctor of Philosophy December 2004 School of Molecular Sciences Victoria University Page 3. .... more ... Doctor of Philosophy December 2004 School of Molecular Sciences Victoria University Page 3. ... David B. Barry. Wayne Laughton, Olga Ki-avaritis, Marlene J. Cran and Stephen W. Bigger, "Properties of Metallocene and Low-Density Polyethylene Blends", presented at 22nd ...
The physicomechanical properties of polymer blend formulations comprising different grades of met... more The physicomechanical properties of polymer blend formulations comprising different grades of metallocene-catalyzed linear low-density polyethylenes (mLLDPEs) with high-density polyethylenes (HDPEs) or a low-density polyethylene (LDPE) were investigated. For blends with HDPE, the addition of mLLDPE improves the Izod impact strength and some tensile properties. For blends with LDPE, adding mLLDPE increases the ductility and the percent elongation at break.
Industrial Crops and Products, 2014
ABSTRACT Composites of poly(lactic acid) (PLA) containing up to 40% (w/w) of kenaf fibre and up t... more ABSTRACT Composites of poly(lactic acid) (PLA) containing up to 40% (w/w) of kenaf fibre and up to 10% (w/w) of thymol were studied to evaluate the mechanical and thermal properties. These composites were compared with control systems containing either no fibre or no thymol and were prepared using melt blending and compression moulding techniques. The composites with 10% (w/w) thymol had the lowest tensile strength with slightly higher flexibility compared with those systems containing lower concentrations of this additive. The tensile properties of composites containing 5% (w/w) thymol demonstrated that the addition of fibre to the PLA/kenaf composites was affected more than the incorporation of the thymol alone. Thermogravimetric analysis of neat PLA and PLA/kenaf composites incorporated with 5% and 10% (w/w) thymol revealed no significant changes in the decomposition temperature. Analysis by differential scanning calorimetry, however, showed a decrease in all of the key thermal transitions with the addition of 5% and 10% (w/w) thymol into the neat PLA and PLA/kenaf composites. The results of the mechanical and thermal properties tests suggest that thymol acts as a plasticizing agent in this composite.
LWT - Food Science and Technology, 2013
ABSTRACT The migration of antimicrobial (AM) agents carvacrol, thymol and linalool from heat pres... more ABSTRACT The migration of antimicrobial (AM) agents carvacrol, thymol and linalool from heat pressed and coated starch-based packaging films into isooctane was investigated and the release of the agents consistently obeyed first-order kinetics. When the test temperature was increased from 15 to 35 degrees C, the diffusion coefficients increased from 6.3 x 10(-13) to 12.9 x 10(-13) m(-2) s(-1) for carvacrol, from 12.0 x 10(-13) to 29.7 x 10(-13) m(-2) s(-1) for thymol and from 9.5 x 10(-13) to 19.0 x 10(-13) m(-2) s(-1) for linalool from the heat pressed starch-based films. The diffusion coefficients of carvacrol, thymol and linalool from coated starch-based films containing increased from 2.2 x 10(-13) to 8.7 x 10(-13) m(-2) s(-1), from 2.7 x 10(-13) to 6.1 x 10(-13) m(-2) s(-1) and from 5.1 x 10(-13) to 9.4 X 10(-13) m(-2) s(-1) respectively between 15 and 35 degrees C. The activation energies for the migration of carvacrol, thymol and linalool from the heat pressed films were 26.2, 33.6 and 25.5 kJ mol(-1) respectively and those for the migration from the coated systems were 31.3, 3.0 and 22.5 kJ mol(-1) respectively. The results suggest that the AM agents show a potential for use as AM packaging materials.
Polymer Degradation and Stability, 2011
The depolymerisation of low molecular weight poly(ethylene oxide) (PEO) under mild conditions was... more The depolymerisation of low molecular weight poly(ethylene oxide) (PEO) under mild conditions was studied using a linear temperature ramped non-isothermal technique and the results compared with those obtained from a conventional isothermal technique. The analysis of the non-isothermal kinetic (NIK) data was performed using an original computer program incorporating an algorithm that systematically minimizes the sum of the squares of the residuals between the experimental data and the calculated theoretical kinetic profile in order to extract the kinetic parameters. The results revealed that the depolymerisation of PEO proceeds in accordance with the Ekenstam model and follows the Arrhenius equation over the temperature range of ca. 40e130 C. The NIK analysis resulted in a two-dimensional convergence to produce a unique solution set for the kinetic parameters of E a ¼ 89.4 kJ mol À1 and A ¼ 9.6 Â 10 6 h À1 . These data are consistent with the results obtained from the isothermal experiments. It is proposed that NIK analysis is a quick and reliable means of obtaining kinetic parameters relevant to lifetime predictions in polymers whose degradation behaviour can be considered to be close to ideal.
Packaging Technology and Science, 2011
The antimicrobial (AM) activity of starch‐based films coated with linalool, carvacrol or thymol a... more The antimicrobial (AM) activity of starch‐based films coated with linalool, carvacrol or thymol against Saccharomyces cerevisiae in vitro and/or inoculated on the surface of Cheddar cheese was investigated. In solid medium using the agar diffusion method and in experiments ...
Packaging Technology and Science, 2014
ABSTRACT Thermoplastic starch (TPS) films containing relatively low [0.75 ± 0.08% (w/w)], interme... more ABSTRACT Thermoplastic starch (TPS) films containing relatively low [0.75 ± 0.08% (w/w)], intermediate [1.08 ± 0.04% (w/w)] and high [3.20 ± 0.29% (w/w)] levels of the antimicrobial (AM) agents carvacrol, linalool and thymol were prepared, and their physico-mechanical and optical properties were evaluated. Addition of these AM agents to TPS film reduced the tensile strength with increasing AM agent content, with a significant effect observed at the highest AM agent concentration. The Young's modulus and elongation at break increased with increasing AM agent concentration, especially at the highest formulation concentration of AM agent. Films having a low or intermediate formulation concentration of AM agent exhibited no significant effect on their water vapour permeability, transparency and thermal properties when compared to the control film. Although scanning electron microscope imaging suggested a significant and progressive change in the surface morphologies of the films with AM agent concentration, the overall effects on the tested properties were not significant. This suggests that the direct incorporation of AM agents into TPS films did not adversely affect the films, particularly at lower AM agent concentrations. Copyright © 2013 John Wiley & Sons, Ltd.
Packaging Technology and Science, 2014
The antifungal activity against Aspergillus niger of the antimicrobial (AM) agents linalool, carv... more The antifungal activity against Aspergillus niger of the antimicrobial (AM) agents linalool, carvacrol and thymol incorporated in the coatings of starch-based films was investigated. The activity was initially determined on a solid medium using the modified microatmosphere method and then examined on Cheddar cheese. On the solid media, all the AM films demonstrated a significant inhibitory effect against A. niger growth. The inhibitory effect of the AM films containing 2.38% (w/w) AM agents is reflected by the colony diameters that were 29.3, 25.4 and 21.3 mm for linalool, carvacrol and thymol, respectively, at 25 C after 7 days incubation compared with the control sample where the colony diameter was 85.3 mm. The AM films containing 2.38% (w/w) linalool, carvacrol or thymol reduced the population of A. niger on the surface of Cheddar cheese by 1.8, 2.0 and 2.2 log CFU/g, respectively, after 35 days of storage at 15 C. The results suggest that starch-based film coated with an AM agent has the potential for being used as a fungicidal packaging system.
Journal of Thermal Analysis and Calorimetry, 2005
ABSTRACT Summary A two-step isothermal annealing (TSIA) procedure is described that enables the e... more ABSTRACT Summary A two-step isothermal annealing (TSIA) procedure is described that enables the endothermic peaks of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and their blends, to be satisfactorily resolved during analysis by differential scanning calorimetry. A modified form of multistep isothermal annealing, the TSIA procedure produces a highly characteristic profile of the blend components by facilitating the segregation of the phases based on branch density. It is proposed that the TSIA procedure may have significant merit in the identification and quantification of the components in an unknown blend as well as increasing the sensitivity in analytical procedures aimed at blend component quantification.
Journal of Plastic Film and Sheeting, 2006
... Author to whom correspondence should be addressed. Email: Stephen.Bigger@vu.edu.au JOURNAL OF... more ... Author to whom correspondence should be addressed. Email: Stephen.Bigger@vu.edu.au JOURNAL OF PLASTIC FILM & SHEETING, VOL. 22APRIL 2006 121 8756-0879/06/02 012112 $10.00/0 DOI: 10.1177/8756087906064605 ß 2006 SAGE Publications ...
Journal of Membrane Science, 2013
Journal of Materials Science, 2005
Films comprising a metallocene-catalyzed linear low-density polyethylene (mLLDPE) blended with ei... more Films comprising a metallocene-catalyzed linear low-density polyethylene (mLLDPE) blended with either of two different low-density polyethylene (LDPE) materials were prepared. The physicomechanical, optical and melt flow properties of the films were measured. A novel adaptation of conventional radar plots was used to process the acquired data to identify the level at which mLLDPE should be incorporated in either of the LDPEs to produce optimal overall properties. In general, the addition of mLLDPE to LDPE improved most of the properties considered and the LDPE material having the higher polydispersity produced blends having superior properties. A level of mLLDPE of between 20-30% (w/w) was required in order to achieve optimization.
Journal of Food Science, 2011
Significant interest has emerged in the introduction of food packaging materials manufactured fro... more Significant interest has emerged in the introduction of food packaging materials manufactured from biodegradable polymers that have the potential to reduce the environmental impacts associated with conventional packaging materials. Current technologies in active packaging enable effective antimicrobial (AM) packaging films to be prepared from biodegradable materials that have been modified and/or blended with different compatible materials and/or plasticisers. A wide range of AM films prepared from modified biodegradable materials have the potential to be used for packaging of various food products. This review examines biodegradable polymers derived from polysaccharides and protein-based materials for their potential use in packaging systems designed for the protection of food products from microbial contamination. A comprehensive table that systematically analyses and categorizes much of the current literature in this area is included in the review.
Journal of Food Science, 2010
The migration of the natural antimicrobial (AM) agents: linalool, carvacrol and thymol, from lowd... more The migration of the natural antimicrobial (AM) agents: linalool, carvacrol and thymol, from lowdensity polyethylene (LDPE) films containing ethylene vinyl acetate (EVA) into the food simulants: isooctane and various ethanol/water mixtures, was studied with a view towards examining the applicability of a first-order kinetic approach as well as a diffusion model approach for describing these systems. The results suggest the proposed models adequately describe the release of AM agents. The combination of kinetic and diffusion analyses can provide additional information about the release process using the same data set. The analyses suggest that the release of linalool from LDPE/EVA depends on the EVA content in the formulation and that an optimum level of EVA is required to minimize the rate of release. An extension to the existing "idealized diffusion" model is proposed that enables the model to be applied to systems that demonstrate a departure from linearity when subjected to conventional analysis. The applicability of the idealized diffusion model was compared with the "simulant-limited" model and the results suggest that the former model is appropriate for describing most real systems when the simulant (or foodstuff) is favored in the partitioning of the AM agent between the film and the simulant.
Journal of Food Science, 2011
Spices and herbal plant species have been recognized to possess a broad spectrum of active consti... more Spices and herbal plant species have been recognized to possess a broad spectrum of active constituents that exhibit antimicrobial (AM) activity. These active compounds are produced as secondary metabolites associated with the volatile essential oil (EO) fraction of these plants. A wide range of AM agents derived from EOs have the potential to be used in AM packaging systems which is one of the promising forms of active packaging systems aimed at protecting food products from microbial contamination. Many studies have evaluated the AM activity of synthetic AM and/or natural AM agents incorporated into packaging materials and have demonstrated effective AM activity by controlling the growth of microorganisms. This review examines the more common synthetic and natural AM agents incorporated into or coated onto synthetic packaging films for AM packaging applications. The focus is on the widely studied herb varieties including basil, oregano, and thyme and their EOs.
Journal of Food Science, 2011
This study investigated the antimicrobial (AM) activity of starch-based films coated with linaloo... more This study investigated the antimicrobial (AM) activity of starch-based films coated with linalool, carvacrol, or thymol against Staphylococcus aureus in vitro or inoculated on the surface of Cheddar cheese. In solid media using the agar diffusion method, the inhibitory effect of linalool, carvacrol, or thymol coated onto the films increased significantly (P≤ 0.05) with the increase in concentration of each AM agent. All the coated films effectively inhibited the growth of S. aureus on the surface of Cheddar cheese. The sensitivity of S. aureus to the AM agents tested in the concentration range of the study is in the order of thymol > carvacrol > linalool.
Journal of Elastomers and Plastics, 2005
... KEY WORDS: LDPE, LLDPE, metallocene-catalyzed PE, film, blends, physicomechanical properties,... more ... KEY WORDS: LDPE, LLDPE, metallocene-catalyzed PE, film, blends, physicomechanical properties, downgauging, radar plots. *Author to whom correspondence should be addressed. E-mail: Stephen.Bigger@vu.edu.au JOURNAL OF ELASTOMERS AND PLASTICS Vol. ...
Journal of Applied Polymer Science, 2013
ABSTRACT The mechanical performance of thermoplastic starch (TPS) films and films made of TPS ble... more ABSTRACT The mechanical performance of thermoplastic starch (TPS) films and films made of TPS blended with an aliphatic polyester (APTPS) was investigated after exposure to water mixtures of various compositions and different levels of relative humidity (RH). Conditioning of TPS films at various RH levels resulted in a noticeable absorption of moisture, particularly at high RH levels, and their mechanical properties decreased significantly. High magnification imaging of the films revealed the presence of significant microcracking on the surface of the TPS films which could potentially result in the increased water absorption and consequent reduction in mechanical integrity. The APTPS film was free of any visible microscopic defects and was also less susceptible to water ingress. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Desalination, 2011
Exposure to relatively low concentrations of chlorinated chemicals such as hypochlorite can reduc... more Exposure to relatively low concentrations of chlorinated chemicals such as hypochlorite can reduce the performance and ultimately result in the failure of polyamide (PA) reverse osmosis membranes. Whereas the tolerance of PA membranes to chloramine solutions is considerably higher than that of hypochlorite, the presence of some metal ions can potentially catalyze and accelerate degradation reactions. Spectroscopic techniques are commonly used to qualitatively assess the chemical degradation of membranes by observing changes in structural peaks. This paper presents a technique to quantitatively evaluate changes in PA membranes exposed to chloramine by means of a peak ratio derived from a typical amide peak and an invariant peak in the same spectrum. The effect of some common metal ions and combinations of these on the peak ratio parameter derived from a typical amide peak is also reported.
Desalination, 2012
In an effort to reduce its environmental impact, the desalination industry constantly seeks more ... more In an effort to reduce its environmental impact, the desalination industry constantly seeks more sustainable operational and maintenance practices. Based on the increasing number of large desalination plants using membrane technology, the resulting number of old reverse osmosis (RO) modules to be discarded is expected to become a critical challenge. Although the fate of old RO membranes has rarely been considered in the past, a wide range of opportunities can be considered for the potential reuse and recycling of the old modules. Reuse options include direct application of the old membranes within lower throughput systems (i.e. brackish water treatment) and chemical conversion into porous, ultrafiltration-like filters. Other options include, direct recycling of the various module components, and energy recovery through incineration. In addition to the remaining technical issues related to the feasibility of these proposed options, strategic and policy challenges will need to be addressed. However, the concept of product stewardship, already implemented in many parts of the world for electronic wastes and packaging, can provide guidelines for future policies for RO disposal. Finally, the framework for a life cycle assessment of the various disposal options is discussed which may provide guidance for the future implementation of these strategies.
... Doctor of Philosophy December 2004 School of Molecular Sciences Victoria University Page 3. .... more ... Doctor of Philosophy December 2004 School of Molecular Sciences Victoria University Page 3. ... David B. Barry. Wayne Laughton, Olga Ki-avaritis, Marlene J. Cran and Stephen W. Bigger, "Properties of Metallocene and Low-Density Polyethylene Blends", presented at 22nd ...
The physicomechanical properties of polymer blend formulations comprising different grades of met... more The physicomechanical properties of polymer blend formulations comprising different grades of metallocene-catalyzed linear low-density polyethylenes (mLLDPEs) with high-density polyethylenes (HDPEs) or a low-density polyethylene (LDPE) were investigated. For blends with HDPE, the addition of mLLDPE improves the Izod impact strength and some tensile properties. For blends with LDPE, adding mLLDPE increases the ductility and the percent elongation at break.
Industrial Crops and Products, 2014
ABSTRACT Composites of poly(lactic acid) (PLA) containing up to 40% (w/w) of kenaf fibre and up t... more ABSTRACT Composites of poly(lactic acid) (PLA) containing up to 40% (w/w) of kenaf fibre and up to 10% (w/w) of thymol were studied to evaluate the mechanical and thermal properties. These composites were compared with control systems containing either no fibre or no thymol and were prepared using melt blending and compression moulding techniques. The composites with 10% (w/w) thymol had the lowest tensile strength with slightly higher flexibility compared with those systems containing lower concentrations of this additive. The tensile properties of composites containing 5% (w/w) thymol demonstrated that the addition of fibre to the PLA/kenaf composites was affected more than the incorporation of the thymol alone. Thermogravimetric analysis of neat PLA and PLA/kenaf composites incorporated with 5% and 10% (w/w) thymol revealed no significant changes in the decomposition temperature. Analysis by differential scanning calorimetry, however, showed a decrease in all of the key thermal transitions with the addition of 5% and 10% (w/w) thymol into the neat PLA and PLA/kenaf composites. The results of the mechanical and thermal properties tests suggest that thymol acts as a plasticizing agent in this composite.
LWT - Food Science and Technology, 2013
ABSTRACT The migration of antimicrobial (AM) agents carvacrol, thymol and linalool from heat pres... more ABSTRACT The migration of antimicrobial (AM) agents carvacrol, thymol and linalool from heat pressed and coated starch-based packaging films into isooctane was investigated and the release of the agents consistently obeyed first-order kinetics. When the test temperature was increased from 15 to 35 degrees C, the diffusion coefficients increased from 6.3 x 10(-13) to 12.9 x 10(-13) m(-2) s(-1) for carvacrol, from 12.0 x 10(-13) to 29.7 x 10(-13) m(-2) s(-1) for thymol and from 9.5 x 10(-13) to 19.0 x 10(-13) m(-2) s(-1) for linalool from the heat pressed starch-based films. The diffusion coefficients of carvacrol, thymol and linalool from coated starch-based films containing increased from 2.2 x 10(-13) to 8.7 x 10(-13) m(-2) s(-1), from 2.7 x 10(-13) to 6.1 x 10(-13) m(-2) s(-1) and from 5.1 x 10(-13) to 9.4 X 10(-13) m(-2) s(-1) respectively between 15 and 35 degrees C. The activation energies for the migration of carvacrol, thymol and linalool from the heat pressed films were 26.2, 33.6 and 25.5 kJ mol(-1) respectively and those for the migration from the coated systems were 31.3, 3.0 and 22.5 kJ mol(-1) respectively. The results suggest that the AM agents show a potential for use as AM packaging materials.
Polymer Degradation and Stability, 2011
The depolymerisation of low molecular weight poly(ethylene oxide) (PEO) under mild conditions was... more The depolymerisation of low molecular weight poly(ethylene oxide) (PEO) under mild conditions was studied using a linear temperature ramped non-isothermal technique and the results compared with those obtained from a conventional isothermal technique. The analysis of the non-isothermal kinetic (NIK) data was performed using an original computer program incorporating an algorithm that systematically minimizes the sum of the squares of the residuals between the experimental data and the calculated theoretical kinetic profile in order to extract the kinetic parameters. The results revealed that the depolymerisation of PEO proceeds in accordance with the Ekenstam model and follows the Arrhenius equation over the temperature range of ca. 40e130 C. The NIK analysis resulted in a two-dimensional convergence to produce a unique solution set for the kinetic parameters of E a ¼ 89.4 kJ mol À1 and A ¼ 9.6 Â 10 6 h À1 . These data are consistent with the results obtained from the isothermal experiments. It is proposed that NIK analysis is a quick and reliable means of obtaining kinetic parameters relevant to lifetime predictions in polymers whose degradation behaviour can be considered to be close to ideal.
Packaging Technology and Science, 2011
The antimicrobial (AM) activity of starch‐based films coated with linalool, carvacrol or thymol a... more The antimicrobial (AM) activity of starch‐based films coated with linalool, carvacrol or thymol against Saccharomyces cerevisiae in vitro and/or inoculated on the surface of Cheddar cheese was investigated. In solid medium using the agar diffusion method and in experiments ...
Packaging Technology and Science, 2014
ABSTRACT Thermoplastic starch (TPS) films containing relatively low [0.75 ± 0.08% (w/w)], interme... more ABSTRACT Thermoplastic starch (TPS) films containing relatively low [0.75 ± 0.08% (w/w)], intermediate [1.08 ± 0.04% (w/w)] and high [3.20 ± 0.29% (w/w)] levels of the antimicrobial (AM) agents carvacrol, linalool and thymol were prepared, and their physico-mechanical and optical properties were evaluated. Addition of these AM agents to TPS film reduced the tensile strength with increasing AM agent content, with a significant effect observed at the highest AM agent concentration. The Young's modulus and elongation at break increased with increasing AM agent concentration, especially at the highest formulation concentration of AM agent. Films having a low or intermediate formulation concentration of AM agent exhibited no significant effect on their water vapour permeability, transparency and thermal properties when compared to the control film. Although scanning electron microscope imaging suggested a significant and progressive change in the surface morphologies of the films with AM agent concentration, the overall effects on the tested properties were not significant. This suggests that the direct incorporation of AM agents into TPS films did not adversely affect the films, particularly at lower AM agent concentrations. Copyright © 2013 John Wiley & Sons, Ltd.
Packaging Technology and Science, 2014
The antifungal activity against Aspergillus niger of the antimicrobial (AM) agents linalool, carv... more The antifungal activity against Aspergillus niger of the antimicrobial (AM) agents linalool, carvacrol and thymol incorporated in the coatings of starch-based films was investigated. The activity was initially determined on a solid medium using the modified microatmosphere method and then examined on Cheddar cheese. On the solid media, all the AM films demonstrated a significant inhibitory effect against A. niger growth. The inhibitory effect of the AM films containing 2.38% (w/w) AM agents is reflected by the colony diameters that were 29.3, 25.4 and 21.3 mm for linalool, carvacrol and thymol, respectively, at 25 C after 7 days incubation compared with the control sample where the colony diameter was 85.3 mm. The AM films containing 2.38% (w/w) linalool, carvacrol or thymol reduced the population of A. niger on the surface of Cheddar cheese by 1.8, 2.0 and 2.2 log CFU/g, respectively, after 35 days of storage at 15 C. The results suggest that starch-based film coated with an AM agent has the potential for being used as a fungicidal packaging system.
Journal of Thermal Analysis and Calorimetry, 2005
ABSTRACT Summary A two-step isothermal annealing (TSIA) procedure is described that enables the e... more ABSTRACT Summary A two-step isothermal annealing (TSIA) procedure is described that enables the endothermic peaks of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and their blends, to be satisfactorily resolved during analysis by differential scanning calorimetry. A modified form of multistep isothermal annealing, the TSIA procedure produces a highly characteristic profile of the blend components by facilitating the segregation of the phases based on branch density. It is proposed that the TSIA procedure may have significant merit in the identification and quantification of the components in an unknown blend as well as increasing the sensitivity in analytical procedures aimed at blend component quantification.
Journal of Plastic Film and Sheeting, 2006
... Author to whom correspondence should be addressed. Email: Stephen.Bigger@vu.edu.au JOURNAL OF... more ... Author to whom correspondence should be addressed. Email: Stephen.Bigger@vu.edu.au JOURNAL OF PLASTIC FILM & SHEETING, VOL. 22APRIL 2006 121 8756-0879/06/02 012112 $10.00/0 DOI: 10.1177/8756087906064605 ß 2006 SAGE Publications ...
Journal of Membrane Science, 2013
Journal of Materials Science, 2005
Films comprising a metallocene-catalyzed linear low-density polyethylene (mLLDPE) blended with ei... more Films comprising a metallocene-catalyzed linear low-density polyethylene (mLLDPE) blended with either of two different low-density polyethylene (LDPE) materials were prepared. The physicomechanical, optical and melt flow properties of the films were measured. A novel adaptation of conventional radar plots was used to process the acquired data to identify the level at which mLLDPE should be incorporated in either of the LDPEs to produce optimal overall properties. In general, the addition of mLLDPE to LDPE improved most of the properties considered and the LDPE material having the higher polydispersity produced blends having superior properties. A level of mLLDPE of between 20-30% (w/w) was required in order to achieve optimization.
Journal of Food Science, 2011
Significant interest has emerged in the introduction of food packaging materials manufactured fro... more Significant interest has emerged in the introduction of food packaging materials manufactured from biodegradable polymers that have the potential to reduce the environmental impacts associated with conventional packaging materials. Current technologies in active packaging enable effective antimicrobial (AM) packaging films to be prepared from biodegradable materials that have been modified and/or blended with different compatible materials and/or plasticisers. A wide range of AM films prepared from modified biodegradable materials have the potential to be used for packaging of various food products. This review examines biodegradable polymers derived from polysaccharides and protein-based materials for their potential use in packaging systems designed for the protection of food products from microbial contamination. A comprehensive table that systematically analyses and categorizes much of the current literature in this area is included in the review.
Journal of Food Science, 2010
The migration of the natural antimicrobial (AM) agents: linalool, carvacrol and thymol, from lowd... more The migration of the natural antimicrobial (AM) agents: linalool, carvacrol and thymol, from lowdensity polyethylene (LDPE) films containing ethylene vinyl acetate (EVA) into the food simulants: isooctane and various ethanol/water mixtures, was studied with a view towards examining the applicability of a first-order kinetic approach as well as a diffusion model approach for describing these systems. The results suggest the proposed models adequately describe the release of AM agents. The combination of kinetic and diffusion analyses can provide additional information about the release process using the same data set. The analyses suggest that the release of linalool from LDPE/EVA depends on the EVA content in the formulation and that an optimum level of EVA is required to minimize the rate of release. An extension to the existing "idealized diffusion" model is proposed that enables the model to be applied to systems that demonstrate a departure from linearity when subjected to conventional analysis. The applicability of the idealized diffusion model was compared with the "simulant-limited" model and the results suggest that the former model is appropriate for describing most real systems when the simulant (or foodstuff) is favored in the partitioning of the AM agent between the film and the simulant.
Journal of Food Science, 2011
Spices and herbal plant species have been recognized to possess a broad spectrum of active consti... more Spices and herbal plant species have been recognized to possess a broad spectrum of active constituents that exhibit antimicrobial (AM) activity. These active compounds are produced as secondary metabolites associated with the volatile essential oil (EO) fraction of these plants. A wide range of AM agents derived from EOs have the potential to be used in AM packaging systems which is one of the promising forms of active packaging systems aimed at protecting food products from microbial contamination. Many studies have evaluated the AM activity of synthetic AM and/or natural AM agents incorporated into packaging materials and have demonstrated effective AM activity by controlling the growth of microorganisms. This review examines the more common synthetic and natural AM agents incorporated into or coated onto synthetic packaging films for AM packaging applications. The focus is on the widely studied herb varieties including basil, oregano, and thyme and their EOs.
Journal of Food Science, 2011
This study investigated the antimicrobial (AM) activity of starch-based films coated with linaloo... more This study investigated the antimicrobial (AM) activity of starch-based films coated with linalool, carvacrol, or thymol against Staphylococcus aureus in vitro or inoculated on the surface of Cheddar cheese. In solid media using the agar diffusion method, the inhibitory effect of linalool, carvacrol, or thymol coated onto the films increased significantly (P≤ 0.05) with the increase in concentration of each AM agent. All the coated films effectively inhibited the growth of S. aureus on the surface of Cheddar cheese. The sensitivity of S. aureus to the AM agents tested in the concentration range of the study is in the order of thymol > carvacrol > linalool.
Journal of Elastomers and Plastics, 2005
... KEY WORDS: LDPE, LLDPE, metallocene-catalyzed PE, film, blends, physicomechanical properties,... more ... KEY WORDS: LDPE, LLDPE, metallocene-catalyzed PE, film, blends, physicomechanical properties, downgauging, radar plots. *Author to whom correspondence should be addressed. E-mail: Stephen.Bigger@vu.edu.au JOURNAL OF ELASTOMERS AND PLASTICS Vol. ...
Journal of Applied Polymer Science, 2013
ABSTRACT The mechanical performance of thermoplastic starch (TPS) films and films made of TPS ble... more ABSTRACT The mechanical performance of thermoplastic starch (TPS) films and films made of TPS blended with an aliphatic polyester (APTPS) was investigated after exposure to water mixtures of various compositions and different levels of relative humidity (RH). Conditioning of TPS films at various RH levels resulted in a noticeable absorption of moisture, particularly at high RH levels, and their mechanical properties decreased significantly. High magnification imaging of the films revealed the presence of significant microcracking on the surface of the TPS films which could potentially result in the increased water absorption and consequent reduction in mechanical integrity. The APTPS film was free of any visible microscopic defects and was also less susceptible to water ingress. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Desalination, 2011
Exposure to relatively low concentrations of chlorinated chemicals such as hypochlorite can reduc... more Exposure to relatively low concentrations of chlorinated chemicals such as hypochlorite can reduce the performance and ultimately result in the failure of polyamide (PA) reverse osmosis membranes. Whereas the tolerance of PA membranes to chloramine solutions is considerably higher than that of hypochlorite, the presence of some metal ions can potentially catalyze and accelerate degradation reactions. Spectroscopic techniques are commonly used to qualitatively assess the chemical degradation of membranes by observing changes in structural peaks. This paper presents a technique to quantitatively evaluate changes in PA membranes exposed to chloramine by means of a peak ratio derived from a typical amide peak and an invariant peak in the same spectrum. The effect of some common metal ions and combinations of these on the peak ratio parameter derived from a typical amide peak is also reported.
Desalination, 2012
In an effort to reduce its environmental impact, the desalination industry constantly seeks more ... more In an effort to reduce its environmental impact, the desalination industry constantly seeks more sustainable operational and maintenance practices. Based on the increasing number of large desalination plants using membrane technology, the resulting number of old reverse osmosis (RO) modules to be discarded is expected to become a critical challenge. Although the fate of old RO membranes has rarely been considered in the past, a wide range of opportunities can be considered for the potential reuse and recycling of the old modules. Reuse options include direct application of the old membranes within lower throughput systems (i.e. brackish water treatment) and chemical conversion into porous, ultrafiltration-like filters. Other options include, direct recycling of the various module components, and energy recovery through incineration. In addition to the remaining technical issues related to the feasibility of these proposed options, strategic and policy challenges will need to be addressed. However, the concept of product stewardship, already implemented in many parts of the world for electronic wastes and packaging, can provide guidelines for future policies for RO disposal. Finally, the framework for a life cycle assessment of the various disposal options is discussed which may provide guidance for the future implementation of these strategies.