An investigation of the long term chemical stability and physical performance of PMD-citronellal acetal compared with dibutyl phthalate and BIS(2-ethylhexyl) terephthalate as plasticisers in selected cosmetic formulations
- Authors: Marx, Amor
- Date: 2019
- Subjects: Plastics -- Additives , Chemistry, Technical , Cosmetics
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/42574 , vital:36669
- Description: Plasticisers are used by cosmetic manufacturers to improve the film forming abilities of a product and increase flexibility of the film formed on the skin or hair surface, as is desired, for example, in nail lacquers and lip coats. In recent years authorities have banned several plasticisers in cosmetic products (mainly phthalates) since these substances may pose a wide range of health risks and can be harmful to the environment. It is, therefore, necessary to find alternative, safe plasticisers, preferably of natural origin e.g. bio-plasticisers which can replace the toxic phthalates and still impart the same desirable properties to the cosmetic products in which they are used. In this study, the novel bio-plasticiser para-menthane-3,8-diol-citronellal acetal (PMD-citronellal acetal) was selected to compare its stability properties and plasticising behaviour with well-known non-phthalate bis(2-ethylhexyl) terephthalate (DEHT) and the problematic dibutyl phthalate (DBP). The objectives were to determine if the novel bio-plasticiser PMD-citronellal acetal plasticising properties and chemical stability are similar or better than DEHT and DBP within two cosmetic formulations, viz. a nail lacquer and a lip coat formulation, after being incubated at elevated temperature (40 ˚C) over a three month period. The results showed that flexibility for all plasticised formulations remained stable at room temperature (21 ˚C) and elevated temperature (40 ˚C). Adhesion performance of DEHT and PMD-citronellal acetal nail lacquer formulations outperformed DBP nail lacquer formulations. Elevated temperature and storage time had no influence on the organoleptic properties of any plasticised formulation. PMD-citronellal acetal plasticised lip coat and nail lacquer formulations outperformed both DEHT and DBP nail formulations with regard to hardness. Fourier Transform Infrared Spectrometry (FTIR) studies revealed that neat DPB, DEHT and Acetal were chemically stable at room temperature and elevated temperature over a three month incubation period. Furthermore, the three plasticised nail lacquer and lip coat formulations remained chemical stable over the three month incubation period at elevated temperature. Chemical stability of the nail lacquer formulations was further evaluated by means of leaching tests using Solid Phase Extraction [1] and Ultra-Performance Liquid Chromatography (UPLC) at two temperatures (31 and 50 °C) and three time intervals (24, 48 and 72 hours). No leaching out of the nail lacquer formulation for Acetal and DEHT could be detected. It was observed that trace amounts of DBP leached from the nail lacquer formulation at 50 °C. DBP leaching decreased over time and was found to be statistically significant over the studied period. It can be concluded that PMD-citronellal acetal can be selected as bio-plasticiser which exhibits similar properties to DEHT based on the performance stability and non-leaching criteria, and can be used as an alternative plasticiser to the toxic DBP in cosmetic formulations.
- Full Text:
- Date Issued: 2019
- Authors: Marx, Amor
- Date: 2019
- Subjects: Plastics -- Additives , Chemistry, Technical , Cosmetics
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/42574 , vital:36669
- Description: Plasticisers are used by cosmetic manufacturers to improve the film forming abilities of a product and increase flexibility of the film formed on the skin or hair surface, as is desired, for example, in nail lacquers and lip coats. In recent years authorities have banned several plasticisers in cosmetic products (mainly phthalates) since these substances may pose a wide range of health risks and can be harmful to the environment. It is, therefore, necessary to find alternative, safe plasticisers, preferably of natural origin e.g. bio-plasticisers which can replace the toxic phthalates and still impart the same desirable properties to the cosmetic products in which they are used. In this study, the novel bio-plasticiser para-menthane-3,8-diol-citronellal acetal (PMD-citronellal acetal) was selected to compare its stability properties and plasticising behaviour with well-known non-phthalate bis(2-ethylhexyl) terephthalate (DEHT) and the problematic dibutyl phthalate (DBP). The objectives were to determine if the novel bio-plasticiser PMD-citronellal acetal plasticising properties and chemical stability are similar or better than DEHT and DBP within two cosmetic formulations, viz. a nail lacquer and a lip coat formulation, after being incubated at elevated temperature (40 ˚C) over a three month period. The results showed that flexibility for all plasticised formulations remained stable at room temperature (21 ˚C) and elevated temperature (40 ˚C). Adhesion performance of DEHT and PMD-citronellal acetal nail lacquer formulations outperformed DBP nail lacquer formulations. Elevated temperature and storage time had no influence on the organoleptic properties of any plasticised formulation. PMD-citronellal acetal plasticised lip coat and nail lacquer formulations outperformed both DEHT and DBP nail formulations with regard to hardness. Fourier Transform Infrared Spectrometry (FTIR) studies revealed that neat DPB, DEHT and Acetal were chemically stable at room temperature and elevated temperature over a three month incubation period. Furthermore, the three plasticised nail lacquer and lip coat formulations remained chemical stable over the three month incubation period at elevated temperature. Chemical stability of the nail lacquer formulations was further evaluated by means of leaching tests using Solid Phase Extraction [1] and Ultra-Performance Liquid Chromatography (UPLC) at two temperatures (31 and 50 °C) and three time intervals (24, 48 and 72 hours). No leaching out of the nail lacquer formulation for Acetal and DEHT could be detected. It was observed that trace amounts of DBP leached from the nail lacquer formulation at 50 °C. DBP leaching decreased over time and was found to be statistically significant over the studied period. It can be concluded that PMD-citronellal acetal can be selected as bio-plasticiser which exhibits similar properties to DEHT based on the performance stability and non-leaching criteria, and can be used as an alternative plasticiser to the toxic DBP in cosmetic formulations.
- Full Text:
- Date Issued: 2019
Disputes, relationships and identity: analysing human-human conflicts as a basis for human-wildlife conflicts in the mid-Zambezi valley, northern Zimbabwe
- Authors: Jani, Vincent
- Date: 2018
- Subjects: Environmental geography , Wildlife management Wildlife conservation Human-animal relationships
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/30364 , vital:30934
- Description: This study analysed how human-human conflicts (HHCs) underlie human-wildlife conflicts (HWCs) in Chapoto Ward in the mid-Zambezi valley, northern Zimbabwe. The analytical framework entailed the use of the Levels of Conflict Model (LCM) – a model that seeks to expose different levels of conflict. To gain a rich understanding of the conflicts under investigation, a qualitative research design was employed with triangulation at its core in order to ensure the necessary quality and rigour of the findings. In this case, four different types of data were used, namely, in-depth interviews with heads of households, key informant interviews, focus group sessions, and document analysis. Thematic and content analysis were used to analyse the data which were classified into the following conflict levels: surface level disputes; an intermediate level involving ongoing conflictual relationships; and a deeper level of conflict rooted in identity. Three key findings were generated. Firstly, a substantial number of long-standing disputes were recorded during the ten-year period (2007-2016). Most of these disputes were not resolved because they had a long and complicated history which resulted in previous disputes resurfacing whenever a current one arose. Secondly, the history of unresolved conflict resulted in mistrust and failure to find common ground between the parties involved in the conflict. Lastly, the source of the disputes and unresolved conflicts was traced back to the identity level. This means that the antagonistic relationships among the stakeholders spilled over into the labelling and stigmatisation of all the groups involved in wildlife management. Thus, conflict between people and wildlife in Chapoto Ward was demonstrated to be a complex issue and underlain by HHC. These findings support the new line of thinking that HWC should not be viewed as simply a problem between people and wildlife but as a conflict between stakeholders with divergent views over wildlife management which manifests as HHC. Furthermore, the degree of polarisation between groups is substantial. In light of these findings, four major conclusions are drawn. Firstly, is the need to shift from narrowly focusing on the proximate conflicts between people and wildlife, to fully understand the complexity of conflict in order to arrive at solutions that successfully mitigate conflict between people and wildlife, and to address the underlying and deep-rooted conflict between stakeholders with divergent wildlife management goals. Secondly, the need for concerted efforts to ensure the involvement of all stakeholders, including women, in wildlife management and conservation by developing structures that enhance active participation of the local people in decision-making, v which promotes the success of conservation initiatives. Thirdly, the need to address the underlying and deep-rooted conflicts over wildlife management by building positive relationships and trust between stakeholders through the holding of regular capacity building workshops based on a more respectful and inclusive process. Fourthly, is the need to consider the interests of both ethnic groups, namely the Doma and the Chikunda by gathering information on the preferences of the identity groups in order to increase cooperation among them. Overall, the thesis introduces a new lens through which one can clearly understand the complexity of the conflict between people and wildlife.
- Full Text:
- Date Issued: 2018
- Authors: Jani, Vincent
- Date: 2018
- Subjects: Environmental geography , Wildlife management Wildlife conservation Human-animal relationships
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/30364 , vital:30934
- Description: This study analysed how human-human conflicts (HHCs) underlie human-wildlife conflicts (HWCs) in Chapoto Ward in the mid-Zambezi valley, northern Zimbabwe. The analytical framework entailed the use of the Levels of Conflict Model (LCM) – a model that seeks to expose different levels of conflict. To gain a rich understanding of the conflicts under investigation, a qualitative research design was employed with triangulation at its core in order to ensure the necessary quality and rigour of the findings. In this case, four different types of data were used, namely, in-depth interviews with heads of households, key informant interviews, focus group sessions, and document analysis. Thematic and content analysis were used to analyse the data which were classified into the following conflict levels: surface level disputes; an intermediate level involving ongoing conflictual relationships; and a deeper level of conflict rooted in identity. Three key findings were generated. Firstly, a substantial number of long-standing disputes were recorded during the ten-year period (2007-2016). Most of these disputes were not resolved because they had a long and complicated history which resulted in previous disputes resurfacing whenever a current one arose. Secondly, the history of unresolved conflict resulted in mistrust and failure to find common ground between the parties involved in the conflict. Lastly, the source of the disputes and unresolved conflicts was traced back to the identity level. This means that the antagonistic relationships among the stakeholders spilled over into the labelling and stigmatisation of all the groups involved in wildlife management. Thus, conflict between people and wildlife in Chapoto Ward was demonstrated to be a complex issue and underlain by HHC. These findings support the new line of thinking that HWC should not be viewed as simply a problem between people and wildlife but as a conflict between stakeholders with divergent views over wildlife management which manifests as HHC. Furthermore, the degree of polarisation between groups is substantial. In light of these findings, four major conclusions are drawn. Firstly, is the need to shift from narrowly focusing on the proximate conflicts between people and wildlife, to fully understand the complexity of conflict in order to arrive at solutions that successfully mitigate conflict between people and wildlife, and to address the underlying and deep-rooted conflict between stakeholders with divergent wildlife management goals. Secondly, the need for concerted efforts to ensure the involvement of all stakeholders, including women, in wildlife management and conservation by developing structures that enhance active participation of the local people in decision-making, v which promotes the success of conservation initiatives. Thirdly, the need to address the underlying and deep-rooted conflicts over wildlife management by building positive relationships and trust between stakeholders through the holding of regular capacity building workshops based on a more respectful and inclusive process. Fourthly, is the need to consider the interests of both ethnic groups, namely the Doma and the Chikunda by gathering information on the preferences of the identity groups in order to increase cooperation among them. Overall, the thesis introduces a new lens through which one can clearly understand the complexity of the conflict between people and wildlife.
- Full Text:
- Date Issued: 2018
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