title: A process for melt grafting itaconic anhydride onto polyethylene

authors: Hanipah, Suhaiza Hanim

subjects: itaconic anhydride

abstract: Currently, extensive research in using bio‐derived polymers is being done, highlighting the
importance of sustainable, green polymeric materials. Some sustainable alternatives to
synthetic polymers include lignin, starch, cellulose or blends of these with petroleum‐based
polymers.
In New Zealand, large quantities of animal derived proteins are available at very low cost,
making it ideal as a sustainable alternative to petroleum‐derived polymers. However, the
processability of most proteins is very difficult, but can be improved by blending with synthetic
polymers, such as polyolefins. To improve, the compatibility between these substances, a
functional monomer could be grafted onto the polyolefin chain. Using an appropriate functional
group, the polyolefin could then react with certain amino acids residues in the protein. Lysine
and cystein are the two most appropriate amino acid residues because of their reactivity and
stability at a wide pH range.
In this study, free radical grafting of itaconic anhydride (IA) onto polyethylene was investigated.
IA was selected because it is capable of reacting with polyethylene and amino acid residues,
such as lysine. The objective of the research was to identify and investigate the effect of
reaction parameters on grafting. These were: residence time, temperature, initial monomer
concentration as well as peroxide concentration and type. Grafting was characterized in terms
of the degree of grafting (DOG), percentage reacted and the extent of side reactions.
The reaction temperature was taken above the melting point of the polyethylene, monomer
and decomposition temperature of the initiator. It was found that above 160 C polymer
degradation occurred, evident from sample discolouration. A higher degree of grafting can be
achieved by increasing the initial monomer concentration up to a limiting concentration. The
highest DOG achieved was about 1.2 mol IA per mol PE, using 2 wt% DCP. When using 2 wt %
peroxide, the limiting concentration was found to be 6 wt% IA, above which no improvement in
DOG was achieved. It was found that DCP is much more effective at grafting, compared to DTBP
because DTBP is more prone to lead to side reactions than DCP.
iv
It was found that a residence time of 168 seconds resulted in the highest DOG, corresponding to
4 extrusions in series. However, it was also found that an increase in residence time resulted in
an increase in polymer degradation. The tensile strength of PE decreased after two extrusions
when using DTBP, and three extrusions, when using DCP. Young's modulus decreased only
slightly, while all samples showed a dramatic decrease in ductility, even after one extrusion. It
was concluded that degradation had a more pronounced effect on mechanical properties than
cross‐linking, and residence time should therefore not exceed three extrusions in series, which
corresponded to about 126 seconds.
It can be concluded that a high reaction temperature and high initiator concentration lead to a
low degree of grafting, accompanied by high cross‐linking and increased degradation. On the
other hand, high monomer concentration and high residence time lead to a high degree of
grafting.
Optimising grafting is therefore a trade off between maximal DOG and minimising side reactions
such as cross‐linking and degradation and optimal conditions do not necessarily correspond to a
maximum DOG. Other factors, such as the use of additives to prevent degradation should also
be investigated and may lead to different optimum conditions.

text: A process for melt grafting itaconic anhydride onto polyethylene Currently, extensive research in using bio‐derived polymers is being done, highlighting the
importance of sustainable, green polymeric materials. Some sustainable alternatives to
synthetic polymers include lignin, starch, cellulose or blends of these with petroleum‐based
polymers.
In New Zealand, large quantities of animal derived proteins are available at very low cost,
making it ideal as a sustainable alternative to petroleum‐derived polymers. However, the
processability of most proteins is very difficult, but can be improved by blending with synthetic
polymers, such as polyolefins. To improve, the compatibility between these substances, a
functional monomer could be grafted onto the polyolefin chain. Using an appropriate functional
group, the polyolefin could then react with certain amino acids residues in the protein. Lysine
and cystein are the two most appropriate amino acid residues because of their reactivity and
stability at a wide pH range.
In this study, free radical grafting of itaconic anhydride (IA) onto polyethylene was investigated.
IA was selected because it is capable of reacting with polyethylene and amino acid residues,
such as lysine. The objective of the research was to identify and investigate the effect of
reaction parameters on grafting. These were: residence time, temperature, initial monomer
concentration as well as peroxide concentration and type. Grafting was characterized in terms
of the degree of grafting (DOG), percentage reacted and the extent of side reactions.
The reaction temperature was taken above the melting point of the polyethylene, monomer
and decomposition temperature of the initiator. It was found that above 160 C polymer
degradation occurred, evident from sample discolouration. A higher degree of grafting can be
achieved by increasing the initial monomer concentration up to a limiting concentration. The
highest DOG achieved was about 1.2 mol IA per mol PE, using 2 wt% DCP. When using 2 wt %
peroxide, the limiting concentration was found to be 6 wt% IA, above which no improvement in
DOG was achieved. It was found that DCP is much more effective at grafting, compared to DTBP
because DTBP is more prone to lead to side reactions than DCP.
iv
It was found that a residence time of 168 seconds resulted in the highest DOG, corresponding to
4 extrusions in series. However, it was also found that an increase in residence time resulted in
an increase in polymer degradation. The tensile strength of PE decreased after two extrusions
when using DTBP, and three extrusions, when using DCP. Young's modulus decreased only
slightly, while all samples showed a dramatic decrease in ductility, even after one extrusion. It
was concluded that degradation had a more pronounced effect on mechanical properties than
cross‐linking, and residence time should therefore not exceed three extrusions in series, which
corresponded to about 126 seconds.
It can be concluded that a high reaction temperature and high initiator concentration lead to a
low degree of grafting, accompanied by high cross‐linking and increased degradation. On the
other hand, high monomer concentration and high residence time lead to a high degree of
grafting.
Optimising grafting is therefore a trade off between maximal DOG and minimising side reactions
such as cross‐linking and degradation and optimal conditions do not necessarily correspond to a
maximum DOG. Other factors, such as the use of additives to prevent degradation should also
be investigated and may lead to different optimum conditions.

year: 2008

title: Geographies that matter: Pregnant bodies in public places

authors: Longhurst, Robyn

subjects: pregnancy

abstract: This thesis has two objectives. First, I argue that there exists a dichotomy between mind and body and that the mind (rationality and masculinity) is privileged over the body (irrationality and femininity). This dichotomy underpins human geographical knowledge as it is currently constituted. I examine examples from time-geography, humanistic geography, medical geography and feminist geography in order to illustrate the ways in which the body is Othered. This Othering of the body in geography serves to marginalise certain individuals and groups, such as women, who are thought to be 'tied to their bodies' and, therefore, incapable of reason. It is a specific notion of knowing as disembodied that marginalises women in the production of geographical knowledge. A privileging of the mind over the body is one of the reasons why, despite feminist interventions, contemporary geography continues to be a largely masculinist discourse. The second objective of this thesis is to contribute to the creation of a 'sexually embodied geography' that contests hegemonic, disembodied, masculinist geographies. I do this by focusing on pregnancy. Using spot observations, focus groups, individual interviews, indepth case-studies, a questionnaire and academic autobiography I conduct a study of the 'lived' geographies of 31 women who are pregnant for the first time and live in Hamilton, AotearoaiNew Zealand. Many of these women tended to withdraw from public places such as night clubs, bars, pubs, restaurants, cafes, and from public activities such as sport and paid employment during pregnancy. Two possible reasons for these pregnant women's withdrawal from public places during pregnancy are: first, that pregnant women are frequently popularly represented as being 'seeping', 'ugly', abject bodies who are not to be trusted in the public realms; and second, pregnant women are frequently represented as being emotional, irrational, and forgetful (read: 'hysterical') and, therefore, not to be trusted in public space. This study offers an example of new possibilities in geography. It is a geography that focuses on the corporeal thereby displacing the tendency to privilege the mind as the dominant term in the mind/body dualism. Focusing on the sexed body may provide feminist geographers with one more way of challenging masculinism and raising questions of sexual difference in geography.

text: Geographies that matter: Pregnant bodies in public places This thesis has two objectives. First, I argue that there exists a dichotomy between mind and body and that the mind (rationality and masculinity) is privileged over the body (irrationality and femininity). This dichotomy underpins human geographical knowledge as it is currently constituted. I examine examples from time-geography, humanistic geography, medical geography and feminist geography in order to illustrate the ways in which the body is Othered. This Othering of the body in geography serves to marginalise certain individuals and groups, such as women, who are thought to be 'tied to their bodies' and, therefore, incapable of reason. It is a specific notion of knowing as disembodied that marginalises women in the production of geographical knowledge. A privileging of the mind over the body is one of the reasons why, despite feminist interventions, contemporary geography continues to be a largely masculinist discourse. The second objective of this thesis is to contribute to the creation of a 'sexually embodied geography' that contests hegemonic, disembodied, masculinist geographies. I do this by focusing on pregnancy. Using spot observations, focus groups, individual interviews, indepth case-studies, a questionnaire and academic autobiography I conduct a study of the 'lived' geographies of 31 women who are pregnant for the first time and live in Hamilton, AotearoaiNew Zealand. Many of these women tended to withdraw from public places such as night clubs, bars, pubs, restaurants, cafes, and from public activities such as sport and paid employment during pregnancy. Two possible reasons for these pregnant women's withdrawal from public places during pregnancy are: first, that pregnant women are frequently popularly represented as being 'seeping', 'ugly', abject bodies who are not to be trusted in the public realms; and second, pregnant women are frequently represented as being emotional, irrational, and forgetful (read: 'hysterical') and, therefore, not to be trusted in public space. This study offers an example of new possibilities in geography. It is a geography that focuses on the corporeal thereby displacing the tendency to privilege the mind as the dominant term in the mind/body dualism. Focusing on the sexed body may provide feminist geographers with one more way of challenging masculinism and raising questions of sexual difference in geography.

year: 1996

title: Joseph Harris Smallman

authors: Hart, Philip

abstract: Born to a mining agent and trained as a mining surveyor, in 1864, less than a year after the birth of his first child, Smallman left England for New Zealand to establish a ‘Mining business’, promising that his family would join him once it was successful. But they were never asked to join him, and after 1870 he ceased to write to his wife. 
The ‘Mining business’ never eventuated, but in 1865 he prospected at Thames, unsuccessfully seeking alluvial gold. Although criticized for living off Maori and doing little prospecting, with his partner he investigated several areas of the Hauraki Peninsula, again unsuccessfully. When the Thames goldfield was opened, with his encouragement, two years later, he mined there for some years, proving himself to be a competent miner but not making his fortune. After working elsewhere, by the mid-1870s he was living with another man’s ‘half-caste’ wife on her land near Te Aroha, having five children with her. Happy to be described as a Pakeha Maori and closely associated with the local hapu, he supported them over land dealings and the development of the district. Despite spending most of his time farming, he remained interested in prospecting, and made some explorations in districts closed to Pakeha. After gold was found at Te Aroha, for a short time he worked with Maori partners in unprofitable claims.
Either before or after his second wife had a child by another man in 1886, he left New Zealand to return to his English family; and remarkably, despite his first wife knowing that his liaison had produced children, she accepted him back after his long absence, and they remained together for the rest of their lives.

text: Joseph Harris Smallman Born to a mining agent and trained as a mining surveyor, in 1864, less than a year after the birth of his first child, Smallman left England for New Zealand to establish a ‘Mining business’, promising that his family would join him once it was successful. But they were never asked to join him, and after 1870 he ceased to write to his wife. 
The ‘Mining business’ never eventuated, but in 1865 he prospected at Thames, unsuccessfully seeking alluvial gold. Although criticized for living off Maori and doing little prospecting, with his partner he investigated several areas of the Hauraki Peninsula, again unsuccessfully. When the Thames goldfield was opened, with his encouragement, two years later, he mined there for some years, proving himself to be a competent miner but not making his fortune. After working elsewhere, by the mid-1870s he was living with another man’s ‘half-caste’ wife on her land near Te Aroha, having five children with her. Happy to be described as a Pakeha Maori and closely associated with the local hapu, he supported them over land dealings and the development of the district. Despite spending most of his time farming, he remained interested in prospecting, and made some explorations in districts closed to Pakeha. After gold was found at Te Aroha, for a short time he worked with Maori partners in unprofitable claims.
Either before or after his second wife had a child by another man in 1886, he left New Zealand to return to his English family; and remarkably, despite his first wife knowing that his liaison had produced children, she accepted him back after his long absence, and they remained together for the rest of their lives.

year: 2016