title: Development of Bloodmeal Protein Thermoplastic Blends

authors: Marsilla, K. I. Ku

abstract: This study investigated the compatibilization of Novatein® Thermoplastic Protein (NTP) blends with other polymers. NTP was blended with three different types of polymers;a petroleum-based polyolefin, (low-linear density polyethylene, LLDPE); a biodegradable synthetic polyester, (polybutylene succinate, PBS) and a bioderived, compostable polyester, (poly (lactic acid), PLA). It was a relatively straightforward process to produce a compatible blend of LLDPE and NTP using a compatibilizer, regardless of the obvious difference in chemical structure between these polymers. Blending NTP with PBS, on the other hand, was much more challenging. It required two compatibilizers, added at different stages of blending to produce a compatible blend. For blends with PLA, a novel copolymer, itaconic anhydride grafted PLA (PLA-g-IA) was produced to be used as a compatibilizer and initial results suggested that PLA-g-IA may be a successful approach. 
Two different methods of compatibilization pathways were explored: the addition of a graft copolymer based on one of the components (in the case of NTP/LLDPE blends) or using compatibilizers that are not chemically the same as either component (in the case of NTP/PBS blends). Polyethylene grafted maleic anhydride (PE-g-MAH) was added to NTP/LLDPE blends and produced a blend with synergistic mechanical properties (the elongation at break exceeded the raw LLDPE properties). The water resistance of NTP was improved after blending with LLDPE, but it may compromise the compostability of the material. For NTP/PBS blends, two compatibilizers with different functional end-groups were used; these were (poly-2-ethyl-2-oxazoline)(PEOX) and (polymeric diphenyl diisocyanate)(pMDI). Using either of the compatibilizers individually in blends containing 50 % NTP resulted in poor mechanical properties. Compatibilization was accomplished with the addition of both two compatibilizers at different stages of blend preparation; PEOX dissolved in water and added during NTP production, while pMDI was added during injection moulding. This approach led to a tensile strength greater than that of pure PBS (24 MPa compared to 22 MPa). Dissolving PEOX in water improved the dispersion of the NTP phase throughout the PBS matrix via hydrogen bonding between water, PEOX and NTP. The addition of pMDI during injection moulding stabilized and strengthened the interactions between PBS and NTP, thereby leading to a superior blend.  
The compatibility between NTP and LLDPE or NTP and PBS were characterized using thermal and morphological properties as well as water resistance. Two Tgs were obtained for all blends, however, the addition of compatibilizers improved the adhesion between phases, evident from broader and lower height of Tg peaks. The morphology provided evidence of a homogenous dispersion of NTP in LLDPE. In NTP/PBS blends, the fracture mechanism changed from brittle to ductile with the addition of PEOX. Both NTP/LLDPE and NTP/PBS blends showed a phase inversion from a particle- dispersed morphology to a co-continuous morphology at compositions greater than 50% NTP. The water resistance also improved with the addition of LLDPE and PBS.   
Reactive extrusion was used to produce a copolymer, itaconic anhydride grafted poly (lactic acid) (PLA-g-IA). Different initiator (dicumyl peroxide) and monomer (IA) concentrations were used to optimize the degree of grafting. 0.75% was the highest degree of grafting and showed minimal chain scission evident from the polymer’s intrinsic viscosity. The reaction kinetics of grafting and the effect of grafting on thermal and mechanical properties were investigated. Grafting increased the crystallization rate of PLA, increased the crystallinity and also raised the thermal decomposition temperature. The mechanical properties of PLA-g-IA blended with PLA were also improved.
Crystallization of PLA and PLA-g-IA were investigated during annealing at different annealing temperatures and durations using differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). The rate of crystallization increased after grafting and affected the formation of PLA crystals by increasing the lattice spacing at the (110) plane, suggesting an expanded helical structure of PLA. The crystallinity of PLA-g-IA was also higher than that of neat PLA.  
Although polymer blending offers an attractive route to modify selected polymer properties, it is not always successful without the addition of compatibilizers. Despite the subtle differences in methods to incorporate compatibilizers, development of NTP blends with different polymers, whether a petroleum based polymer, synthetic biodegradable polyester or bioderived compostable polyester, offers material with improved mechanical properties and thermal stability. Water resistance is also improved, however, biodegradability will likely be compromised if the second polymer is not also biodegradable. These blends offer a potentially wider range of commercial NTP grades.

text: Development of Bloodmeal Protein Thermoplastic Blends This study investigated the compatibilization of Novatein® Thermoplastic Protein (NTP) blends with other polymers. NTP was blended with three different types of polymers;a petroleum-based polyolefin, (low-linear density polyethylene, LLDPE); a biodegradable synthetic polyester, (polybutylene succinate, PBS) and a bioderived, compostable polyester, (poly (lactic acid), PLA). It was a relatively straightforward process to produce a compatible blend of LLDPE and NTP using a compatibilizer, regardless of the obvious difference in chemical structure between these polymers. Blending NTP with PBS, on the other hand, was much more challenging. It required two compatibilizers, added at different stages of blending to produce a compatible blend. For blends with PLA, a novel copolymer, itaconic anhydride grafted PLA (PLA-g-IA) was produced to be used as a compatibilizer and initial results suggested that PLA-g-IA may be a successful approach. 
Two different methods of compatibilization pathways were explored: the addition of a graft copolymer based on one of the components (in the case of NTP/LLDPE blends) or using compatibilizers that are not chemically the same as either component (in the case of NTP/PBS blends). Polyethylene grafted maleic anhydride (PE-g-MAH) was added to NTP/LLDPE blends and produced a blend with synergistic mechanical properties (the elongation at break exceeded the raw LLDPE properties). The water resistance of NTP was improved after blending with LLDPE, but it may compromise the compostability of the material. For NTP/PBS blends, two compatibilizers with different functional end-groups were used; these were (poly-2-ethyl-2-oxazoline)(PEOX) and (polymeric diphenyl diisocyanate)(pMDI). Using either of the compatibilizers individually in blends containing 50 % NTP resulted in poor mechanical properties. Compatibilization was accomplished with the addition of both two compatibilizers at different stages of blend preparation; PEOX dissolved in water and added during NTP production, while pMDI was added during injection moulding. This approach led to a tensile strength greater than that of pure PBS (24 MPa compared to 22 MPa). Dissolving PEOX in water improved the dispersion of the NTP phase throughout the PBS matrix via hydrogen bonding between water, PEOX and NTP. The addition of pMDI during injection moulding stabilized and strengthened the interactions between PBS and NTP, thereby leading to a superior blend.  
The compatibility between NTP and LLDPE or NTP and PBS were characterized using thermal and morphological properties as well as water resistance. Two Tgs were obtained for all blends, however, the addition of compatibilizers improved the adhesion between phases, evident from broader and lower height of Tg peaks. The morphology provided evidence of a homogenous dispersion of NTP in LLDPE. In NTP/PBS blends, the fracture mechanism changed from brittle to ductile with the addition of PEOX. Both NTP/LLDPE and NTP/PBS blends showed a phase inversion from a particle- dispersed morphology to a co-continuous morphology at compositions greater than 50% NTP. The water resistance also improved with the addition of LLDPE and PBS.   
Reactive extrusion was used to produce a copolymer, itaconic anhydride grafted poly (lactic acid) (PLA-g-IA). Different initiator (dicumyl peroxide) and monomer (IA) concentrations were used to optimize the degree of grafting. 0.75% was the highest degree of grafting and showed minimal chain scission evident from the polymer’s intrinsic viscosity. The reaction kinetics of grafting and the effect of grafting on thermal and mechanical properties were investigated. Grafting increased the crystallization rate of PLA, increased the crystallinity and also raised the thermal decomposition temperature. The mechanical properties of PLA-g-IA blended with PLA were also improved.
Crystallization of PLA and PLA-g-IA were investigated during annealing at different annealing temperatures and durations using differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). The rate of crystallization increased after grafting and affected the formation of PLA crystals by increasing the lattice spacing at the (110) plane, suggesting an expanded helical structure of PLA. The crystallinity of PLA-g-IA was also higher than that of neat PLA.  
Although polymer blending offers an attractive route to modify selected polymer properties, it is not always successful without the addition of compatibilizers. Despite the subtle differences in methods to incorporate compatibilizers, development of NTP blends with different polymers, whether a petroleum based polymer, synthetic biodegradable polyester or bioderived compostable polyester, offers material with improved mechanical properties and thermal stability. Water resistance is also improved, however, biodegradability will likely be compromised if the second polymer is not also biodegradable. These blends offer a potentially wider range of commercial NTP grades.

year: 2015

title: Local-foreign dialect discrimination and responses to mixed-dialect duets in the North Island kokako

authors: Bradley, David William

subjects: Callaeas wilson

abstract: Social discrimination based on geographic variation in territorial signals is taxonomically widespread—most studies have found stronger reactions to local than to foreign signals. In birds with male-only song, this discrimination is thought to result in social exclusion and has been suggested as a behavioral barrier to interpopulation genetic exchange. However, little information exists on duetting species in this context, and nothing is known of how “mixed-dialect” pairs are perceived, despite their confirmed occurrence. We addressed these deficiencies using a duetting, endangered Passerine, the kōkako (Callaeas wilsoni). We used reciprocal stereo playback experiments between 2 fragmented populations to present duets from local and foreign dialects (Experiment 1). Additionally, we assessed responses to mixed-dialect pairs by synthesizing duets, a novel technique, to determine which sex contributes the most salient duet components (Experiment 2). Territorial pairs vocally responded to local duets with less delay, and produced more song phrases with a lower diversity, than they did in response to playback of foreign duets. Pairs responded to mixed-dialect duets with equal overall strength regardless of the sex of the local component. Responses to mixed and pure local duets were qualitatively similar. From an evolutionary perspective, this suggests that mixed-dialect pairs can successfully defend territories without social penalties, improving the likelihood of cross-dialect gene flow. These findings have particular importance for conservation efforts like translocation, which often involve individuals from multiple, culturally distinct populations.

text: Local-foreign dialect discrimination and responses to mixed-dialect duets in the North Island kokako Social discrimination based on geographic variation in territorial signals is taxonomically widespread—most studies have found stronger reactions to local than to foreign signals. In birds with male-only song, this discrimination is thought to result in social exclusion and has been suggested as a behavioral barrier to interpopulation genetic exchange. However, little information exists on duetting species in this context, and nothing is known of how “mixed-dialect” pairs are perceived, despite their confirmed occurrence. We addressed these deficiencies using a duetting, endangered Passerine, the kōkako (Callaeas wilsoni). We used reciprocal stereo playback experiments between 2 fragmented populations to present duets from local and foreign dialects (Experiment 1). Additionally, we assessed responses to mixed-dialect pairs by synthesizing duets, a novel technique, to determine which sex contributes the most salient duet components (Experiment 2). Territorial pairs vocally responded to local duets with less delay, and produced more song phrases with a lower diversity, than they did in response to playback of foreign duets. Pairs responded to mixed-dialect duets with equal overall strength regardless of the sex of the local component. Responses to mixed and pure local duets were qualitatively similar. From an evolutionary perspective, this suggests that mixed-dialect pairs can successfully defend territories without social penalties, improving the likelihood of cross-dialect gene flow. These findings have particular importance for conservation efforts like translocation, which often involve individuals from multiple, culturally distinct populations.

year: 2013

title: Māori men: An indigenous psychological perspective on the interconnected self

authors: Rua, Mohi

subjects: Māori men

abstract: The positive relational practices of Māori men are seldom explored in academic research. Responding to this gap in the literature, this article explores how Māori men negotiate a positive sense of self and relationships. This research is guided by kaupapa Māori research practice, Māori cultural concepts, and relational understandings of identity and wellbeing. Our ethnographic approach involved direct observations, engagement in shared cultural practices and narrative interviews. During these interactions, participating men invoked a positive sense of self through accounts of belonging, reciprocity, dialogue, intimacy, and care for themselves, their whānau, and traditions. We found that Māori men's identities are negotiated through interactions with whānau (immediate and extended family), and particular places and practices. Our participants demonstrated how Māori men’s positive self-constructions are fundamentally interconnected with other people, cultural traditions, socio-cultural practices, physical and symbolic places, as well as their own health and the health of those around them.

text: Māori men: An indigenous psychological perspective on the interconnected self The positive relational practices of Māori men are seldom explored in academic research. Responding to this gap in the literature, this article explores how Māori men negotiate a positive sense of self and relationships. This research is guided by kaupapa Māori research practice, Māori cultural concepts, and relational understandings of identity and wellbeing. Our ethnographic approach involved direct observations, engagement in shared cultural practices and narrative interviews. During these interactions, participating men invoked a positive sense of self through accounts of belonging, reciprocity, dialogue, intimacy, and care for themselves, their whānau, and traditions. We found that Māori men's identities are negotiated through interactions with whānau (immediate and extended family), and particular places and practices. Our participants demonstrated how Māori men’s positive self-constructions are fundamentally interconnected with other people, cultural traditions, socio-cultural practices, physical and symbolic places, as well as their own health and the health of those around them.

year: 2017