title: Influence of alkali fiber treatment and fiber processing on the mechanical properties of hemp/epoxy composites

authors: Islam, Mohammad Saiful

subjects: hemp fiber

abstract: Industrial hemp fibers were treated with a 5 wt % NaOH, 2 wt % Na₂SO₃ solution at 120°C for 60 min to remove noncellulosic fiber components. Analysis of fibers by lignin analysis, scanning electron microscopy (SEM), zeta potential, Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXRD) and differential thermal/thermogravimetric analysis (DTA/TGA), supported that alkali treatment had (i) removed lignin, (ii) separated fibers from their fiber bundles, (iii) exposed cellulose hydroxyl groups, (iv) made the fiber surface cleaner, and (v) enhanced thermal stability of the fibers by increasing cellulose crystallinity through better packing of cellulose chains. Untreated and alkali treated short (random and aligned) and long (aligned) hemp fiber/epoxy composites were produced with fiber contents between 40 and 65 wt %. Although alkali treatment generally improved composite strength, better strength at high fiber contents for long fiber composites was achieved with untreated fiber, which appeared to be due to less fiber/fiber contact between alkali treated fibers. Composites with 65 wt % untreated, long aligned fiber were the strongest with a tensile strength (TS) of 165 MPa, Young's modulus (YM) of 17 GPa, flexural strength of 180 MPa, flexural modulus of 9 GPa, impact energy (IE) of 14.5 kJ/m², and fracture toughness (KIc) of 5 MPa m1/2

text: Influence of alkali fiber treatment and fiber processing on the mechanical properties of hemp/epoxy composites Industrial hemp fibers were treated with a 5 wt % NaOH, 2 wt % Na₂SO₃ solution at 120°C for 60 min to remove noncellulosic fiber components. Analysis of fibers by lignin analysis, scanning electron microscopy (SEM), zeta potential, Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXRD) and differential thermal/thermogravimetric analysis (DTA/TGA), supported that alkali treatment had (i) removed lignin, (ii) separated fibers from their fiber bundles, (iii) exposed cellulose hydroxyl groups, (iv) made the fiber surface cleaner, and (v) enhanced thermal stability of the fibers by increasing cellulose crystallinity through better packing of cellulose chains. Untreated and alkali treated short (random and aligned) and long (aligned) hemp fiber/epoxy composites were produced with fiber contents between 40 and 65 wt %. Although alkali treatment generally improved composite strength, better strength at high fiber contents for long fiber composites was achieved with untreated fiber, which appeared to be due to less fiber/fiber contact between alkali treated fibers. Composites with 65 wt % untreated, long aligned fiber were the strongest with a tensile strength (TS) of 165 MPa, Young's modulus (YM) of 17 GPa, flexural strength of 180 MPa, flexural modulus of 9 GPa, impact energy (IE) of 14.5 kJ/m², and fracture toughness (KIc) of 5 MPa m1/2

year: 2010-10

title: The Chemistry of Cycloaurated Complexes

authors: Kilpin, Kelly Joan

subjects: gold

abstract: New cycloaurated complexes have been synthesised and characterised. The biological and catalytic activity (in the addition of 2-methylfuran to methyl vinyl ketone) of selected complexes was evaluated. New complexes reported in this thesis where fully characterised by NMR (¹H, ¹³C and ³¹P when appropriate) and IR spectroscopy, ESI-mass spectrometry and elemental analysis.

The simple cycloaurated iminophosphoranes (2-AuCl₂C₆H₄)Ph₂P=N-R (R = (R,S)-CHMePh, (S)-CHMePh, p-C₆H₄F or But) were synthesised by the reaction of the appropriate ortho-mercurated compound with [Me₄N][AuCl₄] and [Me₄N]Cl in acetonitrile; the complex (2-AuCl₂C₆H₄)Ph₂P=N-(S)-CHMePh was structurally characterised. The cis chloride ligands on the complexes were replaced by chelating dianionic ligands such as thiosalicylate and catecholate - the resulting bis-metallacyclic complexes have a better anti-tumour activity (against P388 murine leukemia cells) than the parent dichlorides. The nitrogen-gold coordinate bond is relatively robust and is not cleaved by cyanide or dithiocarbamate ligands. The reaction of (2-AuCl₂C₆H₄)Ph₂P=N-Ph with PPh₃ results in substitution of the chloride ligand trans to the nitrogen (shown by an X-ray crystal structure). Both the endo ((2-AuCl₂C₆H₄)Ph₂P=NC(O)Ph) and exo ((2-AuCl₂C₆H₄)C(O)N=PPh₃) cycloaurated isomers of the stabilised iminophosphorane Ph₃P=NC(O)Ph were synthesised and structurally characterised.

Cycloaurated Ph₃P=S and Ph₃P=Se were synthesised by a transmetallation reaction from 2-Hg[(C₆H₄)P(E)Ph₂]₂ (E = S or Se). The synthesis of cycloaurated Ph₃P=O by an analogous method was unsuccessful. PhP(S)(NEt₂)₂ was also cycloaurated via a transmetallation reaction. X-ray crystallography confirmed the sulfur (not the nitrogen) was coordinated to the gold centre. The complexes show a similar stability and reactivity to the C,N cycloaurated species - the cis chloride ligands can be replaced by the chelating thiosalicylate ligand. Again the bis-metallacyclic species showed better biological activity than the parent dichloride. 

The direct reaction of the 2-pyridyl sulfonamide ligands 2-(C₅H₅N)CH₂NHSO₂R (R = p-tolyl, Ph or Me), 2-(C₅H₅N)CH₂CH₂NHSO₂R (R = p-tolyl or Ph) or 8-(p-tosylamino)quinoline with refluxing aqueous H[AuCl₄] gave N,N' coordinated complexes containing a five- or six-membered cycloaurated ring. The cycloaurated complexes derived from the ligands 2-(C₅H₅N)CH₂NHSO₂Me and 8-(p-tosylamino)quinoline were structurally characterised. The cycloaurated N,N' systems were not as stable as the C,N systems - reaction with reducing agents led to reduction of Au(III) to Au(I) and elemental gold. 

The 2-pyridine thiocarboxamide ligands 2-(C₅H₅N)C(S)NHR (R= p-tolyl, CH₂Ph, Me, p-C₆H₅OMe) also underwent direct cycloauration upon reaction with H[AuCl₄]. Coordination via the pyridyl nitrogen and sulfur atom was confirmed by an X-ray crystal structure of cycloaurated 2-(C₅H₅N)C(S)NHCH₂Ph. The N,S cycloaurated systems show poor stability in solution and decompose relatively quickly so applications are limited. The ligand with a 2 pyridyl substituent reacted with H[AuCl₄] in a different manner. Instead of cycloauration, the ligand was oxidised and an internal cyclisation occurred to give a 1,2,4-thiadiazolo[2,3-a]pyridinium heterocyclic ring. 

The reaction of the cycloaurated dichloride complexes (2-benzylpyridine)AuCl₂ and (2-AuCl₂C₆H₄)Ph₂P=N-Ph with the tripodal Kläui ligands (Na[(C₅H₅)Co{P(O)R₂}₃], R = OMe or OEt) and Tl[BF₄] resulted in the formation of cationic gold(III) salts. In the solid state the Kläui ligand is strongly coordinated through two of the three oxygen atoms, and weakly by the third, giving the gold a distorted square pyramidal geometry. In solution there is rapid interchange between the coordinated and non-coordinated oxygen atoms.

text: The Chemistry of Cycloaurated Complexes New cycloaurated complexes have been synthesised and characterised. The biological and catalytic activity (in the addition of 2-methylfuran to methyl vinyl ketone) of selected complexes was evaluated. New complexes reported in this thesis where fully characterised by NMR (¹H, ¹³C and ³¹P when appropriate) and IR spectroscopy, ESI-mass spectrometry and elemental analysis.

The simple cycloaurated iminophosphoranes (2-AuCl₂C₆H₄)Ph₂P=N-R (R = (R,S)-CHMePh, (S)-CHMePh, p-C₆H₄F or But) were synthesised by the reaction of the appropriate ortho-mercurated compound with [Me₄N][AuCl₄] and [Me₄N]Cl in acetonitrile; the complex (2-AuCl₂C₆H₄)Ph₂P=N-(S)-CHMePh was structurally characterised. The cis chloride ligands on the complexes were replaced by chelating dianionic ligands such as thiosalicylate and catecholate - the resulting bis-metallacyclic complexes have a better anti-tumour activity (against P388 murine leukemia cells) than the parent dichlorides. The nitrogen-gold coordinate bond is relatively robust and is not cleaved by cyanide or dithiocarbamate ligands. The reaction of (2-AuCl₂C₆H₄)Ph₂P=N-Ph with PPh₃ results in substitution of the chloride ligand trans to the nitrogen (shown by an X-ray crystal structure). Both the endo ((2-AuCl₂C₆H₄)Ph₂P=NC(O)Ph) and exo ((2-AuCl₂C₆H₄)C(O)N=PPh₃) cycloaurated isomers of the stabilised iminophosphorane Ph₃P=NC(O)Ph were synthesised and structurally characterised.

Cycloaurated Ph₃P=S and Ph₃P=Se were synthesised by a transmetallation reaction from 2-Hg[(C₆H₄)P(E)Ph₂]₂ (E = S or Se). The synthesis of cycloaurated Ph₃P=O by an analogous method was unsuccessful. PhP(S)(NEt₂)₂ was also cycloaurated via a transmetallation reaction. X-ray crystallography confirmed the sulfur (not the nitrogen) was coordinated to the gold centre. The complexes show a similar stability and reactivity to the C,N cycloaurated species - the cis chloride ligands can be replaced by the chelating thiosalicylate ligand. Again the bis-metallacyclic species showed better biological activity than the parent dichloride. 

The direct reaction of the 2-pyridyl sulfonamide ligands 2-(C₅H₅N)CH₂NHSO₂R (R = p-tolyl, Ph or Me), 2-(C₅H₅N)CH₂CH₂NHSO₂R (R = p-tolyl or Ph) or 8-(p-tosylamino)quinoline with refluxing aqueous H[AuCl₄] gave N,N' coordinated complexes containing a five- or six-membered cycloaurated ring. The cycloaurated complexes derived from the ligands 2-(C₅H₅N)CH₂NHSO₂Me and 8-(p-tosylamino)quinoline were structurally characterised. The cycloaurated N,N' systems were not as stable as the C,N systems - reaction with reducing agents led to reduction of Au(III) to Au(I) and elemental gold. 

The 2-pyridine thiocarboxamide ligands 2-(C₅H₅N)C(S)NHR (R= p-tolyl, CH₂Ph, Me, p-C₆H₅OMe) also underwent direct cycloauration upon reaction with H[AuCl₄]. Coordination via the pyridyl nitrogen and sulfur atom was confirmed by an X-ray crystal structure of cycloaurated 2-(C₅H₅N)C(S)NHCH₂Ph. The N,S cycloaurated systems show poor stability in solution and decompose relatively quickly so applications are limited. The ligand with a 2 pyridyl substituent reacted with H[AuCl₄] in a different manner. Instead of cycloauration, the ligand was oxidised and an internal cyclisation occurred to give a 1,2,4-thiadiazolo[2,3-a]pyridinium heterocyclic ring. 

The reaction of the cycloaurated dichloride complexes (2-benzylpyridine)AuCl₂ and (2-AuCl₂C₆H₄)Ph₂P=N-Ph with the tripodal Kläui ligands (Na[(C₅H₅)Co{P(O)R₂}₃], R = OMe or OEt) and Tl[BF₄] resulted in the formation of cationic gold(III) salts. In the solid state the Kläui ligand is strongly coordinated through two of the three oxygen atoms, and weakly by the third, giving the gold a distorted square pyramidal geometry. In solution there is rapid interchange between the coordinated and non-coordinated oxygen atoms.

year: 2009

title: Kaumtua Mana Motuhake: A study protocol for a peer education intervention to help Māori elders work through later-stage life transitions

authors: Oetzel, John G.

subjects: Science & Technology

abstract: Background
The Aotearoa/New Zealand population is ageing and numerous studies demonstrate with this phenomenon comes increases in non-communicable diseases, injuries and healthcare costs among other issues. Further, significant inequities exist between Māori (Indigenous peoples of Aotearoa/New Zealand) and non-Māori around poor ageing and health. Most research addressing these issues is deficit oriented; however, the current research project takes a strengths-based approach that highlights the potential of kaumātua (elders) by asserting mana motuhake (autonomy, identity and self-actualisation). We believe that the esteem of elders in Māori culture signals transformative potential. Specifically, this project utilises a ‘tuakana-teina’ (older sibling/younger sibling) peer-educator model, where kaumātua work with other kaumātua in relation to health and wellbeing. The objectives of the project are (a) to develop the capacity of kaumātua as peer educators, whilst having positive impacts on their sense of purpose, health and wellbeing; and (b) to enhance the social and health outcomes for kaumātua receiving the intervention.

Methods
The research is grounded in principles of Kaupapa Māori and community-based participatory research, and brings together an Indigenous community of kaumātua, community health researchers, and academic researchers working with two advisory boards. The project intervention involves an orientation programme for tuakana peer educators for other kaumātua (teina). The research design is a pre- and post-test, clustered staggered design. All participants will complete a baseline assessment of health and wellbeing consistent with Māori worldviews (i.e., holistic model). The tuakana and teina participants will be divided into two groups with the first group completing the intervention during the first half of the project and the second group during the second half of the project. All participants will complete post-test assessments following both interventions allowing comparison of the two groups along with repeated measures over time.

Discussion
The findings will provide an evidence base for the importance and relevancy of kaumātua knowledge to create contextually based and culturally safe age-friendly environments that facilitate engagement and participation by kaumātua for kaumātua. If the model is effective, we will seek to facilitate the dissemination and scalability of the intervention.

Trial registration
Australia New Zealand Clinical Trial Registry (ACTRN12617001396314); Date Registered: 3 October 2017 (retrospectively registered).

text: Kaumtua Mana Motuhake: A study protocol for a peer education intervention to help Māori elders work through later-stage life transitions Background
The Aotearoa/New Zealand population is ageing and numerous studies demonstrate with this phenomenon comes increases in non-communicable diseases, injuries and healthcare costs among other issues. Further, significant inequities exist between Māori (Indigenous peoples of Aotearoa/New Zealand) and non-Māori around poor ageing and health. Most research addressing these issues is deficit oriented; however, the current research project takes a strengths-based approach that highlights the potential of kaumātua (elders) by asserting mana motuhake (autonomy, identity and self-actualisation). We believe that the esteem of elders in Māori culture signals transformative potential. Specifically, this project utilises a ‘tuakana-teina’ (older sibling/younger sibling) peer-educator model, where kaumātua work with other kaumātua in relation to health and wellbeing. The objectives of the project are (a) to develop the capacity of kaumātua as peer educators, whilst having positive impacts on their sense of purpose, health and wellbeing; and (b) to enhance the social and health outcomes for kaumātua receiving the intervention.

Methods
The research is grounded in principles of Kaupapa Māori and community-based participatory research, and brings together an Indigenous community of kaumātua, community health researchers, and academic researchers working with two advisory boards. The project intervention involves an orientation programme for tuakana peer educators for other kaumātua (teina). The research design is a pre- and post-test, clustered staggered design. All participants will complete a baseline assessment of health and wellbeing consistent with Māori worldviews (i.e., holistic model). The tuakana and teina participants will be divided into two groups with the first group completing the intervention during the first half of the project and the second group during the second half of the project. All participants will complete post-test assessments following both interventions allowing comparison of the two groups along with repeated measures over time.

Discussion
The findings will provide an evidence base for the importance and relevancy of kaumātua knowledge to create contextually based and culturally safe age-friendly environments that facilitate engagement and participation by kaumātua for kaumātua. If the model is effective, we will seek to facilitate the dissemination and scalability of the intervention.

Trial registration
Australia New Zealand Clinical Trial Registry (ACTRN12617001396314); Date Registered: 3 October 2017 (retrospectively registered).

year: 2019