title: Modification of kraft wood-pulp fibre with silica for surface functionalisation

authors: Love, Karen T.

subjects: wood

abstract: A new science strategy for natural fibre modification was devised in which glass surface properties would be imparted to wood-derived fibre. The enhancements known from addition of silane reagents to glass fibre–polymer composites could therefore be realised for modified cellulose fibre–polymer composites. A process is described whereby the internal void spaces and micropores of never-dried Kraft pulp fibre walls were impregnated with silica. This was achieved by initial dehydration of never-dried fibre through azeotropic distillation to achieve substitution of fibre water with the silicon chemical solution over a range of concentrations. Kraft fibres were stiffened and made resistant to collapse from the effect of the azeotrope drying. Specific chemical reaction of azeotrope-dried fibre with the reagent ClSi(OEt)3 followed by base-catalysed hydrolysis of the ester groups formed a fibre-bound silica composite. The physico-chemical substitution of water from micropores and internal voids of never-dried fibre with property-modifying chemicals offers possibilities in the development of new fibre characteristics, including fibres which may be hardened, plasticised, and/or stabilised against moisture, biodegradation or fire. The embedded silica may also be used as sites of attachment for coupling agents to modify the hydrophilic character of the fibre or to functionalise the fibre surface.

text: Modification of kraft wood-pulp fibre with silica for surface functionalisation A new science strategy for natural fibre modification was devised in which glass surface properties would be imparted to wood-derived fibre. The enhancements known from addition of silane reagents to glass fibre–polymer composites could therefore be realised for modified cellulose fibre–polymer composites. A process is described whereby the internal void spaces and micropores of never-dried Kraft pulp fibre walls were impregnated with silica. This was achieved by initial dehydration of never-dried fibre through azeotropic distillation to achieve substitution of fibre water with the silicon chemical solution over a range of concentrations. Kraft fibres were stiffened and made resistant to collapse from the effect of the azeotrope drying. Specific chemical reaction of azeotrope-dried fibre with the reagent ClSi(OEt)3 followed by base-catalysed hydrolysis of the ester groups formed a fibre-bound silica composite. The physico-chemical substitution of water from micropores and internal voids of never-dried fibre with property-modifying chemicals offers possibilities in the development of new fibre characteristics, including fibres which may be hardened, plasticised, and/or stabilised against moisture, biodegradation or fire. The embedded silica may also be used as sites of attachment for coupling agents to modify the hydrophilic character of the fibre or to functionalise the fibre surface.

year: 2008

title: A low-toxicity method for the separation of lanosterol and dihydrolanosterol from commercial mixtures

authors: Kavtaradze, Levan K.

subjects: lanosterol

abstract: We describe an inexpensive, low-toxicity and high-yielding method for the production of pure lanosterol and dihydrolanosterol from the commercially available mixture. Optimum conditions are presented for the one-pot production of the intermediate 24,25 vicinal diol of lanosterol acetate (via either epoxidation or hydroxyhalogenation) which is readily separated from the unreacted dihydrolanosterol acetate. The lanosterol diol can then be converted to pure (>97%) lanosterol. Hypophosphorous acid was used for both the conversion of the epoxide to the diol, and as a catalyst for the hydroxyhalogenation by N-halosuccinimides of the olefinic bond.

text: A low-toxicity method for the separation of lanosterol and dihydrolanosterol from commercial mixtures We describe an inexpensive, low-toxicity and high-yielding method for the production of pure lanosterol and dihydrolanosterol from the commercially available mixture. Optimum conditions are presented for the one-pot production of the intermediate 24,25 vicinal diol of lanosterol acetate (via either epoxidation or hydroxyhalogenation) which is readily separated from the unreacted dihydrolanosterol acetate. The lanosterol diol can then be converted to pure (>97%) lanosterol. Hypophosphorous acid was used for both the conversion of the epoxide to the diol, and as a catalyst for the hydroxyhalogenation by N-halosuccinimides of the olefinic bond.

year: 2004-09-01

title: An evaluation of Te Rau Puawai workforce 100: Stakeholder perspectives

authors: Nikora, Linda Waimarie

subjects: Maori students

abstract: To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
There are a number of stakeholders who do not have a direct role in the provision of
Te Rau Puawai. These people are not involved in the day to day running of Te Rau
Puawai (as do, for example, the coordinator, support team or academic mentors),
nevertheless they play an important role, contributing in a variety of ways to the
programme.

text: An evaluation of Te Rau Puawai workforce 100: Stakeholder perspectives To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
There are a number of stakeholders who do not have a direct role in the provision of
Te Rau Puawai. These people are not involved in the day to day running of Te Rau
Puawai (as do, for example, the coordinator, support team or academic mentors),
nevertheless they play an important role, contributing in a variety of ways to the
programme.

year: 2002-05-01