<p>Various chemical properties can be used to characterise dissolving pulp. The quality of the pulp must be carefully controlled to ensure that it meets the requirements for its intended use and the further processes to be applied. If it is to be used to prepare viscose, or other cellulose derivatives, the key prop-erties of the pulp are its accessibility and reactivity. The studies described in this thesis investigated the potential utility of multivariate analysis of chemi-cal and spectral data for determining the properties of dissolving pulp. Dis-solving pulps produced by a two-stage sulfite process, both in the laboratory and a factory were produced pulps for this purpose. The analyses showed that pulp with high reactivity had short cellulose chains, low molecular weight, low polydispersity, low hemicellulose content, high content of ace-tone-extractable compounds, and high surface charge compared to pulp with low reactivity. Important chemical properties of the pulp, such as viscosity and alkali resistance, were successfully predicted from near infrared spectra. Predicting the reactivity, or the viscose filterability, of the pulp was more complex. Several chemical methods for analyzing the reactivity of the pulp were examined. The influence of the cellulose structure at the supermolecu-lar level on the reactivity of the pulp was explored by multivariate analysis of solid state 13C nuclear magnetic resonance spectra. Structural variables considered included: differences in hydrogen bonding, contents of hemicel-lulose, amorphous cellulose and crystalline cellulose I and II. Pulps with high reactivity have higher contents of cellulose I and amorphous cellulose than pulps with low reactivity, which have higher contents of cellulose II and hemicellulose.</p>

Various chemical properties can be used to characterise dissolving pulp. The quality of the pulp must be carefully controlled to ensure that it meets the requirements for its intended use and the further processes to be applied. If it is to be used to prepare viscose, or other cellulose derivatives, the key prop-erties of the pulp are its accessibility and reactivity. The studies described in this thesis investigated the potential utility of multivariate analysis of chemi-cal and spectral data for determining the properties of dissolving pulp. Dis-solving pulps produced by a two-stage sulfite process, both in the laboratory and a factory were produced pulps for this purpose. The analyses showed that pulp with high reactivity had short cellulose chains, low molecular weight, low polydispersity, low hemicellulose content, high content of ace-tone-extractable compounds, and high surface charge compared to pulp with low reactivity. Important chemical properties of the pulp, such as viscosity and alkali resistance, were successfully predicted from near infrared spectra. Predicting the reactivity, or the viscose filterability, of the pulp was more complex. Several chemical methods for analyzing the reactivity of the pulp were examined. The influence of the cellulose structure at the supermolecu-lar level on the reactivity of the pulp was explored by multivariate analysis of solid state 13C nuclear magnetic resonance spectra. Structural variables considered included: differences in hydrogen bonding, contents of hemicel-lulose, amorphous cellulose and crystalline cellulose I and II. Pulps with high reactivity have higher contents of cellulose I and amorphous cellulose than pulps with low reactivity, which have higher contents of cellulose II and hemicellulose.

Kyoto University (京都大学) / 0048 / 新制・論文博士 / 博士(工学) / 乙第12199号 / 論工博第3988号 / 新制||工||1438(附属図書館) / 26271 / UT51-2008-C969 / (主査)教授 堀井 文敬, 教授 渡辺 宏, 教授 金谷 利治 / 学位規則第4条第2項該当

Soil organic matter (OM) is a complex mixture of compounds, mainly derived from plants and microbes at various states of decay. It is part of the global carbon cycle and is important for maintaining soil quality. OM protection is mainly attributed to its association with minerals. However, clay minerals preferentially sorb specific OM structures, and clay sorption sites become saturated as OM concentrations increase. Therefore, it is important to examine how OM structures influence their association with soil minerals, and to characterize other protection mechanisms. Several techniques, which provide complementary information, were combined to investigate OM composition: Biomarker (lignin phenol, cutin-OH acid, and lipid) analysis, using gas chromatography/mass spectrometry; solid-state 13C nuclear magnetic resonance (NMR) spectroscopy; and an emerging method, solution-state 1H NMR spectroscopy. OM composition of sand-, silt-, clay-size, and light fractions of Canadian soils were compared. It was found that microbial-derived and aliphatic structures accumulated in clay-size fractions, and lignin phenols in silt-size fractions may be protected from further oxidation. Therefore, OM protection through association with minerals may be structure-specific. OM in soils amended with maize leaves, stems, and roots from a biodegradation study were also examined. Over time, lignin phenol composition, and oxidation; and aliphatic structure contribution changed less in soils amended with leaves compared to soils amended with stems and roots. Compared to soils amended with leaves and stems, amendment with roots may have promoted the more efficient formation of microbial-derived OM. Therefore, plant chemistry influenced soil OM turnover. Synthetic OM-clay complexes and soil mineral fractions were used to investigate lignin protection from chemical oxidation. Coating with dodecanoic acid protected lignin from chemical oxidation, and overlying vegetation determined the relative resistance of lignin phenols in clay-size fractions from chemical oxidation. Therefore, additional protection from chemical oxidation may be attributed to OM composition and interactions between OM structures sorbed to clay minerals. Overall, these studies suggest that while association with minerals is important, OM turnover is also influenced by vegetation, and protection through association with clay minerals was modified by OM structure composition. As well, OM-OM interaction is a potential mechanism that protects soil OM from degradation.

Soil organic matter (OM) is a complex mixture of compounds, mainly derived from plants and microbes at various states of decay. It is part of the global carbon cycle and is important for maintaining soil quality. OM protection is mainly attributed to its association with minerals. However, clay minerals preferentially sorb specific OM structures, and clay sorption sites become saturated as OM concentrations increase. Therefore, it is important to examine how OM structures influence their association with soil minerals, and to characterize other protection mechanisms. Several techniques, which provide complementary information, were combined to investigate OM composition: Biomarker (lignin phenol, cutin-OH acid, and lipid) analysis, using gas chromatography/mass spectrometry; solid-state 13C nuclear magnetic resonance (NMR) spectroscopy; and an emerging method, solution-state 1H NMR spectroscopy. OM composition of sand-, silt-, clay-size, and light fractions of Canadian soils were compared. It was found that microbial-derived and aliphatic structures accumulated in clay-size fractions, and lignin phenols in silt-size fractions may be protected from further oxidation. Therefore, OM protection through association with minerals may be structure-specific. OM in soils amended with maize leaves, stems, and roots from a biodegradation study were also examined. Over time, lignin phenol composition, and oxidation; and aliphatic structure contribution changed less in soils amended with leaves compared to soils amended with stems and roots. Compared to soils amended with leaves and stems, amendment with roots may have promoted the more efficient formation of microbial-derived OM. Therefore, plant chemistry influenced soil OM turnover. Synthetic OM-clay complexes and soil mineral fractions were used to investigate lignin protection from chemical oxidation. Coating with dodecanoic acid protected lignin from chemical oxidation, and overlying vegetation determined the relative resistance of lignin phenols in clay-size fractions from chemical oxidation. Therefore, additional protection from chemical oxidation may be attributed to OM composition and interactions between OM structures sorbed to clay minerals. Overall, these studies suggest that while association with minerals is important, OM turnover is also influenced by vegetation, and protection through association with clay minerals was modified by OM structure composition. As well, OM-OM interaction is a potential mechanism that protects soil OM from degradation.