Cellulose, starch and their derivatives for industrial applications. Structure-property studies: Dissertation

Research output: ThesisDissertationCollection of Articles

Abstract

Despite the similarity of their structural basic units, cellulose- and starch-based materials behave differently in many industrial applications. In this thesis, the structure and properties of these polysaccharides and their selected derivatives were studied by means of five comprehensive examples. In the first investigation, highly crystalline cellulose was identified from Valonia macrophysa vesicles by atomic force microscopy. The role of water as a possible modifier on the surface of cellulose was found to be very important. The monoclinic phases were found on the cellulose surfaces with a lateral resolution of about 4 Å, indicating that water molecules cannot penetrate and thus disturb the surface structure of monoclinic cellulose. On the other hand, the absence of triclinic phases was explained by the used measuring geometry without liquid cell. The ageing of metastable oat and barley thermoplastic starch films was followed by frictional imaging. As a consequence of the ageing, the films lose some of their mechanical properties. In the oat films, glycerol used as a plasticiser diffused from the starch-glycerol-water matrix to the surface of thermoplastic starch, resulting in areas with low friction. In the case of barley starch films, the ageing first resulted in short range reorientation of polymers and finally slow crystallization of amylopectin branches. Solution precipitation techniques were applied to produce ideally spherical starch ester particles (with a diameter about half the wavelength of visible light), suitable for fillers in paper coatings in the third study. Particles assume their shape and size spontaneously when solvated starch polymer is mixed with non-solvent, due to the free mobility of the modified starch chains. Starch pigment has improved affinity to paper surface and it can be used as such or mixed with other pigments to enhance the optical or printing properties of paper. Starch-based pigmenting materials with improved optical performance were prepared in the laboratory by the complexation approach. Analytical results indicated that the complexation of carboxymethyl starch and inorganics strongly depends on the carboxymethyl group in the starch-based hybrid pigmented materials. The formed insoluble hybrids were mostly amorphous and the crystalline contribution of the inorganic component was not evident. The resulting precipitates exhibited composite structures. Finally, three starch-based and two cellulose-based polymers were selected for flocculation and filtration tests. In shearless dewatering conditions, the retention and dewatering properties of the starch-based polymers were similar to those of commercial polyacrylamide-based polymers. The flow studies in higher shear conditions showed that with the studied dosages the starch-based polymers could not reach the flocculation levels needed to maintain sufficient retention properties. The performance of the cellulose-based polymers as flocculating agents was less efficient. The reasons for the more limited performance of the polysaccharide-based flocculants were too low molecular weight and the charge density distribution. Better understanding of how to improve the hydrodynamic properties of bio-based polymers will be essential when planning new bio-based flocculants. The deeper understanding of the relationships between the desired structures and properties of polysaccharides helps to utilize them more effectively. In this way it is possible to obtain better bio-based and environmentally sustainable products in the competition with the current products based on conventional petrochemistry.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • University of Helsinki
Supervisors/Advisors
  • Tenhu, Heikki, Supervisor, External person
Award date24 May 2013
Place of PublicationEspoo
Publisher
Print ISBNs978-951-38-7997-6
Electronic ISBNs978-951-38-7998-3
Publication statusPublished - 2013
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

Cellulose
Starch
Industrial applications
Derivatives
Polymers
Polysaccharides
Aging of materials
Dewatering
Flocculation
Complexation
Pigments
Glycerol
Thermoplastics
Water
Printing properties
Crystalline materials
Amylopectin
Plasticizers
Coating techniques
Hybrid materials

Keywords

  • cellulose
  • starch
  • derivative
  • industrial
  • application
  • structure
  • property

Cite this

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title = "Cellulose, starch and their derivatives for industrial applications. Structure-property studies: Dissertation",
abstract = "Despite the similarity of their structural basic units, cellulose- and starch-based materials behave differently in many industrial applications. In this thesis, the structure and properties of these polysaccharides and their selected derivatives were studied by means of five comprehensive examples. In the first investigation, highly crystalline cellulose was identified from Valonia macrophysa vesicles by atomic force microscopy. The role of water as a possible modifier on the surface of cellulose was found to be very important. The monoclinic phases were found on the cellulose surfaces with a lateral resolution of about 4 {\AA}, indicating that water molecules cannot penetrate and thus disturb the surface structure of monoclinic cellulose. On the other hand, the absence of triclinic phases was explained by the used measuring geometry without liquid cell. The ageing of metastable oat and barley thermoplastic starch films was followed by frictional imaging. As a consequence of the ageing, the films lose some of their mechanical properties. In the oat films, glycerol used as a plasticiser diffused from the starch-glycerol-water matrix to the surface of thermoplastic starch, resulting in areas with low friction. In the case of barley starch films, the ageing first resulted in short range reorientation of polymers and finally slow crystallization of amylopectin branches. Solution precipitation techniques were applied to produce ideally spherical starch ester particles (with a diameter about half the wavelength of visible light), suitable for fillers in paper coatings in the third study. Particles assume their shape and size spontaneously when solvated starch polymer is mixed with non-solvent, due to the free mobility of the modified starch chains. Starch pigment has improved affinity to paper surface and it can be used as such or mixed with other pigments to enhance the optical or printing properties of paper. Starch-based pigmenting materials with improved optical performance were prepared in the laboratory by the complexation approach. Analytical results indicated that the complexation of carboxymethyl starch and inorganics strongly depends on the carboxymethyl group in the starch-based hybrid pigmented materials. The formed insoluble hybrids were mostly amorphous and the crystalline contribution of the inorganic component was not evident. The resulting precipitates exhibited composite structures. Finally, three starch-based and two cellulose-based polymers were selected for flocculation and filtration tests. In shearless dewatering conditions, the retention and dewatering properties of the starch-based polymers were similar to those of commercial polyacrylamide-based polymers. The flow studies in higher shear conditions showed that with the studied dosages the starch-based polymers could not reach the flocculation levels needed to maintain sufficient retention properties. The performance of the cellulose-based polymers as flocculating agents was less efficient. The reasons for the more limited performance of the polysaccharide-based flocculants were too low molecular weight and the charge density distribution. Better understanding of how to improve the hydrodynamic properties of bio-based polymers will be essential when planning new bio-based flocculants. The deeper understanding of the relationships between the desired structures and properties of polysaccharides helps to utilize them more effectively. In this way it is possible to obtain better bio-based and environmentally sustainable products in the competition with the current products based on conventional petrochemistry.",
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author = "Lauri Kuutti",
note = "Project code: 82416",
year = "2013",
language = "English",
isbn = "978-951-38-7997-6",
series = "VTT Science",
publisher = "VTT Technical Research Centre of Finland",
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school = "University of Helsinki",

}

Cellulose, starch and their derivatives for industrial applications. Structure-property studies : Dissertation. / Kuutti, Lauri.

Espoo : VTT Technical Research Centre of Finland, 2013. 134 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Cellulose, starch and their derivatives for industrial applications. Structure-property studies

T2 - Dissertation

AU - Kuutti, Lauri

N1 - Project code: 82416

PY - 2013

Y1 - 2013

N2 - Despite the similarity of their structural basic units, cellulose- and starch-based materials behave differently in many industrial applications. In this thesis, the structure and properties of these polysaccharides and their selected derivatives were studied by means of five comprehensive examples. In the first investigation, highly crystalline cellulose was identified from Valonia macrophysa vesicles by atomic force microscopy. The role of water as a possible modifier on the surface of cellulose was found to be very important. The monoclinic phases were found on the cellulose surfaces with a lateral resolution of about 4 Å, indicating that water molecules cannot penetrate and thus disturb the surface structure of monoclinic cellulose. On the other hand, the absence of triclinic phases was explained by the used measuring geometry without liquid cell. The ageing of metastable oat and barley thermoplastic starch films was followed by frictional imaging. As a consequence of the ageing, the films lose some of their mechanical properties. In the oat films, glycerol used as a plasticiser diffused from the starch-glycerol-water matrix to the surface of thermoplastic starch, resulting in areas with low friction. In the case of barley starch films, the ageing first resulted in short range reorientation of polymers and finally slow crystallization of amylopectin branches. Solution precipitation techniques were applied to produce ideally spherical starch ester particles (with a diameter about half the wavelength of visible light), suitable for fillers in paper coatings in the third study. Particles assume their shape and size spontaneously when solvated starch polymer is mixed with non-solvent, due to the free mobility of the modified starch chains. Starch pigment has improved affinity to paper surface and it can be used as such or mixed with other pigments to enhance the optical or printing properties of paper. Starch-based pigmenting materials with improved optical performance were prepared in the laboratory by the complexation approach. Analytical results indicated that the complexation of carboxymethyl starch and inorganics strongly depends on the carboxymethyl group in the starch-based hybrid pigmented materials. The formed insoluble hybrids were mostly amorphous and the crystalline contribution of the inorganic component was not evident. The resulting precipitates exhibited composite structures. Finally, three starch-based and two cellulose-based polymers were selected for flocculation and filtration tests. In shearless dewatering conditions, the retention and dewatering properties of the starch-based polymers were similar to those of commercial polyacrylamide-based polymers. The flow studies in higher shear conditions showed that with the studied dosages the starch-based polymers could not reach the flocculation levels needed to maintain sufficient retention properties. The performance of the cellulose-based polymers as flocculating agents was less efficient. The reasons for the more limited performance of the polysaccharide-based flocculants were too low molecular weight and the charge density distribution. Better understanding of how to improve the hydrodynamic properties of bio-based polymers will be essential when planning new bio-based flocculants. The deeper understanding of the relationships between the desired structures and properties of polysaccharides helps to utilize them more effectively. In this way it is possible to obtain better bio-based and environmentally sustainable products in the competition with the current products based on conventional petrochemistry.

AB - Despite the similarity of their structural basic units, cellulose- and starch-based materials behave differently in many industrial applications. In this thesis, the structure and properties of these polysaccharides and their selected derivatives were studied by means of five comprehensive examples. In the first investigation, highly crystalline cellulose was identified from Valonia macrophysa vesicles by atomic force microscopy. The role of water as a possible modifier on the surface of cellulose was found to be very important. The monoclinic phases were found on the cellulose surfaces with a lateral resolution of about 4 Å, indicating that water molecules cannot penetrate and thus disturb the surface structure of monoclinic cellulose. On the other hand, the absence of triclinic phases was explained by the used measuring geometry without liquid cell. The ageing of metastable oat and barley thermoplastic starch films was followed by frictional imaging. As a consequence of the ageing, the films lose some of their mechanical properties. In the oat films, glycerol used as a plasticiser diffused from the starch-glycerol-water matrix to the surface of thermoplastic starch, resulting in areas with low friction. In the case of barley starch films, the ageing first resulted in short range reorientation of polymers and finally slow crystallization of amylopectin branches. Solution precipitation techniques were applied to produce ideally spherical starch ester particles (with a diameter about half the wavelength of visible light), suitable for fillers in paper coatings in the third study. Particles assume their shape and size spontaneously when solvated starch polymer is mixed with non-solvent, due to the free mobility of the modified starch chains. Starch pigment has improved affinity to paper surface and it can be used as such or mixed with other pigments to enhance the optical or printing properties of paper. Starch-based pigmenting materials with improved optical performance were prepared in the laboratory by the complexation approach. Analytical results indicated that the complexation of carboxymethyl starch and inorganics strongly depends on the carboxymethyl group in the starch-based hybrid pigmented materials. The formed insoluble hybrids were mostly amorphous and the crystalline contribution of the inorganic component was not evident. The resulting precipitates exhibited composite structures. Finally, three starch-based and two cellulose-based polymers were selected for flocculation and filtration tests. In shearless dewatering conditions, the retention and dewatering properties of the starch-based polymers were similar to those of commercial polyacrylamide-based polymers. The flow studies in higher shear conditions showed that with the studied dosages the starch-based polymers could not reach the flocculation levels needed to maintain sufficient retention properties. The performance of the cellulose-based polymers as flocculating agents was less efficient. The reasons for the more limited performance of the polysaccharide-based flocculants were too low molecular weight and the charge density distribution. Better understanding of how to improve the hydrodynamic properties of bio-based polymers will be essential when planning new bio-based flocculants. The deeper understanding of the relationships between the desired structures and properties of polysaccharides helps to utilize them more effectively. In this way it is possible to obtain better bio-based and environmentally sustainable products in the competition with the current products based on conventional petrochemistry.

KW - cellulose

KW - starch

KW - derivative

KW - industrial

KW - application

KW - structure

KW - property

M3 - Dissertation

SN - 978-951-38-7997-6

T3 - VTT Science

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -