Sökning: "cellulose I"

Visar resultat 1 - 5 av 335 avhandlingar innehållade orden cellulose I.

1. 1. Mercerization and Enzymatic Pretreatment of Cellulose in Dissolving Pulps

   Författare :Heléne Almlöf Ambjörnsson; Ulf Germgård; Thomas Nilsson; Storker Moe; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; alkali; carboxymethyl cellulose; cellulose I; cellulose II; cellulose dissolution; degree of substitution; enzymatic treatment; filterability; gel formation; mercerization; multivariate analytical methods; NIR FT Raman spectroscopy; sodium hydroxide; zink oxide; Chemical Engineering; Kemiteknik;

   Sammanfattning : This thesis deals with the preparation of chemically and/or enzymatically modified cellulose. This modification can be either irreversible or reversible. Irreversible modification is used to prepare cellulose derivatives as end products, whereas reversible modification is used to enhance solubility in the preparation of regenerated cellulose. LÄS MER

3. 2. Experimental study of alkalinisation of cellulose in industrial relevant conditions

   Författare :Diana Carolina Reyes Forsberg; Ola Sundman; Bertil Eliasson; Ulf Germgård; Umeå universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Mercerisation; Alkalinisation; Cellulose I; Cellulose II; Alkali cellulose; Viscose; Cellulose ether; Carboxymethylcellulose; Sodium glycolate; Sodium diglycolate; Raman spectroscopy;

   Sammanfattning : Mercerisation of cellulose pulp with a solution of NaOH is the first step of manufacturing cellulose-based value-added products, e.g. viscose fibres and cellulose ethers. During this process, cellulose transforms into a swollen crystalline structure, alkali cellulose (Na-Cell). LÄS MER

4. 3. Chemical modification of cellulose-new possibilities of some classical routes

   Författare :Merima Hasani; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Cellulose esters; Cellulose characterization; Cellulose ethers; Cationization; Cellulose nanocrystals; Crosslinking of cellulose;

   Sammanfattning : Owning to its unique structure, along with the inexhaustible renewability, cellulose has been a subject of scientific and commercial interest for over 150 years. However, given attractive structural properties, such as stiffness, hydrophilicity, stereoregularity, potential for chemical modifications and ability to form superstructures, utilization of this biopolymer is far below its potential. LÄS MER

5. 4. Tailoring Cellulose Nanofibrils for Advanced Materials

   Författare :Núria Butchosa Robles; Qi Zhou; Kristiina Oksman; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cellulose nanofibrils; bacterial cellulose; surface modification; carboxymethyl cellulose; polyethylene glycol; chitin nanocrystals; bactericidal activity; nanofibrils orientation; water redispersability; mechanical properties; dye removal; Fiber- och polymervetenskap; Fibre and Polymer Science;

   Sammanfattning : Cellulose nanofibrils (CNFs) are nanoscale fibers of high aspect ratio that can be isolated from a wide variety of cellulosic sources, including wood and bacterial cellulose. With high strength despite of their low density, CNFs are a promising renewable building block for the preparation of nanostructured materials and composites. LÄS MER

7. 5. Cellulose derived carbon dots : From synthesis to evaluation as multifunctional building blocks in biomedical scaffolds

   Författare :Nejla Benyahia Erdal; Minna Hakkarainen; Jukka Seppälä; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cellulose; microwave; carbon dots; polycaprolactone; scaffold; mineralization; drug loading; cellulosa; mikrovågor; kolnanopartiklar; polykaprolakton; stödmatris för vävnadsregenerering; mineralisering; läkemedelsbärare; Fiber- och polymervetenskap; Fibre and Polymer Science;

   Sammanfattning : The implementation of biobased and biodegradable polymeric materials in biomedical applications is often coupled with issues related to their insufficient mechanical properties or limited bioactivity. In this thesis, a perspective on valorization of biomass is presented, demonstrating the transformation of cellulose into biobased carbon nanomaterials with the potential to serve as multifunctional property enhancers in polycaprolactone (PCL) scaffold materials for tissue engineering. LÄS MER