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Visar resultat 1 - 5 av 297 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Microfibrillated cellulose : Energy-efficient preparation techniques and key properties

    Författare :Mikael Ankerfors; Lars Wågberg; Minna Hakkarainen; Paul Gatenholm; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microfibrillated cellulose; microfibrillar cellulose; nanofibrillated cellulose nanofibrillar cellulose; nanocellulose; MFC; NFC; production techniques; energy efficient; gel properties; films; enzymes; carboxymethylation; carboxymethyl cellulose; CMC; mechanical properties; oxygen barrier; homogenization;

    Sammanfattning : This work describes three alternative processes for producing microfibrillated cellulose (MFC) in which pulp fibres are first pre-treated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated with a combined enzymatic and mechanical pre-treatment. LÄS MER

  3. 2. Microfibrillated cellulose: Energy-efficient preparation techniques and applications in paper

    Författare :Mikael Ankerfors; Lars Wågberg; Akira Isogai; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microfibrillated cellulose; microfibrillar cellulose; nanofibrillated cellulose; nanofibrillar cellulose; cellulose nanofibrils; nanocellulose; MFC; NFC; CNF; production techniques; energy efficient; gel properties; films; enzymes; carboxymethylation; carboxymethyl cellulose; CMC; mechanical properties; oxygen barrier; homogenization; linting; papermaking; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : This work describes three alternative processes for producing microfibrillated cellulose (MFC; also referred to as cellulose nanofibrils, CNF) in which bleached pulp fibres are first pretreated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated by a combined enzymatic and mechanical pretreatment. LÄS MER

  4. 3. Nanostructured Cellulose Biocomposites : Effects from dispersion, network and interface

    Författare :Mohd Farhan Ansari; Lars Berglund; Jean-Francois Gerard; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wood; cellulose nanofibrils; hygromechanical properties; network structure; thermoset; polymer matrix composites; natural fiber composites; pulp fiber; strain hardening; humidity; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : The major load bearing component in native wood, cellulose nanofibrils, are potential candidates for use as reinforcement in polymer matrices. This study is based on nanocellulose composites and attempts to prepare and characterize biocomposites with high nanocellulose content and investigate the influence of nanostructure on macroscopic properties. LÄS MER

  5. 4. Swelling of Cellulose Fibrillar Matrices and Gels

    Författare :Pernilla Karlsson; Lars Wågberg; Per Tomas Larsson; Eero Kontturi; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; swelling; hydrogel; cellulose; wood; cellulose fibrils; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : One of the major challenges of today´s society is to find a sustainable way to create a living based on the resources on earth. It is a challenge that includes a transition from fossil-based materials to renewable/biodegradable raw materials and also the creation of an environmentally friendly circular material flow. LÄS MER

  7. 5. Strategies for cellulose fiber modification

    Författare :Per Persson; KTH; []
    Nyckelord :Candida antarctica lipase B; cationic catalysis; cellulose-binding module; dendrimer; enzymatic polymerization; fiber modification; silica-cast replica; sol-gel mineralization; organocatalysis; xyloglucan endotransglycosylase;

    Sammanfattning : This thesis describes strategies for and examples ofcellulose fiber modification.The ability of an engineered biocatalyst, acellulose-binding module fused to theCandida antarcticalipase B, to catalyze ring-openingpolymerization of e-caprolactone in close proximity tocellulose fiber surfaces was explored. LÄS MER