Search for dissertations about: "chain scission"

Showing result 1 - 5 of 11 swedish dissertations containing the words chain scission.

  2. 1. Cellulose degradation in pulp fibers studied as changes in molar mass distributions

    Author : Rickard Berggren; KTH; []
    Keywords : cellulose; kraft pulp; birch; spruce; ozonation; acid hydrolysis; degradation; MMD; size-exclusion chromatography; light scattering; molar mass; chain scission;

    Abstract : In this thesis, size-exclusion chromatography (SEC) of woodpolymers dissolved in lithium chloride/N,N-dimethylacetamide(LiCl/DMAc) has been used to characterize the molar massdistributions (MMD) of wood polymers in pulp fibers afterchemical degradation.Characterization of birch kraft pulps subjected to ozonedegradation and acid hydrolysis, respectively, rendereddifferent changes in the MMD. READ MORE

  4. 2. Plasma Modification of Polypropylene Materials for Improved Adhesion

    Author : Anna Nihlstrand; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; polypropylene; characterization; material composition; lacquer adhesion; plasma modification; chain scission; vacuum-ultraviolet radiation; thermoplastic polyolefin;

    Abstract : Materials based on PP are widely used in industrial applications. To fulfil application demands, components must often be lacquered, printed or glued. As PP is highly unreactive and presents a low surface energy, a pretreatment that can promote bondability is necessary. READ MORE

  5. 3. Modification of stable and degradable polymers by heterogeneous grafting

    Author : Mattias Ohrlander; KTH; []
    Keywords : ;

    Abstract : This thesis summarizes the investigations of the electronbeam initiated grafting of a hydrophilic monomer, acrylamide(AAm), onto three polymers; linear low density poly(ethylene)(LLDPE), poly(&-caprolactone) (PCL) and chemicallycrosslinked poly( 1,5-dioxepan-2-one) (PDXO-X). LLDPE and PCLare semicrystalline and PDXO-X is fully amorphous. READ MORE

  6. 4. Modelling the degradation processes in high-impact polystyrene during the first use and subsequent recycling

    Author : Francisco Vilaplana; Sigbritt Karlsson; Monika Ek; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Recycling; high-impact polystyrene; degradation; quality analysis; thermal analysis; vibrational spectroscopy; chromatography techniques; thermo-oxidation; reprocessing; dynamic mechanical properties; polybutadiene microstructure.; Polymer chemistry; Polymerkemi;

    Abstract : Polymers are subjected to physical and chemical changes during their processing, service life, and further recovery, and they may also interact with impurities that can alter their composition. These changes substantially modify the stabilisation mechanisms and mechanical properties of recycled polymers. READ MORE

  7. 5. Utilizing lignocellulose-based building blocks to develop recyclable polyesters

    Author : Nitin Valsange; Centrum för analys och syntes; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Biobased; Polyester; Recycling;

    Abstract : With the growing global population and the demand for new applications, the production of fossil-based plastics is continuously increasing. This has led to serious environmental concerns about the depletion of fossil resources, land and marine pollution, and generation of greenhouse gas emissions. READ MORE