Sökning: "degradation"

Visar resultat 1 - 5 av 2048 avhandlingar innehållade ordet degradation.

  1. 1. From Fast to Slow Degradation : Different Strategies to Characterise Polymer Degradation by Chromatographic Techniques

    Författare :Guillaume Gallet; KTH; []
    Nyckelord :poloxamer; polylactide; degradation; oxidation. Hydrolysis. Solid phase microextraction;

    Sammanfattning : .... LÄS MER

  2. 2. Degradation of polyethylene pipes distributing chlorinated water : depletion of stabilizers, release of degraded products and polymer degradation

    Författare :Wenbin Yu; Ulf Gedde; Mats Jonsson; Minna Hakkarainen; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; polyethylene pipes; chlorine dioxide; degradation; Polymer chemistry; Polymerkemi;

    Sammanfattning : This thesis presents the study of antioxidants depletions in chlorinated media (10 ppm Cl2 - and ClO2 - aqueous media), polyethylene pipes degradations scenarios and migration of the degraded species to aqueous phase. Pressure testing on pipes and squalane testing with controlled pH aqueous media (6.8 ± 0. LÄS MER

  3. 3. Controlling Polylactide Degradation through Stereocomplexation and Lactic Acid Based Additives

    Författare :Sofia Regnell Andersson; Minna Hakkarainen; Ann-Christine Albertsson; Marek Kowalczuk; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Polylactide; stereocomplex; plasticizer; degradation; degradation products; ESI-MS;

    Sammanfattning : The successful use of degradable materials in new applications depends on our ability to control the degradation process. A number of aspects need to be evaluated including degradation rate, the onset of degradation and the nature, formation and release of degradation products. LÄS MER

  4. 4. Free radical mediated cellulose degradation

    Författare :Erik Johansson; KTH; []
    Nyckelord :free radicals; cellulose; polymer; average chain length; bleaching; TCF; ozone; degradation;

    Sammanfattning : This thesis addresses the mechanisms involved in cellulosedegradation in general and Totally Chlorine Free (TCF) bleachingof pulp in particular. The thesis shows that the cellulosedegradation during high consistency ozone bleaching is explainedby free radical chain reactions. LÄS MER

  5. 5. Environmentally Degradable Polyethylene : Effects of Additives and Environment on the Degradation and Degradation products

    Författare :Farideh Khabbaz; KTH; []
    Nyckelord :LDPE; polyethylene; oxidative degradation; photo-oxidation; thermo-oxidation; degradation products; photosensitisers; pro-oxidant; starch; master-batch; gas chromatography mass-spectrometry; GC-MS; solid phase microextraction; SPME;

    Sammanfattning : This thesis summarises and compares the influences ofdifferent additives (photosensitisers, pro-oxidants, abiodegradable filler) on blown low-density polyethylene (LDPE)films during photo- and thermal degradation with respect tochemical changes in the polymer matrices and identifieddegradation products. Additives studied were irondimethyldithiocarbamate (FeDMC), nickel dibutyldithocarbamate(NiDBC), carbon black, starch, a pro-oxidant that consisted ofmanganese stearate together with styrene butadiene rubber (SBR)or natural rubber (NR) and a master batch containing linearLDPE, starch and pro-oxidant. LÄS MER