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Showing result 1 - 5 of 39 swedish dissertations matching the above criteria.

2. 1. Volumetric Analysis in Mechanical Behaviour and Physical Ageing of Polymers

   Author : Mats Delin; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ageing rate; Gr neisen parameter; bulk modulus; KAHR model; dilatometry; Poisson s ratio; timescale; physical ageing; dynamic mechanical properties; stress relaxation; volume changes; creep; Doolittle s equation;

   Abstract : Volumetric changes associated with the deformation of ideal elastic solids depends on elastic constants of the solid and applied strain. Their magnitude is easily determined from the corresponding Poisson's ratios. READ MORE

4. 2. Viscoelastic properties and plasticization potential of native, residual, and technical lignin

   Author : Åke Henrik-Klemens; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lignocellulose; dynamic mechanical analysis; glass transition temperature; thermoplastic properties;

   Abstract : Lignin in biomass, pulp, and isolated during pulping all have great potential as renewable and inexpensive thermoplastic components and materials, but widespread utilization is hindered by high glass transition temperatures (Tg), brittleness, and poor flow properties. The aim of this thesis is to elucidate what molecular structures govern lignin thermoplasticity and how these can be efficiently manipulated. READ MORE

5. 3. Water diffusion and free volume in hydrophilic polymers

   Author : Charlotte Trotzig; Centrum för analys och syntes; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; free volume; self-diffusion; degree of crystallinity; glass transition temperature; tensile storage modulus; surface tension; isotherm; HPMC; PEO; water; triacetin; clay; Macromolecular chemistry; dynamic mechanical analysis; Fysikalisk kemi; differential scanning calorimetry; nuclear magnetic resonance; positron annihilation; Makromolekylär kemi;

   Abstract : During moisture uptake in polymers, the diffusion of the water molecules is believed to occur via unoccupied voids. These voids are called free volume cavities and their sizes are continuously altered when the moisture content in the polymer is enhanced. READ MORE

6. 4. Macroscopic Volume and Free Volume of Polymer Blends and Pressure-densified Polymers

   Author : Marcus Schmidt; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; free-volume theories; refractive index; Lorentz-Lorenz equation; loss tangent; Avrami equation; freezing fractions; copolymers; polymer blends; pressure dilatometry; Tait equation of state; free-volume distributions; pressure-densified polymers; entropy of melting; dynamic-mechanical analysis; positronium; positron annihilation; free volume; cavity size; polymers; bulk modulus; PVT; phase separation; compressibility; thermal expansivity;

   Abstract : The macroscopic volume V as a function of pressure P and temperature T is obtained from PVT measurements. PVT data is sensitive to the state of polymers and changes therein. Moreover, PVT data gives access to the free-volume fraction. READ MORE

7. 5. Rheological and mechanical properties of systems containing nanocellulose

   Author : Tobias Moberg; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shear rheology; Cellulose nanocrystals; Cellulose nanofibrils; Mechanical properties; Dynamic-mechanical analysis; Composites; Extensional rheology;

   Abstract : Nanocellulose is a cellulose entity at the nanoscale. There are several different types of nanocellulose such as cellulose nanofibrils (CNF), which are long, somewhat flexible fibrils and cellulose nanocrystals (CNC), which are shorter and more rod-like particles. READ MORE