|
|
Preparation and characterization of unsaturated bio-polyester resins
Žůrek, Michal ; Petrůj, Jaroslav (referee) ; Figalla, Silvestr (advisor)
The theoretical part of this work is devoted to the selection of suitable components for synthesis of a branched oligoester and their structural arrangement. Further, oligomers of lactic acid esterified with crotonic acid branched by erythritol or pentaerythritol are discussed. Crosslinking of prepared oligoesters is accomplished by free radical mechanism using vinyl acetate as reactive diluent and 2,2'-azo-bis-isobutyronitrile as initiator. Resin was cured by vinyl acetate in different mass ratios. Results show that there in an optimal ratio for curing between oligoester and reactive diluent. Using less vinyl acetate results in insufficient crosslink density or, on the contrary, using considerable excess of vinyl acetate causes rapid polymerization, that also results in lower density of crosslinking. The crosslink density was determined indirectly by extraction of the soluble part to acetone after curing and drying of the product.
|
|
|
Physico-chemical characterization of 3-hydroxybutyrate with respect to its bioprotective effects
Kahanovská, Kristína ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
The main aim of the work was to verify bio-protective properties of 3-hydroxybutyrate (3HB) in terms of its effect on protein denaturation (especially lipase) and determine the physicochemical characteristics of 3HB that could lead to the explanation of the mechanism of its protective effect. The literature search focused primarily on the mechanism of the protective effect of the compatible solutes. The 3HB belongs to the group of compatible solutes. The protective effect of the 3HB was monitored by Dynamic Light Scattering (DLS). As the other parameters of the aqueous solution 3HB were determined: the dependence of the surface tension on the concentration of the 3HB, the effect of different 3HB concentrations on the zeta potential of the lipase. Hydrophobic and hydrophilic character of the 3HB was characterized with the log Kow parameter. A simple method for quantity determination of the 3HB aqueous solution was optimized. The method is based on conversion of the 3HB into crotonic acid by reaction with sulphuric acid at higher temperatures and on subsequent psectrophotometric determination of the amount of crotonic acid.
|
|
|
Preparation and characterization of unsaturated bio-polyester resins
Žůrek, Michal ; Petrůj, Jaroslav (referee) ; Figalla, Silvestr (advisor)
The theoretical part of this work is devoted to the selection of suitable components for synthesis of a branched oligoester and their structural arrangement. Further, oligomers of lactic acid esterified with crotonic acid branched by erythritol or pentaerythritol are discussed. Crosslinking of prepared oligoesters is accomplished by free radical mechanism using vinyl acetate as reactive diluent and 2,2'-azo-bis-isobutyronitrile as initiator. Resin was cured by vinyl acetate in different mass ratios. Results show that there in an optimal ratio for curing between oligoester and reactive diluent. Using less vinyl acetate results in insufficient crosslink density or, on the contrary, using considerable excess of vinyl acetate causes rapid polymerization, that also results in lower density of crosslinking. The crosslink density was determined indirectly by extraction of the soluble part to acetone after curing and drying of the product.
|
|
|
Physico-chemical characterization of 3-hydroxybutyrate with respect to its bioprotective effects
Kahanovská, Kristína ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
The main aim of the work was to verify bio-protective properties of 3-hydroxybutyrate (3HB) in terms of its effect on protein denaturation (especially lipase) and determine the physicochemical characteristics of 3HB that could lead to the explanation of the mechanism of its protective effect. The literature search focused primarily on the mechanism of the protective effect of the compatible solutes. The 3HB belongs to the group of compatible solutes. The protective effect of the 3HB was monitored by Dynamic Light Scattering (DLS). As the other parameters of the aqueous solution 3HB were determined: the dependence of the surface tension on the concentration of the 3HB, the effect of different 3HB concentrations on the zeta potential of the lipase. Hydrophobic and hydrophilic character of the 3HB was characterized with the log Kow parameter. A simple method for quantity determination of the 3HB aqueous solution was optimized. The method is based on conversion of the 3HB into crotonic acid by reaction with sulphuric acid at higher temperatures and on subsequent psectrophotometric determination of the amount of crotonic acid.
|
guest ::
