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Compatibilization of polymeric blends of poly(lactic acid) PLA
Boldovjaková, Tatiana ; Kučera, František (oponent) ; Petruš, Josef (vedoucí práce)
The bachelor thesis deals with reactive compatibilization of polymer blend of poly(lactic acid) and polyamide 6 of weight ratios 20/80. The method of reactive compatibilization of poly(lactic acid) and polyamide 6 in laboratory kneader at 230 °C and 60 rpm was chosen based on knowledge introduced in the literature review. These blends were reactively compatibilized by poly(lactic acid) grafted with itaconic anhydride, multifunctional epoxide Joncryl, poly(itaconic anhydride) and organic peroxide 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (Luperox 101) at different concentrations for 4 minutes. The effects of reactive compatibilizers and its concentration on morphological, thermal and rheological properties of blends were investigated. Reactive compatibilizer Joncryl improved interfacial adhesion, reduced particle size of dispersed phase, improved thermal stability of blends when compared to uncompatibilized blend. The results show that Joncryl is an effective reactive compatibilizer for blend of poly(lactic acid) and polyamide 6. Poly(lactic acid) grafted with itaconic anhydride did not show desired effect due to the low concentration of anhydride groups. After the addition of poly(itaconic anhydride) and Luperox 101 into the poly(lactic acid)/polyamide 6 blends, side reactions occurred, which was proved by rheological and morphological properties of these blends.
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Post-polymerization modification of polyolefins for the preparation of hydroxylated macroinitiators
Boldovjaková, Tatiana ; Kučera, František (oponent) ; Petruš, Josef (vedoucí práce)
The diploma thesis deals with post-polymerization hydroxylation of polypropylene in solid state. Regarding the literature review, polypropylene was hydroxylated by radical grafting in aqueous solution of potassium persulfate at 100 °C, under nitrogen atmosphere for 60 minutes. Hydroxylation of polypropylene was performed at different concentrations of potassium persulfate (1; 5; 10 mol. %) and two different water/potassium persulfate molar ratios. The effects of reaction system composition and reaction conditions on reaction efficiency, extent of side reactions, thermal and rheological properties of hydroxylated polypropylene were evaluated. The presence and concentration of hydroxyl groups on polypropylene surface was determined by structural analysis (FTIR, XPS), while the highest efficiency was achieved in the presence of nonionic wetting agents, using 10 mol. % potassium persulfate and at lower water/potassium persulfate molar ratio. Based on changes in polypropylene structure, the modification took place mainly in the amorphous phase of the polymer. In addition to hydroxylation, concurrent side reactions have been reported, in particular the oxidation of wetting agents and polypropylene, which has resulted in chain cleavage, reducing the average molecular weight of the polypropylene.
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Post-polymerization modification of polyolefins for the preparation of hydroxylated macroinitiators
Boldovjaková, Tatiana ; Kučera, František (oponent) ; Petruš, Josef (vedoucí práce)
The diploma thesis deals with post-polymerization hydroxylation of polypropylene in solid state. Regarding the literature review, polypropylene was hydroxylated by radical grafting in aqueous solution of potassium persulfate at 100 °C, under nitrogen atmosphere for 60 minutes. Hydroxylation of polypropylene was performed at different concentrations of potassium persulfate (1; 5; 10 mol. %) and two different water/potassium persulfate molar ratios. The effects of reaction system composition and reaction conditions on reaction efficiency, extent of side reactions, thermal and rheological properties of hydroxylated polypropylene were evaluated. The presence and concentration of hydroxyl groups on polypropylene surface was determined by structural analysis (FTIR, XPS), while the highest efficiency was achieved in the presence of nonionic wetting agents, using 10 mol. % potassium persulfate and at lower water/potassium persulfate molar ratio. Based on changes in polypropylene structure, the modification took place mainly in the amorphous phase of the polymer. In addition to hydroxylation, concurrent side reactions have been reported, in particular the oxidation of wetting agents and polypropylene, which has resulted in chain cleavage, reducing the average molecular weight of the polypropylene.
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Compatibilization of polymeric blends of poly(lactic acid) PLA
Boldovjaková, Tatiana ; Kučera, František (oponent) ; Petruš, Josef (vedoucí práce)
The bachelor thesis deals with reactive compatibilization of polymer blend of poly(lactic acid) and polyamide 6 of weight ratios 20/80. The method of reactive compatibilization of poly(lactic acid) and polyamide 6 in laboratory kneader at 230 °C and 60 rpm was chosen based on knowledge introduced in the literature review. These blends were reactively compatibilized by poly(lactic acid) grafted with itaconic anhydride, multifunctional epoxide Joncryl, poly(itaconic anhydride) and organic peroxide 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (Luperox 101) at different concentrations for 4 minutes. The effects of reactive compatibilizers and its concentration on morphological, thermal and rheological properties of blends were investigated. Reactive compatibilizer Joncryl improved interfacial adhesion, reduced particle size of dispersed phase, improved thermal stability of blends when compared to uncompatibilized blend. The results show that Joncryl is an effective reactive compatibilizer for blend of poly(lactic acid) and polyamide 6. Poly(lactic acid) grafted with itaconic anhydride did not show desired effect due to the low concentration of anhydride groups. After the addition of poly(itaconic anhydride) and Luperox 101 into the poly(lactic acid)/polyamide 6 blends, side reactions occurred, which was proved by rheological and morphological properties of these blends.
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