This dissertation work deals with the thermic and the mechanical behavior of plasticized bio-plastics and bio-composites for the 3D printing applications. The influence of plasticizer chemical structure on thermic and mechanical properties of plasticized polymeric blends from the poly-3-hydroxybutyrate and the poly lactic acid was investigated. Used plasticizers are based on derivative of citric acid. The influence of plasticizers on polymeric matrix and their compatibility was estimated by gear torque rate of melt mixer, respectively rate of plasticizer migration from the material during higher temperature. The plasticizer structure influence on the glass transition temperature and on the kinetics of crystallization of plasticized material was investigated by modulated differential scanning calorimetry. The behavior of material during 3D printing was also observed. Mechanical properties of printed samples, especially their elongation at break, were determined by tensile tests. The largest softening effect was observed using tributylcitrate plasticizer, where the glass temperature decreased by 35 °C and elongation at break increased by 150% compared to non-plasticized reference material. This plasticized polymeric blend showed also sufficient 3D printing properties and was used as the matrix for composites in the next part of this work. Composites were filled by kaolin, limestone, halloysit, fumed silica, talc, magnesium hydroxide and chopped flax fibers. Particle distribution in composites in dependence of used surface treatment of filler was observed by scanning electron microscopy. The influence of composite filler on rheological properties, crystallization kinetics and thermal stability of composites, was observed by viscometry and differential scanning calorimetry. Their mechanical properties and heat deflection temperature were observed on samples prepared by 3D print. Kaolin in composite material showed homogeneous particle distribution and insignificant nucleation effect and influence on thermic stability. Composite filled by kaolin also showed 18% smaller warping during 3D printing compared to non-filled reference. Consequently kaolin was evaluated as suitable inorganic filler for bioplastic composite intended for 3D print and this composite was used in the following part of this thesis. Method of mathematical prediction of Young's modulus was described for composite samples prepared by 3D print. Composites filled by one type of filler – kaolin, or limestone, resp. by combination of both fillers were investigated on the basis of the micromechanic Halpin-Tsai model modified by the semiempiric multiparametric Cerny's equation. Additive and combinational method of Young's modulus evaluation is used for composites with hybrid filling. Deflection of measured and theoretical Young's modulus value of composite filled with kaolin was decreased by established correction from 21% to 1% and for composites filled with limestone from 13% to 9%. In this manner it is possible to predict the Young's modulus of the samples prepared by 3D print.

The project Kera-Plast aims to re-loop humans and nature by questioning the current systems and ethics through materiality. Human hair, currently considered as waste, functions as the base for the material exploration fabricated through thermo-compression molding. The flexible, short and opaque keratin-fibers get glued together with heat, pressure and water, acting as a plasticizer during the compression molding process. The results are stiff and remind on plastic due to shine and translucency. Aesthetics and function of the resulting material are controlled and designed by traditional textile techniques as knitting, weaving and non-woven processes. The material samples display the potential of Kera-Plast in the categories of 3D surface structures, patterns, shapeability and the influence of light. The findings also provide information about the parameters for designing with keratin fibers through the thermo-compression process. It can be concluded that despite all ethical and cultural factors, Kera-Plast and its fabrication method has the potential to add a sustainable, functional and aesthetical value to the design field and our future material consumption.

Mechanical properties of (woven carbon fiber / vinyl ester matrix) composites can be greatly improved if the interphase between the reinforcing high-strength low-weight fiber and the thermoset resin is made more compliant. In order to improve the adhesion of the vinyl ester matrix to the carbon fiber, a thermoplastic coating such as poly(vinyl pyrrolidone) (PVP) can be used as an intermediate between the matrix and the fiber. The extent of mutual diffusion at the (sizing material / polymer matrix) interphase plays a critical role in determining the mechanical properties of the composite. In this research, the molecular interdiffusion across a poly(vinyl pyrrolidone))/vinyl ester monomer (PVP/VE) interface is being investigated by Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) spectroscopy. The ATR method which can be used to characterize the transport phenomena, offers several advantages, such as the ability to monitor the diffusion <I>in situ</I> or to observe chemical reactions. In order to separate the effects of the vinyl ester monomer diffusion and the crosslinking reaction, ATR experiments were carried out at temperatures below the normal curing temperature. Diffusion coefficients were determined by following variations in infrared bands as a function of time, and fitting this data to a Fickian model. The values of the diffusion coefficients calculated were consistent with values found in the literature for diffusion of small molecules in polymers. The dependence of diffusion coefficients on temperature followed the Arrhenius equation. Hydrogen bonding interactions were also characterized. The diffusion model used in this study, however, does not seem to be appropriate for the particular (PVP/VE) system. Because the glass transition temperature of the PVP changed as diffusion proceeded, one would expect that the mutual diffusion coefficient did not stay constant. In fact, it was shown that the Tg can drop by 140oC during the diffusion process. A more suitable model of the (PVP/VE) system should take into account plasticization, hydrogen bonding, and especially a concentration dependent diffusion coefficient. Further analysis is therefore needed. / Master of Science

The use of carbon fibre-reinforced plastic technology is steadily gaining traction in the modern automotive industry as a lightweight alternative to conventional materials. The versatile chemical resistance of polyamide resins combined with the high strength properties of carbon fibre filler content aims to meet this growing need in the industry. By employing a number of accelerated and amplified ageing techniques, this work hopes to assess the resilience of carbon fibre-reinforced polyamide composites in a variety of foreseeable chemical, temperature, moisture, and stress environments. The resins included in this characterization study include polyamide-6 (PA6) and polyamide-6,6 (PA6/6). The carbon fibre-reinforced composite specimens are subject to long term immersion in commercial automotive fluids at room and elevated temperatures. Results show that the mechanical properties of both polyamide resins are sensitive to windshield washer fluid exposure, regardless of temperature. The significant drop in glass transition temperature and greater elongation at break confirmed a plasticization effect. The Young’s modulus and tensile strength experienced a loss of approximately 40% at saturation. Elevated temperatures resulted in increased fluid sorption rates of antifreeze and E-20 gasoline into the PA6 composite specimens. Likewise, a corresponding drop in PA6 composite mechanical properties was noted for the antifreeze and E-20 gasoline at elevated temperatures. The mechanical properties of the PA6/6 composite were largely retained in all tested automotive fluids, except windshield washer fluid, at elevated temperatures. The effect of absorbed fluid on mechanical properties tended to increase with higher fibre loadings for the PA6/6 composite and lower fibre loadings for the PA6 composite. Finally, a single parameter acoustic emission testing technique was employed to assess internal damage of stressed PA6 composite specimens exposed to different temperature and humidity levels. However, there was no discernible correlation between environmental stress conditions and internal damage for short term exposure times. / Thesis / Master of Applied Science (MASc) / The use of carbon fibre-reinforced plastic technology is steadily gaining traction in the modern automotive industry as a lightweight alternative to conventional materials. The versatile chemical resistance of polyamide resins combined with the high strength properties of carbon fibre filler content aims to meet this growing need in the industry. By employing a number of accelerated and amplified ageing techniques, this work assessed the resilience of carbon fibre-reinforced polyamide composites in a variety of foreseeable chemical, temperature, moisture, and stress environments. The composite only showed significant sensitivity to windshield wiper fluid in the tests.

No description available.

Conventional studies of ionomers have focused on ionomers bearing monovalent carboxylate or sulfonate pendant ions. There are relatively fewer studies on ionomers containing multivalent pendant ions, such as divalent phosphonate. In this dissertation, poly(ethylene terephthalate) (PET) and polystyrene ionomers with divalent phosphonate pendant ions have been synthesized, and the influence of divalent phosphonate pendant ions on the structure-morphology-property relationship has been compared to the ionomers with monovalent sulfonate pendant ions. The phosphonate groups generated a stronger physically crosslinked network in phosphonated ionomers as compared to sulfonated analogues. Higher plateau modulus, longer relaxation time, and significantly higher zero-shear viscosity were noted for phosphonated ionomers by a dynamic melt rheology study. Compared to the ionic aggregates generated from sulfonate groups, larger ionic aggregates with associated phosphonate groups have been observed. Furthermore, phosphonated ionomers displayed significantly higher glass transition temperatures than sulfonated ionomers. Ionomers have proven to be attractive, interfacially active compatibilizers for a number of polymer blend systems because of specific interactions that may develop between the ionic groups and complementary functional groups on other polar polymers within the blends. The successful compatibilization of polyester/polyamide blends (prepared by solution mixing and melt blending methods) using phosphonated PET ionomers as a minor-component compatibilizer has been demonstrated. The phase-separated polyamide domain dimension decreased with increasing mol % phosphonated monomers and this decrease was attributed to the specific interactions between the ionic phosphonate groups on the polyester ionomer and the amide linkages of polyamide. More importantly, the divalent phosphonate pendant ions are more effective at compatibilizing polyester/polyamide blends in comparison to the monovalent sulfonate pendant ions. Phosphonated PET ionomer-compatibilized polyester/polyamide blends required 6 times fewer ionic monomers to achieve domain dimension < 1 μm as compared to sulfonated PET-containing blends. Deep eutectic solvents (DES) have been reported to be the next generation solvents due to the superior biocompatibility, biodegradability, and sustainability as compared to ionic liquids. Two types of deep eutectic solvents, choline chloride : malic acid (ChCl:MA) and L-arginine : levulinic acid (Arg:LA), have been demonstrated as effective plasticizers for poly(vinyl alcohol) (PVOH) films. The plasticization effects on the properties of PVOH films were evidenced by lower crystallizability and improved film ductility. In addition, ChCl:MA deep eutectic solvent was more effective in plasticizing PVOH as compared to propylene glycol, one of the most widely studied alcohol-type plasticizers. From an applied perspective, DES-plasticized PVOH film is a promising candidate in the packaging market of heath-related products. / Doctor of Philosophy / Non-covalent interactions play an important role on the structure-morphology-property relationship of polymeric materials. Divalent phosphonate pendant ions provide interesting effects on the properties of ionomer and polymer blends as compared to the monovalent sulfonate pendant ions. Ionomers containing phosphonate pendant ions exhibit a significantly stronger physically crosslinked network as compared to sulfonated ionomers. Compared to monovalent sulfonate groups, the divalent phosphonate groups are more effective at compatibilizing polymer blends. Furthermore, the compatibilized poly(ethylene terephthalate)-based blends exhibit improved optical and oxygen barrier properties compared to the base blend without compatibilizer, signifying potential benefits in packaging industry. Poly(vinyl alcohol) is one of the most widely used packaging materials for food, medicine, detergent, etc. The incorporation of deep eutectic solvents as plasticizers significantly improved film ductility. In addition, the plasticization effect for choline chloride-based deep eutectic solvent is more profound than one of the most widely studied alcohol-type plasticizers, propylene glycol. The effective plasticization of poly(vinyl alcohol) using deep eutectic solvents confirmed the potential for future applications in the packaging market of health-related product.

The primary differences between the solventborne and waterborne epoxy printed circuit board (PCB) impregnating resins arise from the distinct physical compositions and drying characteristics of the polymer solution and the latex emulsion. The presence of residual surfactant from the waterborne epoxy emulsion poses a concern for dielectric performance and adhesive durability. Another problem involves the crystallization of insoluble solid dicyandiamide (DICY), which is significantly different in morphology than that found in solution cast resins. A two-stage drying model was employed to gain a better understanding the drying and coalescence processes. The process of surface DICY crystal formation during the drying of glass prepreg sheet was related to a threshold concentration of the curing agent in the impregnating latex resin formulation. Conditions favoring faster drying lead to the rapid formation of a coalesced skin layer of latex resin, thereby trapping the curing agent in the bulk and reducing the surface deposition of DICY by percolating water. Surfactant is believed to remain concentrated in a receding wet zone until it is driven to the surfaces of the glass fibers upon the completion of drying. The copper foil/laminate interface was evaluated by a 90° peel test as part of two different studies: an analysis of the viscoelastic response of the interface during peel and a study of the thermal durability of the copper/laminate interfacial peel strength. The surfactant acted as a plasticizer to toughen the fiber/matrix interphase, resulting in larger observed peel strengths in the latex resin impregnated materials relative to the solventborne system. Surfactant segregated to the fiber surface during coalescence to form a plasticized fiber/matrix interphase; surfactant migrated into the bulk during postcure to yield a more homogeneously plasticized epoxy matrix. Dielectric measurements of neat resin and laminate materials revealed that the dielectric constants of the model resin-impregnated laminates met the performance criteria for PCB substrates of their class, regardless of surfactant content. Overall, the adhesive performance, adhesive durability, and dielectric properties of PCB systems fabricated with model latex epoxy resin, containing native surfactant (5 wt %), met or exceeded the performance of an equivalent solventborne resin impregnated system. / Ph. D.

CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Klára Bílková Title of diploma thesis: Influence of plastification on rheological properties of oligoester of lactic acid and glycolic acid branched with dipentaerythritole Consultant: PharmDr. Eva Šnejdrová, Ph.D. The aim of this diploma thesis was the study of rheological properties of the oligoester of DL-lactic and glycolic acids branched with 1% of dipenthaerythritol (1D) and plasticized with 6 various plasticizers in increasing concentrations. Theoretical part was devoted to fundamentals of rheology and measurements of viscosity using rotational viscometers. It describes basic types and constructions of rotational rheometers and summarizes basic facts about bioadhesion and use of rheological method for assessment of bioadhesion. There were prepared matrices from oligoester 1D and plasticizers in concentrations of 20 %, 30 % and 40 % in the experimental part. These plasticizers were tested: ethyl pyruvate, ethyl salicylate, methyl salicylate, triacetin, tributyrin and triethyl citrate. Rheological properties were examinated at 37 řC using spindle viscometer and at 37 řC and 50 řC using rotational rheometer. Rheograms were used to characterize flow properties of tested...

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Student: Lenka Šišáková Supervisor of Diploma thesis: PharmDr. Eva Šnejdrová, Ph.D. Title of Diploma thesis: Aciclovir release from mucoadhesive matrices The aim of this diploma thesis was the study of the mucoadhesive parameters of plasticized oligoester of lactic acid and glycolic acid and 3% mannitol as a branching monomer. Knowledge of dissolution testing of drug release from dosage form, principal theories and mechanisms of mucoadhesion and mucoadhesion testing of adhesive formulation is described in theoretical part. Matrices formed from terpolymer of D,L-lactic acid, glycolic acid branched with mannitol and 5 % aciclovir were examined in the experimental part. Triethylcitrate (TEC), ethylpyruvate (EP), methylsalicylate (MS) and ethylsalicylate (ES) were used as plasticizers. Dissolution test has been done. Hydrated mucin from porcine stomach was used as a base. Phosphate-citrate buffer pH 7.4 was used as a dissolution medium. Dissolution was defined as a quantity of released aciclovir in to the dissolution medium after 15, 30, 60 and 90 minutes. The quantity of the released aciclovir was defined by a spectrophotometry. In 90 minutes was released 43 % of aciclovir from the matrice...

Esta tese apresenta os resultados da obtenção de eletrólitos sólidos poliméricos a partir dos derivados de celulose - hidroxipropilcelulose (HPC) e hidroxietilcelulose (HEC), ambas comerciais. Para atingir os objetivos do projeto, os dois derivados passaram por diferentes processos sendo que a HEC foi modificada fisicamente por meio de plastificação com glicerol e HPC foi alterada quimicamente. A transformação química consistiu nas reações de oxidação de grupos hidroxila da HPC em grupos cetona que, em seguida, foram submetidos as reações de enxertia com diamina de poli(óxido de propileno) [Jeffamina] resultando em redes por meio de ligações imina. A adição do sal perclorato de lítio, em diferentes concentrações, na matriz plastificada ou entrecruzada, resultou na obtenção de eletrólitos sólidos poliméricos, todos na forma de filmes. A caracterização destes eletrólitos foi realizada com técnicas básicas de caracterização de materiais como: análises térmicas (DSC, TGA), análise térmica dinâmico-mecânica (DMTA), análises estruturais (raios-X), medidas espectroscópicas (IR, UVNIS), análise elementar, microscopia eletrônica de varredura (SEM), e, como a mais importante, medidas de condutividade iônica utilizando a técnica de espectroscopia de impedância eletroquímica (EIS). / The present thesis reports the preparation and characterization of new types of solid polymeric electrolytes (SPE) based on cellulose derivatives such as hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC), both commercial products. Aiming to reach this purpose both derivatives were subjected to modification processes, where HEC were physically modified by plasticization process with glycerol and HPC were submitted to chemical reactions. The latter ones were promoted by the oxidation of HPC hydroxyl groups and ketone groups and then subjected to grafting with diamine poly(propylene oxide) (Jeffamine), resulting in the imine bond network formation. Different concentrations of lithium salt were added to the plasticized and grafted samples, resulting in solid polymeric electrolytes, all in the film form. The characterization of these samples was performed by thermal analysis (DSC, TGA and DMTA), X-ray diffraction (XDR), scanning electron microscopy (SEM), ultraviolet/visible/near-infrared spectroscopy (UV/Vis/NIR) and, as most important, measured of ionic conductivity using the technique of electrochemical impedance spectroscopy (EIS).