Dissertations / Theses: 'Thermoplastic and thermoset polymers'

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Ning, Xin. "Reactive processing and material characterization of thermoplastic and thermoset polymers and their composites." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1059490285.

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Elliniadis, Stavros. "Phase separation in thermoplastic - thermoset polymer blends." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266360.

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Hong, Yifeng. "Processing of expandable thermoplastic/thermoset syntactic foam." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53895.

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While hollow glass microspheres are commonly used in syntactic foam, their abrasive and brittle properties usually result in poor processability and have adverse effects on the foam performance. Therefore, a number of attempts have been made in the industry to replace hollow glass microspheres with polymeric foamed microspheres. Among many choices, expandable thermoplastic (ETP) microspheres filled syntactic foam has shown its high potential to become a novel class of engineering materials, especially for lightweight structural applications. However, conventional processing techniques for syntactic foam usually experience difficulties such as high processing viscosity, low loading of foam fillers, and ineffective microsphere expansion. To address these emerging issues, a microwave expansion process to produce thermoset-matrix syntactic foam containing thermoplastic foam beads was developed in this thesis work. In this process, unexpanded ETP microspheres were directly foamed in uncured thermoset matrix via microwave heating. Expandable polystyrene (EPS) microspheres and epoxy resin were chosen as a model material system. The resin viscosity and specific microwave energy are found to be the two primary control parameters determining the process window. Mechanical characterization showed that the syntactic foam can outweigh neat polymer in lightweight structural applications and was effectively toughened by foamed EPS. Furthermore, the microwave expansion process was found to be capable of molding syntactic foam parts of relatively sophisticated geometry with smooth surfaces. In order to broaden its impact, the microwave expansion process was extended to produce composite EPS foam. This process converts an expandable suspension into a composite foam with a honeycomb-like barrier structure. The suspension viscosity was found to highly influence the foam morphology. Results from mechanical tests showed that the existence of the barrier structure can considerably improve the mechanical performance of the composite foam. Fire-retardation tests demonstrated that the barrier structure can effectively stop the fire path into the foam, suppress toxic smoke generation, and maintain foam structure integrity. A general formulation was developed to model the EPS expansion to optimize the microwave expansion process. A semi-analytical solution was first obtained based on the case of a single bubble expansion in an infinite matrix. The dimensionless bubble radius and pressure are defined and found to be as exponential functions of dimensionless expansion time. The semi-analytical solution can qualitatively predict the radial expansion of EPS microsphere observed in a real-time experiment. To have an accurate prediction, a numerical solution was obtained to the model that couples the nucleation and expansion of multiple bubbles in a finite matrix. The results show that the numerical solution can quantitatively predict the radial expansion of EPS. A parameter sensitivity study was performed to examine the effect of each parameter over the expansion process.

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Yang, Bing. "Thermoplastic and Thermoset Natural Fiber Composite and Sandwich Performance." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500002/.

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The objective of this thesis is to investigate the effects of adding natural fiber (kenaf fiber, retted kenaf fiber, and sugarcane fiber) into polymer materials. The effects are obtained by considering three main parts. 1. Performance in thermoplastic composites. The effect of fiber retting on polymer composite crystallization and mechanical performance was investigated. PHBV/PBAT in 80/20 blend ratio was modified using 5% by weight kenaf fiber. Dynamic mechanical analysis of the composites was done to investigate the glass transition and the modulus at sub-ambient and ambient temperatures. ESEM was conducted to analyze fiber topography which revealed smoother surfaces on the pectinase retted fibers. 2. Performance in thermoset composites. The effect of the incorporation of natural fibers of kenaf and of sugarcane combined with the polyester resin matrix is investigated. A comparison of mechanical properties of kenaf polyester composite, sugarcane polyester composite and pure polyester in tensile, bending, dynamic mechanical thermal analysis (DMA) and moisture test on performance is measured.. 3. Performance in sandwich composites. The comparison of the performance characteristics and mechanical properties of natural fiber composites panels with soft and rigid foam cores are evaluated. A thorough test of the mechanical behavior of composites sandwich materials in tensile, bending and DCB is presented here.

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Codou, Amandine. "La cellulose et le poly(ethylene 2,5-furandicarboxylate) comme précurseurs biosourcés de matériaux thermoplastiques et thermodurcissables : les transitions physiques des biopolymères et l'élaboration des composites." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4123/document.

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La cellulose et le poly(éthylène 2,5-furandicarboxylate) (PEF) sont les deux précurseurs polymériques biosourcés étudiés dans ce travail de thèse. Deux approches ont été envisagées ; l’une se concentrant sur les aspects fondamentaux et l’autre sur l’élaboration de composites à partir de ces polymères. D’une part, la transition vitreuse et la cristallisation non-isotherme du PEF ont été explorées. Une approche cinétique de ces transitions a mis en lumière un comportement particulier du PEF et permet ainsi de mieux appréhender sa mise forme. De plus, la transition haute température de la cellulose Iβ a été étudiée pour la première fois en corroborant des techniques d’analyse thermiques et spectroscopiques complémentaires. En deuxième lieu, l’oxydation contrôlée d’une seule source de cellulose sous l’action du periodate de sodium a permis l’élaboration de composites entièrement cellulosiques qui se démarquent par leur haute performance mécanique. Enfin, le PEF et des nanocristaux de cellulose ont été combinés ce qui a permis l’élaboration de composites thermoplastiques où les cristaux de cellulose semblent jouer le rôle d’agents nucléants
The cellulose and the poly(ethylene 2,5-furandicarboxylate) (PEF) were the two main biobased polymeric precursors employed in this thesis work. Two complementary investigation pathways were explored which respectively focus on the fundamental aspects and on elaboration of composites from these precursors. First, the glass transition and both the melt/glass non-isothermal crystallization of PEF were investigated. A kinetic approach of these transitions revealed a peculiar behavior of PEF which is useful to better understand its processing. In addition, the high-temperature transition of cellulose Iβ was for the first time explored by means of complementary thermo-analytical and spectroscopic techniques. On the other hand, the controlled periodate oxidation of one single cellulose source was employed to generate thermoset-like “all-cellulose composites” marked by their high mechanical performances. Finally, combination of PEF and cellulose nanocrystals allows to obtain transparent thermoplastic composites in which the cellulosic entities might have nucleating effects

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Schuhler, Eliot. "Dégradation des matériaux composites sous l'effet d'une flamme : application à la réaction aux feux des composites utilisés pour les transports et l'énergie Behaviour of aeronautical polymer composite to flame: a comparative study of thermoset- and thermoplastic-based laminate." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMIR27.

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L’utilisation des matériaux composites à matrice polymère dans l’industrie aéronautique offre de nombreux avantages en termes de gain de masse et de résistance à la fatigue ou à la corrosion. Cependant l’utilisation de nouveaux matériaux tels que les composites à matrice thermodurcissable nécessite des efforts conséquents de développement, de test et de vérification. En particulier dans le domaine de la résistance aux incendies. Ce travail porte sur la caractérisation expérimentale de la résistance au feu pour différents types de matériaux composites au moyen d’un brûleur. La première partie de l’étude traite en particulier de la caractérisation du flux thermique lors de l’agression par la flamme. Dans un second temps, la réponse à cette agression thermique est mesurée pour différents matériaux composites. Pour les deux volets de cette étude, les résultats expérimentaux sont confrontés aux résultats issus de simulations numériques avec OpenFoam
Carbone fibers reinforced polymers offer many advantages in terms of weight, fatigue resistance or corrosion in the aerospace industry. However, the use of new materials such as thermosetting matrix composites requires a significant effort of development, testing and validation. In particular in the field of fire resistance. This work focuses on the experimental characterization of fire resistance for different types of composite materials using a flame burner. The first part of the study deals with the characterization of the heat flux during the flame impingement. In a second step, the response to this thermal stress is measured for different composite materials. For both parts of this study, the experimental results are compared to the results obtained from numerical simulations with OpenFoam

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Solouki, Bonab Vahab. "Polyurethane (PU) Nanocomposites; Interplay of Composition, Morphology, and Properties." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1542634359353501.

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Watt, Paula. "Soy-Based Fillers for Thermoset Composites." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1436431761.

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Mezzenga, Raffaele. "Hyperbranched polymers as modifiers for thermoset resins /." [S.l.] : [s.n.], 2001. http://library.epfl.ch/theses/?nr=2428.

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Mohammadzadeh, Maryam. "Characterization of recycled thermoplastic polymers." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19650.

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In this study thermal and mechanical properties and chemical structure of four differentpolymers (PE, PP, polyASA and PVC) were investigated to find out if the recycled polymershad the same properties and can be used in the same applications as the virgins or not.FT-IR was used for investigation of chemical structure. TGA, DSC and thermal stability wereused to compare the thermal properties. Tensile test also used to examine the mechanicalproperties.All the tests showed the recycling process is not done completely well. The differences inresults for virgins and recycled samples are the reasons which verified this claim.The results obtained from this study clarifying that the amount of stabilizer in the recycledpolymers were considerably less than the amount in virgins, means that the company had notadded enough stabilizer during the recycling process.

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Albrecht, Mirko, and Michael Gehde. "Welding of incompatible thermoplastic polymers." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-204024.

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Due to the wide range of properties of plastics (e.g. low density), more and more conventional materials are substituted by polymer materials. Complex requirement profiles on technical parts increase the demand for joining processes that enable the reliable joining of otherwise incompatible thermoplastics. In this case, material bonded connections are approaching their limits. In the following study two incompatible thermoplastic polymers were welded by using polymer blends that are compatible to both components. Industrially relevant thermoplastics polyethylene (PE) and polyamide 12 (PA12) were chosen to demonstrate the potential of an innovative joining technology.

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Daso, Frederick O. (Frederick Odien). "Manufacture of aerospace-grade thermoset and thermoplastic composites via nanoengineered thermal processing." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122408.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 138-149).
Aerospace manufacturers continue to rely on composite materials to make aerovehicles lighter and stronger, particularly employing carbon fiber reinforced plastics (CFRP) using carbon microfiber reinforcement with thermoset and thermoplastic polymer matrices. With the increasing use of such composites, the need for energy-efficient, cost-effective methods to produce composite structures is desired. Traditional curing processes such as autoclaves and ovens rely on convective heat transfer, which has fundamental inefficiencies and several limitations including infrastructure cost and throughput bottlenecks. Similarly, hot presses (usually for thermoplastic matrices) for processing composites through conductive heat transfer are limited to a narrow range of part geometries. Direct Joule heating with carbon nanotube (CNT) film network heaters has shown significant promise to overcome these key manufacturing challenges of composites in the aerospace industry.
This Out-of-Oven (000) conductive curing technique has been shown to cure aerospace-grade out-of-autoclave (OoA) CFRP prepreg laminates with equivalent quality to that achieved with the manufacturer's recommend cure cycle (MRCC) in an oven. Herein are introduced three new advances utilizing OoO heating: i) the first application of OoO heating to processing aerospace-grade thermoplastic (polyetheretherketone, PEEK) CFRP prepreg, ii) a new method to accelerate the cure cycle of OoA CFRP prepreg, and iii) a novel strategy towards eliminating cure-driven deformations within composites with curved geometries via spatially-tailored OoO 'zonal curing'. OoO is found to produce PEEK CFRP plate specimens comparable or better than MRCC autoclave and hot press-produced laminates, both in terms of quality and strength, with advantages in spatial and temporal control noted.
Cure cycle duration for the thermoset OoA CFRP can be shortened by more than 60% while still producing flat laminates with similar quality and (short beam shear, SBS) strength compared to MRCC-produced specimens. The OoO zonal curing is shown via modeling to reduce the cure-driven deformation in thermoset OoA CFRP L-shape cuved parts by at least 11%. By demonstrating OoO curing's several advantages due to the CNT film's ability to maintain thermal stability at high temperatures, the near-instantaneous temporal control, the results in this work show that OoO curing can contribute to the next leap in composites manufacturing capability and technology. While the work herein has focused on aerospace-grade CFRP materials with the highest performance and quality, OoO is applicable to other materials in other industries including wind, ground vehicle, and infrastructure applications of a variety of advanced composites, including glass fiber reinforced plastics (GFRP).
by Frederick O. Daso.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics

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Al-Maliky, Noori Sabih Jarrih. "Strain rate behaviour of thermoplastic polymers." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/11570.

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Polymers are increasingly used in structures that have to withstand impact conditions. This thesis describes an investigation of strain rate properties at room temperature of four engineering polymers; polyethylene (high density, HDPE and ultra high molecular weight, UHMWPE), nylatron and polyetheretherketone (PEEK 150g). A split Hopkinson pressure bar (SHPB) system was used to study the response of these polymers in compression tests at high strain rates up to 10' S-1. Stress equilibrium in SHPB samples was studied theoretically by examining multiple reflection effects during the initial elastic loading of the polymers; this study proved very useful in the analysis of SHPB tests. To cover a wide range of strain rate, compression studies were also made at low strain rates (10-3 _10-2 S-1) using a Hounsfield screw machine. Viscoelastic models have been applied to these results. These models fit quite well with the experimental results of HDPE, UHMWPE, and nylatron, but not to the PEEK due to the yield drop in the stress - strain curves, especially at high strain rates. An exploding wire technique was used as an axial impulsive loading system for hollow cylindrical samples. An image converter camera at framing intervals of 21ls or 10 Ils recorded the radial expansion of the cylinder. The expanding cylinder was used as a driving system for a new technique called the freely expanding ring method, which was used to obtain the stress - strain behaviour of polymeric thin rings placed as a sliding fit on the cylinder. This method produced very high tensile strain rates up to fracture (> 10' S-1). Comparisons have been made between results obtained from the quasi-static, SHPB, and expanding ring tests. The freely expanding ring and SHPB results were in good agreement indicating similar tensile and compressive high strain rate behaviour. The mechanical properties of the above polymers are strongly dependent on strain rate. The Young's modulus and the flow stress increase with increasing strain rate. Nylatron showed high strain rate strain softening at high strain, this was due to the high temperature rise during loading, when the transition temperature (Tg) of the material (50 QC) was exceeded. However, the other materials showed continuous hardening behaviour. Plots of the flow stress at 5% and 10% strain vs log strain rate showed a linear increase up to a strain rate of about 103 S-1. Above 103 s-1, the stress rose more rapidly, but then showed significant drops for nylatron and PEEK. These drops in stress are probably due to both micro crack initiation in the sample and also high temperatures around the crack tips.

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Wise, Roger Jeremy. "Ultrasonic welding of glassy thermoplastic polymers." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624545.

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Vick, Linda Wagnecz. "Solid-state processing of thermoplastic polymers." Diss., Virginia Tech, 1996. http://hdl.handle.net/10919/39161.

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Although compaction and sintering of polymeric powders has been investigated since the early 1970's, this processing method is not widely used, possibly because the fundamental mechanisms which control compaction and sintering have never been fully understood. This study has made significant contributions to our understanding of compaction and sintering of polymers. It was demonstrated that mechanical properties (yield strength, modulus) and physical characteristics (degree of physical aging, glass transition temperature, presence of crystallinity) of the particles, and thus, powder processing, storage, and handling techniques, affect the ability of the polymer to be successfully compacted. The difficulties encountered in sintering polymeric compacts were explained in terms of a loss of configurational entropy of the polymer molecules during compaction, which caused large-scale dimensional recovery in the particles upon heating above T g. Hot compaction (above room temperature, but below Tg) was not found to be useful in eliminating recovery during pressureless sintering. However, consolidation of compacts formed at room temperature (by heating 10-20°C above T g and applying a small pressure (less than 50 kPa» was shown to be a promising processing method.
Ph. D.

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Goonetilleka, M. D. R. J. "Migration of additives from thermoplastic polymers." Thesis, Aston University, 1988. http://publications.aston.ac.uk/9720/.

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A homologous series of ultra-violet stabilisers containing 2-hydroxybenzophenone (HBP) moiety as a uv absorbing chromophore with varying alkyl chain lengths and sizes were prepared by known chemical synthesis. The strong absorbance of the HBP chromophore was utilized to evaluate the concentration of these stabilisers in low density polyethylene films and concentration of these stabilisers in low density polyethylene films and in relevant solvents by ultra-violet/visible spectroscopy. Intrinsic diffusion coefficients, equilibrium solubilities, volatilities from LDPE films and volatility of pure stabilisers were studied over a temperature range of 5-100oC. The effects of structure, molecular weight and temperature on the above parameters were investigated and the results were analysed on the basis of theoretical models published in the literature. It has been found that an increase in alkyl chain lengths does not change the diffusion coefficients to a significant level, while attachment of polar or branched alkyl groups change their value considerably. An Arrhenius type of relationship for the temperature dependence of diffusion coefficients seems to be valid only for a narrow temperature range, and therefore extrapolation of data from one temperature to another leads to a considerable error. The evidence showed that increase in additive solubility in the polymer is favoured by lower heat of fusions and melting points of additives. This implies the validity of simple regular solution theory to provide an adequate basis for understanding the solubility of additives in polymers The volubility of stabilisers from low density polyethylene films showed that of an additive from a polymer can be expressed in terms of a first-order kinetic equation. In addition the rate of loss of stabilisers was discussed in relation to its diffusion, solubility and volatility and found that all these factors may contribute to the additive loss, although one may be a rate determining factor. Stabiliser migration from LDPE into various solvents and food simulants was studied at temperatures 5, 23, 40 and 70oC; from the plots of rate of migration versus square root time, characteristic diffusion coefficients were obtained by using the solution of Fick's diffusion equations. It was shown that the rate of migration depends primarily on partition coefficients between solvent and the polymer of the additive and also on the swelling action of the contracting media. Characteristic diffusion coefficients were found to approach to intrinsic values in non swelling solvents, whereas in the case of highly swollen polymer samples, the former may be orders of magnitude greater than the latter.

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Ståhlberg, Daniel. "Thermoset polymers and coatings subjected to high compressive loads." Doctoral thesis, KTH, Fiber- och polymerteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4091.

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This study describes the mechanical response of thermoset polymers under high compressive loads. The study is divided into two parts. The first part focuses on the behaviour of a powder coating when used in a clamping force joint and how the properties vary when the chemical and physical structure of the coating is changed. The second part discusses the fundamental understanding of the behaviour of thermoset polymers with small thickness-to-width ratio subjected to compressive stresses, the aim being to develop mathematical material models for viscoelastic materials under high compressive loads. In the first part polyester powder coatings were used with variations in molecular weight, number of functional groups of the resin, amount and type of filler and thickness of the coating. The coatings were subjected to conventional tests for coatings and polymers and also to specially designed tests developed to study the behaviour of powder coatings in clamping force joints. The high compressive loads in a clamping force joint put high demands on the relaxation and creep resistance of the coating and the study shows the importance of crosslink density, filler content, and also coating thickness in order to achieve the desired mechanical properties of a coating. A high reactivity of the resin, facilitating a high crosslink density and hence a high Tg, is the most important property of the coating. A film with high crosslink density shows increase in relaxation time and in apparent yield strength under compression, and also an increase in relaxation modulus and storage modulus in tension at temperatures above Tg. Addition of fillers reduces the deformation during compression and tension, but also induces a lower strain at break and hence a more brittle coating. The reinforcing effect of the fillers is pronounced when increasing the crosslink density of the coating, especially in the compression tests. The effect is evident in compression even at low amounts of fillers, where the relaxation time and resistance to deformation are strongly increased. The combination of high crosslink density and addition of fillers is therefore desirable since fillers then can be used moderately in order to achieve a reinforcing effect in compression while minimising embrittlement. The study also showed that increased coating thickness will give rise to defects in the coating, especially voids and blisters due to evaporation of water formed during the curing of the polyester powder coating. These defects will give rise to stress concentrations and increased plastic deformations in the coating, impairing the properties of the clamping force joint. The results from relaxation tests in tension were used to create a micromechanical model. This model was used in finite element modelling to estimate the loss of clamping force in a screw joint and to correlate with the experimental results of the powder coatings. In the second part of the study a well-defined free radically cured vinyl ester resin was used and studied in six different geometries in order to determine the dependence of apparent mechanical properties on the particular size and shape of a sample when it is subjected to high compressive loads. Variation of the specimen thickness, boundary conditions and loading conditions reveals that the geometry of the sample has a significant effect on the mechanical performance of the polymer. The apparent modulus and the yield strength increase dramatically when the thickness-to-width ratio of the sample is reduced, whereas they decrease when the friction between the sample and the compression plate is reduced. The creep strain rate decreases when the thickness of the material is reduced and it decreases even more when the amount of material surrounding the compressed part of the sample is increased. Creep and strain recovery tests on large specimens were used to develop a mathematical model including non-linear viscoelastic and viscoplastic response of a thermoset vinyl ester. The model was used in FEM calculations where the experimental results were compared with the calculated results in order to model the trends of the material response when varying the sample geometry.
QC 20100921

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Ståhlberg, Daniel. "Thermoset polymers and coatings subjected to high compressive loads." Licentiate thesis, KTH, Fibre and Polymer Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1699.

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This study describes the mechanical response of thermosetpolymers under high compressive loads. The study is dividedinto two parts. One part is focusing on the behaviour of apowder coating when used in a clamping force joint and how theproperties varies when varying the physical structure of thecoating. The other part is regarding the fundamentalunderstanding of the behaviour of thermoset polymers with smallthickness-to-width ratio subjected to compressive stresses inorder to develop mathematical material models for theviscoelastic materials.

The first part describes the mechanical behaviour of powdercoatings used under very high compressive loads in clampingforce joints. Carboxyl functional polyester powder coatingscured with hydroxyl functional â-hydroxyalkylamides wereused with variations in coating thickness and amount and typeof filler. The coatings were subjected to conventional testsfor coatings and polymers and also to specially designed testsdeveloped to study the behaviour of powder coatings in clampingforce joints.The results show the importance of correct coatingthickness and filler content in order to achieve the desiredmechanical properties of a coating when used under highcompressive loads. Increased thickness will give rise todefects in the coating, especially voids and blisters due tothe evaporation of water formed during the curing of thepolyester powder coating. The surface roughness of the coatingis also affected by the coating thickness, but the maininfluence originates from the type and amount of filler used.The high compressive loads in a clamping force joint put highdemands on the stability of the coating and the defects must bekept to a minimum. A rough surface and defects such as voidswill give rise to stress concentrations and increased plasticdeformations in the coating, impairing the properties of theclamping force joint.

In the second part of the study a well-defined freeradically cured vinyl ester resin has been used and studied insix different geometries in order to determine the dependenceof apparent mechanical properties on the particular size andshape of a sample when a sample is subjected to highcompressive loads. Variation of the specimen thickness,boundary conditions and loading conditions reveal that thegeometry of the sample has a significant effect on themechanical performance of the polymer. The apparent modulus andthe yield stress increases dramatically when thethickness-to-width ratio of the sample is reduced, whereas theydecrease when the friction between the sample and thecompression plate is reduced. The creep strain rate decreaseswhen the thickness of the material is reduced and it decreasesstill more when the amount of material surrounding thecompressed part of the sample is increased. This effect isimportant when designing parts to be used under compressiveloads. Properties measured macroscopically may not correlatewith the behaviour of the designed part since the geometry mayhave either a reinforcing or destabilising effect on thematerial. Creep and strain recovery tests on large specimensare used to develop a mathematical model including non-linearviscoelastic and viscoplastic response of a thermoset vinylester. The model is used in FEM calculations where theexperimental results are compared with the calculated resultsin order to model the trends of the material response whenvarying the sample geometry.

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Ståhlberg, Daniel. "Thermoset polymers and coatings subjected to high compressive loads /." Stockholm : Chemical Science and Engineering, KTH, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4091.

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Park, In. "Mesostructured silica for the reinforcement of thermoset epoxy polymers." Diss., Connect to online resource - MSU authorized users, 2006.

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Masi, Barbara Ann. "Fabrication methods and costs for thermoset and thermoplastic composite processing for aerospace applications." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/72739.

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Wong, Ka Chun. "Focused Ion Beam Nanomachining of Thermoplastic Polymers." Thesis, North Carolina State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3538536.

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Commercially available Ga⁺ focused ion beam (FIB) instruments with nanometer size probe allows for in situ materials removal (sputtering) and addition (deposition) on a wide range of material. These spatially precise processes have enabled a wide range of nanofacbrication operations (e.g. specimen preparation for analysis by scanning electron microscope, transmission electron microscope, and secondary ion mass spectrometer). While there exists an established knowledge of FIB methods for sample preparation of hard materials, but FIB methodology remain underdeveloped for soft materials such as biological and polymeric materials.

As FIB is increasingly utilized for specimen preparation of polymeric materials, it is becoming necessary to formulate an information base that will allow established FIB techniques to be generalized to this spectrum of materials. A thorough understanding of the fundamental ion-solid interactions that govern the milling process can be instrumental. Therefore, in an effort to make the existing procedures more universally applicable, the interrelationships between target material, variable processing parameters, and process efficiency of the milling phenomena are examined. The roles of beam current, distance (i.e. step size) between successive FIB beam dwell and the time it spent at each dwell point (i.e. pixel dwell time) are considered as applied to FIB nanomachining of four different thermoplastic polymers: 1. low density polyethylene (LDPE), 2. high density polyethylene (HDPE), 3. Polystyrene (PS), and 4. nylon 6 (PA6). Careful characterization of such relationships is used to explain observed phenomena and predict expected milling behaviors, thus allowing the FIB to be used more efficiently with reproducible results. Applications involving different types of polymer composite fiber are presented.

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Hassounah, Ibrahim [Verfasser]. "Melt electrospinning of thermoplastic polymers / Ibrahim Hassounah." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2012. http://d-nb.info/1023021420/34.

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Erdem, Haci Bayram. "Synthesis and Characterization of Thermoplastic Polyphenoxyquinoxalines." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1207147171.

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Kiziltas, Alper. "Microcrystalline Cellulose-Filled Engineering Thermoplastic Composites." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/KiziltasA2009.pdf.

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Baqar, Mohamed Saad. "Methylol-Functional Benzoxazines: Novel Precursors for Phenolic Thermoset Polymers and Nanocomposite Applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1373319624.

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Guo, Haochen. "RECYCLING THERMOPLASTIC EVA (POLYETHYLENE-CO-VINYL ACETATE) WITH IMPROVED PROPERTIES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1585673886043802.

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Damadzadeh, Behzad, and Hamideh Jabari. "Biodegradable Composites : Processing of thermoplastic polymers for medical applications." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19329.

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Despite the recent development in PLA and PLGA based medical devices, there are still needs to further improve the mechanical performance of bioresorbable medical implants and their bioactivity. This is normally done by optimizing the filler compositions in selected groups ofbiodegradable polymer matrices. In this study, the effects of various filler levels on mechanical strength and thermal properties of PLA and PLGA composites were investigated. Composites containing different dosage of osteoconductive HAp with various particles size (0-5μm, 0-50 μm, nano size), β-TCP, bioactive glass and biodegradable Poly-L-lactide and Polylactide-glycolic acid was manufactured with melt blending, using a twin-screw extruder.The samples were investigated by Differential Scanning Calorimetry (DSC), thermo gravimetric analysis (TGA), Scanning Electron Microscopy (SEM), viscometer, three points bending machine, and Optical Microscopy (OM). The Extruder produced a porous profile. The result from TGA and SEM indicated that there was homogenous filler dispersion in the matrix after compounding.The result from DSC and Viscometer shows that there was some degradation duringcompounding. Mechanical properties of composites were modified by adding filler to matrix. The addition of Bioactive glass, as a filler, increases the degradation of the polymer matrix. The best filler that was applied is 0-5μm and nano HAp. Also in in-vitro degradation part of this thesis work, the effects of calcium phosphate materialsare investigated on degradation process.

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29

Neyman, Gennady. "Molecular understanding of the transcrystalline zone in thermoplastic polymers." Case Western Reserve University School of Graduate Studies / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1061480030.

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30

Tan, Xin. "Supramolecular Reinforcement of Thermoset Elastomers by Oligo(ß-Alanine)." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1506083394683621.

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31

Lee, Yong-Joon. "Structure-property behavior of novel high performance thermoplastic and thermoset structural adhesives and composite matrix resins." Diss., This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-06062008-162715/.

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32

Bradley, Jurron. "Consolidation of fiber-reinforced composities with thermoplastic matrices." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/11303.

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33

Quinney, Richard. "The activation of wood fibre for thermoplastic coupling." Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296577.

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34

Marsh, Timothy Edward. "High Performance Hyperbranched Polymers For Improved Processing And Mechanical Properties In Thermoset Composites." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1220652257.

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35

Kilbride, Marianne. "Influence of carbon nanographite and other nanofillers on the properties of thermoset : thermoplastic blends for composite matrices." Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=12800.

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36

Lyons, Jason Michael Ko Frank K. "Melt-electrospinning of thermoplastic polymers : an experimental and theoretical analysis /." Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/367.

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37

Risch, Brian G. "Crystallization behavior and structure property behavior of selected thermoplastic polymers." Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-11082006-133621/.

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38

DeVilbiss, Thomas Alexander. "Carbon fiber surface treatments for improved adhesion to thermoplastic polymers." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/49844.

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The effect of anodization in NaOH, H₂SO₄, and amine salts on the surface chemistry of carbon fibers was examined by x-ray photoelectron spectroscopy (XPS). The surfaces of carbon fibers after anodization in NaOH and H₂SO₄ were examined by scanning transmission electron microscopy (STEM). angular dependent XPS, ultraviolet (UV) absorption spectroscopy of the anodization bath, secondary ion mass spectrometry, and polar/dispersive surface energy analysis. Hercules AS-4, Dexter Hysol XAS, and Union Carbide T-300 fibers were examined by STEM, angular dependent XPS, and breaking strength measurement before and after commercial surface treatment. The fibers from the three companies were anodized to create similar surface chemistry on each fiber. XPS was used to compare the surface chemistry after anodization. Adhesion of carbon fibers to polysulfone, polycarbonate, and polyetherimide was studied using the fiber critical length test. Oxygen and nitrogen were added to the fiber surfaces by anodization in amine salts. Analysis of the plasmon peak in the carbon 1s signal indicated that H₂SO₄ anodization affected the morphological structure of the carbon fiber surface. UV absorption spectra of the anodization bath, SIMS, and angular dependent XPS indicate that NaOH anodization removes amorphous carbon from the fiber. The oxygen and nitrogen content on the fiber surfaces were affected by commercial surface treatment. The Union Carbide fiber had much lower oxygen content after laboratory anodization than the Hercules or Dexter Hysol fibers. The breaking strength of all three fibers was increased by anodization. Laboratory anodization resulted in better fiber/matrix adhesion than the commercial surface treatment for the Hercules and Dexter Hysol fibers. Fiber/matrix adhesion was better for the commercially treated Union Carbide fiber than for the laboratory treated fiber. The work of adhesion of carbon fibers to thermoplastic resins was calculated using the geometric mean relationship. A correlation was observed between the dispersive component of the work of adhesion and the interfacial adhesion.
Ph. D.
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39

Bekhet, Noaman El-Sayed Mohamed. "The biaxial strength and deformation characteristics of highly-oriented polymers." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329783.

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40

Walker, Ian. "Synthesis of novel siloxane containing block copolymers for impact modification of polybutyleneterephthalate." Thesis, Sheffield Hallam University, 1991. http://shura.shu.ac.uk/20485/.

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The aim of this work was to synthesise poly(butyleneterephthalate) (PBT) poly(dimethylsiloxane) (PDMS) block copolymers, containing the hydrolytically stable Si-C linkage. A number of routes involving mutually reactive oligomers were studied. Once synthesised the effect of the copolymer as a toughening agent for the PBT matrix was investigated. Siloxane copolymer precursors were synthesised by an equilibration reaction. The relative molar mass (RMM) of the precursor was governed by the initial ratio of end blocker to cyclic species. The functionality of the precursor determined by the end blocker. alpha, to hydroxy PBT oligomeric precursors were chemically modified, if necessary, to form mutually reactive species. Initial block copolymer synthetic routes concentrated on chloroplatinic acid catalysed hydrosilations in solution. This involved alpha, to di (hydrosilane) PDMS and alpha, to divinyl functionalised PBT. The lack of a suitable common solvent together with competing side reactions limited the progress of this route. Melt hydrosilation reactions proved ineffective also, because of the thermal instability of the catalyst. Further block copolymer experiments involving mutually reactive oligomers were performed in the melt. The most promising of these was one of transesterification. This used alpha,o-hydroxypropyl PDMS (RMM 1000) and alpha,o-hydroxy PBT (RMM 2000) precursors. Analysis indicated successful reaction to form a copolymer of low RMM. A higher RMM copolymer was desirable, for improved mechanical properties, and a number of approaches to achieve this were followed. Problems of competing reactions and ineffective catalysis were encountered. However, a material with promising mechanical properties was formed when using a diisocyanate as a chain extender. A PBT-PDMS copolymer was blended by itself, and also together with high RMM PDMS, in the PBT matrix. The mechanical properties of the blends were studied and compared. An improvement in impact properties, as compared to PBT, was achieved when the copolymer was used as an emulsifying agent in a PBT-PDMS blend.

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41

Kumar, Nishant C. "Anionically Polymerized Supramolecular Thermoplastic Elastomers." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1427128414.

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42

Norpoth, Lawrence R. "Processing parameters for the consolidation of thermoplastic composites." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/19099.

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43

Rohm, Kristen Nicole. "Thermoplastic Polyurethane: A Complex Composite System." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1625604511143102.

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44

Liu, Jieruo. "Manufacturing of Polypropylene (PP)/ Ground Tire Rubber (GTR) Thermoplastic Elastomers Using Ultrasonically Aided Extrusion." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1375290253.

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45

Marsh, Joseph Jack. "Characterisation of crystallisation and melting in thermoplastic polymers using chip calorimetry." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7299/.

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Fast scanning chip-calorimetry was used to explore the crystallisation and melting of three semi-crystalline polymers. The heating and cooling rates required to prevent crystallisation on cooling (from above Tm) and on re-heating (from below T\(_g\)) were determined as: 3,000 and 8,000˚C/s respectively in PCL, 75 and 250˚C/s respectively in PEEK and 10 and 100˚C/s respectively in PLA. The effect of the thermal lag was considered using indium as a standard and corrections of >5˚C were required at rates in excess of 5,000˚C/s. As readily observed in conventional DSC (CDSC), PEEK exhibited a double melting endotherm and this was attributed to a melting-recrystallisation-melting process. The absence of recrystallisation above 250˚C allowed a Hoffman-Weeks analysis to be carried out over a broader temperature range than is general possible in CDSC. The interplay between thermal lag and re-crystallisation was analysed using heating rates covering 5 orders of magnitude. At an optimum heating rate of 1,500 ˚C/s, an equilibrium melting temperature of 359˚C was determined. The consideration of thermal lag led to the measurement of diffusivity using the technique of laser flash apparatus (LFA). The high measurement speed in the LFA allowed a time and temperature resolved study of diffusivity in PLA. LFA, chip-calorimetry and CDSC were used in parallel to explore the cold-crystallisation kinetics of PLA and the development of the relatively unstable α’ crystals. A good correlation between chip-calorimetry and LFA was found, showing an Avrami exponent of 2 and nucleation constant of 6.58 x10\(^5\) and 6.87 x10\(^5\) respectively, corresponding to regime III.

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46

Staicovici, Stefan. "Microwave welding and disassembly of thermoplastic materials using intrinsically conductive polymers /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487948807586222.

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47

Moore, Timothy Graeme, and tim moore@csiro au. "Design and synthesis of biodegradable thermoplastic polyurethanes for tissue engineering." Swinburne University of Technology, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20060223.121928.

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The aim of this study was to design and synthesise thermoplastic biodegradable and biocompatible polyurethanes for tissue engineering applications. A secondary aim was to tailor a range of degradation rates of the polyurethanes to suit a broad spectrum of tissue engineering applications. Various factors were systematically investigated in order to provide a means of controlling mechanical, thermal and degradation properties of the polyurethanes. The factors investigated included variation of the hard segment percentage, the diisocyanate, the soft segment macrodiol as well as the chain extender. Soft segment macrodiols were synthesised for this study including a poly(γ-butyrolactone) macrodiol which has been used to make biodegradable aliphatic poly(ester-urethane) for the first time. A novel range of degradable chain extenders was also developed and has been reported. The polymers were characterised using Gel Permeation Chromatography (GPC), Instron tensile testing, Differential Scanning Calorimetry (DSC) and Shore hardness. Cell culture testing was performed as was a three-month degradation study which showed the polyurethanes to be biocompatible and biodegradable respectively. Selected materials were shown to be suitable for scaffold fabrication using Fused Deposition Modelling (FDM), and the scaffolds made were further shown to support primary fibroblast growth in vitro.

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48

Zhang, Yang [Verfasser]. "The fabrication and application of semi-crystalline and thermoset-thermoplastic composite colloidal particles with well-defined microstructures / Yang Zhang." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1047523825/34.

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49

Ma, Jianxing. "ROLL-TO-ROLL FABRICATION OF NANORODS AND TOWARDS 3D PRINTING OF THERMOPLASTIC SHAPE MEMORY POLYMERS." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468252422.

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50

Foix, Tajuelo David. "Hyperbranched polymers and other highly branched topologies in the modification of thermally and uv cured expoxy resins." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/52795.

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RESUM Les reïnes epoxi constitueixen un dels polímers més emprats en el món de la industria, si bé presenten una sèrie d’inconvenients, els més importants dels quals són: la seva inherent fragilitat, la seva excessiva resistència tèrmica que en dificulta l’eliminació d’un substrat un cop finalitzada la seva vida útil i l’encongiment que experimenten durant el procés de curat. Per tal de reduir o eliminar aquests problemes aquesta tesi proposa l’ús de polímers hiperramificats així com polímers estrella i copolímers lineal-hiperramificat de bloc com a modificants químics de reïnes comercials. Amb aquesta estratègia s’han aconseguit millorar la tenacitat degut a efectes flexibilitzants o a separacions de fase del modificant en la matriu epoxídica, així com reduir l’encongiment en el curat o la degradabilitat de les reïnes, sense afectar altres propietats de la reïna com la seva Tg o la seva duresa.
ABSTRACT Epoxy resins are one of the most used polymers in the field of technological applications. However, they present some drawbacks being the most important the following: they are inherently brittle materials; they present excessive thermal resistance that limits their reworkability; and the shrinkage they experiment during curing. To overcome these problems this thesis proposes the use of hyperbranched polymers, as well as star polymers and lineal-hyperbranched block copolymers as chemical modifiers of commercially available epoxy resins. With this strategy tougher materials have been obtained due to either a flexibilizing effect or a phase separation of the modifier within the epoxy matrix. Moreover, the shrinkage on curing and the degradability of the thermosets have been improved without compromising other properties of the resin such as its Tg or its hardness.

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Dissertations / Theses on the topic 'Thermoplastic and thermoset polymers'

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