Made available in DSpace on 2017-07-10T17:37:31Z (GMT). No. of bitstreams: 1 Tania Pires da Silva.pdf: 493041 bytes, checksum: 3d9daa71e02d7c679bf5b90cf21bb3c5 (MD5) Previous issue date: 2008-12-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of the work was to evaluate the phytotechnical performance of different rootstocks in the formation level on field conditions and the initial development of the graft, as well as the application of auxiliaries technicians to the root potential increment of the rootstocks cuttings of VR 043-43 in nursery conditions. Ligneous cuttings from grapevine VR 043-43 , measuring 20 cm, were stratified for 48h (under the temperature of 4 oC), part of the cuttings were kept under environment temperature (25 } 5 oC). All the cuttings were treated with indolbutyric acid (IBA) in different concentrations of 0, 1.000, 2.000 and 3.000 mgL-1, associated and not associated to boric acid at concentration of 150 μg L-1 for 10sec. The cuttings were planted into polyethylene plastic bags (capacity of 2,5L), filled with clay soil. They were kept in nursery made of shading screen providing 50% of luminosity. The evaluations occurred 120 days after the experiment deployment. In November, the seedlings originated from the rooted cuttings of 17 grapevine rootstocks ( SO4 , Teleki 8B , Harmony , Golia , Riparia de Traviu , Paulsen , 420 A , 99R , 5C , RR101-14 , Kober 5BB , Rupestris Du Lot , IAC 313 Tropical , IAC 766 Campinas , IAC 572 Jales , VR 043-43 and IAC 571-6 Jundiai ) were taken to the field under subtropical conditions (24o33 40 S and 54o04 12 W, 420 m height and Cfa Koppen climate, with annual maximum average temperature of 28,5 oC and minimum of 17,5 oC). After four months, it was evaluated the anthracnose and rust severity on the grapevine leaf sprouting from the rootstocks and more five months of vigor (total branch number, average diameter, biggest branch length and total leaf area fresh mass). In the sequence, it was performed winter graft using BRS Violeta . The evaluated characteristics for this part of the experiment were percentage of tissue union, diameter and graft average length, which happened after 60 days of grafting. It was concluded that the stratification of the cutting is not fundamental to increase the efficiency of the rooting process of the rootstock VR 043-43 . The cuttings should only be treated with IBA at 3.000 mg L-1 in association to boric acid. The rootstocks IAC 572 Jales and IAC 313 Tropical were resistant to the anthracnose and rust. The rootstock IAC 572 Jales was the one that showed greater performance on field, before grafting. The rootstocks SO4 , Harmony , Paulsen and IAC 766 Campinas showed greater vigor to the development of the graft BRS Violeta / O trabalho teve como objetivo avaliar o desempenho vegetativo de diferentes porta-enxertos na fase de formacao a campo e o desenvolvimento inicial do enxerto, bem como o emprego de tecnicas auxiliares para o incremento do potencial rizogenico de estacas do porta-enxerto VR 043-43 em condicoes de viveiro. Estacas caulinares lenhosas de 20 cm comprimento do porta-enxerto de videira VR 043-43 , estratificadas por 48 h (sob temperatura de 4 oC) ou não (ambiente de 25o } 5 oC), foram tratadas em solucao de acido indolbutirico (AIB) nas concentracoes de 0, 1.000, 2.000 e 3.000 mg L-1, associado ou nao com acido borico a 150 μg L-1, por 10 seg. As estacas foram plantadas em saco plastico de polietileno (capacidade de 2,5 L), contendo solo com textura argilosa como substrato e mantidas sob viveiro constituido de tela de sombreamento de 50% de luminosidade, sendo avaliadas apos 120 dias. Em novembro, mudas oriundas de estacas enraizadas de 17 porta-enxertos de videira ( SO4 , Teleki 8B , Harmony , Golia , Riparia de Traviu , Paulsen , 420 A , 99R , 5C , RR101-14 , Kober 5BB , Rupestris Du Lot , IAC 313 Tropical , IAC 766 Campinas , IAC 572 Jales , VR 043-43 e IAC 571-6 Jundiai ) foram levadas a campo, em condicoes subtropicais (24o33 40 S e 54o04 12 W, altitude de 420 m e clima Cfa Koppen, com temperatura media maxima anual de 28,5 oC e minima de 17,5 oC). Passados quatro meses, avaliou-se a severidade da antracnose e ferrugem da videira nas folhas das brotacoes dos porta-enxertos e mais cinco meses o vigor dos mesmos (numero total de ramos, diametro medio, comprimento do maior ramo e massa fresca total media dos ramos). Em seguida, realizou-se a enxertia invernal com garfos da videira BRS Violeta e avaliou-se apos 60 dias a porcentagem de pegamento, o diametro e o comprimento medio do enxerto. Concluiu-se que a estratificacao das estacas nao e fundamental para que haja maior eficiencia do processo de enraizamento do porta-enxerto VR 043-43 , devendo as estacas apenas serem tratadas com 3.000 mg L-1 de AIB, associada ao acido borico. Os porta-enxertos IAC 572 Jales e IAC 313 Tropical foram resistentes a antracnose e a ferrugem. O porta-enxerto IAC 572 Jales foi o que promoveu maior desempenho a campo, previamente a operacao de enxertia. Os porta-enxertos SO4 , Harmony , Paulsen e IAC 766 Campinas promoveram maior vigor ao desenvolvimento do enxerto de BRS Violeta

Background: The 30-day readmission rate is considered a quality of care measure for providers and has become important because providers might face reduced reimbursement from any increase in unplanned readmissions Objective: The aim of the first chapter is to investigate the waiting-length of stay (WLOS) and post-length of stay (PLOS) on the 30-day readmission. In the second chapter, we examined the hospital procedural volume and hospital quality on the 30-day readmission. Our objective in the third chapter is to examine the zip code-level SES factors on the 30-day readmission rates. Participants: patients undergoing isolated coronary artery bypass grafting (CABG) in Virginia Methods: A retrospective study design has been conducted using a multi-level logistic model of increasing complexity for all three chapters. The sample used was from the Virginia Cardiac Surgery Quality Initiative (VCSQI) of the periods 2008-2014, the dataset included patient characteristics. Afterward, we merged the sample with both the Virginia Health Information (VHI) to obtain hospital characteristics (ownership, teaching status, and location), and Agency for Healthcare Research and Quality (AHRF) to obtain county-socio-economic status (SES) characteristics (education, employment, and median household income), the previous SES was used for chapter’s one and two. In chapter three, instead of AHRF, we merged the sample with the American Community Survey (ACS) to obtain zip code-SES characteristics (employment, median household income, education, median house price). The main outcome was the 30-day readmission rate. The analytical sample of chapter one n = 22,097, in chapter two the sample n = 25,531, while in chapter three the sample n= 25,829. We conducted a sensitivity analysis in all three chapters. In chapter one we analyzed the data at the patient level, in chapter two we analyzed the data at the hospital level, while in chapter three we conducted the analysis at the area zip code level. Results: In chapter one, we found that readmitted patients after a prolonged PLOS had increased odds of readmission, by 68.7%, compared to readmitted patients with a shorter PLOS in the fully adjusted model; while, WLOS was not significant at the P < 0.05. In chapter two, the fully adjusted model displayed significant results with a reduced odds in readmissions by 22.8% in the middle-volume hospitals compared to the low-volume hospitals, while the middle-quality hospitals had increased odds of readmission by 23.5% compared to the low-quality hospitals. In chapter three, statistically, we did not find that area zip code-SES had an effect on the 30-day readmission rate. While, geographically, we found that addresses of individuals were clustered in certain areas of Virginia. Conclusion: In chapter one, patients undergoing CABG and experience a prolonged PLOS of > 6 days are at risk to be readmitted within 30-days of the procedure. In chapter two, the higher volume hospitals (middle-volume) compared to low-volume hospitals showed a significant reduction in odds in the 30-day readmissions, especially after adjusting the model with hospital quality. In chapter three, even though, there was no association of area-SES with 30-day readmission, in the maps, we found a cluster of patient addresses in the southern parts of Virginia with an increased readmission, which is considered underprivileged area; and the fact might be due to the proximity of these areas to cardiovascular hospitals. Policy Implication: In chapter one, the study provided a model for clinicians to stratify patients at risk of readmission, especially patients with risks of staying longer in the hospital after CABG. In chapter two, policymakers and the CMS should find new ways to help hospitals with low-volumes to reduce their isolated-CABG readmission rates and be able to compete with high-volume hospitals. In chapter three, no significant correlation between area-SES and readmission for patients who underwent CABG was found; these backs prior notion that SES should not be adjusted for the reimbursement penalties of the Hospital Readmission Reductions Program (HRRP) on hospitals

L’ingénierie des biomatériaux a connu un essor prodigieux ces dernières décennies passant de matériaux simples à des structures plus complexes, particulièrement dans le domaine cardiovasculaire. Cette évolution découle de la nécessité des biomatériaux de permettre la synergie de différentes propriétés, dépendantes de leurs fonctions, qui ne sont pas forcément toutes compatibles. Historiquement, les premiers matériaux utilisés dans la conception de dispositifs médicaux étaient ceux présentant le meilleur compromis entre les propriétés physico-chimiques, mécaniques et biologiques que nécessitait leur application. Cependant, il se peut que le dispositif possède les bonnes propriétés physico-chimiques ou mécaniques, mais que sa biocompatibilité soit insuffisante induisant ainsi des complications cliniques. Afin d’améliorer ces propriétés biologiques tout en conservant les propriétés de volume du matériau, une solution est d’en modifier la surface. L’utilisation d’un revêtement permet alors de moduler la réponse biologique à l’interface biomatériau-hôte et de diminuer les effets indésirables. Ces revêtements sont optimisés selon deux critères principaux : la réponse biologique et la réponse mécanique. Pour la réponse biologique, les deux approches principales sont de mettre au point des revêtements proactifs qui engendrent l’adhérence, laprolifération ou la migration cellulaire, ou passifs, qui, principalement, sont inertes et empêchent l’adhérence de composés biologiques. Des revêtements plus complexes utilisent les deux approches permettant l’adhérence spécifique de certainescellules tout en empêchant l’adhérence d’autres composants biologiques. Cette pratique est très utile pour lutter contre la resténose, complication survenant après opération de l’athérosclérose qui obstrue les vaisseaux sanguins. Une pratique courante est la pose d’un stent qui permet d’ouvrir l’artère de nouveau et de rétablir le flux sanguin. Le phénomène de resténose obstrue de nouveau le vaisseau sanguin, majoritairement par la prolifération incontrôlée de cellules musculaires lisses. La recherche sur les revêtements contre la resténose vise à inhiber la prolifération de ces cellules tout en facilitant la ré-endothélialisation. Les revêtements permettraient alors, à la fois de favoriser l’adhérence et la prolifération de cellules endothéliales et de limiter celles des cellules musculaires lisses à la surface du stent ou en limitant toute adhérence non-spécifique. Il a été démontré lors d’études précédentes qu’un copolymère à base de dextrane et de poly(méthacrylate debutyle) (PBMA) répondait à ces critères biologiques et qu’il possédait en plus une bonne résistance à la déformation, paramètre important lié à la déformation induite lors de l’implantation d’un stent. L’approche de ce projet était d’utiliser ce copolymère comme revêtement de stent et d’en améliorer la stabilité à long terme en formant des liens covalents avec le substrat. Pour ce faire, cela nécessitait l’activation de la partie dextrane du copolymère afin de pouvoir le greffer au substrat. Il était important de vérifier pour chaque étape l’influence des modifications effectuées sur les propriétés biologiques et mécaniques des matériaux obtenus, mais aussi d’un point de vue de la chimie, l’influence que cette modification pouvait induire sur la réaction decopolymérisation.... / The last decades have witnessed the remarkable growth of biomaterial science and engineering field, especiallyfor cardiovascular applications, for which devices have evolved from simple material to complex structures.This development has stemmed from the necessity for biomaterials to exhibit different properties, related totheir function, which are not always inherently compatible. Historically, the first materials selected for medicaldevices conception were the ones exhibiting the best compromise between all the physicochemical, mechanicaland biological requirements. Nevertheless, while physicochemical and mechanical properties are often handilycombined, the development of materials which also possess suitable biological properties have proved to bemuch more challenging, leading to clinical complications.Surface modification represents a valid solution to improve the biological performances of medical deviceswhile maintaining the bulk properties of the material. Biomaterial coatings may modulate the biologicalresponse at the biomaterial-host interface and decreases the undesirable effects. Coatings have been optimizedin regards to two main aspects: the biological response and the mechanical response. For the biologicalresponse, the two main approaches consist in 1) inducing cell adhesion, proliferation or migration with proactivecoatings and 2) using inert material, mostly, and avoiding the adhesion of any biological componentswith passive coatings.More complex coatings include the two approaches, allowing the adhesion of a specific type of cell whilerepelling other biological components adhesion. This method has been very useful against the restenosisphenomenon which obstructs blood vessels. A common practice is vessel stenting, a procedure that enables thereopening of the vessel and the restoration of the blood flow. Restenosis causes the new narrowing of the vessel,mostly due to uncontrolled smooth muscle cell proliferation. Researchers looked for coatings capable oflimiting the restenosis occurrence by inhibiting this cell proliferation along with facilitating the reendothelialization.Thus, the coatings would be able to improve endothelial cells adhesion and proliferation andto inhibit smooth muscle cells ones as well as avoiding non-specific adhesion.Previous studies showed that a copolymer made of dextran and poly(butyl methacrylate) (PBMA) demonstratedsuch biological properties and a good resistance to deformation, which is an important parameter related to thedeformation implied in a stent implantation. In this work, the approach was to use this copolymer as a stentcoating and to increase its long-term stability by providing covalent bonds with the substrate. To do so, thedextran part of the copolymer firstly needed to be activated in order to be grafted to the surface. Thus, it wasimportant to ascertain the influence of the multiple modifications on the biological and mechanical propertiesof the resulting materials at each step, but also towards a chemical point of view, the influence that thesemodifications may have on the subsequent copolymerization.

Les propriétés mécaniques de films polymériques peuvent être considérablement améliorées par l'inclusion de nanoparticules au sein de la matrice du fait de deux effets majeurs : (i) la structure locale de la dispersion des charges et (ii) la modification potentielle de la dynamique et de la conformation des chaînes à l'interface charge/polymère. Néanmoins, les mécanismes précis qui permettent de relier ces contributions à l'échelle nanométrique aux propriétés macroscopiques des matériaux, et en particulier aux propriétés mécaniques, sont actuellement mal décrits. Dans ce contexte, nous avons synthétisé des nanocomposites modèles à base de nanoparticules magnétiques de maghémite γ-Fe2O3 (nues ou greffées d'une couronne de polystyrène (PS) par polymérisation radicalaire contrôlée) dispersées dans une matrice de PS, que nous avons caractérisé en couplant la diffusion de rayonnement (Rayons X et neutrons) et la microscopie électronique à transmission. En jouant sur différents paramètres tels que la taille des particules, la concentration, ou le rapport de taille entre les chaînes greffées et celles de la matrice pour les charges greffées, nous avons obtenu des nanocomposites présentant un éventail de dispersions de charges variées, contrôlées, parfaitement reproductibles, allant de particules individuelles ou d'agrégats ramifiés jusqu'à la formation d'un réseau de charges connecté. En appliquant un champ magnétique externe durant la synthèse des nanocomposites, nous sommes parvenus à aligner les différentes structures le long de la direction du champ et ainsi former des matériaux présentant des propriétés remarquables de renforcement anisotropes. La conformation des chaînes au sein des nanocomposites, déterminée expérimentalement grâce aux propriétés spécifiques de contraste neutronique du système, n'est pas affectée par la présence des charges, quels que soient le degré de confinement des chaînes, l'orientation, la dispersion ou l'état de surface des charges. L'alignement des charges sous champ magnétique a permis de décrire précisément l'évolution du module de renforcement des matériaux avec la réorganisation structurale locale des charges et des chaînes sous étirement, et de finalement mettre en évidence le rôle majeur joué par la réorganisation des charges sous déformation dans les mécanismes de renforcement.

In this study, dendronization and grafting via controlled polymerization techniques, atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP), have been explored. Modification of surfaces and cellulose using these techniques, which enable grafting of well-defined polymer architectures, has been investigated. The interest in using cellulose stems from its renewability, biocompatibility, high molecular weight, and versatile functionalization possibilities. Dendronization was performed using disulfide-cored didendrons of 2,2-bis(methylol)propionic acid (bis-MPA) on gold surfaces, for the formation of self-assembled monolayers. It was found that the height of the monolayer increased with increasing dendron generation and that the end-group functionality controlled the wettability of the modified surface. Superhydrophobic cellulose surfaces could be obtained when a ‘graft-on-graft’ architecture was obtained using ATRP from filter paper after subsequent post-functionalized using a perfluorinated compound. The low wettability could be explained by a combination of a high surface roughness and the chemical composition. Biobased dendronized polymers were synthesized through the ‘attach to’ route employing dendronization of soluble cellulose, in the form of hydroxypropyl cellulose (HPC). The dendronized polymers were studied as nanosized objects using atomic force microscopy (AFM) and it was found that the dendron end-group functionality had a large effect on the molecular conformation on surfaces of spun cast molecules. ATRP of vinyl monomers was conducted from an initiator-functionalized HPC and an initiator-functionalized first generation dendron, which was attached to HPC. The produced comb polymers showed high molecular weight and their sizes could be estimated via AFM of spun cast molecules on mica and from dynamic light scattering in solution, to around 100-200 nm. The comb polymers formed isoporous membranes, exhibiting pores of a few micrometers, when drop cast from a volatile solvent in a humid environment. HPC was also used to initiate ROP of ε-caprolactone, which was chain extended using ATRP to achieve amphiphilic comb block copolymers. These polymers could be suspended in water, cross-linked and were able to solubilize a hydrophobic compound. / QC 20100826

La polymérisation radicalaire contrôlée par le nitroxyde SG1 (NMP) du styrène et de l'acrylate de n-butyle a été menée à partir de particules de silice mésoporeuse fonctionnalisées par un amorceur de NMP, selon la technique du grafting from. Des silices de morphologies variées ont été utilisées, et des matériaux hybrides à fort taux de polymère ont été obtenus. La cinétique de la polymérisation et les caractéristiques du polymère greffé ont été étudiées, en présence éventuellement d'amorceur libre en solution. Des particules hybrides sphériques et creuses ont aussi été synthétisées selon la technique du grafting onto. Une couche de poly(N,N-diéthylacrylamide) est greffée à l'extérieur de la particule, constituée d'une sphère creuse de silice mésoporeuse, dont les pores sont orientés radialement depuis la surface. La charge et la libération du zoledronate, dans une solution saline, ont montré que la structure creuse de la particule permet de charger plus de principe actif qu'une silice mésoporeuse conventionnelle.

Stem cell synthesized extracellular matrix (ECM) may serve as a replacement for current bone grafting techniques. The overall goal of this thesis is to quantify the osteoinductivity of the ECM produced by human amniotic fluid stem cells (AFS cells), compare it to that of human mesenchymal stem cells (MSC), and assess its potential for use in bone tissue engineering therapies. Each stem cell type was cultured in osteogenic media to produce the ECM, which was then decellularized via freeze/thaw cycling and DNase treatment. The success of the decellularization was confirmed with live/dead staining and DNA quantification. A series of in vitro studies were performed to evaluate the characteristics of the ECM relevant to a bone tissue engineering therapy. Reseeded MSCs were able to attach to and proliferate on both ECM types in both 2D and 3D culture. In 2D, cells cultured on both ECM types showed increased levels of calcium deposition. Additionally, cells cultured on the MSC ECM showed increased alkaline phosphatase activity. A synergistic effect on osteogenic differentiation was observed when the osteoinductive factor dexamethasone was added to the culture. In 3D, both ECM types increased the mineralized matrix production of reseeded MSCs. The AFS ECM had a greater effect than the MSC ECM. When ECM was used to treat a rat femoral segmental defect in vivo, it was found that each ECM type increased the rate of bridging of the defect when compared to collagen coated scaffolds. However the ECM did not have a significant effect on the volume of mineralized matrix within the defect site in this study.

Binäre Polymerbürsten bestehen aus zwei verschiedenen Polymertypen, die nebeneinander auf dem gleichen Trägermaterial verankert sind. Wenn diese Polymere unterschiedliche Benetzungseigenschaften haben, können damit schaltbare Oberflächen produziert werden. Abhängig vom Lösungsmittel, dem man die binäre Polymerbürste aussetzt, streckt sich entweder das hydrophile oder das hydrophobe Polymer zum Lösungsmittel hin, während die zweite Komponente nahe der Oberfläche verbleibt. Durch diese vertikale Phasenseparation kann temporär eine bestimmte Oberflächeneigenschaft erzeugt werden. Allerdings verschwindet diese sofort wieder, wenn ein anderes Lösungsmittel die binäre Bürste benetzt, sei es durch direkten Kontakt oder über die Gasphase. In der vorliegenden Arbeit wurde untersucht, ob es möglich ist, neuartige schaltbare binäre Polymerbürsten bestehend aus einem hydrophilen und einem hydrophoben Polymer angebunden auf Siliziumwafern herzustellen, deren Schaltfähigkeit durch photochemische Vernetzung unterbunden werden kann. Geprüft worden ist unter anderem, inwiefern sich hydrophober und hydrophiler Zustand der Schicht fixieren lassen und ob daraus resultierend, eine entsprechende Strukturierung der Oberfläche nach Bestrahlung durch eine geeignete Fotomaske oder durch fokussiertes Licht nachweisbar ist. Als hydrophobe Komponente wurden photovernetzbare Styren/2-(4’-Styryl)-inden-Copolymere verwendet, als hydrophile Komponente kam Polyvinylpyridin zum Einsatz. Mit einem speziellen Oberflächeninitiator konnten durch „Grafting from“ binäre Polymerbürsten mit bis zu 300 nm Schichtdicke erzeugt werden. Es ist gelungen, diese schaltbaren Schichten durch selektive photochemische Vernetzung einer der Bürstenkomponenten im hydrophilen oder im hydrophoben Zustand zu fixieren, was durch Kontaktwinkelmessung nachgewiesen werden konnte. Wie beabsichtigt, verlieren dabei die vernetzten Bereiche ihre Schaltfähigkeit. Es ließen sich feine Oberflächenstrukturen mittels Bestrahlung durch eine Fotomaske erzeugen, die sichtbar werden, wenn man sie mit Wasser benetzt bzw. Wasserdampf aussetzt.

Surface modification techniques have played important roles in various aspects of modern technology. They have been employed to improve substrates by altering surface physicochemical properties. An ideal surface modifying technique would be a method that is applicable to any kind of materials prepared from a wide range of polymers and that can occur under mild reaction conditions. The work in this thesis has utilized four main concepts: I) the development of a ‘grafting-from’ technique by covalently growing polymer grafts from particle surfaces, II) the presence of steric and electrosteric forces due to long-range repulsive interactions between particles, III) a combined surface grafting and layer-by-layer approach to create polyelectrolyte multilayers (PEMs) on particle surfaces to fabricate strong and functional materials, and IV) the roles of hydrophilic polymer grafts and substrate geometry on surface degradation. A non-destructive surface grafting technique was developed and applied to polylactide (PLA) particle surfaces. Their successful modification was verified by observed changes to the surface chemistry, morphology and topography of the particles. To quantify the aggregation behavior of grafted and non-grafted particles, force interaction measurements were performed using colloidal probe atomic force microscopy (AFM). Long-range repulsive interactions were observed when symmetric systems, i.e., hydrophilic polymer grafts on two interacting surfaces, and asymmetric system were applied. Electrosteric forces were observed when the symmetric substrates interacted at pH 7.4. When PEMs were alternately assembled on the surface of poly(L-lactide) (PLLA) particles, the grafted surfaces played a dominated role in altering the surface chemistry and morphology of the particles. Three-dimensional scaffolds of surface grafted particle coated with PEMs demonstrated high mechanical performance that agreed well with the mechanical performance of cancellous bone. Nanomaterials were used to functionalize the scaffolds and further influence their physicochemical properties. For example, when magnetic nanoparticles were used to functionalize the scaffolds, a high electrical conductivity was imparted, which is important for bone tissue regeneration. Furthermore, the stability of the surface grafted particles was evaluated in phosphate buffered saline (PBS) solution. The nature of the hydrophilic polymer grafts and the geometry of the PLLA substrates played central roles in altering the surface properties of films and particles. After 10 days of PBS immersion, larger alterations in the surface morphology were observed on the film compared with microparticles grafted with poly(acrylic acid) (PAA). In contrast to the PAA-grafted substrates, the morphology of poly(acrylamide) (PAAm)-grafted substrates was not affected by PBS immersion. Additionally, PAAm-grafted microparticulate substrates encountered surface degradation more rapidly than PAAm-grafted film substrates. / <p>QC 20151002</p>

In present study, high energy electrons were used to modify blends based on RP and PP under two conditions: stationary and in-stationary conditions. Modification of blend under stationary condition is a process which is established in industrial application and where required absorbed dose is applied to form parts (after molding) at room temperature and in solid state. On the contrary, the modification of blend with high energy electrons under in-stationary condition is a new process (electron induced reactive processing) where required absorbed dose is applied to a molten state during melt mixing process. The modification of blend based on RP and PP under stationary condition resulted in slightly enhancement of tensile properties while the modification of this blend under in-stationary condition resulted in deterioration of tensile properties due to degradation of the PP matrix. Thus, special grafting agent (GA) is required for improving the tensile properties. The effect of different GAs on tensile, thermal, dynamic mechanical as well as morphological properties and melt flow properties of blends based on RP and PP were determined. The optimum absorbed dose for modification of blend based on RP and PP under both conditions was evaluated. In addition, the effect of treatment parameters of electron induced reactive processing was investigated.