The aim of this research work was to improve the compatibility of polymer blends made from poly(lactic acid) and natural rubber (PLA/NR blends) by using modified natural rubber as a compatibilizer. Natural rubber was chemically modified into two categories: natural rubber grafted poly(vinyl acetate) copolymer (NR-g-PVAc) and block copolymers (PLA-NR diblock copolymer and PLA-NR-PLA triblock copolymer). PLA/NR blends were prepared by melting blending in a twin screw extruder and compression molded to obtain a 2-mm thick sheet. The blends contained 10-20 wt% of NR and modified NR, and the impact strength and tensile properties were investigated. The compatibilization effect was determined by DMTA, DSC and SEM. NR-g-PVAc was synthesized by emulsion polymerization to obtain different PVAc graft contents (1%, 5% and 12%). Characterization by DMTA showed an enhancement in miscibility of the PLA/NR-g-PVAc blends. NR-g-PVAc could be used as a toughening agent of PLA and as a compatibilizer of the PLA/NR blend. The block copolymers were synthesized following two routes: (1) hydroxyl telechelic natural rubber (HTNR) and lactide and (2) HTNR and PLA prepolymer. In the former route, lactide was in situ polymerized via a ring opening polymerization to be a PLA block segment during block copolymerization. In the latter route PLA prepolymer was synthesized by a condensation polymerization of L-lactic acid prior to block copolymerization. Both block copolymers acted as good compatibilizers for the PLA/NR blend by increasing the impact strength and decreasing the NR particle size. Triblock copolymers provided higher impact strength than diblock copolymers, and they were a less effective compatibilizer than NR-g-PVAc. In contrast to NR and NR-g-PVAc, the block copolymer was not a good toughening agent for PLA.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: John L. Brash. Includes bibliographical references. Also available online.

Thesis (Ph. D.)--Biomedical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Nie, Shuming; Committee Member: Bao, Gang; Committee Member: Chung, Leland; Committee Member: Murthy, Niren; Committee Member: Prausnitz, Mark.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (p. [148]-178).

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-08-28T17:47:20Z No. of bitstreams: 1 TeseJPFS.pdf: 7489825 bytes, checksum: c319cc8a992956b23bf6db8d3857c32c (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-01-17T18:50:59Z (GMT) No. of bitstreams: 1 TeseJPFS.pdf: 7489825 bytes, checksum: c319cc8a992956b23bf6db8d3857c32c (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-01-17T18:51:10Z (GMT) No. of bitstreams: 1 TeseJPFS.pdf: 7489825 bytes, checksum: c319cc8a992956b23bf6db8d3857c32c (MD5) / Made available in DSpace on 2018-01-17T19:05:30Z (GMT). No. of bitstreams: 1 TeseJPFS.pdf: 7489825 bytes, checksum: c319cc8a992956b23bf6db8d3857c32c (MD5) Previous issue date: 2017-06-23 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / In this work conductive polymer nanocomposites (CPNs) based on block copolymers and multi walled carbon nanotubes (MWCNT) were obtained. Two of the copolymers were commercial: polystyrene-b-polybutadiene-b-polystyrene (SBS), and polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS). The other copolymer was synthesized: polystyrene-b-poly(vinylidene fluoride) (PS-b-PVDF). Three systems of block copolymer/MWCNT were then obtained and studied for specific purposes. The SBS/MWCNT was produced using two routes: the solution and melt mixing. The influence of the processing conditions on the structure and on the electrical conductivity of these nanocomposites were evaluated and compared. For the second system, SEBS/MWCNT, the aim was evaluate the influence of the grafting of MWCNT with PS on the conductivity of the nanocomposites. For the third system, PS-b-PVDF/MWCNT, the aim was to evaluate the influence of the polymer matrix on the conductivity of the nanocomposites. The nanocomposites had their electrical properties evaluated by measurements of DC electrical conductivity and AC impedance spectroscopy. Their morphologies were evaluated by atomic force microscopy (AFM) and electron microscopy; and their structures were analyzed by small angle X ray scattering (SAXS). The results showed that the higher electrical conductivities and the lower percolation thresholds were obtained for the SBS/MWCNT nanocomposites obtained by the solution technique. The SEBS/MWCNT nanocomposites with PS grafted on MWCNT had higher conductivity than the non-grafted systems. The nanocomposites PS-b-PVDF/MWCNT had also better conductivities than the PVDF/MWCNT. Therefore, it was shown that both the modification of the processing, as well as the filler and the matrix are suitable approaches to control the structures and the electrical conductivity of CPNs based on MWCNT and block copolymers. / Neste trabalho de doutorado foram obtidos nanocompósitos poliméricos condutores (NPCs) baseados em copolímeros em bloco e nanotubos de carbono de paredes múltiplas (MWCNT). Dois dos copolímeros utilizados são comerciais: os triblocos poliestireno-b-polibutadieno-b-poliestireno (SBS), e o poliestireno-b-poli(etileno-butileno)-b-poliestireno (SEBS). O outro copolímero foi sintetizado: o poliestireno-b-poli(difluoreto de vinilideno) (PS-b-PVDF). Três sistemas copolímero em bloco/MWCNT foram então obtidos e estudados com objetivos específicos. Para o primeiro sistema, SBS/MWCNT, o objetivo foi o de avaliar e comparar a influência do processamento na condutividade elétrica dos nanocompósitos. Para o segundo sistema, SEBS/MWCNT, o objetivo foi o de avaliar a influência da enxertia de PS nos MWCNT nas condutividades dos nanocompósitos. Para o terceiro sistema, PS-b-PVDF/MWCNT, o objetivo foi o de avaliar a influência da matriz polimérica na condutividade elétrica. Os nanocompósitos tiverem suas propriedades elétricas avaliadas por medidas de condutividade elétrica DC e por espectroscopia de impedância AC; tiveram suas morfologias avaliadas por microscopia de força atômica (AFM) e microscopia eletrônica, e suas estruturas avaliadas por raios X de baixo ângulo (SAXS). Os resultados mostraram que as maiores condutividades elétricas e menores limites de percolação foram obtidos para os nanocompósitos SBS/MWCNT processados por mistura por solução em relação aos obtidos por mistura no estado fundido; para os nanocompósitos SEBS/MWCNT com MWCNT enxertados com PS em relação aos não enxertados; para os nanocompósitos do copolímero PS-b-PVDF/MWCNT, em relação aos do homopolímero, PVDF/ MWCNT. Desta maneira, ficou demonstrado que tanto a modificação do processo, quanto da carga, quanto da matriz podem induzir a diferentes estruturações do material e podem ser meios favoráveis para controle da condutividade elétrica de NPCs baseados em copolímeros em bloco e MWCNT. / FAPESP: 2014/17597-2 / FAPESP: 2015/09924-6 / CNPq: 141456/2013-2

Ce travail de thèse s'inscrit dans le cadre d'une collaboration entre Arkema - Groupe de Recherches de Lacq (GRL) et le Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA) et porte sur la synthèse et l'étude de la nanostructuration de copolymères à blocs constitués d'au moins un bloc biodégradable en vue de préparer des masques de gravure par nano-lithographie. Le premier chapitre est dédié à la description des approches lithographiques développées afin de faire le point sur les principales avancées ainsi que sur les verroux technologiques à lever concernant la miniaturisation des composants électroniques via les approches top-down et bottom-up. Un intérêt particulier a été porté sur l'approche bottom-up reposant sur l'auto-assemblage dirigé de copolymères à blocs étant donné que des morphologies bien définies et de faibles dimensions sont accessibles. Les propriétés du PS-b-PMMA ainsi que celles de copolymères à blocs constitués d'un bloc biodégradable sont également discutées afin de souligner l'importance du développement de nouveaux copolymères à blocs. La deuxième partie de ce manuscrit porte sur la synthèse et la caractérisation de copolymères à blocs par polymérisation organocatalysée et contrôlée par ouverture de cycle (ROP) de lactones et de carbonates. Une étude de la nanostructuration de copolymères à blocs composés de poly(ε-caprolactone), de poly(β-butyrolactone) ou de poly(triméthylène carbonate) a été réalisée afin d'évaluer les morphologies ainsi que les espacements de domaines correspondants. La forte incompatibilité des blocs des copolymères synthétisés a permis l'observation de nanostructurations lamellaires et cylindriques ayant des espacements de domaines de l'ordre d'une dizaine de nanomètre. Nous avons également remarqué que la cristallisation du bloc de poly(ε-caprolactone) empêche la nanostructuration à grande échelle des copolymères correspondants. Dans une troisième partie, nous avons tout d'abord cherché à inhiber la cristallisation de la poly(ε-caprolactone) par copolymérisation aléatoire. Une évaluation de la réactivité du co-monomère, ainsi que du taux minimum requis pour rompre totalement la cristallinité du copolymère, en fonction de la structure du co-monomère employé a été effectuée. La synthèse de copolymères à blocs constitués d'un bloc de copolyester aléatoire amorphe ("PCLam.") a par la suite été réalisée pour évaluer l'impact de l'inhibition de la cristallinité sur la nanostructuration de ces nouveaux copolymères à blocs. Cette stratégie a permis la ségrégation de phase en nano-domaines de géométries bien définies. Des morphologies cylindriques présentant un espacement de domaines compris entre 15,3 et 19 nm ont été déterminées par analyses SAXS et par microscopie (AFM) dans le cas de films minces préparés à partir de "PCLam."-b-Krasol H-b-"PCLam.". / The present work is in the frame of a collaboration between Arkema - Groupe de Recherche de Lacq (GRL) and the Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA). This work consists in the preparation of block copolymers containing at least one biodegradable block in order to study their nanostructuration aiming at preparing etching mask by nanolithography. The first part of this work is dedicated to the description of lithographic processes in order to summarize the major advances and the technological bolts to unlock concerning the electronic component miniaturization by top-down and bottom-up approaches. Particular interest has been given to the bottom-up approach based on the direct self-assembly of block copolymer due to the fact that well defined morphologies are accessible at small scale. The properties of the PS-b-PMMA as well as those of block copolymers containing one biodegradable block are also discussed to underline the importance of the development of new block copolymers. The second part of this manuscript concerns the synthesis and characterization of block copolymers by organocatalyzed controlled ring opening polymerization (ROP) of lactones and carbonates. A study of block copolymer nanostructuration has been performed for copolymers containing one block of poly(ε-caprolactone), poly(β-butyrolactone) or poly(trimethylene carbonate) in order to determine their morphologies and the corresponding domain-spacing. The high block incompatibility of the synthesized copolymers enables lammellar and cylindrical nanostructurations with domain-spacing in the order of ten nanometers. We also noticed that the crystallization of the poly(ε-caprolactone) block prevent the large-scale nanostructuration of the corresponding copolymers. In a third part, we got interested to inhibit poly(ε-caprolactone) crystallization by random copolymerization. Co-monomers reactivity and their minimal loading required to fully inhibit copolymer crystallinity have been determined to investigate the impact of co-monomer structure. Then, block copolymers containing one or two amorphous random copolyester block(s) have been synthesized to evaluate the impact of crystallinity inhibition on their nanostructuration ability. This strategy allowed the phase segregation in nano-domains of well defined geometries. Cylindrical morphologies presenting a domain spacing between 15.3 and 19 nm have been determined by SAXS analysis and microscopy (AFM) in the case of thin films prepared from "PCLam."-b-Krasol H-b-"PCLam.".

Doctor of Philosophy / Department of Chemistry / Takashi Ito / This dissertation describes single-molecule tracking (SMT) measurements for the quantitative characterization of one-dimensional (1D) nanostructures in 200 nm-thick surfactant-templated mesoporous silica (STMS) and cylinder-forming polystyrene-poly(ethylene oxide) diblock copolymer (CF-PS-b-PEO) films with a μm-scale thickness. SMT is advantageous for the characterization of nanomaterials over conventional methods because it permits the simultaneous and quantitative assessment of the nanoscale and microscale morphologies, and mass-transport properties of the materials with a high nanometer-scale resolution under ambient conditions. It offers a unique means for the assessment and evaluation of the μm-scale nanostructure alignment in polymer films induced by vertical spin-coating (for STMS films), directional solution flow and solvent-vapor penetration (SVP) methods (both for CF-PS-b-PEO films), highly crucial for many potential technological applications using the materials. Through this work, we have identified suitable sample preparation conditions (e.g. solvent, temperature or solution flow rate) for obtaining highly-ordered mesoporous and microdomain structures over a long-range (> 5 μm). For the quantitative assessment of the 1D SMT data, orthogonal regression analysis was employed, providing assessment of the in-plane orientation and size of individual nanostructures with nanometer-scale precision. The analysis of the 1D trajectory data allowed the radius (ca. 11 nm) of cylindrical PEO microdomains to be estimated, yielding results consistent with the AFM results (ca. 14 nm). The distribution of the trajectory angles offered the estimation of the average orientation and order of the nanostructures in domains/grains for a μm-wide region of the polymer films, revealing the higher efficiency of SVP in the nanostructure alignment as compared to the spin coating and solution flow approaches. Systematic SMT measurements across the film depth and along lateral mm-scale distances afforded valuable insights into the shear- and solvent-evaporation-based alignment mechanisms induced by solution flow and SVP/spin coating approaches, respectively. Fluorescence recovery after photobleaching (FRAP) measurements in a SVP-aligned CF-PS-b-PEO film permitted the longer-range mass-transport properties to be probed, reflecting the effective continuity of the aligned cylindrical nanostructures over > 100 μm in length. In this dissertation, FRAP and more importantly SMT methods have provided a unique and useful means for the in-depth characterization of morphology and mass-transport characteristics in thin polymer films under ambient conditions, in confined spaces, and with a nanometer-scale resolution.

O objetivo desta dissertação é a utilização de metodologias de RMN para caracterizar a separação de fases e, em algum grau, a dinâmica de segmentos moleculares em copolímeros em bloco. Na primeira parte do trabalho, técnicas de RMN de Difusão de Spins, cujo fenômeno envolvido traz informações sobre a formação de domínios de segmentos moleculares, foram exploradas no sentido de avaliar seu desempenho assim como as principais dificuldades experimentais. Para isso, foi usado como referência o copolímero tri-bloco SEBS (Estireno-EtilenoButileno-Estireno), cuja morfologia é bem conhecida. Os testes experimentais foram realizados em equipamentos de RMN com campo magnético de 0.5 T e 9.4 T, sendo que em baixo campo uma proposta alternativa de tratamento dos dados foi utilizada. Como já apontado na literatura, os resultados indicaram que embora seja possível realizar tais experimentos em baixo campo a análise dos dados se torna mais complexa devido aos tempos de relaxação T1 mais curtos, tornando necessário o uso de simulações numéricas, que fazem a análise mais dependente de modelos específicos. A segunda parte do trabalho foi dedicada ao estudo de copolímeros em bloco compostos por polióxidoetileno (POE) ou Polietileno Glicol (PEG - POE de baixo peso molecular) e poliestireno (PS) e atambém copolimeros a base de PS e acrilatos ramificados com POE (PMAPEG - do inglês Poly Methyl Acrilate Polyethylene Glicol). Nesses estudos, técnicas de RMN de 1H e 13C como função da temperatura foram usadas para estudar as principais transições dinâmicas das cadeias de POE. Foi demonstrado que, embora o comportamento dinâmico das cadeias de POE seja similar em todos os copolímeros estudados, nas amostras de copolímeros com PMAPEG o grau de heterogeneidade dos movimentos das cadeias de POE é consideravelmente menor, o que foi atribuído ao empacotamento local semelhante e mais regular nos segmentos PMAPEG. Experimentos de RMN de Difusão de Spins foram utilizados nos estudos de morfologia, sendo demonstrada a separação de fases com formação de domínios em todas as amostras, com a regularidade desses domínios dependendo da composição. As dimensões médias dos domínios foram estimadas e os resultados correlacionados com os aspectos dinâmicos. / The main objective of this dissertation is the use of NMR methods to characterize the phase separation and, to some extent, the dynamics of the molecular segments in block copolymers. In the first part, NMR Spin Diffusion methods were explored in order to evaluate their performance as well as the main experimental difficulties. For that, a reference tri-block polymer SEBS (styrene-block-butadiene-block-styrene), which had a well known morphology, was used. The experimental tests were carried out in NMR equipments with magnetic field of 0.47 T and 9.4 T and at low filed an alternative proposal for data analysis was used. A already shown in the literature, the results indicated that , despite being possible to accomplish these experiments in low field, the data analysis become more intricate due to the shorter T1 values at this magnetic field, requiring the use of numerical simulations, which make the method more model dependent. The second part was dedicated to the study of copolymers consisting of Polyoxyethylene (PEO) or Polyethylene Glycol (PEG-low molecular weight PEO) and polystyrene (PS) as well as copolymers based on PS and Poly acrylates with PEO branches (PMAPEG -Poly Methyl Acrylate Polyethylene Glicol). In these studies, 1H and 13C NMR methods as function of temperature were used to characterize the main dynamic transitions in the PEO chains. It was shown that, despite similar dynamic behavior was observed in all samples, the PS-PMAPEG copolymers present a smaller degree of motional heterogeneity, which was attributed to the similar local packing of the PMAPEG chains. Using Spin diffusion NMR information about the morphology of the samples were obtained, showing evidences of phase separation and domain formation in all samples, being the regularity of the domain related with the sample composition. The average domain sizes were estimated.

Orientador: Watson Loh / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T17:10:15Z (GMT). No. of bitstreams: 1 Silva_RodrigoCardosoda_D.pdf: 8247158 bytes, checksum: 473fe7463d68c6d0e0bc41282c54596d (MD5) Previous issue date: 2002 / Doutorado / Físico-Química / Doutor em Ciências