Síntese e Caracterização de Poliuretanos em Dispersão Aquosa à Base de Polibutadieno Líquido Hidroxilado e Diferentes Diisocianatos

Coutinho, Fernanda M. B.; Delpech, Marcia C.; Alves, Tito Lívio Moitinho; Gomes, Ailton S.

doi:10.1590/s0104-14282002000400007

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…This second reaction path results in a loss of stoichiometry, as well as to the formation of polymers with a lower molar mass [14,15] , and thus, is usually sought to be minimized. In this sense the use of a slowly reacting diisocyanate, as isophorone diisocyanate (IPDI), is advised for the synthesis of PUU via direct miniemulsion polymerization in order to reduce the reaction with water which composes the continuous phase [5,13,16] . Several vegetable oils that are mainly composed of triacylglycerols have attracted the attention of pharmaceutical and cosmetic industries due to their properties.…”

Section: Introductionmentioning

confidence: 99%

Preparation of poly(urethane-urea) nanoparticles containing açaí oil by miniemulsion polymerization

Valério¹,

Araújo²,

Sayer³

2013

Polímeros

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Polyurethane nanoparticles (NPs) are promising candidates for the controlled and targeted delivery of therapeutics in a variety of biomedical applications. In this work, a report is made of NPs produced by miniemulsion polymerization with isophorone diisocyanate (IPDI) and castor oil, glycerol, and poly(ethylene glycol) (PEG) with molar masses 400 and 1000 as monomers and Tween 80, Span 80 and Lutensol AT 25 as surfactant and açaí oil as costabilizer. Stable dispersions with sizes between 100 -500 nm were achieved. The effects from polyol, types and concentration of surfactant and reaction temperature on the size of the NPs and weight average molar mass were evaluated. Morphological characterization was accomplished using images from Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM).

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Section: Introductionmentioning

confidence: 99%

Preparation of poly(urethane-urea) nanoparticles containing açaí oil by miniemulsion polymerization

Valério¹,

Araújo²,

Sayer³

2013

Polímeros

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“…Diisocyanates can have different structures, such as aromatic, aliphatic, cycloaliphatic, or polycyclic. The most reported systems in the literature are based on dihydroxylated polyether or polyester and aliphatic diisocyanates [19] . These compounds are responsible for the so-called rigid segment in the PU structure, giving polymers properties such as hardness, shear strength, and elastic modulus in traction and/or compression [20] .…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Surface and micromechanical analysis of polyurethane plates with hydroxyapatite for bone structure

et al. 2022

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To analyze the surface topography and mechanical properties of a polyurethane derived from castor oil reinforced with hydroxyapatite (PU-HA) for bone fixation. The surface analysis was performed by Scanning Electron Microscopy (SEM) and the mechanical properties by Vickers microhardness and tensile tests. The SEM images showed that the PU surface presented important characteristics for materials intended for bone fixation, such as an irregular and porous surface. The analysis showed a surface with alternating areas with depressions and elevations of approximately 80±100 µm, presence of pores of 12 µm in size. The microhardness analysis showed values of 0.42±1.01 HV for PU-HA plates, lower in relation to the poly lactic-co-glycolic acid (PLGA) plate (control group). The elastic modulus and ultimate tensile strength of 317.4 MPa, and 35.57 MPa for PLGA sample, 1.187 MPa, and 0.29 MPa for PU-HA sample. The PU produced showed good surface properties, however demands better mechanical properties.

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“…Este trabalho teve por objetivo: (1) sintetizar formulações não-poluentes à base de dispersões aquosas poliuretânicas, contendo segmentos hidrofílicos nas cadeias poliméricas e argila adicionada ao meio aquoso, e (2) testar a permeabilidade ao dióxido de carbono (CO 2 ) de membranas densas obtidas a partir do espalhamento das dispersões. [1][2][3][4][6][7][8]23,26,[31][32][33][34][35][36] . Em reator de três vias, a mistura de DMPA, PPG e EG-b-PG foi seca a 90°C, por 40 minutos, sob agitação.…”

Section: -Avaliação Das Propriedades De Barreira De Membranas Obtidasunclassified

“…Os sistemas poliuretânicos se destacam, devido à grande versatilidade e ampla diversidade de aplicações [1][2][3][4] . As cadeias apresentam uma alternância, determinada na etapa da síntese, entre segmentos flexíveis e rígidos.…”

Section: Introductionunclassified

Avaliação das Propriedades de Barreira de Membranas Obtidas a partir de Dispersões Aquosas à Base de Poliuretanos e Argila

Barboza¹,

Delpech²,

Garcia³

et al. 2014

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Resumo: Formulações de aplicação não-poluente à base de poliuretanos em dispersão aquosa (WPUs), com adição de argila montmorilonita hidrofílica (CWPUs), foram sintetizadas. A permeabilidade ao dióxido de carbono (CO 2 ) de membranas densas obtidas a partir do espalhamento das dispersões foi avaliada. Os reagentes empregados na síntese dos materiais foram: poli(glicol proplilênico) (PPG), copolímero em bloco à base de segmentos de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), ácido dimetilolpropiônico (DMPA), diisocianato de isoforona (IPDI) e etilenodiamina (EDA), como extensor de cadeia, levando à formação de ligações de ureia. Diferentes formulações foram obtidas variando-se a proporção de segmentos à base de poli(glicol etilênico) (PEG) e o teor de argila (0,5 e 1 %). As dispersões foram avaliadas em termos de teor de sólidos e viscosidade aparente. As membranas foram caracterizadas por espectrometria na região do infravermelho (FTIR) e permeabilidade ao dióxido de carbono (CO 2 ). A influência nas propriedades de barreira, conferida pela presença da argila e do copolímero em bloco, foi verificada por ensaios de permeabilidade. A permeabilidade ao CO 2 aumentou com o aumento no teor segmentos de PEG e diminuiu com a inserção da argila, uma vez que esta é impermeável a gases, formando caminhos preferenciais na matriz polimérica que retardam a difusão das moléculas de gás. Palavras-chave: Poliuretanos, dispersões aquosas, argila, montmorilonita, membranas, permeabilidade a gases, propriedades de barreira. Evaluation of Carbon Dioxide Gas Barrier Properties of Membranes Obtained from Aqueous Dispersions Based on Polyurethane and ClayAbstract: Non-polluting aqueous polyurethane-based dispersions were synthesized in the presence and absence of montmorillonite hydrophilic clay (WPUs and CWPUs, respectively). The permeability of carbon dioxide (CO 2 ) through dense membranes obtained from the dispersions was evaluated. The reagents used in the synthesis of the materials were: poly(propylene glycol) (PPG), block copolymer of poly(ethylene glycol) and poly(propylene glycol) (EG-b-PG), dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI) and ethylene diamine (EDA) as chain extender, leading to the formation of urea linkages. The proportion of poly(ethylene glycol) (PEG) segments and clay content (0.5 and 1%) was varied in the formulations. The dispersions were evaluated in terms of solids content and apparent viscosity. The membranes were characterized by infrared spectrometry (FTIR) and permeability to carbon dioxide (CO 2 ). The influence on the gas barrier properties, imparted by different contents of PEG segments in polyurethane chains, and by the clay in the formulations was verified. The permeability of CO 2 increased with increasing amounts of PEG segments and decreased with the insertion of clay, since the latter is impermeable to gas and forms, in the polymeric matrix, tortuous pathways that retard gas diffusion.

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Síntese e Caracterização de Poliuretanos em Dispersão Aquosa à Base de Polibutadieno Líquido Hidroxilado e Diferentes Diisocianatos

Cited by 5 publications

References 6 publications

Preparation of poly(urethane-urea) nanoparticles containing açaí oil by miniemulsion polymerization

Preparation of poly(urethane-urea) nanoparticles containing açaí oil by miniemulsion polymerization

Surface and micromechanical analysis of polyurethane plates with hydroxyapatite for bone structure

Avaliação das Propriedades de Barreira de Membranas Obtidas a partir de Dispersões Aquosas à Base de Poliuretanos e Argila

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