Structural characterization and mass transfer properties of nonporous-segmented polyurethane membrane: Influence of the hydrophilic segment content and soft segment melting temperature

Mondal, Subrata; Hu, Jinlian

doi:10.1016/j.memsci.2005.09.029

Cited by 54 publications

(16 citation statements)

References 15 publications

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“…The DSC and WAXD of four polyurethane samples used in the present study have been quantified previously by the present authors [12,13]. From the results of these measurements (the data are listed in Table 2), we have previously made the following conclusions: (a) little amount of PEG 3400 (5 wt.%) decreased the order structure due to chain entanglement posses by PEG 3400; (b) percent crystallinity was increased with increasing PEG 3400 content in SPU, may be some aggregation of crystalline PEG 3400 domain would occurs for samples having higher PEG 3400 content (10 wt.%), which increases the over all crystallinity of SPU; (c) the order structure in mixed block polyol's SPU increased when both polyol blocks are crystallizable in pure form, in contrast noncrystallizable block causes soft-soft segment phase mixing and decreases the over all crystalline structure.…”

Section: Results From Waxd and Dscmentioning

confidence: 99%

“…In all cases polyethylene glycol (M n = 3400 g mol −1 , PEG 3400) was used as hydrophilic segment in order to enhance the hydrophilicity. The details compositions of SPUs are given in Table 1 and synthesis process were reported elsewhere [12,13].…”

Section: Methodsmentioning

confidence: 99%

“…The gaps between the membrane and water surface were about 4 mm. The cups were placed in a constant temperature chamber at the desired temperature (12,18,25,35 or 45 • C). The weight losses after 24 h were measured.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Free volume and water vapor permeability of dense segmented polyurethane membrane

Mondal

Yong

2006

Journal of Membrane Science

111

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Section: Results From Waxd and Dscmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Free volume and water vapor permeability of dense segmented polyurethane membrane

Mondal

Yong

2006

Journal of Membrane Science

111

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“…Fatores como o tipo de monômeros, a massa molar do poliol, o extensor de cadeia (aminados ou hidroxilados) e o método de síntese, podem ser planejados para controlar a estrutura e a morfologia dos poliuretanos resultantes. Isto, por sua vez altera as propriedades de transferência de massa, taxa de penetração das moléculas de gás ou líquidos através da membrana, a qual é regida pela estrutura química e dinâmica das cadeias moleculares [27][28][29] . A presença de argilas dispersas na matriz polimérica é uma maneira de controlar a permeabilidade e/ou seletividade da membrana.…”

Section: -Avaliação Das Propriedades De Barreira De Membranas Obtidasunclassified

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

Polímeros

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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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“…Ultrafine fibers provide unexpected high surface area to volume ratios and are of interest for many applications, ranging from textile to composite reinforcement, sensors, biomaterials and membrane technology [170]. Apart from that, it is worth mentioning that the temperature dependency of water-vapor permeability (WVP) is an important criterion, which has to be taken into account for the effective utilization of polymers in water-proof textiles [171,172]. Jeong et al [173] discovered that better WVP can be obtained for thermoplastic SMPUs with lower T g values.…”

Section: Processing and Environment As Functional Determinantsmentioning

confidence: 99%

Review on the Functional Determinants and Durability of Shape Memory Polymers

Pretsch

2010

Polymers

112

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Shape memory polymers (SMP) belong to the class of stimuli-responsive materials and have generated significant research interest. Their capability to retain an imposed, temporary shape and to recover the initial, permanent shape upon exposure to an external stimulus depends on the "functional determinants", which in simplistic terms, can be divided into structural/morphological and processing/environmental factors. The primary aim of the first part of this review is to reflect the knowledge about these fundamental relationships. In a next step, recent advances in shape memory polymer composites are summarized. In contrast to earlier reviews, studies on the impairment of shape memory properties through various factors, such as aging, compression and hibernation, lubricants, UV light and thermo-mechanical cycling, are extensively reviewed. Apart from summarizing the state-of-the-art in SMP research, recent progress is commented.

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Structural characterization and mass transfer properties of nonporous-segmented polyurethane membrane: Influence of the hydrophilic segment content and soft segment melting temperature

Cited by 54 publications

References 15 publications

Free volume and water vapor permeability of dense segmented polyurethane membrane

Free volume and water vapor permeability of dense segmented polyurethane membrane

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

Review on the Functional Determinants and Durability of Shape Memory Polymers

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