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Changes in gas - transport properties with the phase structure of blends containing styrene − butadiene − styrene triblock copolymer and poly (2,6 - dimethyl - 1,4 - phenylene oxide) / K. W. Song in Industrial & engineering chemistry research, Vol. 49 N° 14 (Juillet 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6587–6592 Titre : Changes in gas - transport properties with the phase structure of blends containing styrene − butadiene − styrene triblock copolymer and poly (2,6 - dimethyl - 1,4 - phenylene oxide) Type de document : texte imprimé Auteurs : K. W. Song, Auteur ; K. R. Ka, Auteur ; C. K. Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 6587–6592 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas  transport  properties Résumé : Blend films prepared from styrene−butadiene−styrene triblock copolymer (SBS) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) in various compositions were examined to explore their application as gas separation membranes. PPO formed a single-phase mixture with hard styrene segments in SBS regardless of the blend composition. Therefore, an increase in the hard-phase volume with PPO blending resulted in phase structure changes: As the PPO content in the blend increased, the hard phase that was dispersed in the matrix formed by butadiene soft segments was converted into a continuous lamellar structure and finally formed a matrix of the blend by phase inversion. A decrease in the gas permeability and an increase in the gas selectivity were observed with increasing PPO content. The continuous soft phase was changed to the discrete phase in blends containing between 40 and 50 wt % PPO. As a result, an abrupt decrease in the gas permeability was observed at around these blend compositions. Permeability coefficients showed a small decrease as the upstream gas pressure increased when the hard phase formed a matrix, whereas they were not changed regardless of the upstream gas pressure when the soft segments formed the continuous phase. Plasticization caused by a polar penetrant was not observed in the SBS/PPO blend membranes. Our results show that blend films exhibiting desired gas permselectivity can be fabricated by controlling the phase-separated structure of SBS/PPO blends. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100565q [article] Changes in gas - transport properties with the phase structure of blends containing styrene − butadiene − styrene triblock copolymer and poly (2,6 - dimethyl - 1,4 - phenylene oxide) [texte imprimé] / K. W. Song, Auteur ; K. R. Ka, Auteur ; C. K. Kim, Auteur . - 2010 . - pp. 6587–6592. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6587–6592 Mots-clés : Gas  transport  properties Résumé : Blend films prepared from styrene−butadiene−styrene triblock copolymer (SBS) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) in various compositions were examined to explore their application as gas separation membranes. PPO formed a single-phase mixture with hard styrene segments in SBS regardless of the blend composition. Therefore, an increase in the hard-phase volume with PPO blending resulted in phase structure changes: As the PPO content in the blend increased, the hard phase that was dispersed in the matrix formed by butadiene soft segments was converted into a continuous lamellar structure and finally formed a matrix of the blend by phase inversion. A decrease in the gas permeability and an increase in the gas selectivity were observed with increasing PPO content. The continuous soft phase was changed to the discrete phase in blends containing between 40 and 50 wt % PPO. As a result, an abrupt decrease in the gas permeability was observed at around these blend compositions. Permeability coefficients showed a small decrease as the upstream gas pressure increased when the hard phase formed a matrix, whereas they were not changed regardless of the upstream gas pressure when the soft segments formed the continuous phase. Plasticization caused by a polar penetrant was not observed in the SBS/PPO blend membranes. Our results show that blend films exhibiting desired gas permselectivity can be fabricated by controlling the phase-separated structure of SBS/PPO blends. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100565q

Characteristics of polyurethane elastomer blends with poly (acrylonitrile - co - butadiene) rubber as an encapsulant for underwater sonar devices / H. G. Im in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7336–7342 Titre : Characteristics of polyurethane elastomer blends with poly (acrylonitrile - co - butadiene) rubber as an encapsulant for underwater sonar devices Type de document : texte imprimé Auteurs : H. G. Im, Auteur ; K. R. Ka, Auteur ; C. K. Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 7336–7342 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermoplastic  Elastomer Résumé : Thermoplastic polyurethane elastomer (TPU) is widely used as an encapsulant in undersea sonar devices. Since sonar encapsulants are filled with a paraffin oil to prevent the ingress of seawater into the transducer, encapsulant materials possessing a lower swelling ratio for seawater and paraffin oil, along with better mechanical strength than TPU after impregnation, are desirable. To fabricate polymeric materials for application in sonar encapsulants, TPUs prepared with poly(tetramethylene glycol) (PTMG) and methyldiphenyldiisocyanate (MDI) were blended with poly(acrylonitrile-co-butadiene) rubber (NBR) containing various amounts of acrylonitrile (AN). The swelling ratios of the TPU/NBR blends in seawater were all lower than that of TPU, regardless of the AN content of the NBR, and the swelling ratio gradually decreased with increasing AN content of the NBR. The TPU blend with NBR containing 43 wt % AN exhibited a lower swelling ratio than TPU in paraffin oil. In addition, the TPU/NBR43 blend exhibited enhanced mechanical strength, as compared to TPU after being impregnated with seawater and paraffin oil. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100975n [article] Characteristics of polyurethane elastomer blends with poly (acrylonitrile - co - butadiene) rubber as an encapsulant for underwater sonar devices [texte imprimé] / H. G. Im, Auteur ; K. R. Ka, Auteur ; C. K. Kim, Auteur . - 2010 . - pp. 7336–7342. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7336–7342 Mots-clés : Thermoplastic  Elastomer Résumé : Thermoplastic polyurethane elastomer (TPU) is widely used as an encapsulant in undersea sonar devices. Since sonar encapsulants are filled with a paraffin oil to prevent the ingress of seawater into the transducer, encapsulant materials possessing a lower swelling ratio for seawater and paraffin oil, along with better mechanical strength than TPU after impregnation, are desirable. To fabricate polymeric materials for application in sonar encapsulants, TPUs prepared with poly(tetramethylene glycol) (PTMG) and methyldiphenyldiisocyanate (MDI) were blended with poly(acrylonitrile-co-butadiene) rubber (NBR) containing various amounts of acrylonitrile (AN). The swelling ratios of the TPU/NBR blends in seawater were all lower than that of TPU, regardless of the AN content of the NBR, and the swelling ratio gradually decreased with increasing AN content of the NBR. The TPU blend with NBR containing 43 wt % AN exhibited a lower swelling ratio than TPU in paraffin oil. In addition, the TPU/NBR43 blend exhibited enhanced mechanical strength, as compared to TPU after being impregnated with seawater and paraffin oil. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100975n