Porous phase-inversion membranes of complex morphology were obtained on the basis of aromatic polyamidoimides with different numbers of hydroxyl groups in the diamine component of the repeating unit.The influence of t...Porous phase-inversion membranes of complex morphology were obtained on the basis of aromatic polyamidoimides with different numbers of hydroxyl groups in the diamine component of the repeating unit.The influence of the quality of the precipitant(nonsolvent)applied in membrane preparation(i.e.,the use of“strong”or“weak”nonsolvent)on structural and morphological features of polymer membranes of various chemical compositions was studied.Investigation of dilute solutions of membrane-forming polymers by optical methods revealed the changes in the state of the system both in the presence of a solvent and in the presence of a nonsolvent.On the basis of the obtained results,it was possible to estimate the sensitivity of the studied polymer/solvent/nonsolvent system to changes in the copolymer composition(a number of hydroxyl groups in the repeating unit).展开更多
The manufacturing process of poly(vinylidene fluoride)microporous films containing through flow channels and permeable to liquids has been elaborated.The process is based on polymer melt extrusion with subsequent stag...The manufacturing process of poly(vinylidene fluoride)microporous films containing through flow channels and permeable to liquids has been elaborated.The process is based on polymer melt extrusion with subsequent stages of annealing,uniaxial extensions("cold"and"hot"drawing),and thermal stabilization.The effect of orientation parameters(melt draw ratio and extension degrees)on overall porosity,permeability,morphology,and content of polar piezoactiveβ-phase in crystalline structure of the films was investigated by filtration porosimetry,sorptometry,scanning electron microscopy,X-ray scattering,and mechanical properties measurements.It is shown that the through pores were formed by a percolation mechanism.It is observed that permeability and theβ-phase content increased with the growth of extension degree at the pore formation stages but the portion ofβ-crystallites decreased with increasing melt draw ratio at extrusion,which permitted to regulate the combination of through permeability and piezoactivity values by variation of the preparation process parameters.展开更多
基金the framework of State Programs of IMC RAS(No.122012000452-9).
文摘Porous phase-inversion membranes of complex morphology were obtained on the basis of aromatic polyamidoimides with different numbers of hydroxyl groups in the diamine component of the repeating unit.The influence of the quality of the precipitant(nonsolvent)applied in membrane preparation(i.e.,the use of“strong”or“weak”nonsolvent)on structural and morphological features of polymer membranes of various chemical compositions was studied.Investigation of dilute solutions of membrane-forming polymers by optical methods revealed the changes in the state of the system both in the presence of a solvent and in the presence of a nonsolvent.On the basis of the obtained results,it was possible to estimate the sensitivity of the studied polymer/solvent/nonsolvent system to changes in the copolymer composition(a number of hydroxyl groups in the repeating unit).
文摘The manufacturing process of poly(vinylidene fluoride)microporous films containing through flow channels and permeable to liquids has been elaborated.The process is based on polymer melt extrusion with subsequent stages of annealing,uniaxial extensions("cold"and"hot"drawing),and thermal stabilization.The effect of orientation parameters(melt draw ratio and extension degrees)on overall porosity,permeability,morphology,and content of polar piezoactiveβ-phase in crystalline structure of the films was investigated by filtration porosimetry,sorptometry,scanning electron microscopy,X-ray scattering,and mechanical properties measurements.It is shown that the through pores were formed by a percolation mechanism.It is observed that permeability and theβ-phase content increased with the growth of extension degree at the pore formation stages but the portion ofβ-crystallites decreased with increasing melt draw ratio at extrusion,which permitted to regulate the combination of through permeability and piezoactivity values by variation of the preparation process parameters.
