SBS嵌段共聚物分子结构对其在溶液中链形态的影响

线形两嵌段(SB)苯乙烯-丁二烯嵌段共聚物、线形三嵌段(SB)2]和星形四臂三嵌段(SB)4]的苯乙烯-丁二烯-苯乙烯(SBS)嵌段共聚物溶于四氢呋喃(THF)和环己烷(CH)中,通过黏度法获得它们的特性黏数并计算其黏度半径(Rη);采用静态激光光散射法研究了它们在溶液中的第二维利系数和均方根旋转半径(Rδ).由于...

EFFECT OF MOLECULAR ARCHITECTURE ON MORPHOLOGY OF SBS BLOCK COPOLYMERS IN SOLUTION

Linear diblock(SB)styrene-butadiene block copolymer,linear triblock (SB)2]and star-shaped four-arm triblock (SB) 4 ] poly(styrene-block-butadiene-block-styrene) copolymers were respectively dissolved in tetrahydrofuran(THF) and cyclohexane(CH),and then their intrinsic viscosities were measured.The obtained viscosity radii(Rη) of the polymers in those solvents were calculated by a modified Einstein equation.The radii of gyration(Rg) of the polymers dissolved in each solvent under different temperatures were obtained from static laser light scattering measurements.Due to the similarity between Rη and hydrodynamic radius(Rh),the characteristic parameter ρ(= Rg/Rh),which can be used to describe the morphology of a polymer chain in solution,can be calculated by ρ = Rg/Rη.The ρ value of(SB)4 in THF is 1.51,but is 0.76 in CH,showing flexible chain and hard sphere morphology,respectively.The ρ values of (SB)2 are 0.97 and 0.81 in THF and CH,which are located in the region of hollow sphere morphology.However,the ρ values of SB are greater than 1,showing flexible chain morphology in both solvents.Therefore,the molecular architecture of a polymer has great influence on the morphology.