Diblock, triblock, and graft copolymers of styrene and p-hydroxystyrene: Synthesis, miscibility, and compatibility studies

New di- and triblock copolymers of styrene and p-hydroxystyrene were synthesized by living anionic polymerization of styrene and protected p-hydroxystyrene, p-tert-butyldimethylsilyloxystyrene, with sec-butyllithium as the initiator either in a nonpolar solvent, benzene, at room temperature under high vacuum conditions (1 {dollar}times{dollar} 10{dollar}sp{lcub}-4{rcub}{dollar} torr) or in THF at {dollar}-{dollar}78{dollar}spcirc{dollar}C under an argon atmosphere, followed by removal of the tert-butyldimethylsilyl group. The block copolymers were characterized and showed narrow molecular weight distributions. The thermal degradation of each of the copolymers started at 350{dollar}spcirc{dollar}C. Two glass transition temperatures, the lower one belonging to the styrene block and the higher one to the p-hydroxystyrene block, were measurable for each of the copolymers.; New methacrylate-terminated functional macromonomers of p-(t- butyldimethylsilyl)oxystyrene with controlled and narrow molecular weights were synthesized by living anionic polymerization with sec-butyllithium as the initiator in THF at {dollar}-{dollar}78{dollar}spcirc{dollar}C under an argon atmosphere, followed by end-capping with ethylene oxide and subsequent termination with methacryloyl chloride. Each of the macromonomers had a narrow monomodal molecular weight distribution and high monofunctionality.; New graft copolymers of styrene (backbone) and p-hydroxystyrene (side chain) were synthesized by free radical copolymerization of styrene with the macromonomers using AIBN as initiator in toluene solution, followed by removal of the t-butyldimethylsilyl group. Each of the polystyrene-g-poly(p-hydroxystyrene) copolymers had a monomodal molecular weight distribution. Two glass transition temperatures were clearly detected for each of the graft copolymers.; The solubilities of a polystyrene-b-poly(p-hydroxystyrene) (PS-b-PHOST) copolymer (MW = 10,000-10,000) in different solvents were tested. The solution properties of the copolymer were investigated by viscometry and light scattering.; Binary and ternary blends of a PS-b-PHOST copolymer ({dollar}alphabeta{dollar}, MW = 10,000-10,000) with various homopolymers were systematically studied. In binary {dollar}alphabeta{dollar}/C blends in which the homopolymers C, poly(ethylene oxide) (PEO), poly(vinyl pyridine) (PVPy), and poly(n-butyl acrylate) (PnBA), have strong attractive interactions via hydrogen-bonding with the {dollar}beta{dollar} block but are immiscible with the {dollar}alpha{dollar} block, microphase separation was the dominant mechanism. The attractive interaction parameter {dollar}xi{dollar} appeared to be the major factor which influenced the phase separation mechanism. The results obtained with three different molecular weights of PEO (1,540, 18,500, and 100,000) suggested that the molecular weight effect became less important when {dollar}xi{dollar} was sufficiently negative. In PVPy blends, the microphase separation mechanism did not change as the amount of the homopolymer increased. Phase separation in PnBA/copolymer blends seems to follow the macro-micro mechanism. In blends of the diblock copolymer with poly(vinyl methyl ether) which was miscible with both blocks, PVME acted as a polymeric solvent for the copolymers and gave a single phase mixture when present in sufficient amount. The block copolymer reduced the domain size in PS/poly(ethyl oxazoline) blends. In PS/poly(methyl methacrylate) and PS/poly(n-butyl methacrylate) blends, the morphology was changed to a co-continuous pattern upon incorporation of the copolymer.