Effect of poly(4-tert-butylstyrene)block length on the microphase structure of poly(ethylene oxide)-b-poly(4-vinylbenzyl chloride)-b-poly(4-tert-butylstyrene)triblock terpolymers

A series of linear poly(ethylene oxide)-b-poly(4-vinylbenzyl chloride)-b-poly(4-tert-butylstyrene)(PEO_(113)-b-PVBC_(130)-b-Pt BS_(x)or E_(113)V_(130)T_(x))triblock terpolymers with various lengths x(=20,33,66,104,215)of Pt BS block were synthesized via a two-step reversible addition-fragmentation chain transfer(RAFT)polymerization.The E_(113)V_(130)T_(x)triblock terpolymers were non-crystalline because the PVBC and Pt BS blocks strongly hindered the crystallization of PEO block.The effects of Pt BS block length x on the phase structures of E_(113)V_(130)T_(x)triblock terpolymers were investigated by combined techniques of small-angle X-ray scattering(SAXS)and transmission electron microscopy(TEM).It was found that with increasing x from20 to 215,the phase structure of E_(113)V_(130)T_(x)triblock terpolymers became more ordered and changed from disordered structure,hexagonally-packed cylinder(HEX),hexagonally perforated layer(HPL),to lamellar(LAM)phase structures.Temperature-variable SAXS measurements showed that the HEX,HPL and LAM phase structures obtained for E_(113)V_(130)T_(66),E_(113)V_(130)T_(104)and E_(113)V_(130)T_(215)by thermal annealing,respectively,were thermodynamically stable in the temperature range of 30-170℃.

Sulfur-substitution-enhanced crystallization and crystal structure of poly(trimethylene monothiocarbonate)

In this paper,the crystallization behavior of a novel poly(monothiocarbonate),poly(trimethylene monothiocarbonate)(PTMMTC),was investigated and compared with its polycarbonate analogue,poly(trimethylene carbonate)(PTMC).It is found that PTMMTC exhibits strong crystallizability,while un-stretched PTMC is amorphous.DSC and DMA results reveal that PTMMTC possesses higher glass transition temperature(T_(g))andβ-transition temperature(T_(β))than PTMC.Simulation based on density functional theory(DFT)shows that,the bond angle of C-S-C is evidently smaller than that of C-O-C,and thus a larger dipole moment.This leads to the stronger intermolecular interaction and more rigid chain confor-mation in PTMMTC,which is the origin of sulfur-substitution enhanced crystallization.The crystal struc-ture of PTMMTC was preliminarily determined for the first time.PTMMTC has an orthorhombic crystal structure with a planar zig-zag chain conformation.The parameters of unit cell are a=10.74 A,b=4.79 A,and c(fiber axis)=7.74 A.