Synthesis, transport, and sorption properties and free volume of polystyrene derivatives containing Si and F

Abstract

Gas permeation, sorption, and free volume was studied in a series of glassy vinylic type Si‐containing polymers. They included p‐substituted derivatives of polystyrene, which were compared with polystyrene, and poly(vinylphenyldimethyl silane). The strongest increase in permeability and diffusion coefficients were observed for the polymer containing the Si(CH3)3 group directly attached to phenylene ring. An introduction of spacers between phenylene ring and Si(CH3)3 group results in much lower gas permeability. Positron annihilation study of free volume in these polymers showed that lifetime spectra are composed of four components. It implies that size distribution of free volume in these polymers, which are characterized by a modest level of gas permeability, is bimodal, a feature previously observed only for extra large free volume and permeability materials such as poly(trimethylsilyl propyne). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1612–1620, 2000

PtBS‐b‐P4VP and PTMSS‐b‐P4VP Isoporous Integral‐Asymmetric Membranes with High Thermal and Chemical Stability

“…The objective of our work is to use block copolymers, in which the matrix forming PS‐block is functionalized with a bulky tert ‐butyl‐ ( t B) or trimethylsilane‐group (TMS) in para position, to improve the stability of the resulting membrane. The functionalization is associated with a drop in the bulk density, due to a less efficient packing from 1.055 g · cm −3 (PS) to 0.94 g · cm −3 (P t BS) or 0.963 g · cm −3 (PTMSS), respectively. In addition the glass transition temperatures ( T g ) of P t BS (147 °C) and PTMSS (134 °C) are significantly higher than of PS (100 °C) .…”

“…The functionalization is associated with a drop in the bulk density, due to a less efficient packing from 1.055 g · cm −3 (PS) to 0.94 g · cm −3 (P t BS) or 0.963 g · cm −3 (PTMSS), respectively. In addition the glass transition temperatures ( T g ) of P t BS (147 °C) and PTMSS (134 °C) are significantly higher than of PS (100 °C) . Investigations on P t BS and PTMSS containing block copolymers show that their segment–segment interaction parameters χ clearly exceed those of similar block copolymers providing a PS‐block .…”

Synthesis and gas permeation parameters of metathesis polytricyclononenes with pendant Me3E‐groups (E = C, Si, Ge)

“…An increase in main chain flexibility or a substituent flexibility as a rule results in a decrease of gas permeability for light gases. The relationship between gas permeability of a polymer and its main chain flexibility can be illustrated for polymers of different classes: polyphenylacetylenes and polystyrenes, ROMP polynorbornenes and addition polynorbornenes . The influence of the flexibility of a substituent on gas permeability of polymers was demonstrated for polymers containing ‐SiMe 3 /SiMe 2 CH 2 SiMe 3 /SiMe 2 CH 2 CH 2 SiMe 3 and by the example of alkyl substituents in polyacetylenes and addition polynorbornenes .…”

“…These works demonstrated that not only rubbery materials, but also some glassy polymers can reveal high permeability. Subsequently, the same group was introduced in various main chains: in polyacetylenes, polynorbornenes, polystyrene, polyphenylene oxide, and others. In this regard an important stride was a discovery of poly(trimethylsilylpropyne) .…”

Structure-Gas Transport Property Relationships of Poly(dimethylsiloxane-urethane) Nanocomposite Membranes

“…This seems to be mainly due to high interactions between O 2 gas and high concentration of silicon and oxygen atoms that constitute POSS cage. It is reported that O 2 gas has more interaction with the polar groups and silicon atoms of polymers that lead to higher solubility of oxygen gas in the membranes (Khotimskii et al, 2000). In the case of CyPOSS incorporated membranes, an increase in the POSS content leads to the presence of either more urethane linkages or unreacted triol functional groups of POSS and Si atoms of POSS molecules in the membranes.…”