Crystalline Complex of Syndiotactic Polystyrene with Poly(ethylene Glycol) Dimethyl Ethers

Abstract

It has been clarified that syndiotactic polystyrene (sPS) forms co-crystalline structures with polyethylene glycol dimethyl ethers (PEGDMEs) with molecular weights ranging from 178 to 1,000 g·mol(-1) through a guest exchange procedure assisted by a plasticizing agent. The PEGDME molecules are incorporated into the spaces between sPS polymer sheets consisting of (T(2)G(2))(2) helices. The results of X-ray diffraction and gravimetric measurements suggest that one or less molecules are included per unit cell for PEGDME with average molecular weight of 1,000 g·mol(-1), which indicates the possibility that longer polymeric molecules can be introduced into sPS lattices with multiple site occupation.

Simultaneous SAXS and WAXS Study on the Guest Exchange Process of Syndiotactic Polystyrene: Crystalline Complex Formation with Triethylene Glycol Dimethyl Ether

“…For example, spot C in the equator and spot D in the first layer became more intense. Similar intensity variations were observed in the resultant sPS/TEGDME cocrystal film in the previous study 22. On the other hand, the 010 and $ \overline 2 $ 10 reflections (spots A and B in the equator) started to change in intensity from the beginning, as shown in Figure 3 and Figure 4a.…”

“…The polymer‐crystalline‐region‐based complex found in sPS is unprecedented in synthetic polymers with respect to considerable variety of guest molecules. The potential of sPS cocrystal states as new kinds of functional polymer materials attracts attention, and many studies are actively being carried out 12–23…”

“…Recently, it has been found that chemical compounds having ethylene oxide (–CH 2 CH 2 O–) repeat units have a high affinity with sPS lattice and the formation of sPS cocrystals with crown ethers, and a series of polyethylene glycol dimethyl ethers can be achieved through the guest‐exchange procedure 13, 14, 22. How such relatively large molecules can intrude into the lattice of sPS cocrystals and replace the original guest is of interest.…”

Development of a Simultaneous SANS/FTIR Measuring System

“…Under the standard ambient conditions, TEGDME molecules in the sPS cocrystal film are distributed not only in the crystalline region but also in the amorphous region. 13 Since the distribution of TEGDME within the d-sPS matrix is the main cause for the contrast in SLD between amorphous and crystalline regions (μ amor and μ cryst ), the IR spectral changes suggest that the SANS profile changes can be chiefly ascribed to the changes in distribution of TEGDME, such as migration to the amorphous region and evaporation from the film. By combining the SANS and FTIR information and considering the characteristics of sPS cocrystal and TEGDME, the following structural changes can be Figure 2 on a sPS/ TEGDME cocrystal film.…”

“…The sample thus prepared forms a δ monoclinic clathrate structure, 12 where TEGDME molecules are encapsulated in the cavities in the crystalline region consisting of sPS helices. 13 All simultaneous SANS/FTIR experiments were carried out by using the above-mentioned experimental setup installed at KWS2 of the Jülich Centre for Neutron Science (JCNS) outstation at Heinz Maier-Leibnitz Center (MLZ) in Garching, Germany.…”