Cross-Linking Induced Phase Separation in SAN/SMA Semi-interpenetrating Polymer Networks Observed by Solid State NMR and Site Specific Isotope Enrichment

Abstract

The effect of selective cross-linking of poly(styrene-co-maleic anhydride) (SMA) in an initially fully miscible blend with poly(styrene-co-acrylonitrile) (SAN) is studied as a function of cross-link density.Site specific 13 C-enriched SMA and SAN obtained by total synthesis and CP 3 magic angle spinning NMR spin diffusion techniques are used. The cross-linking of SMA results in the formation of a semiinterpenetrating network (semi-IPN) and induces phase separation. The characteristic domain sizes increase roughly linear with the amount of cross-links on a scale of 0-100 nm. The fraction of SAN and SMA that remains homogeneously mixed is also determined, and it is shown to decrease with increasing cross-link density.

2D13C–13C MAS NMR Correlation Spectroscopy with Mixing by True 1H Spin Diffusion Reveals Long-Range Intermolecular Distance Restraints in Ultra High Magnetic Field

“…200 nm (16,18). This value for the diffusivity has also been used for experiments employing moderate MAS frequencies (14)(15)(16)(19)(20)(21). The favorable polarization transfer properties of 1 H can be combined with the superior spectral resolution of 13 C nuclei in a 2D 13 C-13 C MAS CP 3 correlation spectroscopy experiment (14,15).…”

“…The favorable polarization transfer properties of 1 H can be combined with the superior spectral resolution of 13 C nuclei in a 2D 13 C-13 C MAS CP 3 correlation spectroscopy experiment (14,15). In an early application of this method, the morphology and phase separation of 13 C-labeled semi-interpenetrating networks were investigated (15,20). In the solid state NMR of complex solid-type biological assemblies, for example membrane proteins, the same principles could be applied to probe shorter range intra-and intermolecular distances for structure determination.…”

Synthetic aspects and characterization of polypropylene–silica nanocomposites prepared via solid-state modification and sol–gel reactions

“…A number of monomers, such as maleic anhydride [33,34], methacrylic acid [35,36] and vinylsilane (VTES) [36,37] have been used in previous SSM studies. These monomers upon grafting provide polarity and reactivity to PP.…”

“…Based on these findings, a reaction mechanism for the grafting is proposed in Scheme 1. Part of the VTES may graft as monomeric unit on PP (structure III), similar to the grafting of maleic anhydride [33]. The other part of VTES grafted as monomeric unit on PP may then propagate to yield a polymer of VTES grafted on PP (structure IV).…”

Preparation of flexible and transparent SMA films by simple composite with MBS potential for negative birefringence compensator

“…So, it is challenge to prepare flexible and thermally stable SMA films to improve their application as LCDs optical compensators. Although many methods has been reported to improved the strength of SMA, such as crosslinking and functional groups‐grafting,15, 16 composite is a simple and effective method to improve the mechanical properties including strength and flexibility 17, 18…”