It was shown that a fine fibril structure of a thermotropic liquid
crystalline polymer (TLCP)(poly(ester amide)) can be developed in a shear flow field of a
thermoplastic matrix (polyamide, nylon 46)
when the viscosity of the latter is lower than that of the former.
Addition of a third component, a
functionalized elastomer (maleic anhydride grafted
ethylene−propylene−diene terpolymer, MA-EPDM)
that interacts with the matrix polymer (nylon 46) and the thermotropic
liquid crystalline polymer,
facilitates the structural development of the TLCP by acting as a
compatibilizer at the interface. Maleic
anhydride grafted to EPDM reacts with TLCP and nylon 46.
Morphological observation determined the
significance of compatibilization in immiscible polymer blends.
The compatibilizer brings about good
adhesion at the interface, reduces the droplet size, and enables finely
dispersed liquid crystalline polymer
to be deformed in shear flow without strong elongation even though the
viscosity of the matrix was much
lower than that of the liquid crystalline polymer. Fibrous
structural development was observed in the
edge area of the extruding strand without elongation and also in the
central region with weak elongation.
Mechanical properties were significantly improved by good adhesion
and fibril generation, which were
ascribed to the produced compatibilizer. These results have
important implications in that they provide
a means to produce strong and tough in situ composites when
the viscosity of the matrix polymer is
lower than that of a dispersed liquid crystalline polymer that is
immiscible with the matrix polymer.
SUMMARY: Poly(styrene-co-4-tert-butyldimethylsilyloxystyrene) as a precursor of hydroxyl-functionalized syndiotactic polystyrene was successfully synthesized via (g 5 -indenyl)trichlorotitanium (IndTiCl 3 )-catalyzed copolymerization of styrene with 4-tert-butyldimethylsilyloxystyrene in toluene at 25 8C in the presence of methylaluminoxane (MAO) ([Al]/[Ti] = 2 000). The amount of styrene derivative incorporated into the polymeric chain for a 20,7 : 1 mole feed ratio of styrene to 4-tert-butyldimethylsilyloxystyrene was found to be 1,8 mol-% from a 1 H NMR analysis. The styrene derivative was successfully prepared from 4-hydroxybenzaldehyde via first protecting the hydroxyl group using tert-butyldimethylchlorosilane followed by the 'Wittig-type' reaction with the 'Tebbe' reagent. The yield was about 82 wt.-% on the basis of the initial amount of 4-hydroxybenzaldehyde used.
Reactive extrusions were performed with blends of nylon 6 and a liquid crystalline copolyesteramide (LCP) including a functionalized elastomer (maleic anhydride grafted ethylene‐propylene‐diene terpolymer). The functionalized elastomer acts as a compatibilizer at the interface. The thermal behavior of the blends suggests partial compatibility of the components endowed by the produced graftcopolymer. A finer dispersion was observed for the compatibilized blends. Fine fibrils were also observed even when no extensional force was applied, indicating the importance of interfacial adhesion for the dispersed phase deformation. The shear viscosity of the ternary blend was lower than those of the neat polymers. The mechanical properties of the compatibilized blends, however, were not significantly improved except when an optimum amount of compatibilizer was added. Explanations for the compatibilizing action of the elastomer and mechanical performance of the ternary blends are presented.
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