Search

Polymer grafted inorganic nanoparticles attract significant attention, but pose challenges because of the complexity. In this work, a facile strategy to the graft polymer onto the surface of nanoparticles have been introduced. The vinyl functionalized SiO2 nanoparticles (NPs) were first prepared by the surface modification of the unmodified SiO2 using γ-methacryloxy propyl-trimethoxylsilane. The NPs were then mixed with polyvinylidene fluoride (PVDF), which was followed by the Co-60 Gamma radiation at room temperature. PVDF molecular chains were chemically grafted onto the surface of SiO2 nanoparticles by the linking of the double bond on the NPs. The graft ratio of PVDF on SiO2 NPs surface can be precisely controlled by adjusting the absorbed dose and reactant feed ratio (maximum graft ratio was 31.3 wt%). The strategy is simple and it should be applied to the surface modification of many other nanoparticles. The prepared PVDF-grafted SiO2 NPs were then dispersed in the PVDF matrix to make the nanocomposites. It was found that the modified NPs can be precisely dispersed into the PVDF matrix, as compared with pristine silica. The filling content of modifications SiO2 NPs on the PVDF nanocomposites is almost doubled than the pristine SiO2 counterpart. Accordingly, the mechanical property of the nanocomposites is significantly improved. [ABSTRACT FROM AUTHOR]

In this work, the localization of reactive compatibilizer (RC, containing poly(methyl methacrylate) (PMMA) backbone with randomly distributed glycidyl methacrylate (GMA) on it) at the polyvinylidene fluoride/poly(l-lactic acid) (PVDF/PLLA) interface has been manipulated by means of GMA contents. At the very beginning of mixing, RC tends to stay in the PVDF phase due to the miscibility between PVDF and PMMA. Upon further shearing, more and more PLLA chains have been grafted on PMMA backbone, producing PLLA–g–PMMA copolymer. The balanced stress on two sides accounts for the localization of compatibilizers at the PVDF/PLLA interface. Finally, the stress of the PLLA side has been enhanced remarkably due to the higher graft density of PLLA, resulting in the enrichment of the copolymer in the PLLA matrix. The migration of RC from the PVDF phase to the immiscible interface and PLLA matrix can be accelerated by employing RC with higher GMA content. Furthermore, the compatibilizer localization produces a significant influence on the morphology and ductility of the PVDF/PLLA blend. Only when the compatibilizers precisely localize at the interface, the blend exhibits the smallest domain and highest elongation at break. Our results are of great significance for not only the fabrication of PLLA with high ductility, but also the precise localization of compatibilizers at the interface of the immiscible blend. [ABSTRACT FROM AUTHOR]

Polymer blend nanocomposites with the nanoparticles exclusively located at the interface have attracted significant attention while the compatibilization functions of such nanoparticles in the blends are still controversial. Herein, the pristine boehmite nanorods (p-BNRs) and epoxide group modified boehmite nanorods (m-BNRs) have been synthesized and incorporated in the immiscible Poly(l -lactide)/Poly(1,4-butylene succinate) (PLLA/PBSU) blends. It is found that both p-BNRs and m-BNRs are thermodynamically located at the interface and the phase morphologies of the two nanocomposites are very similar at the same nanofiller loadings. However, the two nanocomposites exhibit different mechanical properties. The PLLA/PBSU blend nanocomposites with m-BNRs show increased elongation at break, enhanced notched impact strength and improved yield strength, as compared with the binary PLLA/PBSU blends. In contrast, p-BNRs lead to drastically deteriorating mechanical properties of the PLLA/PBSU blends even with all p-BNRs located at the interface. The investigation indicates that p-BNRs at the interface have barren surface and are lack of specific interactions with the polymers in the neighboring phases. In contrast, the epoxide groups on m-BNRs reacted with the end carboxylic acid groups of both PLLA and PBSU and the polymer chains were chemically bonded onto the surface of nanorods. The chemically bonded polymer chains on the nanorods at the interface can entangle with the molecular chains of the two polymers to enhance the interfacial adhesion. This paper demonstrates the significance of molecular chain entanglements of the compatibilizing nanoparticles and paves a new possibility to fabricate new materials with simultaneously enhanced strength and toughness. Image 1 • Ternary Poly(l -lactide)/Poly(1,4-butylene succinate)/boehmite nanorods nanocomposites were prepared. • Both pristine boehmite nanorods and epoxide groups modified boehmite nanorods are thermodynamically located at the interface of PLLA/PBSU. • Barren nanorods deteriorate the mechanical properties of PLLA/PBSU blends, but surface grafted nanorods enhance the mechanical properties drastically. • Molecular entanglements of the grafted nanorods are the prerequisite for the compatibilization of immiscible polymer blends. [ABSTRACT FROM AUTHOR]